fyxmW Uttivmitj Jibtatg 
 
 THE GIFT OF 
 
 4.U7-0 ^ mIM^ 
 
NATIONAL ACA1>EMY OF SCIENCES. 
 
 VOL. V. 
 
 THIRD MEMOIR. 
 
 REPORT OF STUDIES OF ATMOSPHERIC ELECTRICITY. 
 
The original of this book is in 
 the Cornell University Library. 
 
 There are no known copyright restrictions in 
 the United States on the use of the text. 
 
 http://www.archive.org/details/cu31924032182580 
 
REPORT OF STUDIES OF ATMOSPHERIC ELECTRICITY. 
 
 By T. O. Mendenhaxl. 
 
 [Eead by Peemibsion of the Chief Sibhai, Opficeb, April 18, 1889.] 
 
 INTRODUCTION. 
 
 The existence of atmospheric electricity is a modern discovery, yet there is reatson for 
 believing that it was utilized as a means of -weather forecasting 300 years ago. It isv^lated pu 
 good authority that — 
 
 There had existed from time immemorial, in one of the bastions of the castle of Duino, situated in Frione, on 
 the banks of the Adriatic Sea, a pointed rod standing in a vertical position. In summer, when the weather had the 
 appearance of being stormy, the soldier who mounted guard in the bastion, examined the iron rod, aud presented to 
 it the point of an iron halbert, which was always ready for this purpose, and whenever he perceived that the iron rod 
 gave sparks or displayed a small gerbe (sheaf) of fire at its point, be rang a bell to give notice to the country people 
 who were working in the fields, or to the fishermen who were at sea, that stormy weather was approaching. 
 
 The custom was said to be of great antiquity and is mentioned in a letter dated 1602. It is 
 an interesting anticipation of modern methods not only in the method of making forecasts but in 
 their distribution. 
 
 Many phenomena similar to that exhibited by the pointed collector in this first electrical 
 observatory, on the banks of the Adriatic, were known to the ancients and are mentioned by 
 Herodotus, Plutarch, Pliny, and other early historians ; and in the commentaries on Osesar's African 
 war, attributed to Hertins, a storm which was very disastrous to the Eoman army is descrilDed, 
 during which the shafts of the javelins of the fifth legion seemed to be on fire. 
 
 Almost nothing was then known of electricity, although some isolated facts relating to it 
 had been recognized for nearly two thousand years. 
 
 Dr. Gilbert, who died in 1603, first studied the subject experimentally and invented the name 
 which it bears. His experiments, prodigious in number, were fertile both in methods and results, 
 and the science was industriously cultivated by those who followed him. 
 
 A century and a half elapsed, however, before the identity of lightning and electricity was 
 established or, indeed, suspected. 
 
 That light often accompanied exhibitions of electrical effects was noticed by Hawksbee, who 
 made an extended series of experiments on the subject; by Otto Guericke, the famous Bur- 
 gomaster of Magdeburg, who observed both the light and the sound accompanying electric exci- 
 tation ; and by Dr. Wall, who made a communication to the Eoyal Society of London in 1708, 
 describing numerous experiments with a long and tapering piece of amber. 
 
 He says, " Upon drawing the piece 'of amber swiftly through the woolen cloth, and squeezing 
 it pretty hard with my hand, a prodigious number of little cracklings were heard, every one of which 
 produced a little flash of light." He further adds, " This seems in some degree to represent thunder 
 and lightning." 
 
 S. Mis. 94: 8 U3 
 
114 MEMOIRS OF THE.N4.TIONAL ACADEMY OF SCIENCES. 
 
 Indeed, as the experimental study of electricity continued, continually improved instruments 
 and devices enabled electricians to produce effects of increasing magnitude, so that the resemblance 
 between the electricity of the laboratory and that of nature became constantly more noticeable, and 
 the numerous analogies between the two did not escape the attention of several sagacious observers. 
 
 Among these was the distinguished Abb6 Nollet, and a brief discussion of the subject pub- 
 lished by him several years before Franklin's discovery is worthy of quotation. He says : 
 
 If anyone should take upon.him to prove, from a well-connected comparison of phenomena, that thunder Is, in 
 the hands of nature, what electricity is in ours; that the wonders which we now exhibit at our pleasure are little 
 imitations of those great effects which frighten us, and that the whole depends upon the same mechanism ; if it is to 
 be demonstrated that a cloud, prepared by the action of the winds, by heat, by a mixture of exhalations, etc., is 
 opposite to a terrestrial object; that this is the electrized body, and at a certain proximity from that which is not, 
 I avow that this, idea, if it was well supported, would give me a great deal of pleasure; and in support of it, how 
 many specious reasons present themselves to a man who is well acquainted with electricity. The universality of the 
 electric matter, the readiness of its action, its inflammability and its activity in giving fire to other bodies, its prop- 
 erty of striking bodies externally and internally, even to their smallest parts, the remarkable example we have of 
 this effect in the experiment of Leyden, the idea which we might truly adopt in supposing a greater degree of electric 
 power, etc., all these points of analogy which I have been some time meditating, begin to make me believe that one 
 might, by taking electricity for the model, form to oneself in relation to thunder and lightning, more perfect and 
 more probable ideas than have been offered hitherto. 
 
 It remained for Dr. Franklin, one of the most brilliant philosoohers in any age, to establish 
 the identity of lightning and electricity. 
 
 Within barely 2 years after he made his first experiment in electricity he had formulated the 
 aaalogje^jetween the , two far more completely and more logically than ^nyone else, and had 
 devis(w' Che tessCffo which his hypothesis must be subjected. 
 
 The germ of this splendid discovery seems to have existed in his mind during the year 1749, 
 and finally his thoughts took definite form in the following passages, which occur in his notebook 
 under date of November 7 of that year. 
 
 Electrical fluid agrees with lightning in these particulars : (1) Giving light ; (2) color of the light; (3) crooked 
 direction; (4) swift motion; (5) being conducted by metals; (6) crack or noise in exploding ; (7) subsisting in water 
 or ice; (8) rending bodies it passes through; (9) destroying animals; (10) melting metals; (11) firing inflammable 
 substances ; (12) sulphurous smell. 
 
 The electric fluid is attracted by points. We do not know whether this property is in lightning. But since they 
 agree in all the particulars wherein we can already compare them, is it not probable they agree likewise in thisT 
 
 Let the experiment be made. 
 
 This statement of the problem, marvelous for its brevity and directness, was afterward 
 elaborated somewhat and communicated to his friend, Mr. Collinsou, in London, from wioni he 
 had received his first " electrical tube." 
 
 The novel and ingenious suggestion of drawing lightning from the clouds, and testing its 
 identity with electricity, was soon known throughout Europe, and attracted much attention, 
 especially in France. 
 
 The celebrated naturalist, Buffon, seems to have been the first to attempt the performance 
 of Franklin's experiment. He arranged upon a high tower an insulated bar of iron, which he 
 connected with a conductor and a set of electrical bells by means of which he might receive notice 
 of the presence of the " electric fluid," and it is said that "he waited with anxiety for the first 
 storm of thunder." 
 
 He had also recommended M. D'Alibard to construct a similar apparatus at Marly, about 6 
 leagues from Paris. 
 
 This arrangement, the first " collector of atmospheric electricity," consisted of an irou rod 40 
 feet long, sustained by three poles and insulated by means of silk strings and a stool with glass 
 feet. 
 
 It was with this apparatus that the experiment was first successfully performed, and curiously 
 enough neither Franklin, to whom belonged the major part of the glory of the occasion, nor Buffon 
 who had suggested the attempt, ncr D'Alibard, who had erected the apparatus, was present. The 
 longed-for thunder storm came during the absence of the latter, and one Coififter, a joiner, to whom 
 the care of the "thunder rod" had been intrusted, was the first to draw a spark from the charged 
 
MEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES. 115 
 
 ,./ 
 conductor. He was speedily joined, however, by the curate of Marly, for whom he had been 
 instructed to send whenever a thunder storm should approach, that he might serve as an intelligent 
 witness, and shortly after by the entire population of the village, notwithstanding the violent rain 
 and hail. 
 
 This was on the 10th of May, 1752, ever memorable in the history of electricity. 
 
 On the 18th of May, M. Delors, of Paris, was successful in collecting considerable quantities 
 of electricity by means of a bar of iron 99 feet high, insulated upon a cake of rosin 2 feet square 
 and 3 inches thick, and on the 19th of May, Bufibn was rewarded by the passage of a storm cloud 
 near enough to his newly established electrical observatory to enable him to draw several electrical 
 sparks from his insulated conductor. 
 
 These experiments were made before Franklin had himself carried out his own suggestion ; 
 but in June, 1752, without the knowledge of what had been accomplished in France, he raised his 
 famous electrical kite, with results familiar to every schoolboy. 
 
 Immediately a host of observers all over Europe, and others besides Franklin in America, 
 repeated this experiment in various forms, and the identity of the electricity of the atmosphere 
 was established beyond question. 
 
 In these earlier experiments it was only attempted to obtain manifestation of electricity 
 during the passage of storm clouds, known as thunderclouds, but the question of the possibility of 
 electrical effects from the atmosphere in its usual or normal condition very soon presented itself. 
 Monnier, who had studied the electricity of the air during thunder storms, was the first to discover 
 that very often, and perhaps always, a quantity of electricity existed in the atmosphere, when there 
 was no appearance of thunder. He communicated the results of his experiments to^^e^Koyal 
 Academy of Sciences at Paris on the 15th of November, 1752. N» 
 
 This phase of the subject was immediately taken up by the Abbe Mazeas, who made an 
 extensive series of experiments in the summer of 1753. His " collector " consisted of an iron rod 370 
 feet long, raised 90 feet above the ground. It was insulated by silken cords, and in lieu of an 
 electrometer or electroscope, a large key was suspended to the end of the rod. He attempted, 
 however, to compare the intensities at different times by measuring the distance through which 
 light bodies would be attracted by his conductor. 
 
 With this apparatus he made numerous experiments, reaching results many of which were 
 trustworthy, while in others he was misled by the imperfections of his equipment. 
 
 Among the observers of this period, none were so industrious as Signor Beccaria, and, indeed, 
 it may almost be said that the foundations of our knowledge of atmospheric electricity were laid 
 
 by him. 
 
 Some difficulty was experienced by all of the earlier observers in distinguishing the nature of 
 the electricity of the atmosphere ; that is, in determining whether it was positive or negative. 
 
 Dr. Franklin devised a simple and elegant method for comparing it with that produced by the 
 friction of a glass rod. 
 
 Some European observers, including Beccaria, depended upon the nature of the glow or 
 illumination of a point attached to the conductor. Beccaria used rods and also kites for collectors 
 and found that the higher the rods or the more elevated the kites the stronger the electrification, 
 an observation of great importance. 
 
 Having two rods for collecting electricity and conveying it into his house, one of which was 
 30 feet higher than the other and distant from it about 140 feet, he noted the interesting fact that 
 when a spark was drawn from the higher one the electrification of the other rod was instantly 
 diminished. He observed the appearance of negative electricity during, or rather after, the 
 passage of a thunder cloud, the charge having been positive at its approach, but his apparatus was 
 incapable of revealing the rapid fluctuations in sign which are now known to take place. He was 
 also the author of ingenious theories regarding the formation of clouds, rain, snow, and hail, in which 
 he believed that electricity played an important part. Beccaria was probably the first to attempt 
 to make use of electrical observations in a systematic way as a means of weather forecasting. 
 
 All of these studies emphasized the necessity for the use of some more delicate and more 
 accurate method of detecting and measuring atmospheric electricity. As early as 1752, Nollet had 
 employed an electrometer consisting of two simple threads which were separated from each other by 
 
116 MEMOIRS OF THE NATIONAL ACADEMY OP SCIENCES. 
 
 the action of repulsion when the conductor to which they were attached was electrified, the distance 
 of separation indicating the intensity of electrification. This was probably the first attempt to 
 reduce the measure of the intensity to the reading of an angle. 
 
 Cavallo substituted-two firm metal wires for the threads used by NoUet, and a few years later, 
 in 1784, De Saussure greatly improved this form of electrometer, converting it into an instrument > 
 of considerable precision and capable of yielding quantitative results. Small pith balls were 
 attached to the free ends of the fine wires ; a scale was arranged so that the degree of separation 
 of the balls could be observed, and by the method of " division of charge" the instrument was 
 calibrated so that its different indications were fairly comparable. 
 
 De Saussure's method of collecting at first was by means of a fine silver wire 60 or 60 feet in 
 length, to one end of which was attached a lead ball weighing a few ounces. The other end was 
 attached to the electrometer in such a way that when the ball was cast into the air the wire would 
 be readily detached from the instrument, leaving it charged with the electricity which it had 
 acquired at the moment the limit of the length of the wire was reached. 
 
 He found by an ingenious experiment that the charge was not due to the friction of the ball 
 with the air, but a little- later he adopted as a collector a conductor terminating in a metallic 
 point which could be placed at different elevations. With this apparatus De Saussure made an 
 extensive series of observations which added largely to the existing knowledge of the subject. 
 He found a diurnal period in the intensity of electrification, observing that it presented two maxima 
 and two minima. He observed the great influence of local surroundings, finding no indication 
 of electrv^ty " in houses, under trees, in streets, in courts, and in general in localities wholly 
 
 He- agreed vnth Cavallo and other observers in the statement that there was always much 
 stronger electrification in the winter than in the summer. 
 
 Volta also engaged himself in the study of the subject, and besides several improvements on 
 the electrometer as used by De Saussure, he hit upon the capital device of using a burning match 
 or some slow-burning combustible on the end of the point attached to his conductor. This greatly 
 increased the rapidity with which the electrometer was charged, and thus caused it to keep more 
 nearly in accordance with the electrical condition of the atmosphere. 
 
 Both Volta and De Saussure adopted the evaporation hypothesis in explanation of the origin 
 of the electricity of the atmosphere, afilrming that it was due to evaporation from the earth's 
 surface, while Franklin had attributed it principally to the action of the sea. 
 
 During the first half of the present century much progress was made in the study of the 
 subject, especially in the improvement of instrumental methods. 
 
 Several electrometers were specially designed for use in the study of atmospheric electricity, 
 and systematic and long-continued observations were carried on by a number of European 
 observers. The labors of Peltier deserve especial mention, not only on account of his improvements 
 in instrumental devices, but as well for his careful and painstaking study of principles involved. 
 
 He declared, as the result of a well-conducted series of experiments, that the electrification of 
 the conductor was due entirely to induction and not to actual contact with the air. 
 
 He used movable collectors and endeavored to protect his apparatus from the inductive 
 influence of surrounding bodies. 
 
 Lament used an electrometer of his own invention in a long series of observations at Munich. 
 
 A decided advance was made by Dellman in the construction of an instrument of much merit 
 with which he made observations at Kreuznach, and which has been extensively used elsewhere. 
 
 Dellman used a movable collector which was raised and lowered at each observation. The first 
 extensive series of observations on atmospheric electricity in America were made by means of 
 Dellman's instruments by Dr. A. Wislizenus, at St. Louis, Mo., beginning in 1861 and extending 
 through about 11 years. 
 
 The principal results of these observations have been included in this report. Dellman's 
 electrometer is capable of giving quantitative results, but only at the expense of considerable time 
 and labor at each observation. 
 
 In fact, none of the instruments devised up to the time Sir William Thomson attacked the 
 problem were exactly suitable for continuous quantitative work. 
 
MEMOIRS OF THE NATIONAL ACADEMY OP SCIENCES. 117 
 
 The labors of this distinguished philosopher revolutionized electrostatic measurement. His 
 now universally known absolute electrometers furnished the much desired meaos of reducing all 
 ■ observation to a common unit and his quadrant electrometer proved to be an instrument combining 
 in itself the widest range of sensibility and the utmost convenience in manipulation. Suited 
 for continuous registration as well as for observations at stated periods it has almost entirely 
 superseded all other forms. The waterdroppiug collector devised and introduced by Thomson 
 also offers numerous advantages over any other, being almost the only one available in continuous 
 registration. The "burning match" or "lantern" of Volta is, under certain conditions, more 
 desirable, but difficulties of iusulation and steady maintenance have prevented its general use. 
 
 Thomson's apparatus was established at the Kew Observatory about 1861, and photographic . 
 records of potential variations have been maintained with more or less regularity up to the 
 present time. The electrometer has been modified by Mascart, Edelmann and others, and has been 
 extensively used at various points in Europe in meteorological observatories both public and 
 private. 
 
 The work of Palmieri, Director of the observatory on Mt. Vesuvius, constitutes, perhaps, the 
 only extensive series of observations made within recent years in which instruments founded on 
 the original designs of Sir William Thomson have not been used. 
 
 The origin and development of the series of studies of atmospheric electricity carried on by 
 the Chief Signal Officer may be briefly described as follows : 
 
 In 1871, shortly after the beginning of the meteorological work of the • service, Professor 
 Lapham of Milwaukee, a well-known scholar who had been influential in the Congr«i^8ional 
 legislation establishing the Weather Bureau, suggested to General Myer, then Chief Sigy.^Ofacer, 
 the desirability of making observations upon atmospheric electricity. The eftSire wolFk oi the 
 service being at that time new and its organization necessarily somewhat incomplete, it was not 
 considered wise to undertake the work. 
 
 In 1877 Dr. Channing, of Providence, wrote the Chief Signal Officer relative to his own 
 observations of noises hoard on the telephone, which was just then being brought to the attention 
 of the public, and suggesting its use in thunder-storm predictions. 
 
 This matter was referred to Professor A. Graham Bell, who undertook to consider the construc- 
 tion of special forms of telephonic apparatus adapted to this study. 
 
 In the mean time the question of the relation of the electrical conditions of the atmosphere 
 to health conditions had interested medical experts for many years, and in 1879 the American 
 Medical Association appointed a committee and authorized expenditures for the maintenance of 
 electrical observations at several stations for the purpose of medical research. This committee 
 sent a communication to the Chief Signal Officer offering to bear the expense of the necessary 
 apparatus if the latter would undertake the observations, and further correspondence was had 
 on the same subject in 1882 and 1883 between the Chief Signal Officer and Dr. J. N. Toner, of 
 Washington, D. C, and Dr. N. J. Davis, of Chicago, 111. 
 
 All of this correspondence and all questions pertaining to the subject had been referred from 
 time to time to Cleveland Abbe, professor and assistant in the office of the Chief Signal Officer, 
 who has served as meteorologist since the establishment of the Weather Bureau. 
 
 Having expressed to General Hazen, then Chief Signal Officer, the belief that in additioii to 
 the importance of the subject from a medical standpoint, it was worth while for the service to 
 inquire whether electrical disturbances would be of any service in weather forecasting, especially 
 in the case of thunder storms or tornadoes, Professor Abbe was auihorized to consult with Professor 
 H. A. Eowland of Johns Hopkins University, one of the first authorities on the subject, and to 
 request him to devise some plan by means of which observations of real value might be made at 
 the stations occupied by the weather service, so that the offer of the American Medical Association 
 might be accepted. Professor Rowland took an active interest in the matter, and at the 
 International Congress of Electricians assembled at Paris in 1881, to which he was a delegate 
 from the United States, he moved the formation of an international commission for the purpose of 
 organizing and directing an investigation of atmospheric electricity. Such a commission was 
 ordered, some other duties relating to the study of earth currents, electric registration of 
 meteorological phenomena, etc., being assigned to it. 
 
118 MEMOIRS OF THE NATIOl^TAL ACADEMY OF SCIENCES. 
 
 He also examined the apparatus at Kew and that of Mascart, 
 
 On his return, in November, 1881, he communicated the results of his observations to 
 Professor Abbe, expressing some doubt as to the utility of going into the work unless better and 
 more uniform' systems could be adopted and the observations could be extended to all parts of the 
 world. 
 
 He expressed his willingness, however, to establish an observatory at Baltimore. The subject 
 was again brought to the attention of the Chief Signal Officer, the possibility of obtaining from 
 the investigation some assistance in the prediction of thunder storms and tornadoes being 
 emphasized, and he determined to undertake the study of the subject. 
 
 It was arranged that when the class of observers then under instruction at Fort Myer should 
 graduate (June, 1882,) some of its members should be made special students of electricity 
 preliminary to their appointment as special electrical observers. 
 
 Through the interest of Professor Eowland, of Johns Hopkins University, and Professor 
 Trowbridge, of Harvard University, the cooperation of these institutions was secured, and Park 
 Morrill, Alexander G. McAdie, and Austin L. McEae, all of the Signal Corps, were sent, the former 
 to Johns Hopkins University and the two latter to Harvard University for the purpose of making 
 preliminary studies and observations, under the special direction of Professor Eowland at 
 Baltimore and Professor Trowbridge at Cambridge. An electrometer with photometric registering 
 apparatus, as designed and arranged by Mascart, was obtained from Paris, and installed in a 
 suitable room specially loaned for the purpose by the authorities of Johns Hopkins University' at 
 Baltiiiipre, and the two men sent to Cambridge were granted special facilities for their work by 
 Pro^;5£,^^rowbridge and the authorities of Harvard University. 
 
 Ue^er the sM^ection of Professor Trowbridge a good deal of time was spent in the study of 
 different forms of electrometers, some new forms being specially designed and constructed, and 
 experiments were made with different varieties of collectors. Experiments on atmospheric 
 electricity at high altitudes, collected by a kite, were made by McAdie at Blue Hill observatory, 
 near Boston, and communicated to the American Academy of Arts and Sciences in June, 1885. 
 A paper on the subject was also prepared by Morrill and published by the Chief Signal Officer. 
 
 Much of the successful beginning of the work must be attributed to the interest taken in the 
 work by Professors Eowland and Trowbridge and to their active and continued cooperation. 
 
 ^ The photographic registering apparatus of Mascart arrived in July, 1883, and was shortly after 
 put in operation. 
 
 In June, 1884, Professor Abbe was directed by the Chief Signal Officer to visit Baltimore and 
 Cambridge and examine the progress of the work. On his return a letter was received from the 
 Department of State, through the Secretary of War, transmitting to the Chief Signal Officer 
 resolutions passed by the International Congress of Electricians which had held its second meeting 
 in June, 1884. 
 
 These resolutions expressed the desire of the Congress that observations be undertaken by all 
 countries, and that such results as might be collected be sent each year to the International Bureau 
 of Telegraph Administration at Berne, which will make a digest of them and communicate it to 
 the various Governments. The subject was also presented to the conference of electricians held in 
 Philadelphia in September, 1884, in connection with the electrical exposition then in progress by 
 Professor Abbe, who, with Lieut. -James Allen, was a delegate from the office of the Chief Signal 
 Officer. Circulars had previously been sent to many prominent electricians, telegraph and 
 telephone companies, and the numerous replies received enabled the Chief Signal Officer to 
 formulate a series of questions which he submitted to the Philadelphia conference throu^^h his 
 delegates, Professor Abbe and Lieutenant Allen. " 
 
 A committee was appointed by the President of the conference, Professor H. A. Eowlmd to 
 consider the subject, with instructions to report within three months. The committee consisted 
 of Professor Abbe, chairman, Lieut. James A lien. Professor J. Trowbridge, Dr. W. W. Jacques Mr 
 F. N. Gisborne, Mr. W. H. Preece, and Professor F. E. Nipher. ' 
 
 A preliminary report was made by this committee during the session of the conference 
 in which the United States Government was urged to take steps to secure on a larger scale 
 observations of atmospheric electricity and strength of earth currents. Another meeting of the 
 
MEMOIKS OF THE NATIONAL ACADEMY OF SCIENCES. 119 
 
 committee was held in Baltimore early in October, 1884, at which Sir William Thomson, Lord 
 Bayleigh, and Professor Eowland were present as invited guests. At this meeting it was 
 learned through Mr. Preece, who was also a member of the International Commission, that no 
 definite instructions or plan of operations had yet been formulated or agreed upon by that body, 
 and it was agreed that while the whole subject mightf be considered as yet in its experimental 
 stage, it was of the utmost importance that the studies already undertaken should be pursued 
 with vigor and that the operations under the direction of the Chief Signal Officer should, if 
 possible, be enlarged. 
 
 In the latter part 'of 1884 the writer was appointed by the Chief Signal Officer to assume the 
 direction of the work as a part of his duties as chief of the ijhysical laboratory and instrument 
 division of the office in Washington. 
 
 It was determined to extend the operations in the study of atmospheric electricity as soon as 
 possible, provided the necessary appropriation of funds could be secared. Experiments bearing 
 on the question of exposures, collectors, electrometers, etc., were begun in the spring of 1885, 
 although the only available place for the work was quite unsuitable and it had to be carried on 
 under great difficulties. 
 
 The nature of the observations was such that it seemed desirable, indeed almost necessary, 
 that the new stations to be established should be located at some educational institution, in 
 connection with a physical laboratory, so that the observer might be constantly advised by 
 and be, in some degree, under the direction of the professor of physics. With this end in view, 
 arrangements were made for the establishment of electrical stations at the following points : 
 
 The Office of the Chief Signal Officer, Washington, D. C. 
 
 Johns Hopkins University, Baltimore, Md. 
 
 Harvard University, Cambridge, Mass. 
 
 Tale University, New Haven, Conn. 
 
 Cornell University, Ithaca, N. Y. 
 
 Ohio State University, Columbus, Ohio. 
 The station at Cambridge was afterwards removed to the Massachusetts Institute of Tech- 
 nology. 
 
 The service is greatly indebted to the governing authorities of all of these institutions, and 
 especially to the following gentlemen : 
 
 Professor H. A. Eowland, Johns Hopkins University. 
 
 Professor John Trowbridge, Harvard University. 
 
 Professor Arthur W. Wright, Tale University. 
 
 Professor W. A. Anthony, Cornell University. 
 
 Professor E, S. Nichols, Cornell University. 
 
 Professor B. P. Thomas, Ohio State University. 
 
 Professor E. H. Mark, Ohio Meteorological Bureau. 
 
 Mr. B. W. Snow, Ohio State University. 
 
 Professor Charles E. Cross, Massachusetts Institute of Technology. 
 All of these gentlemen not only devoted a good deal of time to the work as it was in progress, 
 contributing valuable suggestions and advice to the observer, but in all instances they furnished 
 rooms suitable for the establishment of the instruments, and in many the instrumental equipment 
 itself, at least up to the time of the arrival of the apparatus purchased by the Chief Signal Officer, 
 and. all of this without expense to the Government. The funds available in the office for this 
 work being only sufficient to purchase the necessary apparatus, it is not too much to say that the 
 carrying out of the investigation was only possible through the assistance thus rendered. The 
 importance of emphasizing this acknowledgment of indebtedness is due to the peculiar conditions 
 under which much Government work is done, in virtue of which those engaged in it may accept 
 such favors from the general public, or from public or private institutions, without being able to 
 make any sort of a return in kind. 
 
 Of those persons connected with the service who were detailed as observers or who contributed 
 to the work, in one way or another, special mention should be made of Professor Cleveland 
 Abbe, to whom its inception was almost entirely due, Junior Professors Marvin and Eussell, who 
 
120 MEMOIES OP THE NATIONAL ACADEMY OP SCIENCES. 
 
 rerdered invaluable assistance in the experimental work carried on in the laboratory as well as in 
 several series of special observations, and the following members of the Signal Corps, who were 
 detailed as observeis at the several stations, or who were on duty as assistants in the laboratory 
 during the progress of the work : Dannhauser, Day, Passig, Hammond, McAdie, McEae, Morrill, 
 Parker, Schultz, and Strong. 
 
 Several of these performed special service, and mention should be made here of two somewhat 
 elaborate memoirs 9f a historic nature, on the electrometer prepared by A. G. McAdie and A. L. 
 McRae. It was originally intended to combine these for publication in this report, but as the 
 information which they contain is now generally accessible, especially in the article on electrometers 
 in the last edition of the Encyclopaedia Britannica, it has been thought best to confine the detailed 
 description of instruments to those actually made use of in the investigation. 
 
 Mr. McEae also made translations of several important memoirs in foreign languages. 
 
 Before the work was fairly under way, difiQculties of a serious nature arose out of the 
 question of the right of the Chief Signal Oflcer to expend money for the purpose of carrying it on, 
 the wording of the act making the appropriation being such that it was thought to be a matter of 
 doubt. Although the Chief Signal Officer entirely approved of the plan of operations, it appeared 
 to be impossible to avoid long delays in procuring the necessary instruments for preliminary 
 studies and for properly equipping the several stations. The location of the laboratory in 
 Washington, although the best available, was entirely unsuitable for actual experimentation, and 
 in spite of efforts to further the work much less was accomplished during the years 1885 and 1886 
 than would otherwise have been possible. In the latter part of the year 1886, the writer resigned 
 his position in the service, but General Hazen, the Chief Signal Officer, urged that he continue 
 the direction c^the work in atmospheric electricity. Accordingly, an electrical station was 
 es^^lished at the Eose Polytechnic Institute, Terre Haute, Ind., and Sergeant A. L. McEae, who 
 had for some time been at Columbus, Ohio, was placed in charge as observer. 
 
 The death of General Hazen occurring shortly after, his successor. General Greely, who was 
 much interested in the work, continued it as then organized until, on the failure of Congress to 
 make certain appropriations, he was compelled a few months later to reduce the number of stations, 
 maintaining only those at Washington, Boston, Ithaca, and Terre Haute. 
 
 It was found necessary to close the station at Baltimore on account of the removal of the 
 physical laboratory to the new building completed in 1887, and Sergeant Morrill was directed to 
 remove the photographic equipment to Boston. Owing to difficulties met with in its installation, 
 continuous registration was not resumed until the summer of 1888. In August of that year all 
 observations were discontinued. It was thought that a sufficient number had been accumulated 
 to decide the question of their use in weather forecasting, and, in fact, their study up to that date 
 gave little encouragement in that direction. 
 
 The labor of tabulating and classifying the large number of observations has been entirely 
 performed by Sergeants McEae and Schultz, who were detailed for that purpose by the Chief 
 Signal Officer. The writer wishes to acknowledge the intelligent and conscientious performance 
 of the work in a manner possible only through their familiarity with and interest in it. 
 
 In addition to their labor in the preparation of the tables of observations for publication, 
 Sergeant Schultz, whose detail extended beyond that of Sergeant McEae, has constructed all of 
 the numerous diagrams illustrating the results. 
 
 In considering the outcome of this work especial attention is requested to the conditions under 
 which it was done. As already stated, before it was really begun, the Chief Signal Officer, was 
 constrained, by decisions of Department authorities, to restrict it to avi attempt to answer the 
 question, " In the present state of meteorological science can observations of atmospheric electricity 
 be utilized in forecasting the weather ?" 
 
 No studies or investigations whicli did not bear upon this question were proper or allowable. 
 
 While it is believed that the answer to this query which the results aflford fully justifies the 
 time and labor expended, it will be seen that under the circumstances many questions of great 
 scientific interest and of important bearing on current theories as to the origin of the electricity of 
 the atmosphere had to be set aside for those likely to be of immediate pt-actical value. 
 
MEMOIES OF THE NATIONAL ACADEMY OF SCIENCES. 121 
 
 INSTKUMENTS AND METHODS. 
 
 TJie electrometer, — All of the electrometers used were of the form known as the Thomson 
 quadrant. Several of them were Mascart's modification of the Thomson quadrant, manufactured 
 by Oarpentier. The apparatus for photographic registration used at Baltimore, and for a short 
 time at Boston, was constructed by Dubosq. Experience in the use of this led to several 
 modifications as to detail which were made by Sergeant Morrill from time to time on the advice of 
 Professor Eowland. 
 
 The Mascart electrometer is so widely known and has been so frequently described that it is 
 unnecessary to insert a description here. 
 
 The earlier observations at Cambridge were made by a modified Clifton electrometer, changes 
 having been made to secure greater convenience of manipulation and more ready access to the 
 various parts of the instrument. A multiple quadrant instrument was also designed by Professor 
 Trowbridge and constructed under his direction. It differed from the ordinary form in that each 
 quadrant was compounded of four, placed one upon another. The aluminum needle was also 
 compound, consisting of four single needles attached to the same axis so as to move in the cells 
 formed by the compound quadrants. A light aluminum index placed above the needle moved 
 over a graduated arc so that direct readings of deviations were made. 
 
 The importance of securing high insulation of all parts connected with the collector was not 
 at first fully appreciated, and most of the first instruments used were faulty in that respect. A 
 number of experiments were made for the purpose of overcoming this difficulty as well as some 
 others which seemed to be inberent in the Mascart electrometer. 
 
 At first, and continuously with the photographic apparatus, the silk fiber suspension was used, 
 the charge being conveyed to the needle in the ordinary way, that is to say, by me^k of a platifium 
 wire connecting the needle to the sulphuric acid in the shallow glass jar immediately below it- 
 Besides the insulation of the system, which was irregular and sometimes very bad, difficulties, 
 appeared with considerable frequency, giving rise to changes in the apparent zero of the needle. 
 Doubtless some of this variability is to be charged to the silk fiber, but much of it- is 
 unquestionably due to a sluggishness in the movement of the platinum wire in the sulphuric acid. 
 
 It was finally determined to resort to a wire suspension, through which the charge could be 
 communicated to the needle, thus suppressing the connection between the needle and the acid. 
 
 The potentials to be measured ranging from zero to some hundreds and often thousands of 
 volts, no great sensitiveness was desirable, and wires of extreme fineness were not necessary. The 
 fixed end of the wire was supported by a brass cap on the glass tube through which the wire 
 passed, and some difficulty was experienced in finding glass of sufficiently high insulating power 
 for this purpose. 
 
 The wire suspension in its final form gave very satisfactory results, however, in the matter of 
 insulation, and when properly prepared was more constant in its zero reading. 
 
 The dish of sulphuric acid was still retained for the purpose of keeping the inside of the 
 instrument free from moisture. Modifications were also made for securing greater freedom of 
 access to all of the parts of the instrument. 
 
 Several instruments of this type were constructed and supplied to several stations, taking the 
 place, at Ithaca, of a Thomson quadrant by White, of Clasgow, the use of which had been kindly 
 allowed by Professor Anthony, of Cornell University, and at Boston of the instruments formerly 
 used at Cambridge. Eecord should also be made of the fact that a Thomson portable, by Elliot 
 Brothers, was used for a short time in Cambridge, and also at Columbus, Ohio. 
 
 Although these instruments were free from the most serious difificulties found in connection 
 with those first used, and were, iu the main, satisfactory, they were still somewhat faulty in 
 certain particulars, and in an atmosphere nearly or quite saturated with moisture, their insulation 
 was often lower than was desirable. 
 
 Still further improvements suggested themselves, and finally the construction of an instrument 
 embodying all of the modifications of the Mascart pattern, which experience had commended, was 
 confided, through the firm of Jas. W. Queen & Co., of Philadelphia, to the well-known 8oci6t6 
 Cenevoise. 
 
122 
 
 MEMOIES OF THE KATIONAL ACADEMY OF SCIENCES, 
 
 The essential variations from the Mascart pattern are as follows : „„..„„„h«,1 hv 
 
 The glass tube, to the top of which the suspension wire was attached, was surrounded by 
 
 nirs^Su^srwed into the brass rin. cemented to the foot of the larger, and openings 
 were provided in this ring so that when the large" tube was screwed to the top of the electrical cae, 
 communication existed between the annular space separating the tubes and the interior of the case 
 A brass cap was cemented to the upper end of the large tube, long enough to cover entirely 
 the inner tube with its terminal suspension device, and terminating in a short, brass tube to which 
 
 rubber tubing could be easily attached. ,,«,., . .-u „„„„„;^,. 
 
 The upper part of this brass cap could be readily removed to afford access to the suspension 
 arrangement at the end of the inner glass tube. Theobject of thus incasing the tube supporting 
 the suspension wire was to provide for the maintenance of a dry exterior surface. 
 
 Fig. u,. 
 
 The best obtainable insulating glass proved to be hygroscopic in some degree,but by the 
 above arrangement, air dried by the sulphuric acid within the case could be drawn up into the 
 space between the two tubes, thus securing a dry atmosphere on both sides of the supporting tube. 
 This suspension system rested upon a support similar to the well known mirror box used by 
 Edelmann in his galvanometers. The cylinder to which the glass front was attached not only 
 revolved through a large angle, thus affording a wide range, but could also be entirely lifted off 
 of the instrument, thus exposing the mirror and making it perfectly easy to attach the suspension 
 wire. 
 
MEMOIRS OP THE NATIONAL ACADEMY OF SCIENCES. 123 
 
 The aluminum wire to which, the mirror was attached terminated just above the latter in a 
 very small screw clamp and a similar clamp was fastened to the lower end of the sliding brass rod 
 which moved in a friction-bearing at the upper end of the suspension tube. The suspension wire 
 was firmly held by these clamps and a new one could be inserted at any time in a few seconds 
 without disturbing any other part of the instrument. 
 
 The ingenuity of the makers also provided an accurate and delicate adjustment of the mirror 
 about a horizontal axis lying in its plane. The needle was of aluminum and of the ordinary form. 
 A wire extended from its lower surface to the space below the quadrants and was terminated in a 
 short slip of mica, so. that an air damper might be used if desired, or liquid damping arranged 
 for. Wide doors on opposite sides afforded convenient access to the quadrants and the interior of 
 the case. 
 
 The workmanship throughout was of a high character and fully up to the standard so 
 generally maintained by th^ Soci4t6 Genevoise. 
 
 Fig. a shows the instrument with the window cylinders removed. 
 
 I» all of the instruments except that for photographic registration, readings were made by 
 means of the ordinary lamp and scale method, the scale being usually drawn upon ground glass 
 and distant about one metre from the electrometer. 
 
 Method of using the electrometer. — Three methods of charge and connection for the quadrant 
 electrometer have been used and recommended by different authorities, each of which undoubtedly 
 has peculiar advantages under certain conditions. 
 
 Following Sir William Thomson's classification, in two of these the charge is heterostatic, and 
 in the third it is idiostatic. 
 
 In the first, the needle of the electrometer is maintained at a constant poffcoatial, and one 
 pair of quadrants is connected with the earth and the other to the body whose potential is to be 
 measured. In the second, the two pairs of quadrants are charged to the same potential, the signs 
 being opposite, and the needle is joined to the body whose potential is to be measured. 
 
 In the third, both the needle and one set of quadrants are joined to the body under 
 examination, while-the other set of quadrants is connected with the earth. 
 
 These methods, in the order given, are frequently referred to as the method of Thomson, of 
 Mascart, and of Joubert, and they will be so designated here. 
 
 The last, that of Joubert, is evidently not suitable for use in the-^tndy of atmospheric 
 electricity, and it is necessary to choose between the first two. 
 
 In order to be able to state clearly the reasons for deciding in favor of the second, it may be 
 well to state briefly some theoretical considerations, which have not always received t^e attention 
 they deserve. 
 
 The general equation for the quadrant electrometer as given by Clerk Maxwell is as follows : 
 
 in which = moment of couple acting on the needle. 
 a = a constant depending on the instrument. 
 A and B = potential of quadrants. 
 C = potential of needle. , 
 
 In the Thomson method of mounting, one quadrant is connected with the earth and its 
 potential is zero. The equation then becomes 
 
 0=a{AG-lA^) 
 
 and, a and C being constant, it represents a common parabola. 
 
 If a curve be constructed from observations, the deflections being platted as abscissas and the 
 potentials of the quadrant as ordinates, as has been done from actual experiments, the paints 
 determined hj observation being indicated on the curve, it will be seen that the assumption 
 ordinarily made, namely, that the deflections are proportional to the potentials, is only 
 approximately correct through a relatively small range. For a short distance on either side 
 of the origin the curve is approximately a straight line, but it is worthy of note that the 
 
124 MEMOIRS OF THE NATIONAL ACADEMY OF S0IEN0B8. 
 
 inclination to the axis is different on the two sides, and that it is therefore important that care 
 should be taken in comparing potentials to see that the signs of the charges on the needle and 
 on the quadrant are similarly related to each other in both cases. If O, the potential of the 
 needle, is very large compared with A, and this is generally recommended, the error in assuming 
 that a straight line will represent the observations is very small. 
 
 Thus if 0== 5,000 and A is not greater than 100, the error will not exceed 1 per cent., and in 
 general, as the equation easily shows, if is the potential of the needle and e is the fractional 
 error permissible, the maximum potential which can be measured is A = 2eO. 
 
 In the Mascart method of mounting, A and B are equal, constant and of opposite sign. The 
 general equation then reduces to this : 
 
 e=2aAC. 
 
 Here 6 and are the variables and the equation is that of a straight line; in other^ words, the 
 deflections will now be proportional to the potential of the needle. 
 
 Gouy, in the Journal de Physique for March, 1888, show« that the general expression for 
 the moment of the couple acting on the needle of the quadrant electrometer, in the case of a 
 symmetrical charge, as given by Maxwell, is incomplete, in that it lacks a term to express the effect 
 of what he terms the " electric directing couple." 
 
 The existence of this couple he establishes by vibrating the needle uncharged, first when the 
 quadrants are also at zero potential and then with increasing differences of potential between 
 them. In the case cited by him the period of the needle was 13 seconds with the quadrants 
 uncharged and this was reduced to 1.45 seconds when the difference of their potential was 1,400 
 volts. The di^lacement of the needle from its zero brings into existence a force opposing this 
 displacement, which force, according to the experiments of G-ouy is proportional to the square of 
 the differences of potential between the two sets of quadrants. 
 
 Including the term expressing this effect and also the suspension couple, supposed in this case 
 to be torsional, the completed equation would stand as follows : 
 
 6'=fl'(A-B)[0-J(A+B)]-/3(A-B)(y2-?(y. 
 
 in which, in addition to the terms-already defined, 
 - (J = deflection. 
 s =moment of suspension couple for unit deflection. 
 yS=moment of electric couple for unit deflection. 
 Supposing as before, A=B, this becomes 
 
 0=2aAG-{^pA^+s)S=O 
 
 when the needle is at rest. 
 Hence, 
 
 ^ 2«A0 
 
 0=-; 
 
 "4y»A2+f. 
 
 Here S and are the variables and the equation is again that of a straight line. 
 
 It may be worth while to point out one of the results of the existence of this " electric directing 
 couple," which is indicated by Gouy in the paper referred to above and which further illustrates 
 the advantage of this method of mounting the electrometer. 
 
 It is clear that the sensibility of the electrometer will not continually increase with the 
 increasing charge on the quadrants, for of the two opposing couples, one increases simply as the 
 difference of potential of the quadrants and the other as the square bf this difference. The curve 
 of sensibility will therefore have a maximum point. 
 
 An examination of the equation shows that the rapidity with which this curve falls off on 
 either side of the maximum point depends, other things being equal, on the magnitude of the 
 suspension couple, being less as this couple is greater. 
 
 It follows from this interesting fact that a stiff suspension affords a relatively long range about 
 the point of maximum sensitiveness throughout which it is sensibly the same ; that is to say. 
 
MEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES. 125 
 
 considerable variations may be made in the charge upon the quadrants without altering the 
 deflection of the needle for unit potential. 
 
 As it is next to impossible to maintain a constant quadrant charge by means of ordinary 
 batteries, it is important to take advantage of this fact by using wire suspensions and a greater 
 number of cells. 
 
 The Mascart method of mounting also possesses advantages in the matter of insulation. In 
 studying atmospheric electricity, where generally although the potential may be high the quantity 
 is small, it is essential that that part of the electrometer which is in connection with the collector 
 should be well insulated. 
 
 The quadrants are usually supported by short glass stems, while- the length of the needle 
 suspension may be anything desired, and it is thus easier to secui'e high insulation of the needle 
 than of the quadrants. 
 
 For these reasons the Mascart method was used in all of the work, except durtng some of the 
 earlier experiments at Cambridge, in which the Thomson plan was followed. 
 
 Charging batteries. — In nearly all cases a water battery was used for charging the quadrants 
 and generally the form adopted by Mascart, consisting of small porcelain cups imbedded in 
 parafflne, filled with pure water and joined in series by metallic couples consisting of small strips of 
 cojjper and zinc soldered together and bent into a proper form. These batteries are by no means 
 constant in their potentials, and require considerable attention on account of loss by evaporation, 
 and danger from dust, which often contains foreign matter enough to produce decided changes in the 
 electromotive force of the cells, and as this change is not always the same throughout, the battery, 
 the middle point of which is connected with the earth, is thrown out of balance so that the charges 
 on the quadrants are no longer equal. ' 
 
 A number of experiments were made at Cambridge, under the direction of Professor 
 Trowbridge, with the well-known Beetz battery, prepared by inserting copper and zinc wires in the 
 two arms of a bent glass tube which had been filled on the one side with a paste made of plaster 
 of Paris and a copper sulphate solution, and on the other with a similar paste of zinc sCilphate. 
 The ends of the tube are sealed with parafline, after the setting of the plaster takes place. A 
 considerable number of these cells were prepared at Cambridge and they appeared to be very 
 satisfactory as to constancy, even after more than a year after their construction. 
 
 Certain mechanical diflQculties prevented their general use, the principal being their somewhat 
 fragile nature, in virtue of which they^were liable to accidents resulting in damage, neither the 
 nature nor the location of which could be readily determined. 
 
 The ordinary water batteries, with all of their parts exposed and easily supplied, were better 
 suited for use at the various stations. 
 
 They were in boxes containing fifty cells each, that number being generally sufficient and 
 often more than sufBcient for producing the necessary charge in the quadrants. The middle point 
 of the battery was connected with the earth and the zinc and copper terminals to the two sets of 
 quadrants. 
 
 As already stated, it is very difficult to secure an exact equality of potential on both sides of 
 the earth connection, owing to inequality in the cells. On this point M. Gouy, in the paper 
 already quoted, makes the very important suggestion that sensible equality may be secured by 
 joining the poles of the charging battery by an extremely high resistance, the middle point of which 
 is connected with the earth, the battery being otherwise entirely insulated. This method would 
 eliminate inequality of the cells and is to be strongly recommended where work of high precision 
 is desired. 
 
 For purposes of calibration reference was .usually had to some standard battery at hand. 
 In the experimental work in the laboratory at Washington a collection of nearly a hundred cells 
 of the ordinary gravity battery was used, the potential of which was always known by means of 
 pne of Sir William Thomson's gravity volt-meters, which was joined in circuit with the battery 
 and a very high resistance. A very convenient battery for calibration, especially where a large 
 number of cells is required, is the water battery devised by Professor Eowland and described by 
 him in the Philosophical Magazine for March, 1887. It is easily prepared, and a large number of 
 cells occupy a very small space. 
 
126 MEMOIRS OP THE NATIONAL ACADEMY OF SCIENCES. 
 
 COLLECTORS. 
 
 The water-dropping collector, as devised by Sir William Thomson, is the only one which has 
 been very generally used in observations of atmospheric electricity. 
 
 In the observations of Wislizenus in this country and those of several European observers, 
 notably Palmieri, other forms have been made use of, but the many advantages of the water 
 dropper in the way of convenience and especially for continuous registration have led to its well 
 nigh universal adoption. 
 
 In the course of this investigation, experiments were made with the burning match or flame 
 collector and with one or two other forms which will be shortly described. The water-dropping 
 collector was in general use at the stations, however, the form usually adopted being that of a 
 cylindrical vessel of galvanized iron large enough to contain sufficient water for a run of 24 hours. 
 
 This vessel was mounted on three large insulators of the Mascart pattern, and to the lower 
 part of the cylinder was attached a long brass tube about 1 centimetre in diameter and 2 or 3 
 metres in length. The outer end of this tube was provided with a close-fltting cap, in which was 
 a small orifice through which the stream of water flowed, breaking into drops at a distance of 10 to 
 20 centimetres. To prevent the bending or breaking of the tube, a wire attached to the upper rim 
 of the iron vessel was fastened to it near its outer end. At nearly all of the stations arrangements 
 existed for filling the collector at any time by turning a stopcbck. At Cornell University, 
 where in several respects the arrangements were more perfect than elsewhere, the collector was 
 mounted on a table running on casters so that it could readily be moved back and forth, the whole 
 being completely within the room whenever desirable, except at the time of observation. One of 
 the objections to the water-dropping collector is its liability to freeze in extremely cold weather, 
 and in some cases the photographic registration was interrupted in this way. The station at 
 Ithaca was one of the most exposed, but trouble from freezing was avoided in the manner described. 
 
 At other stations when the collector could not easily be moved, the difficulty could generally 
 be overcome by removing the tube and warming it just previous to an observation. 
 
 At Baltimore Sergt. Park Morrill designed, under the direction of Professor Eowland, a 
 mechanical collector by which it was hoped that the objections to the water dropper might be 
 avoided and all exposures made strictly comparable with each other. 
 
 Something of the same kind had also been attempted at Cambridge. 
 
 To serve for photographic or other continuous registration it is necessary that the collector 
 shall be continuous in its operation and sufficiently " quick " in its action to enable it to follow 
 close upon the electrical variations, which are often quite rapid. In this respect the water-dropping 
 type oft'ers greafr advantages. 
 
 It was finally determined to construct a mechanical collector, following the designs of Row- 
 land and Morrill, but unfortunately it was not completed until the whole work was just about to 
 close, so that nothing very definite can be said as to its performance. 
 
 The principal parts of the machine are shown in Fig. 1, and a brief description of it is as follows: 
 
 An insulated conductor, which will be called the inductor, is fixed in position and continuously 
 covered and uncovered by a metallic cap at the end of a revolving avm moved by clockwork, the 
 cap being always connected with the earth. Simultaneously the inductor is alternately connected 
 with the earth and to an electrometer, the earth connection being made either when the cap covers 
 itx)r when free, and the connection tQ the electrometer being made at the opposite phase of the 
 action. If the earth connection be made when the inductor is covered by the earth cap, it is 
 thereby freed from charge and, when uncovered, assumes the potential of the air. 
 
 If the earth connection be made when the inductor is freely exposed, it is charged by induction 
 and, upon being insulated and covered by the earth cap, it assumes an equal potential of opposite 
 sign. 
 
 The electrometer reaches its true readings by successive approximations with each succeeding 
 contact, the rapidity of its action depending on the relative capacities of the inductor and the 
 electrometer. 
 
MEMOIRS OF THE NATIONAL ACADEMY OP SCIENCES. 
 
 127 
 
 Fig. 1 shows the iustrument and Fig. 2 the same with the outer cover removed. The 
 inductor is at a and the revolving arms and earth caps at h. In Fig. 2 the glass stem insulating 
 and supporting the inductor is seen at o and the close chamber closed by glass sides at d, within 
 which the contacts are made and which contains a vessel of sulphuric acid for drying. Contact 
 between the inductor and the contact wheel is maintained by the wire e. 
 
 ElG.l. 
 
 Fig. 2. 
 
 In Fig. 3 the details of the instrument are shown on a large scale. The lower two-thirds of the 
 cut shows the drums and wheel work by which the axle shown on the left, is driven. 
 
 The sides of the acid chamber have been removed showing the leaden vessel g containing 
 sulphuric acid. 
 
 The wheel Ti, driven by the revolving axle, supports by glass rods an insulated ring and contact 
 pin. The contact spring i makes the ground connection through the pin, the ring being constantly 
 in contact with the wire e. The connection with the electrometer is made at the opposite side of 
 the contact ring from i, by a spring not shown, connected to a binding post from which a wire is 
 carried to the electrometer. The contact wheel h revolves twice as fast as the axle so as to go 
 through the two phases of its action for each of the two earth caps carried by the revolving arms i. 
 The socket, the base of which is seen at d, supports the inductor. If tlTfe fixed inductor, which 
 is exposed to inductive action^ were completely covered by the earth cap, the potential measured 
 would be that of the.air at the same height. But, in addition to the inductor proper there is a 
 supporting rod and an umbrella to protect from rain which can not be covered by the cap and, in 
 consequence the potential is lower than would be obtained by the water dropper at the same 
 height. 
 
 The inductor being only partially freed from charge when covered by the earth cap and con- 
 nected to the earth, for absolute values the results obtained would require the introduction of a 
 correction factor. The electric action of the collector is fully as rapid as that of the water dropper 
 and it gives a curve of the same character but with smaller values. 
 
128 
 
 MEMOIBS OF THE NATIONAL ACADEMY OP SCIENCES. 
 
 Sergeant Morrill also experimented upon a flame collector, especially with a view to overcome 
 one of the principal objections to that form, its liability to be extinguished by the wind, rain, etc. 
 He was quite successful in designing a form which during the short period of its use, before the 
 termination of the work, gave very satisfactory results. 
 
 The principle upon which blowing out was prevented was that the lamp must be so constructed 
 that the wind would exert equal pressures on the feed air and on the escaping gases. This was 
 accomplished by surrounding the proper chimney (made of metal) by a second chimney, causing 
 the feed air to pass down between the two, and by surmounting the whole by an open cone. Gas 
 was used and was admitted to the lamp through the hollow stem of a large Mascart insulator 
 which supports the lamp. 
 
 Fig. 3. 
 
 .■ JKi^^""^^. ^^^ collector complete. The insulator, supporting the apparatus, rests on air 
 tight rubber packing, and is held firmly by metallic straps. The tube shown in the foreground 
 conducts the gas to the base of the insulator. 
 
 Eig 5 is a sectional drawing of the same. A is the baseboard to which the insulator B is 
 attached by a collar and the straps 0. The gas enters at the pipe D, passing by the hollow stem E 
 to the argand burner F. G and G, are the inner and outer chimneys, respectively. H is a solid 
 collar around the stem B to support the outer chimney G,. The coue J is supported by three 
 brackets, K. L is an umbrella to protect the insulator from rain. The course of the feed air and 
 ot the products of combustion is shown by arrows. 
 
 Some diflSculty in the use of this collector was found to be due to variations in pressure of the 
 
MEMOIRS OP THE NATIONAL ACADEMY OP SCIENCES. 
 
 129 
 
 gas supply, and this was obviated by the addition of a governor, made in the manner shown in 
 the sectional drawing, Pig. 6. Gas enters through the stopcock B, and passes to the collector by 
 the pipe C. A burner is first selected which will burn freely enough at the minimum pressure or 
 less. Water is introduced into the vessel A to such a height that its elevation above the bottom 
 of the pipe O gives this pressure, that is, the proper burning pressure, which may be less than the 
 
 Fig. 4. 
 
 minimum of supply, but not more. If the adjustment be to less than the minimum pressure 
 occurring, the stopcock B is turned partly off, so that, at the time of minimum pressure, the gas 
 just forces the water to the bottom of the pipe 0. When the pressure rises, gas escapes from the 
 bottom of the pipe C, and thence to the air by tlie pipe D, while the pressure to the collector 
 remains the same. 
 
 It is evident that by the use of either of these collectors, well-defined exposures may be obtained. 
 The mechanical collector is nearly symmetrical about a vertical axis, and the lamp collector is 
 entirely so. If such a collector be placed in the center of a circular, plane, metallic surface, whose 
 radius is large, compared with the elevation above it of the inductor of the mechanical collector 
 or the apex of the lamp collector, the potential determined would be proportional to the "elevation 
 of such collecting point and results at different statioiis ought to be directly comparable. 
 
 EXPOSURES. 
 
 The ideal exposure for a collector in the study of atmospheric electricity would be on a large, 
 flat plain, free from buildings, trees, or other elevated points,^ 
 S. Mis. 94 9 
 
130 
 
 MEMOIRS OF THE Is^ATIONAL ACADEMY OP SCIENCES. 
 
 C 
 
 Indeed, it would not differ greatly from the ideal exposure for other meterological instruments, 
 thermometers, rain gauges, wind vanes, anemometers, etc. Such exposure, however, is practically 
 unattainable, and in the present instance it was necessary to accept whatever arrangements were 
 available at the several points where stations were located. 
 
 The electrometer, charging batteries, etc, were generally 
 established in some room temporarily vacant, or, in the absence of 
 such, in an unused part of an occupied room . Where this room was . 
 near the top of the building and was lighted by a window opening 
 upon a clear space, not hemmed in or in any way surrounded 
 by walls, the collector was mounted near the window, the tube 
 projecting from the same, generally as far as IJ to 2 metres. 
 In other cases the collector was mounted near a suitably ex- 
 posed window away from the observing room, and connection 
 was made by means of Mascart suspension insulators. 
 
 The first arrangement was preferred, as the insulation of the 
 system was then much more perfect. The height of the collec- 
 tors from the ground varied from 10 to 20 metres. It was not 
 possible to secure any uniformity in this, nor in the direction 
 [orientation) of the exposures. As a matter of fact, experience 
 demonstrated that for the purposes of this investigation such 
 uniformity was by no means essential, as will be shown in the 
 consideration of simultaneous observations at points near to 
 each other. 
 
 B 
 
 =5^ 
 
 =0= 
 
 D 
 
 Fig. 6. 
 
 HOTJBS OF OBSEB.VATION. 
 
 The recorded time of all observations is that of the seventy -fifth meridian. 
 
 Except in the case of photographic registration, observations were made at four or five stated 
 "hours each day. This was the rule for days on which the indications were fairly steady and 
 without rapid fluctuation. At all stations, observations of much greater frequency were occasionally 
 made, even in " steady weather," and in some instances hourly records were made for several 
 months. , 
 
 In all cases the observers were instructed to increase the frequency of their observations on 
 the appearance of a thunder storm or any indication of unusual electrical conditions. 
 
 At such times readings were made every few seconds, so that the records are quite as valuable 
 as those furnished by photographic registration. During the last year of the work, regular 
 observations were made at Boston, Ithaca, Washington, and Terre Haate at 9 a. m., 11 a. m., 
 1 p. m., 3 p. m., and 5 p. m., with additions of series of observations of greater frequency whenever 
 the conditions seemed to make it desirable. 
 
 The spot of light, the position of which on the screen indicated the potential of the collector, 
 was rarely absolutely at rest for any length of time, and the number recorded for any regular 
 observation was always the mean of several readings made every minute, both before and after 
 the stated hoar. A, calibration of the electrometer was made generally once every day so that 
 fluctuations in the potential of the charging battery were accounted for. 
 
 Usually not more than fifty cells were used in charging the quadrants, and when the 
 indications were unusually strong, so as to approach the limits of the scale, this number was 
 reduced so that readings were still possible. On many occasions, however, the limit of the 
 instrument was reached, and the spot of light would leave the scale entirely. 
 
 The Strength of the suspension wire was generally such that records were possible up to 
 near the "sparking" limit. The highest potential measurable at most of the stations was 
 approximately 5,000 volts, and in some instances this would ^be exceeded during a whole day, 
 sparks passing almost continuously between the needle and the electrometer quadrants. 
 
 At Terre H-aute, one of Thomson's electrostatic voltmeters, which had a high maximum limit 
 was used at such times. The insulation in this instrument is excellent, and its performance was 
 very satisfactory. 
 
MEMOIRS OF THE NATIONAL ACADEMY OP SCIENCES. 131 
 
 In continuous registration the calibration constant was marked on the photograph sheet. The 
 time registration, as it existed in the instrument when first received, was found to be defective, 
 but modifications were made by Morrill sending the time record satisfactorily. 
 
 To reduce the time records to local mean time, the following approximate corrections must be 
 applied. 
 
 Minutes. 
 
 Boston '. +16 
 
 Ithaca — 6 
 
 Baltimore - — 6 
 
 Washington — 8 
 
 Columbus , —32 
 
 Terre Haute -, ,. —50 
 
 PEELIMINAKY AND SIMXJLTANEOTJS OBSEEVATIONS. 
 
 In the summer of 1885 it became possible to begin, at the office of the Chief Signal Officer 
 in Washington, a series of experiments bearing on the question of exposure for the purpose of 
 determining to what extent it would be necessary to insist on similarity of arrangement at the 
 different stations. 
 
 The circumstances under which these experiments were made were extremely unfavorable. 
 
 The working laboratory was in the basement of a building, No. 1704 G street, northwest. 
 The only available open space was a small area on one side of the rear of this room, about 8 metres 
 wide by 12 long, entirely surrounded by brick walls up to a height of 18 to 20 metres. 
 
 The roof of one of these buildings could be used, and in order to obtain a more elevated and 
 more free exposure for experimental purposes, a mast was erected on this roof, reaching a height 
 above it of about 15 metres. 
 
 At its top was a projecting beam somewhat less than a metre long, to which pulleys were 
 attached. 
 
 Over these pulleys small brass chains ran, reaching the ground about 30 metres, below, and 
 by means of which two collectors were raised and lowered. 
 
 These collectors were of the water-dropping type, consisting of small metallic vessels, with 
 dropping tubes about 30 centimetres in length. They were attached to the chains by insulators 
 and connected to the electrometer below by means of fine wire. It was difficult to Insure a very 
 perfect insulation of the system, but that of the two collectors was sensibly the same and suffi- 
 ciently good for the purpose. 
 
 Two electrometers were carefully adjusted until they had practically the same constant, giving 
 nearly identically the same indications when attached to the same collector. 
 
 With this arrangement a number of experiments were made to determine the degree of 
 agreement between the indications of two collectors, as nearly alike as possible, and exposed as 
 nearly in the same way as possible. 
 
 It was at once discovered that considerable differences in the potential indicated by the two 
 collectors existed. It was found, however, that so long as the collectors remained at a given 
 height, the difference between their indications was practically constant, so that when their curves 
 were drawn they agreed almost exactly in form. As was to be expected, the differences increased 
 with the elevation of the collectors. 
 
 The collectors were interchanged in their position as to the mast, and in their electrometer 
 connections. It was found that the innermost collector, that nearest the mast, always gave the 
 lower potential. 
 
 The conclusion drawn from these experiments was that while it would be very difficult under 
 ordinary circumstances to secure two exposures which should.indicate the same absolute potentials, 
 there was little doubt but that two collectors placed very near to each other would show similar 
 potential variations. 
 
 In the spring of 1886 more electrometers were available, and simultaneous observations were 
 resumed with increased distances between the collectors. An instrument was established in what 
 was known as the " instrument room," the exposure being on the north side of a large lattice- work 
 shelter, the height of the nozzle being about 14 metres from the ground, and the stream of water 
 was broken at a point a little less than 2 metres from the lattice work. 
 
132 
 
 MEMOIRS OF THE NATIONAL AOADEMl OF SCIENCES. 
 
 The collector was a large cylindrical metallic vessel mounted as already described. This 
 station was about 100 metres distant from the mast at the laboratory, from which the second 
 collector was suspended at a height of 3 metres from the roof on which it was located. 
 
 It will be seen that these exposures were, in some respects, quite different, yet generally 
 their potential curves were quite similar. Pigs. 7 and 8 show two examples of simultaneous 
 observations at these two points, covering a half hour each day, during which readings were 
 made with such frequency as to be practically equivalent to a continuous record. 
 
 Volts. 
 400 
 
 4- 200 
 
 -j- -j^ 
 
 ( ; 
 
 
 ' ^ ,' 
 
 7 • '■■■■' 
 
 ' 
 
 "i.'i ^ °^C H ^\-.^ - --~-^ 
 
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 ^ V •; <■ __- - 
 
 __--_, z_ ._ : 
 
 t .j- 
 
 - - - _ _ -\iL . _ -- - - 
 
 
 
 ■ 
 
 - - ^ 
 
 11:05 a.m. __ ^ __ 11:35 a. m. 
 
 Mast collector. 
 
 ■ Shelter collector. 
 
 riG. 7.— Comparison of exposures, WashiDgton, D, C, May 5, 1886. 
 
 They were first printed in the Monthly Weather Eeview for April, 1886, and are selected as 
 good illustrations of movements on both sides of the line of zero potential. The curves showing 
 positive readings are not in as close agreement as those showing negative, and in both cases it 
 
 1:35 p.m. 
 
 2:10 p. m. 
 
 Mast collector. Shelter collector. 
 
 Fig. 8.— Comparison of exposnres, Washington, D. 0., May 5, 1886. 
 
 Will be observed that while the general movements at the two stations were very similar there 
 were at times considerable differences in rate and direction of changes of potential These 
 differences are much greater than in the cases of two collectors only a metre apart, and it is clear 
 that even when two points are not further separated than 100 metres, indications of variations in 
 potential may be quite dissimilar. 
 
 In August, 1888, similar comparisons were made by Morrill at Boston, using his flame 
 collectors, one of which was exposed on a balcony about 15 metres above the ground and another on 
 the roof of the same building 7 or 8 metres above the first. During these observations the weather 
 
MEMOIES OF THE NATIONAL ACADEMY OP SCIENCES. 
 
 133 
 
 Volta. 
 1000 
 
 + 500 
 
 12:32 
 
 12; 30 
 
 P.M. 
 12:40 
 
 12:50 
 
 was very warm, sky overcast with cumulo-stratus clouds, light nortliwest winds. Shortly after 
 noon a shower appeared in the west and passed around to the south, not reaching the station. 
 Figs. 9 and 10 show the potential curves drawn from observations made every 2 minutes at each 
 collector. 
 
 In all cases the roof collector shows the greatest range of 
 moment, that exposure being undoubtedly much more free than 
 the other; but the general character of the changes is nearly the 
 same in both. 
 
 The next step in the matter of comparative observations was 
 to increase very considerably the distance between the two sta- 
 tions. Through the courtesy of the late Professor Baird, then 
 Secretary of the Smithsonian Institution, an electrometer with 
 accessory apparatus was mounted in the central tower of that 
 building, the exposure being from a north window, at a height 
 of about 17 metres. The other station was that of the instru- 
 ment room at the Signal Office already referred to, the distance 
 between the two being approximately 1 mile. During several 
 days simultaneous observations were maintained at these two 
 points and some of the results are shown in Figs. 11 and 12. 
 In all cases the observations were not less frequent than once in 
 5 minutes, and when the movements of the needle were rapid 
 they were made as often as once a minute. It would be impossible to plot all of the more minute 
 
 
 
 
 - 
 
 
 
 r 
 
 r- 
 
 r 
 
 
 
 
 ■ 
 
 
 r- 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 z, 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
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 ■ 500 
 
 a: Potential on balcony. &: Potentialon roof. 
 
 Fig. 9.— Comparison of exposnres, Boston, 
 Mass., August 17, 1888. 
 
 Volta. 
 2,000 
 
 9:36 a, in 
 
 0:50 a. 
 
 m. 
 
 10 5 
 
 . m 
 
 
 0:10 
 
 a. 
 
 m 
 
 0:20 a 
 
 m. 
 
 11:19 8 
 
 . in. 
 
 0:31a 
 
 m 
 
 
 0:41s 
 
 . I 
 
 n. 
 
 
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 a. 
 
 m. 
 
 12:01 
 
 p. m. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
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 +1,000 
 
 —1,000 
 
 2,000 
 
 a: Potential on balcony. 6 •• Potential on roof. 
 
 Fig. 10. — Comparison of exposnres, Boston, Mass., Angnat 17, 1888. 
 
 tnovememts without producing confusion in the diagram, but the more important changes are cor- 
 rectly represented. 
 
134 
 
 I^EMOIRS OP THE NATIONAL ACADEMY OP SCIENCES. 
 
 Pig. 11 shows the potential variation during several hours of June 4, 1886, a day on which 
 the weather was fair with gentle variable winds. Considerable difference in both character and 
 magnitude of variation in potential are indicated- 
 
 u m. 4 p. m. 
 
 a: Smithsonian Institution. 
 
 b: Signal Office. 
 
 Pig. 11. — CntfVea allowing tlio variations in potential during a aeries of aimultaueous obaervationa taken at the Smithsonian Inatitntion 
 and Signal Offloe, Washington, D. C, June 4, 1886. Fair weather with gentle, variable winds. 
 
 Pig. 12 exhibits the results of observations on Juue 11, 1886. Ou that day the sky was clear 
 in the morning ; the weather was warm and cumulus clouds appeared in the afternoon. 
 
 Ifc is selected as a day on which no special electrical activity took place or was to be expected. 
 It shows that under such conditions, two stations, 1 mile apart, are subjected to influences 
 producing limited variations quite independent of each other. 
 
 Volts. 9 a. m. 10 a. m. 
 200 
 
 1 p.m. 2 p.m. 3 p.m. 4 p.m. 5 p. m. 
 
 + 100 
 
 a: Smithsonian Institution. 
 
 
 
 
 
 
 
 '*\-^'^ \^X S t% -4 I ^^ 
 
 LJi ^1 ^1 S^^^, ^t ^^7- 
 
 ts-V -i^-s^i 7 ^ C 
 
 _ __V - - t 
 
 1 - - r 
 
 
 
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 ' _yV, ^_ ^/ t^^v ^ ^ 
 
 --^^t--,\^^\'5^^'^'^^ ^"^1-^^^- z 
 
 _^=>^ -v^ 7^2 -^i ^ V , 
 
 r Ay 
 
 
 
 
 
 
 
 
 b: Signal Oflioo. 
 
 Fig. 12.— Curves ahowing variations of potential during a series of aimultaneons observatioua taken at the Smithsonian Institntion and 
 
 , Signal Office, Washington, B. C, June 11, 1880. 
 
 In Pig. 13, showing observations on June 14, 1886, there is seen to be at once a greatly increased 
 range of disturbance and a strong resemblance in the extent and character of the movement of the 
 needles at the two stations. That day was sultry and rainy ; a thunder storm passed over the 
 city between 1 p. m. and 4 p. in. and light rain fell at intervals between these hours. The line a, 
 representing potentials at the Smithsonian Institution, shows a strong movement of the needle at 
 4 p. m. and for a time after that hour which the needle at the Signal Office does not seem to have 
 
MEMOIRS OF THE NATIONAL ACADEMY OP SCIENCES. 
 
 135 
 
 followed. In other respects the flactuations are very similar, and it is easy to see that the 
 prevailing disturbance was sufficiently extensive to influence both stations. These diagrams fairly 
 represent a number of sets of observations simultat^eously recorded at these two points. 
 
 The Washington Monument, which was completed in the winter of 1885, offered a point of 
 exposure in the vicinity of the two already made use of, and through the kindness of Gen. T. L. 
 Casey, Chief of Engineers, U. S. Army, opportunity was afforded for the establishment of a station 
 on its summit, or rather at the base of -the pyramid which completes the shaft. 
 
 Volts. 
 800 
 
 a 
 
 a. 
 
 m 
 
 
 
 10 
 
 a. 
 
 m 
 
 
 
 W 
 
 a. 
 
 m 
 
 
 
 2 
 
 m 
 
 
 ip. 
 
 m. 
 
 
 2 
 
 p- 
 
 ID 
 
 
 
 3p 
 
 m. 
 
 *p- 
 
 m. 
 
 5 
 
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 m. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
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 a: Smithsoniau Institution &; Signal Office. 
 
 EiG. 13. — Carvea shomng Taxiations of potential during a aeries of simnltaneona observations taken at tlie Smithonian Institution and the 
 
 Signal Office, Washington, D. C, on June 14, 1886. 
 
 The tube of the collector was projected from one of the south windows, its height above the 
 ground being about 155 metres (508 feet) and its distance from the Signal Office about 1,000 metres 
 (three-fifths of a mile). Several sets of simultaneous observations, often extending through the 
 whole 24 hours of the day, were made at these two stations, readings being made every 5 minutes. 
 Fig. 14 shows the results for June 27, 1880. The weather conditions during this period 
 were about as follows: Clear weather, with northwest wind, from midnight to 10 a. m.; cloudy 
 from 11 a. m. to 3 p. m.; fair, with southwest wind, from 3 to 4:15 p. m.; light sprinkling rain from 
 4:19 to 4:25 p. m. and from 5:10 to 5:20 p. m.; cloudy, with west wind, from 5:50 to 10:10 p. m.; light 
 rain from 10:12 p. m. to midnight. 
 
 The diagram shows a good deal of activity throughout the whole day, and a general 
 resemblance between the indications at the two points. Minor variations are far from being in 
 agreement, however. 
 
 Fig. 15 shows the continuance of the observations during the first 9 or 10 hours of the next 
 day, June 28. Light rains continued at intervals, with westerly wind from midnight to 4:15 a. m. ; 
 cloudy, with northerly winds, after that hour. The prevailing tendency at the Monument was 
 toward lower potential, and the diagram shows a strong movement to the negative side between 8 
 a. m. and 9 a. m. 
 
136 
 
 MEMOIRS OP THE ^ATIOSiAL ACADEMY OF SCIENCES. 
 
 At the Signal Office, however, the general tendency is toward higher potential, with an 
 apparent participation in a limited degree, in the disturbances between 8 a. m. and 9 a. m. 
 
 MID. 
 
 Tolts. 12 1 2 
 600 
 
 + 300 
 
 a ; Signal Office. 
 
 b: Monument. 
 
 Fig. 14.-^Cnrves showing variations of potential during a series of simaltaneons observations taken on top of Washington Monument 
 
 "and at the Signal Office, Washington, D. C, June 27. 1886. 
 
 a r Signal Oflioe. 
 
 b: Mouumout. 
 
 Vm. 15.— Curves showing variations of potential during a series of simultaneous observations taken on top of Washington Monument 
 
 and at the Signal Office, Washton, D. C, June 28, 1886. 
 
MEMOIRS or THE NATIOjfAL ACADEMY OF SCIENCES. 
 
 137 
 
 The results of observations made during a part of July 17, 1886, are exhibited in Fig, 16 and 
 show unusual disturbances at the summit of the Monument, which were hardly perceptible at 
 the Signal Office. On that day the sky was cloudless, the atmosphere hazy, the wind from the' 
 southwest and light; no indications of rain. During the forenoon the needle at the Monument 
 oscillated almost continually, indicating variable, high, positive potentials, often exceeding the 
 range of the instrument, which was about 3,000 volts. 
 
 During the afternoon the movements were less violent, although apparently the meteorological 
 conditions remained sensibly the same. The Signal Office curve shows relatively low potential 
 and little variation. 
 
 olts. 9 a. m. 10 a. m. 11 a. m. 12 m. 1 p. 
 
 m. 2 p. m. 3 p. m. 4 p. m. 5 p. m. 
 
 1,600 J. ■ n---- 
 
 ~^ 
 
 ■ If 
 
 
 r 
 
 1 
 
 
 
 1,400 T 
 
 
 .. - J. 
 
 
 t 
 
 
 r 
 
 
 
 
 
 
 
 
 
 
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 I 
 
 
 
 
 
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 r 
 
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 rS7T - 
 
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 ----'^^ /^S^ ^>^^- 
 
 '^■^s ■'^ 
 
 = -' '^^-J-'^'^x..'^ 
 
 
 0^ Jl ■ 7 - 
 
 
 a : Signal Office. 
 
 b : jU^onameDt. 
 
 Fig. 16.— Curves showing variations of potential during a aeries of simultaneous observations taken on top of Washington Monument 
 
 and at the Signal O&oe, Washington, D. C, July 17, 1886. 
 
 On July 14, 1886, during the progress of a series of- simultaneous observations at the 
 Monument and the Signal Office, a thunder squall came up suddenly during the passage of which 
 the observer at the Monument made the following observations : At 2:45 p. m. the sky was covered 
 with a pallium of stratus clouds, and distant thundering was audible; darker cumulus clouds came 
 rapidly from the west, and by 3:15 p. m. the storm was overhead ; two very vivid lightning flashes, 
 with sharp and loud thunder, occurred about this time; at 3:40 the storm had passed. The 
 collector was exposed from the window on the south side, the height above the ground being about 
 508 feet. When connected with the collector the needle was greatly excited, moving ffom one 
 side to the other rapidly. 
 
 The greatest deflection noticed showed a negative potential equivalent to about 3,000 volts. 
 Sparks, however, were constantly passing between the wire-suspending fiber and the neck of 
 the brass top-plate of the electrometer. In addition to the rapid oscillatory movements of the 
 needle there was an up-and-down jumping disturbance. As it was impossible to do anything with 
 the electrometer as then arranged, the wire connecting it with the collector was removed and a 
 wire connected with the ground, held about 3 millimeters away from the side of the collector. 
 Sparks passed continuously at a rate of about 10 to 15 per second. 
 
138 
 
 MBMOIES OF THE NATIONAU ACADEMY OP SCIENCES. 
 
 By measurement the length of the spark was 4 millimetres. There were two intense lightning 
 Jlashes about 3:10 p. m., seemingly in close proximity to the Monument. Simultaneously with the 
 lightning the following phenomena were aotieed : 
 
 (1) An alteration in the character of the stream of water issuing from the nozzle of the 
 collector. 
 
 Previous to the flash, and apparently depending upon the degree of electrification, the stream 
 would be twisted and split into many fine threads and sprays ; but instantly, with the occurrence 
 of the flash, the stream resumed its normal character, maintaining it for a few seconds and then 
 gradually becoming more and more distorted until the occurrence of another flash, when the same 
 state of things was repeated. 
 
 Volts. 9 a.m. 0:30 a. m. 10 
 
 a, m, ' 0:30 a, m. 11 a. m 
 
 
 
 i 
 
 
 y^iv Tt 
 
 
 
 
 V7 - 
 
 
 
 1 
 
 
 r 
 
 
 x 
 
 
 \ 
 
 
 I 
 
 
 t 
 
 \J~ 
 
 I 
 
 4Cl 
 
 I \ 
 
 ^ I 
 
 I \ 
 
 
 
 
 
 
 V -1 ^ 
 
 
 Jv-Ti 
 
 
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 ^^^^ h 
 
 
 
 
 
 
 
 
 
 gOQ 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 400 
 
 
 
 
 
 
 ^^\ iZ^^-'^S 
 
 s 
 
 ^ ^^^ ^^ 
 
 
 200 ^ 
 
 -,?" y v-- 
 
 a: South HiU. 
 
 6; Cornell Univeraity. 
 
 FIG. 17.-CurveB showiDg the yariationa in potential during a series of observations taken at intervals of five minutes, at South Hill 
 Ithaca, H. Y., and at Cornell Univeraity, Ithaca, If. Y., March 10, 1888. 
 
 (2) There was noticed a cessation of the sparking between the collector and the ground wire 
 simultaneously with the flash. 
 
 Then, long before thunder was heard (in one case 8 seconds), the sparking would again 
 begin and increase rapidly. At 3:40 p. m. the storm appeared to be oyer, and at this time the 
 electrometer indications were positive and much more constant. Phenomena similar to the above 
 were observed, during the progress of the work, at nearly all of the stations. 
 
 Eesults very similar to those obtained in Washington on July 17 are shown in Fig. 17, which 
 represents a series of 5 minute observations at Ithaca, N. Y. The regular station of that point 
 was at Cornell University, which is situated on a hill about 400 feet higher than the level of Cayuga 
 lake and the valley surrounding it. 
 
 The elevated position of this station was doubtless one of the principal causes of the extreme 
 ranges and rapid variation of potential so often observed there. 
 
 By the cooperation of Mr. E. T. Turner a station was established temporarily at South Hill, 
 not far from the University but about 105 metres lower. 
 
 The observations, shown in Fig. 17 were made on the morning of March 10, 1888. The sky 
 was about seven-tenths cloudy, and a fresh south wind was blowing. 
 
.MEMOIRS OF THE NATIOXAL ACADEMY OF SCIENCES. 
 
 139 
 
 There is a general movement towards tower potential shown in both curves, but otherwise 
 th^re is little resemblance between the two. Essentially the same thing is shown in Pig. 18 when 
 further simultaneous observations made at the same stations are exhibited. On May 9, 1888, the 
 weather was damp and sultry ; about seven-tenths of the sky was hidden by clouds, and a fresh 
 southeast wind was blowing. On May 21 the weather was clear with a light northerly wind. 
 
 s. 9 a m. 10 a 
 
 m. 11 a. m. 7 p. m. 
 
 8 p. m. 9 p. m. 10 p. 1 
 
 n. 
 
 
 " ^- ^- 
 
 
 
 
 - 4 -2 
 
 
 
 
 
 r 
 
 
 
 - i: J : 
 
 
 
 
 - I- 1 
 
 
 
 
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 ? 
 
 
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 t A ^ 
 
 
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 200 VS- 
 
 
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 ■ 
 
 
 
 7 
 
 
 100 
 
 
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 ^ Z'^'''*^ 
 
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 100 _ . 
 
 
 
 ' 
 
 a: South Hill. 6; ComeU Uniyersity. 
 
 Fig. 18 — Carres showing the Tarlations in potential during the time simultaneous observations were taken at South Hill and Cornell TJni- 
 
 versity, Ithaca, If, T., May 9 and 21, 1888. 
 
 SIMULTANEOUS OBSERVATIONS AT STATIONS WIDELY SEPARATED. 
 
 As soon as several of the regular stations were equipped, a series of simultaneous observations 
 at short intervals was undertaken, for the purpose of determining whether any special electrical 
 conditions were likely to prevail over a large district, and particularly whether variations_going 
 on at one place were preceded, accompanied, or followed by similar variations at other places. 
 Arrangements were made for a series of 5-mmut^ observations, 8xte?;^ng through 72 hours at 
 Ithaca, N. Y., Columbus, Ohio, Washington, D. C, and Baltimore, Md. -, 
 
 The readings began at noon on April 7, 1886, and continued until noon of the 10th. The 
 results are shown in Pigs. 19, 20, and 21, each chart showing 24 hours. 
 
 On the second day the photographic register at Baltimore failed to do its work properly, and as 
 no arrangements for eye observations had been made, the record for the second day of that station 
 was lost. A brief synopsis of the weather at the various stations during these observations is as 
 follows : 
 
 FIRST TWBNTY-FOUK HOUE8. 
 
 Ithaca, N. Y. — Light snow from 12 m. on the 7th to 3:40 p. m. ; cloudy from 3:40 to 5:40 p. m. ; 
 light snow 5:40 p. m. to 3 a. m. on the 8th ; cloudy from 3 a. m. to 12 m. ; temperature stationary, 
 about zero ; brisk northwesterly wind. 
 
 Golumbus, Ohio. — Cloudy from 12 m. to 8 p, m. ; clear 8 p. m. to 12 m. on the 8th ; falling 
 temperature; high northwesterly wind 12 m. to 5 p. m. ; light northwesterly 5 p. m. to 9 p. m. ; 
 gentle northerly wind 9 p. m. to 4 a. m. on the 8th ; gentle southwesterly wind from 4 a. m. to 12 m. 
 
 Washington, D. C. — Cloudy with light showers of rain from 12 m. to 5:30 p. m. ; cloudy from 
 5:30 p. m. to 12 m. on the 8th ; falling temperature ; light westerly wind 12 m. to 5 p. m. ; brisk 
 northwesterly wind 5 p. m. to 12 m. on the 8th. 
 
 Baltimore, Md. — Cloudy with light rain 12:35 to 12:45 p. m. and from 4:45 to 7 p.m., followed 
 by clear weather ; falling temperature ; brisk northwesterly wind. 
 
140 
 
 MEMOIES OF THE NATIONAL ACADEMY OF SCIENCES. 
 
 SECOND TWBNTY-FOUK HOURS. 
 
 Ithaca, N. r.— Fair from 12 m. to 4 p. m.; clear from 4 p. m. to 12 m. on the 9tli ; rising 
 temperature; fresh northwesterly wind 12 m. to 6 p. m.; gentle northwesterly wind from 6 p. m. 
 to 6 a. m. on the 9th ; gentle southeasterly wind from 6 a. m. to 12 m. 
 
 M. 
 10 11 12 
 
 b: Columbus, Uiiio. 
 
 c: Washington, D. C 
 
 d: Baltimore, Md. 
 
 a: Ithaca, N. Y. 
 
 Fjo. 19- — Curves showing tlie Tariations in potential during a series of simultaneous observations taken at intervals of five minutes from 12 m. 
 
 April 7 to 12 m. April 8, 1886. 
 
 M. 
 
 10 11 12 
 
 + 200 
 
 a: ltliaca,N.Y. b: Columbus, OUlo. e: Washington, D. C. 
 
 riG. 20 — Curves showing the variations in potential during a series of simnltaueous observations taken at Intervals of five minutes from 12 1 
 
 April 8 to 12 m. April 0, 1886. 
 
MBMOIES OP THE NATIOISTAL ACADEMY OP SCIENCES. 
 
 141 
 
 Columbus, Ohio. — Cloudless sky, slowly rising temperature, light southei'ly winds. 
 Washington, D. 0. — Cloudy from 12 in. to 3 p. m,; fair 3 to 4 p. m. ; clear 4 p. m. to 12 m. on 
 the 9th ; rising temperature ; light northwesterly winds. 
 
 THIKD TWENTY FOUR HOURS. 
 
 'Ithaca, N. T. — Fair weather, about five-tenths cirro-stratus clouds during the time, stationary 
 temperature, gentle variable winds. 
 
 Columbus, Ohio. — Cloudy from 12 m. to 10 p. m.; clear from 10 p. m. to, 5 a. m. on the 10th ; 
 cloudy.5 a. m to 12 m. ; rising temperature ; fresh southerly winds. 
 
 Washington, D. C. — Clear weather, stationary temperature, light southerly winds. 
 
 Baltimore, Md. — Clear weather, rising temperature, light southerly winds. 
 
 It should be noted that the scale on which the diagrams are made does not permit of the 
 representation of minor variations in potential which were constantly occurring. The principal 
 changes and general movements, however, are well shown. Throughout the last two days the 
 conditions as to weather were essentially the same at all of the stations. In some instances the 
 diagrams show changes of considerable similarity ; in others, so unlike that the coincidence of 
 movement can hardly be regarded as other than accidental. 
 
 ,^ ,^ M. P.M. MID. A.M. M. 
 
 Volt8.I2 1234 56 789 10]] 12 1 2 3 45678 9 10 11 12 
 
 
 
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 a : Ithaca, IT. Y. 
 
 b : Columbua, Ohio. 
 
 c: Waahington, D. C. 
 
 d: Baltimore, Md. 
 
 Fie. 21.— Curves showing tUe variations In potential during a seriesof simultaneous observations taken at intervals of five minutesfrom 12 m. 
 
 Aprii 9 to 12 m. April 10, 1886. 
 
 In Pebruary, 1888, another series of simultaneous observations, extending through 24 hours, 
 was undertaken at Boston, Washington, Ithaca, and Terre Haute, beginning at 12 m. on the 17th 
 and ending at 12 m. on the 18th. During this time the three northern stations were under the 
 influence of two slight barometric depressions. One of these centers was over Ifova Scotia and 
 influenced the weather conditions at Boston from 12 m. on the 17th until 12 midnight. 
 
 The other was over the lake regions, influencing the conditions at Terre Haute during the 
 whole 24 hours, and at Ithaca from 7 p. m. on the 17th, to 4 a. m. on the 18th. The pressure at 
 Washington was nearly stationary during the 24 hours. It was sensibly stationary at all of the 
 stations from 6 a. m. until 12 m. on the 18th. During the night of the 17th and early morning of 
 the 18th there was a light fall of snow at the lower lake stations, throughout New York and the 
 New England States, and at Philadelphia, Pa. At Washington the clouds on the night of the 
 17th were so thin that stars were visible through them ; and the same thing was true where the 
 precipitation at no time exceeded a " snow-mist." 
 
 To avoid confusion, the potential diagrams are shown separately for each station in Figs. 22, 
 23, 24, and 25, and notes as to weather conditions for each hour are added. 
 
 An examination of these diagrams reveals some points of resemblance between the movements 
 
142 
 
 MEMOIES OF THE NATIONAL ACADEMY OF SCIENCES. 
 
 at Boston and Washington, and also between tliose at Ithaca and Terre Haute. An unusual 
 disturbance seems to have occurred between 8 p. m. and 10 p. m. at both Boston and Washington ; 
 a decided rise and fall in potential occurs at Washington at about 7 a. m., which appears to be 
 imitated in some degree at Boston about 8:30 a. m. 
 
 M. 
 
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 Tig. 22.— Carve showing five minute observations of potential at Boston, Mass., from 12 m. February 17 to 12 m. February 18, 1888. 
 
 The general movements, however, are not very similar. At both Ithaca and Terre Haute the 
 range of variation is much greater from midnight until noon than during the first 12 hours, and 
 
 Volts. 12 
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 NW.,Ught,fair. 
 
 W., light, fair. 
 S., light, fair. 
 
 S., light, fair. 
 S., light, clondy. 
 
 S., Ught, clondy. 
 S., light, fair. 
 
 SE., light, cloudy. 
 SE., light, cloudy. 
 
 NE., light, cloudy. 
 SE,, light, cloudy. 
 
 NE., light, dense haze. 
 ISTE., light, clondy. 
 
 Calm, cloudy. 
 
 Calm, clondy, clouds 
 very thin. 
 
 Calm, cloudy, clonds 
 very thin. 
 
 Calm, cloudy, clouds 
 
 very thin. 
 Calm, cloudy, clouds 
 
 very thin. 
 
 Calm, clondy. 
 
 Calm, fair, light fog. 
 Calm, foggy. 
 
 Calm, light fog. 
 ITW., light, clear. 
 
 NW 'brisk, clear. 
 NW., fresh, clear. 
 
 Fig. 23.— Curve showing flve-minnto observations of potential at Washington, D. C, from 12 m. February 17 to 12 m. February 18, 1888. 
 
 both diagrams show a sudden but short drop to negative potential between half past seven and 
 eight in the morning. 
 
MEMOIES OP THE NATIONAL ACADEMY OP SCIENCES. 
 
 143 
 
 It seems difficult to believe that these similarities of movement have no special significance, 
 but it will be observed that there are many simultaneous movements in opposite directions, some 
 of which are little less marked than those referred to. 
 
 Occasionally instances occur in which the potential changes at two stations widely separated 
 resemble each other so much that it seems almost certain that for some hours both stations have been 
 subject to the same general electrical influences. Illustrations of this are shown in Pigs, 26 and 
 27, where observations at Washington and Ithaca, taken at the regular hoiirs of observation, on 
 February 10 and 11, 1888, are plotted side by side. At Washington, on the 10th, t^ere was light 
 snow from 9 a, m. to 4 p. m. ; light sleet, 4 to 7 p. m. ; temperature stationary, at about 19° ; light 
 northerly wind. 
 
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 Fig. 24. — Gnrve showing five-minute obseryations of potential at Ithaca, If.T., from 12 m. February 17,' to 12 m. February 18,1888. 
 
 At Ithaca, cloudy from 9 a. m. to 3:30 p. m. ; very light snow from 3:30 to 6 p. m. ; 
 temperature rose from — 9° at 9 a. m. to 12° at 6 p. m. ,• brisk southeasterly wind all day. 
 
 On the 11th, at Washington, sleet fell from 9 to 10 a. m,; light rain from 10 a. m. to 5p. m. ; 
 temperature stationary, at about 31° ; light northerly wind» 
 
 At Ithaca, cloudy weather, with very light snow, 9:20 to 10:20 a. m. ; temperature stationary, 
 at about 22°; gentle southwesterly wind from 10:30 a. m. to 5 p. m. 
 
 On Pebruary 10 the diagram shows a fall to negative potential at both stations, remaining 
 negative at Washington during the remainder of the observations, while at Ithaca a change to 
 high positive occurs at about 4 p. m. 
 
144 
 
 MBMOIES OF THE NATIOlJfAL ACADEMY OP SCIENCES. 
 
 On the llth the movements resemble each other very much, although the potential is constantly 
 negative until nearly 1 p. m. at Washington, while it is high positive at Ithaca throughout the 
 day. 
 
 SPECIAL OBSBK¥ATIONS. 
 
 Several of the regular observers were requested to make special observations, at shorter 
 intervals than usually allowed, on days and occasions when unusual or abnormal electric conditions 
 seemed to prevail. They were directed to record the effect, if any, of local causes, such as dust 
 clouds, haze, mist, etc.,. and to especially observe the appearance of negative electricity on clear 
 days. ' 
 
 Fig. 25.— Carve showing flve-minute obaervations of potential at Terre Haute, Intl., from 12 m. February 17 to 12 m. February 18, 1888. 
 
 A few of these results have been charted and are exhibited herewith. It was at one time the 
 general belief that negative electricity would not be indicated during clear weather, and that it 
 would only be found as an accompaniment of precipitation, if not at the place of observation in 
 the immediate neighborhood. ' 
 
 Sir William Thomson in his article on atmospheric electricity in Mchol's Cyclopfed^a, speaks 
 of an observation by Piazzi Smyth, on the summit of the Peak of Teueriffe as "one remarkable 
 exception," and suggests that in this case the test as to equality might have been deceptive. 
 Negative electricity ia clear weather was observed, however, at most if not all of the Signal Service 
 stations on numerous occasions during the progress of the work. In many cases precipitation 
 occurred at points from 10 to 100 miles distant, but in others clear weather prevailed over 
 almost the entire country. A number of instances of negative potential during clear weather 
 occurred at Ithaca, where careful attention was given to the matter of special observation by Mr 
 
MEMOIE8 OF THE NATIONAL ACADEMY OF SCIENCES. 
 
 145 
 
 Schultz, the observer in charge during 1887 and 1888. Figs. 28, 29, and 30 exhibit some of, these 
 observations. , 
 
 VoltR. 9 a.m. 10 a.m. 11 aim. 13 m, Ip. m. 2 p, m. 3 p.m. 4p.mi 5 p. m. 6 p.m. 7 p.m. 
 
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 Fig. 26. — Curves showing the variations of potential at Washington, D. C, and Ithaca, N. T., on rebrnary 30, 
 
 Volts. 9 a. m, 10 a, m. 11 a. m. 12 m. 1 p. m, 2 p. m. 3 p. m. 4 p. m. 5 p. m. 
 
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 Fio. 27 Curves showing the variations of potential at Washington, D. C, and Ithaca, N. Y., 
 
 on February 11, 1888. 
 
 S. Mis. 94 10 
 
146 
 
 MEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES. 
 
 Fig. 28 shows observatioas on November 29, 1887. The weather was clear throughout the 
 day at Ithaca, but snow fell all day at Eochester and Oswego, N. Y. ; at all Lower Lake Signal 
 Service stations and at some points about 20 miles distant from the station. 
 
 Volts. 9 a. m. 10 a. m. 11a.m. 12 m 
 
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 SE., gentle, clear. 
 
 NW., fresh, clear. 
 
 NW., fresh, clear. 
 
 NW., fresh, fair. 
 
 NW., fresh, clear. 
 
 NW., fresh, clear. 
 NW., fresh, fair. 
 
 I"iG. 28.— Curve showing the variations in potential at Ithaca, N. T., on November 29, 1887, clear weather prevailing at this station. 
 
 Fig. 29 is for April 17, 1888. The weather was clear during the morning with fresh 
 northwesterly winds. Not more than two-tenths of the sky was clouded at any time before 11:30 
 a. m. There was a dense haze along the northwestern horizon ; clouds traveled from north to south. 
 
 ^olts. 
 
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 Fia. 29.— Curve showing the variationa in potential auriug clear weather at Ithaoa, N. Y., April 17, 1888. 
 
MEMOIES OF THE NATIONAL ACADEMY OF SCIENCES. 
 
 147 
 
 As the cloudiness increased the indications became more steady. Daring the afternoon the 
 sky was completely clouded and no rapid variations were observed. Light rain and snow fell at 
 all Canadian and New York Lower Lake stations during the morning and afternoon. 
 
 Fig. 30 shows variations of potential on a day, April 25, 1888, which was clear at all of the 
 stations. The weather synopsis is as follows : 
 
 At Ithaca: One-tenth cirrus clouds from 9 to 11 a m.; sky perfectly clear from 11 a./m. to 4:30 
 p. m.; a few very small clouds from 4:30 to 5 p. m.; light northerly wind. 
 
 At Terre Haute: clear from.9 a. m. to 1 p. m.; fair from 1 to 5 p. m.; fresh southerly wind. 
 
 VoUa. 9 a. ra. 
 
 + 200 
 
 10 a. m. 11 a. m. 
 
 12 m. 
 
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 ffl : Ithaca, N. T. 
 Fio.30 Curves 
 
 6.- Terre Haute, Iiid. c; Boston, Mass. 3; WaaMngfon, B.C. 
 showing the variations in potential on a cloudless day, April 25, 1888. 
 
 At Boston: No clouds except occasional small patches ; negative reading at 11 a. m., without 
 a visible cloud, and no wind to raise dust. No other negative value observed during the day. 
 Light haze in the afternoon; fresh easterly wind. 
 
 Washington, D. C: clear all day; light northeasterly wind. Eapid fluctuations during 
 the entire day will be noticed as having occurred at Ithaca. The dotted line is drawn for 
 comparison with the lines representing the other stations and shows potential at the regular hours 
 of observation. 
 
 A few illustrations may also be given of the electrometer records preceding and durfng 
 precipitation, not including thunder storms. Pig. 31 for October 20, 1887, shows a steady change 
 from a strong negative at the 9 o'clock observation to a steady but low positive. There were no 
 rapid variations in potential at any time during the day. Until 10:30 a. m. the weather was 
 unusually pleasant at Ithaca and at surrounding stations. The sky was perfectly clear and there 
 was a light southerly wind. 
 
 At 10:30 a. m. the wind suddenly increased in force, cloudiness increased rapidly, and by 11:30 
 a; m. the station was within a well-developed storm. Eain began at 7:05 p. m. Eain fell throughout 
 ihe Lower Lake region during the evening. 
 
 Fig. 32 shows variations of potential on a rainy day at the same station, Ithaca, N. T. 
 
 The greatest fluctuatipns occurred from 13 to 12:30 p. m. There was no precipitation from 
 12:05 to 12:25 p. m., but during that time the clouds were very low and enveloped the station. The 
 
148 
 
 MEMOIES OP THE NATIONAL ACADEMY OP SCIENCES. 
 
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 riQ. 31.— Cnrve showing variations of potential preceding precipitation, Ithaca, N. Y., October 20, 1887. 
 
 I'M. 32 — Curve showing the variations in potential on a rainy day. May 16, 1888, at Ithaca, N. T. 
 
MEMOIRS OF THE NATIONAL ACADEMY *OE SCIENCES. 
 
 149 
 
 small stars at the upper and lower limits of the diagram indicate where sparking occurred between 
 the needle and the quadrants of the electrometer. Pig. 33 also shows potential changes before, 
 during, and after precipitation on what would ordinarily be called a "rainy day." The station was 
 Ithaca and the day May 18, 1888. 
 
 Fig. 34 exhibits observations taken at Terre Haute on a cloudy day. 
 
 Eain fell at Chicago, nearly 200 miles away, between noon and 3 p. m. 
 
 Fig. 35 shows observations at Ithaca while rain was falling at New York City and stations in 
 its vicinity. At Ithaca the sky was clear from 9 to 9:40 a. m. Cloudiness increased from one-tenth 
 at 9:40 to flve-tetiths at 11 a. m., then decreased. Sky clear from 3 to 3:40 p. m.; about four-tenths 
 clouded from 4 to 6 p. m. Brisk northwesterly winds all day with stationary temperature. 
 
 Volts. 9 
 
 a.m. 
 
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 FjG. 33.— Curve showing variations of potential before, daring, and after precipitation on a rainy day, May 18, 1888, Ithaca, N. Y. 
 
 Fig. 36 shows observations of potential, mostly negative, during April 12, 1888, at Ithaca. 
 From 11 a. m. to 6 p. m. the weather was cloudy ; very light snow fell from 2:20 to 3:20 p. m. The 
 sky was perfectly clear after 6 p. m. at Ithaca, and at the 10 p. m. observation clear sky was 
 reported from all stations in the Canadian Lower Lake region, in Ohio, New York (except at Oswego), 
 Pennsylvania, and New England (except at Block Island). Snow fell after midnight at all New- 
 England stations and at Albany, N. Y. No snow at Ithaca ; brisk northwesterly wind all day. A 
 faint aurora was observed from 8 to 11 p. m. It is impossible to say whether the tolerably marked 
 fluctuations of the needle during this time are to be in any way attributed to the aurora. A few 
 
150 
 
 MEMOIES OF THE NATIONAL ACADEMY OF SCIENCES. 
 
 weeks later an opportunity occurred for observing the behavior of the electrometer during the 
 occurrence of a brilliant aurora, and the result is shown in Fig. 37. 
 
 The weather was cloudy during the morning, fair during the afternoon, and clear at mght ; 
 the barometer was stationary, the temperature rising ; a brisk northwesterly wind blew during the 
 
 Volts. 9 
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 Fig. 34. — Curve showing the variations in potential on a cloudy day, October 21, 1887, Terre Haute, lad. 
 
 day and a gentle southeasterly wind at night. During the aurora there was bright moonlight ; a 
 single narrow, filmy streamer of cirrus clouds extended across the sky from east through the 
 zenith to a point a little north of west. 
 
 Volts. 9 a. m. 10 a. m. 11 
 
 a.in. 12 m. 1p.m. 
 
 2p. m 
 
 3 p.m. 
 
 4 p. m. 5 p 
 
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 Fig. 35.-Curve showing the variations of potential at Ithaca, N. T., on April 16, 1888, While rain was faUing at New York City and stations 
 
 in its vicinity. 
 
MEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES. 
 
 151 
 
 At 10:30 p. ID. it disappeared, except at the zenith, and there it was broken into small 
 cirro-stratus clouds extending southeast to northwest. Notwithstanding the brightness of the 
 moon the aurora was unusually brilliant from 8:30 p. m, until after midnight. Bright, broad, 
 colored streamers were observed at long intervals along the northern horizon. Deflections of the 
 needle did not occur simultaneously with the appearance of streamers. 
 
 Fig. 36.— Curre showing the variations in potential at Tthaoa, U. T., on April 12, 1888, from 11 a. m. to 11 p. m. 
 
 No streamers were observed after 10:30 p. m,, at which time the aurora became a diffused 
 yellow light, covering the whole northern horizon. During the appearance of the aurora the 
 atmosphere was unusually transparent. ' 
 
 Volts. Ua.m. 12m. 1p.m. 2p.m. 3p.m. 4p.m. 5p.m. 6p.m. 7p.m. 8p.m. 9p.m. lOP"'.. 11p.m. 
 
 400. 1 1 1 1 ■■ 1 1 I . ■ 1 |.[ 1 1 f-' - - 1 1 1 1 1 1 1 r-r- 
 
 
 
 
 
 
 
 
 
 
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 Fig. 37.— Curve showing potentials on a day on which a brilliant aurora was ohserved. May 20, 1888, Ithaca, N. T. 
 
 It will be observed that the indications of the electrometer were positive throughout the day 
 and night, and that no unusual fluctuations occurred. ^ 
 
 The effect of dust, haze, smoke, etc., in producing negative potential has been noticed by more 
 than one observer. 
 
152 
 
 MEMOmS OP THE NATIONAL ACADEMY OE SCIENCES. 
 
 Several instances of the action of clouds of dust were noted by Sergeant Morrill, at Boston. On 
 March 7, 1888, in the afternoon, the potential was observed to fall rapidly from— 90 to— 270 upon the 
 rising of an especially heavy cloud of dust, and similar phenomena were observed on April 7. On 
 June 27, from 1 to 3 p. m., the potential was very Variable and generally negative. 
 
 A fall of potential could be certainly predicted when a dust cloud was seen rising. On other 
 days when high winds and dust clouds prevailed negative potential was observed. Pig. 38 shows 
 the potential diagram for October 31, 1887, at Terre Haute, Ind., and the rapid fall from high 
 positive to negative potential is almost certainly due to the presence of smoke and haze. 
 
 Volts. 9 a. m 
 
 
 
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 in 
 
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 .-Curve showing effect of smoke and haze formations Just after sunset ,.., 
 
 Terre Haute, lud. 
 
 ii cloudless day, October 31, 1887, 
 
 h« J?.?^""" Pbenomenon was frequently observed during the autumn when the formation of a 
 haze or tog just as the sun was setting was a comi^ion occurrence 
 
 The station at Terre Haute was located in the vicinity of railway yards, some of the tracks 
 being within three or four hundred metres of the collectors with no in ervening buildings 
 The observer in charge, Sergeant McEae, was led to believe that the movement of trains ia the 
 neighborhood of the station had a sensible influence on the potential indicated ani it s not 
 impossible that the discharge of steam of the eugiues or the production of dust clouds mght have 
 
 showthee.ectofamorningfog,astenaft;e^:^^^^^^^^^^ 
 
 train m the afternoon .s noted, under conditions likely to show an influence, but none la d fee ed 
 
 with dear teathir at !,W ' r' *'f '""' ''"''"" "' ^^^«^«^ 1^' ^^^i, a cloudless day 
 with clear weather at all surrounding stations and a high wind prevailing. Very high positive 
 
MEMOIRS OF THE NATIONAL ACADEMY OP SCIENCES. 
 
 153 
 
 potential was noted previous to the high wind, sparking betweeh needle and quadrants taking 
 place. During the continuance of the high wind, however, the potential was low positive and 
 unusually steady. 
 
 Volts. 9a.m, 10a.m. lla.in. 12in. 1p.m. 2p.m. 3p.m. 4p.m. 5p.m. 
 
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 Pig. 39. — Curve showing suppy}sed effect of a passing train upon the potential on a clear day, October 6, 1887, 
 
 Terre Haute, Ind. 
 
 Volta. 
 
 9 a. m. 10 a. m. 
 
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 aos clearing. 
 Train started 
 Train still going. 
 
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 Fia. 40.,— Curve showing the variations in potential during a fog in the morning, November 5, 18S7, Terre Haute, Ind. 
 
154 
 
 mbmoi;es of the hatiokal academy oe sciences. 
 
 I 
 
 The direct action of a single cloud or group of clouds in producing a fall of potential was 
 often observed. Among other instances Sergeant Morrill at Boston noted the following: In the 
 morning of January 3, 1888, the potential had been steadUy positive. At 11:30 a. m. it was +32, 
 from which it fell steadily at the approach toward the zenith of a small cumulus cloud, reaching 
 -21. As this cloud passed away, the potential rose to +6, again falling to —31 as a larger mass 
 of cumulus clouds approached. Later the sky became overcast and the potential became steadily 
 negative. 
 
 Volts. 
 
 9 a. 
 
 m. 
 
 10 
 
 a. m. 
 
 
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 m. 
 
 
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 Fig. 41. — Curve 8ho"wirg the variations in potential before and during a high wind, October 13, 1887, Terre Haate, Ind. 
 
 On June 7 at 5:30 p. m. the potential fell from +43 to —173 and then rose slowly to its former 
 value. The rise and fall occupied about 15 minutes and coincided with the appearance over 
 the buildings to the west of a fleecy cirro-stratus cloud and its disappearance over the institute 
 building in which the electrometer was located. Again, on June 9, the potential was positive 
 all day up to 5 p. m. At that hour it fell from +73 to —113, then rising to +52. The sky 
 was nearly free from clouds and the fluctuation coincided with the approach and departure of a 
 cirro-stratus cloud, passing about 15° from the zenith. The inductive action of the cloud was 
 plainly suggested in all of these cases. 
 
 MONTHLY AND HOURLY MEAN POTENTIALS. 
 
 The observations at all of the stations, except Baltimore, being rarely continuous throughout 
 day and night, the data for obtaining monthly and hourly means is not as satisfactory as could be 
 desired. During the last year of the work five regular observations were taken each day, the 
 hours being 9 and 11 a. m. and 1, 3, and 5 p. m. If the mean of these correctly represented the 
 mean of a continuous series, then nothing more could be desired for the determination of monthly 
 means. The only way of ascertainiug the relation of the mean of readings at these hours to 
 the real daily mean is by reference to the Baltimore observations. Accordingly two sets of 
 
MEMOIRS OP THE NATIONAL ACADEMY OP SCIENCES. 
 
 155 
 
 monthly means have been computed for that station ; one based on hourly records, drawn from 
 the photographic registration, and the other upon records at the five regular hours, drawn from the 
 same source. Pig. 42 shows the results exhibited in an annual curve of potential, the continuous 
 line having been constructed from hourly readings and the broken line from readings at 9. a. m,, 
 11 a. m., 1 p. m., 3 p. m., and 5 p. m. 
 
 olta. 
 150 
 
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 a: Based on hoarly readings. 
 
 b ; Based on readings at 9 a. m., 31a. m., 1 p. m., 3 p. m., and 5 p. m. 
 
 Fig. 42.— Carres showing the mean potential for each month at Baltimore, Md., for a period of thirty-one months, January, 1885, to July, 1887. 
 
 / 
 
 It is interesting to see that there iS a fairly close agreement in the character and extent of the 
 fluctuations, although the mean from the five observations falls considerably below that based 
 upon hourly readings. 
 
 As the essential matter is the variation in potential and not its absolute value, it is clear that 
 monthly means based on observations at the above hours nhist have considerable significance. 
 
 Mar. Apr. May. June. July. Aug. 
 
 Volts, Jan. 
 150 
 
 Feb. 
 
 Sept. 
 
 Oct 
 
 Nov. 
 
 Dec. Jan. 
 
 IT— - -- - __------ --.. , 
 
 
 ^ ^"^ 
 
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 -i." __ _ __: __z___ 
 
 5 - - - - 2^- 
 
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 ::::::V::::::::::::::i?:::::::::: ::::::::::::::::::::::::: 
 
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 +50 
 
 Fia. 43. — Curve showing the mean potential for each month at Baltimore, Md., excluding days on which thunderstorms occurred. 
 
 Accordingly several diagrams exhibiting these means at several stations have been prepared. 
 Fig. 43 shows the monthly means for Baltimore after excluding from the records those belonging 
 
156 
 
 MBMOIES OF THE NATIONAL ACADEMY OF SCIENCES. 
 
 to days on which thunder storms occurred. Thunder storms are always accompanied by extreme 
 electrical activity with large range of potential, but since positive and negative deflections are 
 generally about equal in number and magnitude, the effect on the monthly mean is not large, 
 especially where observations are continuous, as was the case at Baltimore. It will be seen that 
 the two diagrams for that station do not differ greatly. 
 
 ^olts. 
 
 Jan. 
 
 
 
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 FlQ. 44.— CnrYe slowing the mean potential for each month at Terre Haute, Ind., for a period of one year. 
 
 Figs. 44, 45, 46, and 47 show monthly mean curves for Terre Haute, Washington, D. C, 
 Ithaca, and New Haven. The first two and the last include only a single year, and that of Ithaca 
 includes two years. The first three curves are shown in I^ig. 48 and also the means of 6 months 
 at Boston. The low potential continually recorded at New Haven makes it impossible to represent 
 it fairly on the same scale. Terre Haute and Washington agree very fairly in the general form of 
 the diagrams, and that for Ithaca is not greatly different except in the wider fluctuation from 
 January to May and the extremely low potential during April, the minimum occurriog in that 
 month. During April at that station negative electricity was observed almost constantly. 
 
 Fici. 45.-Cnrvo showing (ho mean potential for each month at Washington, D, C, for a period of one year, 
 
 Eeference has already been made to the work of Dr. Adolphus Wislizenus, of St. Louis, Mo., 
 who made a series of observations extending from 1861 to 1872, inclusive. A Dillman torsion 
 balance electrometer, was used and readings were made at 6 a. m., 9 a. m., 12 m., 3 p. m., 6 p. m. 
 and 9 p. m. Dr. Wislizenus has kindly allowed the use of his observations and they have been 
 discussed to some extent in reference to monthly and hourly means, as well as in reference to 
 weather and precipitation. 
 
 Volume II of the Transactions of the St. Louis Academy of Sciences contains the complete 
 record for 1861, and Volume III contains a summary of the records for 13 years. In 1888 
 
MEMOIES OP THE NATIONAL ACADEMY OF SCIENCES. 
 
 157 
 
 Prof. Francis E. Nipher, of Washington University, St. Louis, calibrated tlie electrometer used 
 by Dr. Wislizenus and published his results in the Traijsactions of the St. Louis Academy for that 
 year. The readings have therefore been reduced to volts by means of Professor Nipher's 
 calibration. Fig. 49 shows two monthly mean curves for St. Louis, based upon these observations, 
 one of which represents the means for a period of 12 years, and the other for the year 1861. 
 
 Volts. Jan. , Feb. Mar. Apr. May. Jnne. July. Aug. Sept. Oct. Nov. Deo. 
 
 lUU • 
 
 
 t 
 
 
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 7- 
 
 5i: - - -- - ' 
 
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 =,^ 
 
 
 
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 Fig, 46.— Curve showing the mean potential for each month at Ithaca, TS. T., for a period of two yeara. 
 
 Through the kindness of Professor Christie, Astronomer Eoyal of Great Britain, the published 
 records of work in atmospheric electricity at the Kew Observatory have been received, and they 
 have been analyzed in reference to some points considered in this report. A Thomson quadrant 
 electrometer with ^elf-registering attachment is in use, with a water- dropping collector. The 
 results examined are for observations extending from 1879 to 1886 inclusive. 
 
 Volts. Jan. Feb. Mar. Apr. May. June. July. Aug. Sept. Oct. Nov. Dec. Jan. 
 
 751 I 1 1 1 1 r-T rn [— i r-| 1 
 
 
 
 
 
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 Fig.' 47 Curve showing the mean potential for each month at Kew Haven, Conn., for a period of one year. 
 
 In these records an arbitrary scale is employed. The monthly means for this period of 8 
 years are shown in Fig. 50, while the means based on observations during 2 years, 1885 and 1886, 
 are shown in Fig. 51. 
 
158 
 
 MEMOIRS OF THE NATIOIJAL ACADEMY OF SCIENCES. 
 
 The determination of the diurnal potential curve requires, of course a large number of 
 observations at short intervals extending through the entire day, and it is only at Baltimore that 
 a sufficient number are available. Series of continuous observations at other stations were made 
 
 Sept. 
 
 Oct. 
 
 Nov. 
 
 Dec. Jan. 
 
 - 100 
 
 2f.n | I I I I I I I I I t I I I I I I I I I I I I 1 I I I I I I I I I I I I I I r I I I I I I I I i i I ■ I ■■ ' 
 
 FIG. 48.-Curve83howing the mean potential for each monthat (o) Washington, D. C, (6) Boston, Mass., (») Terre Haute, Ind., (d) Ithaca, N. T. 
 
 several times but very often under abnormal conditions which would be likely to exercise an 
 undue influence over the result. Hourly means have been computed for every hour of the day at 
 Baltimore and for the regular hours of observation at other stations. In making these reductions it 
 
 Nov. 
 
 Dec. 
 
 Jan. 
 
 Fig. 49.— » ; Curve showing the mean potential for each mouth, at St. Louis, Mo., for a period of twelve years, January, 1861, to December, 
 1872. b : Curve showing the mean potential for each mouth, at the same place, during 1861. In both cases the observations are those of Dr. 
 A. Wislizenus. 
 
MEMOIES OF THE NATIONAL ACADEMY OP SCIENCES. 
 
 159 
 
 has been tbought desirable to eliminate tbe undue influence of certain months of the year in which 
 potentials were abnormally high, and this has been done by first regarding the mean potential for 
 each month as the unit and then computing the mean of these results for each hour for all of the 
 months included. The numbers thus obtained indi( ate ratio variations above and below the mean 
 
 VoltB. 
 
 400 
 
 Jan. 
 
 
 
 Feb 
 
 
 
 
 War. 
 
 
 
 
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 Fig. 50 — Curve showing tlie mean potential for each month for a period of eight years, 1879-'86 (hoth included), at Kew Observatory, 
 
 Grreenwioh, England. The scale is arbitrary. 
 
 and are converted into absolute potentials in volts by multiplying by the mean value. In most 
 cases, and especially where a large number of observations is available, they do not differ greatly 
 from a simple mean of hourly observations. 
 
 Volte. Jan. Feb. Mar. Apr. 
 
 May. June. July. Aug. Sept. Oct. 
 
 
 Kov. 
 
 Dec. Jan. 
 
 400 --^ ---- _-- : 
 
 
 
 
 
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 Fig. 51. — Curve ah.o'wiug the mean potential for each month at Grreenwichj England, for a period of two years (1885- 
 
 arbitrary. 
 
 The scale is 
 
 Fig. 52 shows hourly means for Baltimore, including all days on which registration was made, 
 the total time covered being nearly 3 years, while Fig. 53 shows means when only clear and fair 
 days were used. About 200 days in all are included. 
 
160 MEMOIRS OP THE :srATIONAL ACADEMY OF SOIEFOES. 
 
 Tolts. 12 3 4 __ 5 6 7 8 9 10 
 150 
 
 „ p M MID. A. M. 
 
 *■"■ - u 12 1 2 3 4 5 6 7 8 9 10 11 ]2 1 
 
 100 
 
 +50 
 
 1 
 
 FlQ. 62.— Curve sho-wing the mean potential for eaoli hour of the day, including all days, at Baltimore, Md. 
 
 A.M. M. . P.M. MIU, A.M. 
 
 Volta.l 2 34 5 6 7 89 10 1112 1 2 3 4 5 67 8 9 10 11 12 1 
 
 200| I 1 1 1 I I 1 1 1 1 1 1 1 1 1 1 1 
 
 
 
 
 
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 riG. 53.— Curve showing the mean potential for each hour, on clear and fair days, at JJaltimore, Md. 
 
MEMOIRS OP THE NATIONAL ACADEMY OF SCIENCES. 
 
 161 
 
 Ffgs. 54 and 55 show similar curves for Ithaca. The whole time is divided iuto two periods 
 and each is represented on the diagram. The separation has been made because of the fact that 
 exposures quite different were in use during the two periods. Figs. 56 and 57 show hourly means 
 for the 4 stations at which observations were made during the last year of the work, and Pigs. 58 
 and 59 show similar curves for New Haven. 
 
 Volts. 
 300 
 
 9 a.m. 
 
 
 
 
 
 
 
 
 
 
 
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 a 
 
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 p.m. 
 
 
 
 
 
 
 
 
 
 
 
 
 
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 Fig. 54. — Curves showing the mean potential at each hour of obaenration, including all days, Ithaca, 'N. T,, (I) July, 1886, to September, 1887 ; 
 
 (11) October, 1887, to Angust, 1888. 
 
 ToltB. 
 
 9 
 
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 riG. 5S.— Curves showing the mean potential at each hour ot observation, on clear and fair days, at ItIiaoa,N.T., (I) JiUy,1886, to Septem- 
 ber, 1887 i {II) October, 1887-, to August, 1888. 
 
 S. Mis. §4—11 
 
162 
 
 MEMOIRS OF THE NATIONAL ACADEMY OP SCIENCES. 
 
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 Rg.66.— Cnrves showing the mean potential at each honr of observation, iiloluding aU days, for a period of eleven monUis, at (a) "Wast- 
 ington, D. C, (!>) Terre Haate, Ind., (c) Boston, Mass., (d) Ithaca, N. T. 
 
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 Fig. 67.— Curves showing the mean potential at each hour of observation, on dear and fair days, at (a) Washington, D. C, October, 1887, 
 to August, 1888; (6) Torre Haute, Ind., October, 1887, to August, 1888; (c) Boston, Mass., December, 1887, to August, 1888; (d) Ithaca, N.T., 
 October, 1887, to August, 188a 
 
MEMOIES OF THE NATIONAL ACADEMY OF SCIENCES. 163 
 
 olta. 
 
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 Fig. 58.— Ctirve showing tha mean potential at each lionr of observation, including all dajs, at 'Sew Haven, Conn., from July 30, 188S, 
 
 to August 1, 1887. 
 
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 Pig. 69.— Cnrve showing the mean potential on clear days, at ea<!h hour of obserratito, at New Haven, Conn., ftom July 30, 1886, 
 
 to August 1, 1887. 
 
164 
 
 MBMOIES OF THE NATIONAL ACADEMY OF SCIENCES. 
 
 Fig 60 shows hourly means for the St. Louis observations, the lower line representing the 
 reduction of all observations for 12 years, and those derived from the 8 years' records of the Kew 
 Observatory are shown in Fig. 61. 
 
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 Fig. 60.— I : Onrve showing mean potential at ea«n hour of observation, indading all days, Irom Jaimarv 1, 1861, to December 31, 1872. 
 II: CaiTe showing mean potential at each hour of observation, including all days, from January 1,1861, to December 31, 1861. ni: Curve 
 showing mean potential at each hour of observation on clear and fair days during 1861. All from observations of Dr. A. Wislezenus, at St. 
 liOnis, Mo. 
 
 Volts. 1 
 400 
 
 300 
 
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 A.M. 
 
 5 6 
 
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 FiQ. 61.— Curve showing the mean potential in arbitrary units for each hour of the day. Including all days, for a period of eight years, 1878-'86 
 
 (both included), at the Kew Observatory, Greenwich, England. 
 
MEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES. 
 
 165 
 
 Most of these results, as illustrated in the diagrams, seem to indicate the existence of two 
 principal maxima of potential in the day, and also, in a general way, that one of these occurs not 
 many hours before noon and the other towards the latter part of the day. 
 
 No very close agreement exists, however, and the evidence is rather in favor of the conclusion 
 that the lime at which these maxima occur depends largely on location. The observations at 
 Baltimore, at St. Louis, and at Greenwich are, of course, the most valuable in determining this, and 
 it will be seen that they differ materially as to the location of the maxima, although in agreement 
 as to their existence and, in a general way, as to the part of the day in which they occur. 
 
 Volts. 9 a.m. 
 2,000 
 
 10 a^ m. 11 a. m. 
 
 12 m. 
 
 1 p. m. 2 p. m. 
 
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 Fie. 62.— Curre showing variations of potential at Ithaca, N. T., May 31, 1888, a day on which a thnnderatorm occurred. Sparks passed from 
 
 needle to quadrants almost obntinually from 3:15 to 4:30 p. m. 
 
 POTENTIAL DURING THUNDEKSTOEMS. 
 
 On many occasions special observations at short intervals were made during thunderstorms, 
 including often some hours before and after the thunderstorm proper. The characteristic feature of 
 the electrometer records on such occasions is the rapidity and extent of the potential iluctuations. 
 Almost invariably the needle vibrates with unusual rapidity from side to side, going beyond the 
 registering capacity of the instrument in both positive and negative directions, and much sparking 
 from the needle to the quadrants usually occurs. 
 
166 
 
 MEMOIRS OF THE NATIONAL ACADEMY OP SCIENCES. 
 
 A good illustration of such a record is shown in Fig. 62 which exhibits the variations of 
 potential at Ithaca on May 31, 1888, a thunderstorm occurring between 3 and 5 p. m. of that day. It 
 will be observed that, in this instance, while the storm was raging at a distance of several miles, it 
 produced little if any effect upon the movements of the needle. In some other cases the potential 
 at the observing station was very materially affected when a thunderstorm was so distant that 
 the thunder could not be heard. Pig. 63 shows observations made before, during, and after a 
 thunderstorm at Terre Haute on July 8, 1887. Here it will be noticed that violent fluctuations 
 occurred when the thunderstorm was distant, and that an hour later amid heavy rain and thunder 
 at the station, the movements of the needle were comparatively moderate. The diagrams showing 
 
 r^ 
 
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 a,m. 
 
 
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 SW., light, fair. 
 
 Threatening, distant thnnder. 
 E., light, threatening, heavy thnn- 
 der, sparks. 
 
 S£., light, threatening, heavy thnn- 
 der ; rain began 4:46. 
 SE., fresh, heavy rain and thnnder. 
 
 Eain ended 5:45 P. M. 
 
 b 
 
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 Fig. 63.— Cnrve showing variations of potential beforj, during, and after a thunderstorm with rain, at Terra Haute, Ind., July 8, 1887. 
 
 potential variations at Baltimore during thunderstorm days are reduced copies of the photographic 
 records and have been selected from a large number as fairly representing the whole collection. 
 
 Aside from the general characteristics already mentioned, the rapidity and range* of fluctuation, 
 these potential curves seem to have little in common. 
 
 The examination of a few cases only might lead to interesting conclusions, which would almost 
 certainly be overthrown by the study of a greater number. 
 
MEMOIRS OF THE NATIONAL AOADEMY OF SCIENOES. 167 
 
 Sometimes the potential falls rather steadily until the violent movements begin, but sometimes 
 it rises just as long and steadily. In many cases the violent fluctuations start from a high positive, 
 while in many others the reverse is the case. The storm is usually accompanied by precipitation; 
 sometimes this begins before the needle starts on its series of swings from side to side, and 
 sometimes these movements precede precipitation. The steady rise in potential for some hours 
 immediately following a thunderstorm may mean that clear and fair weather is to be expected. 
 
 Fig. 71, showing the curve for September 19, 1886, is good evidence that it may also be 
 interpreted to mean that another thunderstorm is just at hand. The diagrams, May 7, 8, and 9, 
 1887 (Figs. 72 and 73), are interesting as showing a series of thunderstorms occurring as parts or 
 elements of a continuous rainstorm. 
 
 Although these records are somewhat unsatisfactory as far as throwing any light upon the 
 nature of thunderstorms, it must not be forgotten that, with the exception of a single instance 
 already mentioned, a set of simultaneous observations at the Signal Office and the Smithsonian 
 Institution at Washington, none of these storms has influenced more than one station. The 
 complete electric investigation of the storm would demand a large number of observing stations, 
 relatively near to each other, by means of which a full history of the potential changes about and 
 in all parts of the storm could be obtained. 
 
 Such an examination might result in bringing order and system out of what seems at present 
 little less than confusion. 
 
168 
 
 MEMOIRS OP THE NATIOKAL ACADEMY OP SCIENCES. 
 
 M) I n m F V vr Vn vmiilix: Iet mk i it m i\^ v vt vhyiii k x X[ mid 
 
 ri6. 64.-Photogi-apliio record of variations of poteatial at Baltimore, May 19 to 20, 1884. Thaaderstorm on night of Wth ; rain 9 to 10:30 p. m. 
 
 51) I ff I IV V VI VDW KlXllXim I I 1 IV V VI AlVI K X HMD 
 
 Fie. 65.— Photographic record of variations of potential at Baltimore, May 23 to 24, 1884. Thunderstorm on the night of the 23d ; rain 8 to 11:45 p. m., . 35 inch. 
 
 M) I r IB IV V vivnvffiiK x xi m i i i iv v vi wvi k xxi md 
 
 Fig. 66.— Photographic record of variations of potential at Baltimore, May 24 to 25, 1884. Thunderstorm in the evening of the 24th ; rain 8:40 to 9:20 p. m. 
 
MEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES. 
 
 169 
 
 ffl) I I M RT V v[ m Iviiiiiixiiix ximki imFvvivirvnrixxxrMD 
 
 Kio. G7.— Pbotograp-hicrecoid of variationa of potential at Baltimore, July 15 to 16, 1886. Xhunderstorm on afteruoou of 15tb. ; rain 6;20 to 10:45 p.m., 2.09 inches. 
 
 ffl)I I lI^TV^lVttVDIKXXrMlI H I H^VVIVIIMKXXIM) 
 
 Fig. 68, — Pliotographic record of TarlatioDs of poteiiUal at Baltimore, July 21 to 22, 1885. Silent lightning in the south, 4 to 5 p. m. of tLo Slat. 
 
 MD I n IS 
 
 xxEMiMi niiv^vvivffwixxxr 
 
 FlQ. 68.— Photographic record of variations of potential at Baltimore, July 26 to 27, 1886. Thunderstorm on afternoon of 28th ; rain 4:30 to 11:30 p. m., l.li 
 
 inches. 
 
170 
 
 MEMOIRS OP THE NATIONAL ACADEMY OF SCIENCES. 
 
 ffl) I I WW V ^ ww.ix xx[mi I iFVTi mm k x ximd 
 
 Fig. 70.— Pliotographic record of variations of potential at Baltimore, Angasc 17 to 18, 1886. Thunderstorm on afternoon of ITth ; rain 3:10 to 5:35 p. m. 
 
 M) I I 1 IV 
 
 VHVIIXXXIMI 1 IIVVVrVffVliriXXXIMD 
 
 riQ. 72.-PhotograpMo record of variations of potential at Baltimore, May 7 to 8, 1887. Thunderstorms with continuous rainstorm. 
 
MEMOIRS OF THE NATIONAL ACADEMY OF SOIENOES. 
 
 171 
 
 W K X XTffl 
 
 III IV V \r WW K X XIMD 
 
 Pia.73. — P}iotographlo record of variations of potential at Baltimore, May 8 to 9, 1887. ThanderstoTms with continuous rainstorm. 
 
 POTENTIAL, DURING GALES OP WIND. 
 
 During the year 1887 a number of special observations were made of the potential indicated 
 before, daring, and after high winds. 
 
 / The following notes were made by Mr. A, L. McKae, observer at Terre Haute, Ind.: 
 
 April 4, 1887. — Wind brisk in a. m. Threatening with westerly gale in p. m. Positive in a. m. ; steady negative 
 in p. m. 
 
 April 15, 1887. — Fair to cloudy weather. Wind brisk to gale winds all day. Variable positive and negative? all day. 
 
 Jpril 18, 1887. — Rain and sleet followed by snow in a. m. Fresh northerly winds in a. m. Gale northerly in p. m. 
 from 12 to 3. . 'Negative during rain and sleet and part of the snow. Positive during the gale. 
 
 April 22, 1887. — Northwesterly gale during a thunderstorm, 10 to 10:20 a. m. Variable positive and negative 
 before, during, and after the gale. ' 
 
 April 23, 1887. — Brisk to gale westerly winds all day. -Steady positive all day. Threatening and cloudy. 
 
 April 28, 1887. — Westerly gale from 10 a. m. to 5 p. m. Steady positive. Fair, with a trace of rain at 3 p. m. 
 
 April 29, 1887. —Gale to brisk northwesterly to westerly winds all day. Steady positive, except at 10:11 a. m. was 
 negative for a few seconds. Clear weather. 
 
 May 2, 1887. — Westerly gale from 12:40 to 1 p. m. Variable negative and positive before, during, and after the gale. 
 Thnuderstorm and raiu. 
 
 May 26, 1887. — Fair weather ; westerly to northwesterly, brisk to gale from 12 m. to 6 p. m. Variable positive. 
 
 June 23, 1887. — Wind brisk to gale from 11 a. m. to 1 p. m. Variable negative and positive with threatening weather. 
 
 July 9, 1887. — Negative at 12 m ., positive rest of the time. Wind brisk to gale from 12 m. to 5 p. m. Fair weather. 
 
 ^Mjrmst2, 1887. — Northeasterly gale to east brisk from 10 a. m. to 5 p. m. Variable negative and positive. Clear 
 weather. 
 
 August 4, 1887. — -Northerly gale from 3:40 to 4 p. m. Thunder and threatening just before rain. Steady positive 
 during gale. Negative noted before and after. Westerly gale 4:57 to 5:10 p. m. High negative during rain and 
 thunderstorm. 
 
 . September 7, 1887. — Westerly to northwesterly brisk to gale from 12 m. to 7 p. m. Clear weather. Steady positive. 
 
 SUMMARY. 
 
 Weather. 
 
 Gales. Negative, ^'i^^'^ 
 
 Clear (4) 
 
 Cloudy (3) 
 
 Threatening 
 
 Thunder and rain 
 Snow 
 
 Total 
 
 14 
 
 On one clear day and on one cloudy day the potential was negative 
 for only a few minutes. On one thunderstorm day the potential was 
 positive during the gale but negative before and after it. The po- 
 tential was negative before the gale dnring snow. 
 
172 MEMOIBS OF THE NATIONAL ACADEMY OF SCIENCES. 
 
 GENBBAL KESULTS. 
 
 The publication of the complete series of observations at all stations would add so largely to 
 the bulk of this report that it has not been thought advisable. Such abstracts as appear to be of 
 the greatest interest and importance have been made, however, and in the case of two stations all 
 of the observations are presented. These are Baltimore and Ithaca j the former is of great value 
 on account of the fact that the work was maintained for a greater length of time than at any other 
 station and also because the photographic registration in use at that station furnishes a continuous 
 record for both night and day. In the preparation of tables from the photographic sheets, hourly 
 ordinates were drawn and measured by reference to a calibration mark which was photographed 
 on the sensitive plate as often as was necessary. The results are shown in Table A. 
 
 The location of the station at Ithaca beipg somewhat peculiar owing to its elevation, and the 
 results interesting owing to the frequency of the appearance of negative potential, complete 
 records from that station are exhibited in Table B. A change of exposure, and of observer also, 
 having been made about October 1, 1887, the series is broken into two parts, each part being sum- 
 marized. Brief notes as to weather and wind on every da;y are appended. 
 
 The record at New Haven is less complete, some of the observation books having been 
 unfortunately lost. A nearly complete series extending over 1 year, from August 1, 1886, to July 
 31, 1887, will be found in Table O. 
 
 As the most promising analysis of the results appeared to be that which would reveal the 
 relation between electric potential and precipitation, the observations on clear and fair days have 
 been separated from the others and are collected for the various stations in Tables C to K, inclus- 
 ive. By clear and fair days are here meant those on which the sky was at no time more than 
 three-fourths covered by clouds, no precipitation occurring and the electric potential being 
 continuajly positive. Brief weather notes are appended and the days are generally arranged in 
 groups of ten, sums and means being found for each. 
 
 The Baltimore observations, however, have been collected into groups of 30 days each. 
 Where a considerable change iu the conditions under which the work was done has occurred, such 
 as a change in exposure, electrometer, observer, etc., the results are sometimes summarized 
 accordingly. This is the case with the observations at Ithaca, Boston, and Columbus. At the 
 latter station a Thomson portable electrometer, by White, of Glasgow, was in use in 1887 and up 
 to the end in July, 1888, The arrangements for the use of the Mascart quadrant, which had been 
 in use before, were quite unsatisfactory, as it was necessary to carry the wire joining the collector 
 to the needle on the outside of the building in which they were located, for some distance, and it 
 was difficult to maintain good insulation. Some other differences in the way in which the 
 observations are grouped and summarized in the tables arise out of differences in the number 
 made per day, etc., and will be self-explanatory. 
 
 In the next series of tables,' L to T inclusive, is given the electric potential of the air on days 
 on which precipitation occurred at the place of observation, attention being given only to the 
 sign of the electrification. 
 
 With a single exception, the exhibit of numerical results is in each case preceded by 
 extracts from the daily journal of the observer, giving brief notes of interest iu regard to other 
 meteorological conditions which existed at the time. The results are then tabulated as follows : 
 In the first column the date is given ; in the second the time of the beginning and ending of 
 precipitation j then two columns headed respectively " before " and " during"— and each subdivided 
 into three, and referring specifically to oTjservations made before precipitation and after precipita- 
 tion. The first subdivision of the former is headed " no observation." 
 
 When a mark is found iu that column opposite any date the raeaaing is that no observation 
 was made before the beginning of precipitation, that is to say, it began before the first observation 
 of the day. 
 
 The next subdivision is headed " negative first observed " aod in it will be found the time, in 
 hours, of the first observation of negative electricity before the beginning of precipitation. If 'no 
 negative was observed before precipitation began, a mark is made in the third subdivision. 
 
MEMOIES OF THE NATIONAL ACADEMY OF SCIENCES. 173 
 
 Marks in the three subdivisions nnder " during " imply " no observations during precipita- 
 tion," if in the first, "negative potential observed " if in the second, and "no negative observed" if 
 in the third. 
 
 " Negative after precipitation " heads the next column and brief meteorological notes are in 
 the last. 
 
 In the case of the Baltimore observations it was possible to know with great certainty just 
 when negative electricity was observed previous to precipitation, and the time column is therefore 
 subdivided into several parts so as to exhibit more definitely the time of its appearance. 
 
 Of the St. Louis observations only those of the year 1861 are available for this table, the 
 others having been published by summary. 
 
 The arrangement of Table T, containing a r6sum6 of 8 years' observation at the Eoyal 
 Observatory of Greenwich, is necessarily unlike that of the others. The time of beginning and 
 ending of precipitation is not given in the published reports. 
 
 Only the prevailing kind of electricity is given, and for this purpose the day is divided, 
 generally into four or five periods, and one kind of electricity is put down as prevailing during 
 each period. 
 
 Thus, if the potential was positive during an afternoon except for a brief period when negative 
 was recorded, the prevailing electricity would be recorded as positive. In this way slight 
 precipitation may have occurred with negative electricity and still the potential recorded as 
 positive. In this table, if precipitation and negative potential were both observed on the same 
 day, that day is noted in the first column under " negative and precipitation." 
 
 Thus, in some cases, there may have been no negative either immediately before, during, or 
 after the precipitation as there is no means of determining accurately the time relation between 
 the two. The table is valuable, however, as showing the relative number of appearances of the 
 two phenomena on the same day. 
 
 Supplementary to this series of tables and of equal importance in determining whether any 
 relation exists between the appearance of negative electricity and precipitation are the notes made 
 at the various stations of the occurrence of negative potential without precipitation, arranged 
 under U to Y inclusive. 
 
 It is here shown that in many instances while there was no precipitation at the place of 
 observation, it occurred within a radius of 200 miles, and to its influence may often be attributed 
 the negative potential observed. 
 
 At the same time it will also be noted that there are many appearances of negative potential 
 which can not be thus accounted for, nor by the appearance of clouds or other phenomena with 
 which it is often associated. As an illustration, at Boston, on April 25, 1888, the observer notes 
 " negative reading without a visible cloud and no wind to raise dust. Generally clear throughout 
 the eastern part of the country. No other negative values seen during the day." 
 
 A table summary of the Baltimore notes is given, in which the relation between the appearance 
 of a negative potential without precipitation, and the direction of the prevailing wind is shown 
 The days^are also classified into " cloudy " and " clear " and the number in each column indicates 
 the number of times negative electricity without precipitation was observed in each month, 
 under conditions indicated at the head of the column. Perhaps the most notable feature of this 
 summary is the absence of any record of the occurrence of the phenomena during southwest winds. 
 
 R:6SUM]fi AND CONCLUSIONS. 
 
 As already stated in the introduction, the primary and it may be said the sole object of this 
 
 investigation was to determine whether observations on atmospheric electricity could be made 
 
 useful in weather forecasting. 
 
 The regults obtained have, therefore, been classified and studied with this object in view. 
 Early in the progress of the work, the extreme local chara(!ter of the phenomena exhibited 
 
 became evident. It was found that instruments similar in every respect, separated by a distance 
 
 of a hundred metres might give very dissimilar indications. 
 
174 
 
 MEMOIES OF THE NATIONAL ACADEMY OP SCIENCES. 
 
 It may Ibe well to repeat here that when reference is made to agreement or disagreement of 
 observations, the absolute potential indicated is not considered. 
 
 This depends so largely on the nature and locality, and especially the elevation of the 
 exposure, that absolute values are as yet not comparable, although it is believed that some of 
 the devices suggested in the consideration of " Instruments and Methods " are capable of making 
 them so. As the matter appears at present, however, this does not seem to be of great importance, 
 as it is in the variations of potential as compared with variations in other meteorological elements 
 that any systematic relations between them must be sought for. Experiments already described 
 seemed to prove that even when great difference exists in absolute values, these variations will 
 be sensibly in agreement whenever the exposures are near enough together to insure subjection 
 to the same electrical influences. That this influence often controls or is uniform over only a small 
 area was soon demonstrated, as also that at times when the disturbance was more energetic 
 the area involved, in which a fairly uniform series of changes could be observed, was greatly 
 increased. 
 
 The cpmparison of simultaneous observations at 5-minute intervals, extending through several 
 days at the various stations, failed to show any similarity of fluctuations or movement of electric 
 disturbance from one part of the country to another, and the same conclusion must be drawn from 
 the regular observations. It must be said, however, that the number of stations (at no time greater 
 than six), distributed as they were over a wide extent of country, was too small to justify great 
 coniidence in this negative result. The well-known electric activity about the time of the 
 occurrence of precipitation, whether as rain, snow, hail, or sleet, was made the subject of special 
 examination, attention being particularly called to the appearance of negative potential in connection 
 therewith. Observers were instructed to study the appearance of negative electricity before and 
 during precipitation, and at one time the hope was indulged in by the writer as well as by several 
 of the observers that this phenomenon might afford great assistance in the prediction of local 
 storms, rains, snows, etc., which offer so much difficulty in forecasting by presfent methods. 
 
 Further observation and investigation, however, did not justify this expectation, serving 
 rather to Increase the range of meteorological conditions under which negative potential might be 
 looked for, and to diminish the definiteness of relationship between it and precipitation. That 
 negative electricity is tolerably certain to be observed in connection with precipitation in a majority 
 of cases is doubtless true, but it does not appear in such a way as to be of any value in forecasting. 
 
 A general summary of the results bearing on this question, as shown in the tables on previous 
 pages, will be useful in this connection. 
 
 It is as follows, the numbers in each case showing (1) the total number of cases of precipitation 
 in which observations were made before precipitation began; (2) the number of these iu which 
 negative potential was observed before precipitation began, and (3) the number in which no 
 negative was observed before the beginning. It should also be stated that " before precipitation " is 
 intended to cover a period of several hours, so that aU cases are included in which there is any 
 reasonable probability of the two phenomena being related to each other. 
 
 Negative potential preceding precipitation. 
 
 station. 
 
 Totar cases. 
 
 Negative pre- 
 ceding. 
 
 Ko negative 
 preceding. 
 
 Terre Haute 
 
 90 
 72 
 97 
 346 
 49 
 38 
 67 
 34 
 
 59 
 
 43 
 
 68 
 
 190 
 
 20 
 
 12 
 
 9 
 
 5 
 
 31 
 
 29 
 29 
 156 
 29 
 26 
 58 
 29 
 
 Columbus • 
 
 Ithaca .. 
 
 Baltimore 
 
 Washington 
 
 Boston 
 
 St. Louis 
 
 New Haven 
 
 Total 
 
 793 
 
 406 
 
 387 
 
 
MBMOIES OF THE NATIONAL ACADEMY OP SCIENCES. 175 
 
 It thus appears that negative electricity preceded precipitation, the time varying from a few 
 minutes to more than 10 hours, in a littla more than half of nearly 800 cases, the percentage of its 
 appearance being 53, while that of its non-appearance was 47. But notice should be taken of the 
 negative character of some of this evidence, in that because many of the observations are eye 
 observations, generally made at stated periods, it is impossible to say with certainty that negative 
 potential did not occur at some time without being noted by the observer. 
 
 That such was not the case in any great degree is shown by an examination of the Baltimore 
 observations, which constitute almost half of the above totals, and in which it was possible 
 al ways to know whether negative potential had occurred. In this case the percentage of its 
 appearance was 55 and of its non-appearance 45, being but little different from the results obtained 
 from all stations. 
 
 Owing to the nature of the Kew tables already referred to, it is impossible to analyze the 
 results so as to bear directly on the question. It is Interesting, however, to note the following 
 summary of these observations, it being remembered that reference is had only to the occurrence 
 of negative potential and precipitation on the same day : 
 
 AT KEW. ' 
 
 Negative with precipitation 1,141 
 
 Precipitation without negative 722 
 
 Negative without precipitation 167 
 
 Prom which it will be seen that the two phenomena occurred on the same day in 1,141 cases, 
 and separately in 889 cases. 
 
 But if it could be shown that negative potential invariably preceded precipitation, it would 
 be still more important to inquire whether precipitation always followed the appearance of negative 
 potential. An examination of the notes which bear on this question, presented in previous pages, 
 shows that 311 cases have been noted in which negative potential was indicated unaccompanied 
 by precipitation. In a considerable number of these, perhaj)s one-half, it was observed that 
 precipitation was either actually taking place within what might be called a reasonable distance 
 from the station, or that it did follow .at some neighboring point within a few hours. 
 
 In many cases, however, nothing of the kind took place. At Baltimore, where 126 cases of 
 " negative without precipitation" were observed, 26 only were followed by precipitation at that 
 station on the following day. 
 
 Indeed, it appears to be abundantly proved that negative electricity may he. and was frequently 
 observed, apparently without being in any way related to precipitation, past, present, or future, 
 and that it may be due to other causes, many of which are extremely local in their character. 
 
 Taking the facts above related into consideration, it seems safe to conclude that observations 
 on atmospheric electricity do not promise to be of great service in forecasting the weather. The 
 subject is one of great complexity, and, undoubtedly, owing to the local character of the phenomena, 
 a rather close distribution of a large number of observers over a comparatively small area would 
 tend to remove some doubts as to its utility which may exist. 
 
 Unfortunately the work requires observers of more than usual skill and intelligence and the 
 equipment of a station is somewhat expensive. A number of intelligent and willing volunteers 
 might undertake such an investigation, and the appliances now in the possession of the Chief 
 Signal Officer might be wisely employed in the further study of the subject, and that without 
 additional expense, by placing equipments at several of the more important stations of the service, 
 where the employment of two or three observers would allow of the observations being carried on 
 withput special assignment. 
 
 It would be particularly desirable that some of the later forms of collectors be thoroughly 
 tested and that a study be made of some other phases of the subject, such as the measurement of 
 the "potential gradient" and its relation to weather phenomena, concerning which interesting 
 conclusions have been reached through the recent researches of Prof. Pranz Exner.* 
 
 The conditions under which the present investigation was made and the restrictions to which 
 it was necessarily subjected, forbade an invasion of much territory of great scientific interest. 
 
 * Eepertorium der Physik, 1888 March 31, 1889. 
 
176 
 
 MEMOIES OF THE NATIONAL ACADEMY OF SOIBNGES. 
 
 Table K.^-Hourly records, drawn from continuous photographic 
 . JANUARY, 1885." 
 
 Day of month. 
 
 1 a. m. 
 
 2 a. m. 
 
 3 a. m. 
 
 la. m. 
 
 5 a. m. 
 
 6 a. m. 
 
 7 a. m. 
 
 8 a. m. 
 
 9 a. m. 
 
 10 a. m. 
 
 11 a. ra. 
 
 12"m. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 2 
 
 100 
 
 75 
 
 80 
 
 - 50 
 
 75 
 
 40 
 
 140 
 
 75 
 
 
 
 90 
 
 —120 
 
 150 
 
 60 
 
 50 
 
 125 
 
 75 
 
 75 
 
 - 50 
 
 10 
 
 40 
 
 150 
 
 150 
 
 
 
 160 
 
 —100 
 
 175 
 
 50 
 
 50 
 
 100 
 75 
 50 
 
 — 60 
 
 — 75 
 40 
 
 150 
 200 
 
 — 10 
 150 
 
 —150 
 
 140 
 
 50 
 
 .50 
 
 100 
 
 75 
 
 75 
 
 — 75 
 
 250 
 
 40 
 
 140 
 
 175 
 
 
 
 150 
 
 —125 
 
 140 
 
 50 
 
 50 
 
 ioo 
 
 75 
 
 60 
 
 - 75 
 
 150 
 
 40 
 
 125 
 
 150 
 
 
 
 150 
 
 —150 
 
 175 
 
 60 
 
 50 
 
 100 
 
 150 
 
 50 
 
 — 75 
 150 
 
 
 125 
 150 
 
 — 10 
 75 
 
 —100 
 
 250 
 
 75 
 
 — 75 
 
 50 
 
 150 
 
 25 
 
 — 75 
 200 
 
 10 
 
 150 
 
 150 
 
 10 
 
 50 
 
 — 30 
 200 
 
 30 
 —100 
 
 25 
 
 50 
 
 
 
 — 50 
 100 
 
 50 
 
 200, 
 
 100 
 
 25 
 
 30 
 
 — 30 
 175 
 
 40 
 —200 
 
 25 
 25 
 
 — 5 
 
 — 30 
 
 — 50 
 75 
 
 150 
 
 150 
 
 10 
 
 25 
 
 — 10 
 150 
 
 75 
 —225 
 
 25 
 100 
 
 — 10 
 
 - 30 
 50 
 75 
 60 
 
 200 
 
 - 10 
 10 
 
 — 5 
 150 
 100 
 
 -275 
 
 40 
 100 
 
 - 10 
 
 - 10 
 25 
 75 
 50 
 
 150 
 
 10 
 
 
 
 
 
 150 
 
 50- 
 
 —250 
 
 30 
 125 
 
 — 25 
 
 — 10 
 25 
 75 
 30 
 
 150 
 25 
 
 — 10 
 
 
 
 150 
 
 20 
 
 -125 
 
 3 
 
 4 
 
 5 
 
 6... 
 
 7 
 
 8 
 
 9.„ 
 
 10 
 
 11 
 
 12 
 
 13 -• 
 
 14 
 
 15 
 
 16 
 
 17 
 
 - 10 
 50 
 
 — 20 
 50 
 
 - 40 
 30 
 
 — 60 
 25 
 
 — 50 
 20 
 
 — 30 
 
 10 
 
 — 5 
 10 
 
 5 
 
 10- 
 
 10 
 
 20 
 
 10 
 20 
 
 5 
 20 
 
 5 
 20 
 
 18 
 
 19 
 
 20 
 
 150 
 
 120 
 
 100 
 
 90 
 
 100 
 
 100 
 
 120 
 
 125 
 
 150 
 
 100 
 
 100 
 
 75 
 
 21 
 
 22 
 
 10 
 
 10 
 
 —150 
 
 40 
 
 30 
 
 40 
 
 75 
 
 
 
 1S5 
 
 100 
 
 40 
 20 
 —120 
 50 
 25 
 20 
 100 
 
 0' 
 ]75 
 100 
 
 40 
 
 20 
 
 —125 
 
 60 
 
 25 
 
 40 
 
 150 
 
 
 
 150 
 
 110 
 
 50 
 
 20 
 
 — 90 
 
 60 
 
 25 
 
 40 
 
 150 
 
 
 
 150 
 
 100 
 
 50 
 
 20 
 
 - 50 
 
 40 
 
 40 
 
 40 
 
 150 
 
 
 
 125 
 
 100 
 
 60 
 
 10 
 
 — 30 
 
 30 
 
 50 
 
 50 
 
 150 
 
 
 
 160 
 
 100 
 
 60 
 1.0 
 
 — 10 
 
 
 
 100 
 
 75 
 
 - 10 
 
 
 250 
 100 
 
 60 
 
 5 
 
 
 
 — 10 
 
 ^ 50 
 
 150 
 
 
 
 10 
 
 75 
 
 150 
 
 40 
 
 5 
 
 30 
 
 - 10 
 
 50 
 
 125 
 
 —150 
 
 175 
 
 30 
 
 5 
 
 50 
 
 - 10 
 
 10 
 
 100 
 
 —150 
 
 10 
 
 50 
 
 150 
 
 10 
 
 
 
 30 
 
 — 10 
 30 
 75 
 
 —100 
 
 20 
 
 40 
 
 160 
 
 10 
 
 5 
 
 75 
 
 — 10 
 75 
 .75 
 
 — 75 
 10 
 40 
 
 150 
 
 23 
 
 24 
 
 25 
 
 26 
 
 27 
 
 28 
 
 29 
 
 30 
 
 31 
 
 
 1.235 
 
 48 
 
 1,470 
 
 57 
 
 1,270 
 49 
 
 1,605 
 62 
 
 1,495 
 
 58 
 
 1,525 
 59 
 
 1,520 
 
 58 
 
 1,140 
 42 
 
 870 
 32 
 
 815 
 30 
 
 760 
 29 
 
 825 
 31 
 
 
 
 FEBRUAEY, 1885. 
 
 1 
 
 10 
 25 
 25 
 50 
 75 
 100 
 150 
 40 
 
 10 
 20 
 25 
 50 
 20 
 50 
 100 
 30 
 
 10 
 20 
 25 
 10 
 20 
 25 
 100 
 40 
 
 - 5 
 10 
 25 
 30 
 10 
 25 
 75 
 10 
 
 
 
 
 
 \ 
 
 
 
 
 2 
 
 10 
 25 
 25 
 
 50 
 90 
 
 « 
 
 10 
 25 
 20 
 30 
 — 10 
 100 
 20 
 
 10 
 
 
 
 50 
 
 20 
 
 — 5 
 125 
 
 — 5 
 
 20 
 10 
 10 
 20 
 
 100 
 50 
 
 5 
 
 90 
 20 
 
 50 
 80 
 
 10 
 — 10 
 20 
 40 
 
 20 
 50 
 
 10 
 10 
 — 10 
 30 
 
 50 
 50 
 
 
 
 100 
 
 50 
 
 10 
 
 
 75 
 40 
 
 3 
 
 4 
 
 5 
 
 6 
 
 7 
 
 8 
 
 9 
 
 10 
 
 50 
 
 — 1(1 
 
 
 30 
 10 
 60 
 
 - 30 
 40 
 
 
 
 50 
 
 25 
 
 150 
 
 100 
 
 100 
 
 100 
 
 250 
 
 10 
 
 
 
 10 
 
 
 
 — 10 
 
 
 
 — .5 
 10 
 50 
 
 — 50 
 30 
 50 
 
 . 60 
 
 
 
 150 
 
 100 
 
 110 
 
 100 
 
 
 
 75 
 
 — 10 
 
 
 
 
 
 — 10 
 
 
 
 20 
 
 ID 
 
 50 
 
 —100 
 
 25 
 
 
 
 50 
 
 
 
 80 
 
 100 
 
 100 
 
 125 
 
 — 50 
 25 
 10 
 
 
 
 20 
 
 — 10 
 
 
 25 
 10 
 50 
 
 — 75 
 10 
 10 
 40 
 
 
 
 50 
 
 100 
 
 90 
 
 125 
 
 
 
 10 
 
 — 10 
 
 
 
 30 
 
 - 10 
 
 
 
 25 
 
 20 
 
 60 
 
 —200 
 
 
 
 
 
 50 
 
 — 5 
 30 
 
 110 
 
 60 
 
 125 
 
 —100 
 
 
 
 25 
 
 
 
 
 
 - 10 
 
 
 
 40 
 
 10 
 
 90 
 
 —200 
 
 
 
 
 
 50 
 
 - 5 
 20 
 
 110 
 30 
 
 200 
 
 75 
 
 75 
 
 10 
 
 
 
 100 
 
 - 10 
 
 
 
 100 
 
 20 
 
 110 
 
 —300 
 
 
 
 25 
 
 75 
 
 
 
 20 
 
 90 
 
 25 
 
 175 
 
 75 
 
 25 
 
 
 
 
 
 200 
 
 - 10 
 
 — 5 
 75 
 50 
 
 125 
 
 —100 
 
 
 
 25 
 
 100 
 
 
 
 to 
 
 75 
 
 10 
 100 
 
 50 
 100 
 
 25 
 
 /I 
 
 
 
 - 10 
 
 — 5 
 50 
 60 
 
 125 
 
 —200 
 
 
 
 30 
 
 100 
 
 
 
 
 
 60 
 
 10 
 
 75 
 
 50 
 
 25 
 
 50 
 
 200 
 
 — 10 
 
 — 5 
 ' 30 
 
 20 
 125 
 
 50 
 
 
 25 
 
 80 
 
 
 
 40 
 
 — 10 
 40 
 50 
 20 
 25 
 50 
 
 20 
 
 
 
 — 10 
 
 10 
 
 50 
 
 100 
 
 
 
 
 
 50 
 
 
 
 
 
 
 
 30 
 
 125 
 
 25 
 
 40 
 
 
 
 60 
 
 30 
 
 20 
 25 
 
 — 10 
 
 
 
 60 
 
 100 
 
 — 10 
 
 
 
 40 
 
 
 
 
 
 
 
 . 30 
 
 100 
 
 25 
 
 75 
 
 150 
 
 50 
 
 85 
 
 11 
 
 12 
 
 13 
 
 14 
 
 15 
 
 16 
 
 17 
 
 18 
 
 19 
 
 20 
 
 21 
 
 22 
 
 23 
 
 24 
 
 25 
 
 26 
 
 27 
 
 28 
 
 Sums 
 
 
 1,420 
 55 
 
 965 
 39 
 
 685 
 27 
 
 625 
 25 
 
 420 
 18 
 
 690 
 30 
 
 725 
 33 
 
 1,040 670 
 
 860 
 36 
 
 670 
 
 28 
 
 955 
 40 
 
 Means 
 
 
 
 
MEMOIRS OF THE NATIONAL AOADEMY OF SCIENCES. 
 
 177 
 
 registration, at Baltimore, Md., 1885, 1886, and 1887. 
 
 JANUARY, 1885. 
 
 Ip. m. 
 
 2 p.m. 
 
 3 p. I 
 
 4 p. m. 
 
 5 p. m. 
 
 fl p. tn. 
 
 7 p. m. 
 
 8 p. m. 
 
 p.m. 
 
 10 p. m. 
 
 np.m. 
 
 12 mid. 
 
 Kemarks. 
 
 10 
 
 50 
 
 250 
 
 iOO 
 
 75 
 
 75 
 
 100 
 
 100 
 
 100 
 
 100 
 
 100 
 
 100 
 
 W. br.,r.,8l.,8u. 
 
 30 
 
 50 
 
 60 
 
 75 
 
 75 
 
 80 
 
 100 
 
 100 
 
 125 
 
 125 
 
 100 
 
 80 
 
 NW.br., clear. 
 
 100 
 
 150 
 
 150 
 
 125 
 
 100 
 
 100 
 
 125 
 
 125 
 
 125 
 
 100 
 
 100 
 
 90 
 
 SEifr.,lair. 
 
 - 25 
 
 — 25 
 
 — 25 
 
 — 25 
 
 - 25 
 
 — 25 
 
 - 25 
 
 — 25 
 
 — 25 
 
 — 25 
 
 - 25 
 
 - 25 
 
 Var. lt.,sn.,8l.,r. 
 
 150 
 
 125 
 
 150 
 
 150 
 
 125 
 
 125 
 
 150 
 
 150 
 
 125 
 
 
 
 50 
 
 150 
 
 SW.lt., rain. 
 
 — 75 
 
 100 
 
 
 
 150 
 
 75 
 
 —100 
 
 60 
 
 60 
 
 50 
 
 50 
 
 50 
 
 40 
 
 SE.fr., rain. 
 
 75 
 
 75 
 
 75 
 
 75 
 
 90 
 
 100 
 
 100 
 
 90 
 
 75 
 
 100 
 
 125 
 
 125 
 
 W.br.,fair. 
 
 75 
 
 100 
 
 100 
 
 100 
 
 90 
 
 150 
 
 150 
 
 100 
 
 125 
 
 75 
 
 50 
 
 50 
 
 SW.fr., fair. 
 
 150 
 
 100 
 
 100 
 
 100 
 
 100 
 
 50 
 
 50 
 
 50 
 
 40 
 
 
 
 — 10 
 
 
 
 SW. fr., clear, fog. 
 
 60 
 
 70 
 
 75 
 
 75 
 
 60 
 
 60 
 
 50 
 
 150 
 
 1 100 
 
 75 
 
 100 
 
 75 
 
 NW.br., clear. 
 
 10 
 
 20 
 
 100 
 
 75 
 
 80 
 
 30 
 
 80 
 
 50 
 
 10 
 
 —150 
 
 —150 
 
 — 75 
 
 SE. fr., rain. 
 
 — 10 
 
 75 
 
 100 
 
 110 
 
 125 
 
 110 
 
 125 
 
 150 
 
 ' 150 
 
 175 
 
 175 
 
 200 
 
 Do. 
 
 65 
 
 80 
 
 65 
 
 65 
 
 65 
 
 75 
 
 80 
 
 75 
 
 ; 100 
 
 1 65 
 
 75 
 
 50 
 
 NW.fr., fair. 
 
 125 
 
 160 
 
 100 
 
 125 
 
 100 
 
 75 
 
 75 
 
 60 
 
 50 
 
 1 50 
 
 80 
 
 60 
 
 E. fr., clear. 
 S.fr., sleet, rain. 
 
 io 
 
 ioo 
 
 30 
 
 20 
 
 125 
 
 lib 
 
 125 
 
 ioo 
 
 110 
 
 100 
 
 50 
 
 25 
 
 E. It., rain, fog. 
 
 5 
 
 
 
 ' 5 
 
 — 5 
 
 5 
 
 
 
 10 
 
 10 
 
 10 
 
 10 
 
 30 
 
 30 
 
 NW. g.,rain. 
 NW.fr., clear. 
 NW.fr., fair. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 50 
 
 ■60 
 
 50 
 
 50 
 
 60 
 
 60 
 
 80 
 
 80 
 
 ioo 
 
 ' ioo 
 
 100 
 
 75 
 
 
 
 
 
 
 
 
 
 
 
 
 
 NW.lt., cloudy. 
 SW.lt., clear. 
 
 — 25 
 
 - 10 
 
 - 10 
 
 — 50 
 
 — 5 
 
 
 
 10 
 
 
 
 25 
 
 20 
 
 20 
 
 25 
 
 5 
 
 5 
 
 40 
 
 30 
 
 30 
 
 25 
 
 50 
 
 25 
 
 5 
 
 5 
 
 5 
 
 5 
 
 NW.br., clear. 
 
 40 
 
 50 
 
 75 
 
 60 
 
 100 
 
 60 
 
 50 
 
 40 
 
 40 
 
 10 
 
 —100 
 
 -175 
 
 SW. Ir., snow, sleet. 
 
 10 
 
 
 
 75 
 
 50 
 
 75 
 
 100 
 
 100 
 
 75 
 
 75 
 
 100 
 
 75 
 
 60 
 
 Var., It., snow. 
 
 250 
 
 200 
 
 200 
 
 300 
 
 275 
 
 10 
 
 75 
 
 60 
 
 60 
 
 50 
 
 70 
 
 50 
 
 W. It., cloudy. 
 
 75 
 
 50 
 
 50 
 
 80 
 
 75 
 
 50 
 
 60 
 
 50 
 
 ! 75 
 
 60 
 
 50 
 
 30 
 
 NW.br., clear. 
 
 100 
 
 130 
 
 100 
 
 100 
 
 100 
 
 50 
 
 75 
 
 100 
 
 90 
 
 90 
 
 100 
 
 150 
 
 NW.br., fair. 
 
 — 50 
 
 350 
 
 350 
 
 250 
 
 100 
 
 75 
 
 60 
 
 75 
 
 50 
 
 25 
 
 10 
 
 
 
 N. ]t.,8now. 
 
 100 
 
 110 
 
 100 
 
 110 
 
 125 
 
 150 
 
 130 
 
 200 
 
 150 
 
 50 
 
 125 
 
 150 
 
 SW.fr., clear. 
 
 200 
 
 175 
 
 165 
 
 165 
 
 125 
 
 150 
 
 50 
 
 50 
 
 100 
 
 75 
 
 50 
 
 120 
 
 W.fr.,fair. 
 
 140 
 
 130 
 
 150 
 
 150 
 
 100 
 
 50 
 
 50 
 
 75 
 
 75 
 
 75 
 
 60 
 
 
 
 NE.lt., fair. 
 
 1,650 
 
 2,480 
 
 2,680 
 
 2,610 
 
 3,425 
 
 1,835 
 
 2,145 
 
 2,175 
 
 2,115 
 
 1,510 
 
 1,465 
 
 1,465 
 
 59 
 
 89 
 
 96 
 
 93 
 
 87- 
 
 66 
 
 1 
 
 77 
 
 78 
 
 76 
 
 54 
 
 52 
 
 54 
 
 
 FEBRUARY, 1885. 
 
 100 
 
 100 
 
 75 
 
 75 
 
 50 
 
 75 
 
 60 
 
 50 
 
 50 
 
 50 
 
 50 
 
 30 
 
 NW. fr., snow. 
 
 75 
 
 80 
 
 100 
 
 100 
 
 90 
 
 75 
 
 50 
 
 50 
 
 80 
 
 75 
 
 100 
 
 30 
 
 NW. br., clear. 
 
 100 
 
 150 
 
 100 
 
 75 
 
 60 
 
 20 
 
 25 
 
 50 
 
 20 
 
 20 
 
 60 
 
 50 
 
 NE. It., cloudy. 
 
 10 
 
 
 
 100 
 
 100 
 
 50 
 
 — 50 
 
 —200 
 
 —150 
 
 100 
 
 100 
 
 50 
 
 100 
 
 S. It., rain. 
 
 10 
 
 25 
 
 60 
 
 75 
 
 75 
 
 25 
 
 30 
 
 30 
 
 — 50 
 
 
 
 250 
 
 -25 
 
 N. fr., rain, snow. 
 
 25 
 
 50 
 
 60 
 
 60 
 
 75 
 
 90 
 
 100 
 
 110 
 
 125 
 
 125 
 
 100 
 
 110 
 
 NW. fr., snow. 
 
 100 
 
 75 
 
 100 
 
 80n 
 
 100 
 
 75 
 
 75 
 
 105 
 
 , 110 
 
 90 
 
 100 
 
 75 
 
 S. fr., cloudy. 
 NE. It., fair. 
 NE. fr., rain, t. s. 
 
 — 25 
 
 — 50 
 
 — 20 
 
 
 
 
 
 —150 
 
 300 
 
 —200 
 
 — 200 
 
 —200 
 
 300 
 
 —150 
 
 30 
 
 25 
 
 25 
 
 20 
 
 20 
 
 
 
 — 30 
 
 
 
 — 20 
 
 — 10 
 
 — 10 
 
 — 25 
 
 N. fr., rain,- snow. 
 
 25 
 
 40 
 
 30 
 
 30 
 
 50 
 
 50 
 
 30 
 
 
 
 
 
 
 
 
 
 
 
 NW. br., clear.- 
 
 50 
 
 60 
 
 60 
 
 50 
 
 6a 
 
 50 
 
 50 
 
 75 
 
 50 
 
 25 
 
 25 
 
 40 
 
 NW. It., fair. 
 
 — 50 
 
 200 
 
 -^ 10 
 
 125 
 
 80 
 
 25 
 
 20 
 
 20 
 
 20 
 
 50 
 
 50 
 
 20 
 
 E. It., snow. 
 
 50 
 
 10 
 
 — 5 
 
 
 
 — 5 
 
 100 
 
 -100 
 
 150 
 
 — 10 
 
 100 
 
 125 
 
 100 
 
 NE. fr., snow. 
 
 90 
 
 110 
 
 125 
 
 130 
 
 125 
 
 100 
 
 10 
 
 50 
 
 10 
 
 10 
 
 10 
 
 - 20 
 
 SE. fr., clear. 
 
 60 
 
 50 
 
 50 
 
 40 
 
 30 
 
 25 
 
 5 
 
 10 
 
 10 
 
 30 
 
 40 
 
 40 
 
 E. br., rain, snow. 
 
 25 
 
 40 
 
 30 
 
 50 
 
 50 
 
 60 
 
 50 
 
 50 
 
 25 
 
 250 
 
 — 50 
 
 50 
 
 NW. fr., snow. 
 
 60 
 
 50 
 
 40 
 
 30 
 
 25 
 
 20 
 
 — 5 
 
 30 
 
 40 
 
 40 
 
 50 
 
 60 
 
 Do. 
 
 
 
 30 
 
 60 
 
 30 
 
 5 
 
 75 
 
 50 
 
 60 
 
 40 
 
 100 
 
 25 
 
 10 
 
 NW. fr., clear. 
 
 — 50 
 
 10 
 
 30 
 
 - 30 
 
 25 
 
 
 
 .50 
 
 125 
 
 100 
 
 100 
 
 125 
 
 150 
 
 NW. br., clear. 
 
 250 
 
 200 
 
 225 
 
 200 
 
 130 
 
 100 
 
 100 
 
 100 
 
 100 
 
 50 
 
 125 
 
 125 
 
 NW. fr., clear. 
 
 150 
 
 125 
 
 100 
 
 75 
 
 75 
 
 50 
 
 60 
 
 50 
 
 50 
 
 60 
 
 75 
 
 75 
 
 Do. 
 
 100 
 
 100 
 
 110 
 
 110 
 
 125 
 
 90 
 
 75 
 
 80 
 
 90 
 
 75 
 
 100 
 
 100 
 
 Do. 
 
 175 
 
 200 
 
 150 
 
 150 
 
 , 175 
 
 125 
 
 75 
 
 75 
 
 200 
 
 —100 
 
 150 
 
 250 
 
 SW. fr., snow. 
 
 125 
 
 125 
 
 100 
 
 TOO 
 
 ■ 75 
 
 80 
 
 75 
 
 100 
 
 100 
 
 80 
 
 75 
 
 50 
 
 N. fr., snow. 
 
 /150 
 
 175 
 
 125 
 
 100 
 
 eo 
 
 50 
 
 — 50 
 
 20 
 
 10 
 
 100 
 
 100 
 
 50 
 
 NE. It., snow, sleet. 
 
 50 
 
 30 
 
 60 
 
 50 
 
 20 
 
 20 
 
 30 
 
 30 
 
 25 
 
 ' 25 
 
 30 
 
 25 
 
 NE. It., snow. 
 
 75 
 
 60 
 
 75 
 
 80 
 
 100 
 
 150 
 
 125 
 
 100 
 
 80 
 
 100 
 
 100 
 
 100 
 
 SW. fr., clear. 
 
 1,760 
 
 2,070 
 
 1,955 
 
 1,965 
 
 1,725 
 
 1,330 
 
 1,060 
 
 1,170 
 
 1,155 
 
 1,345 
 
 2,155 
 
 1,420 
 
 65 
 
 77 
 
 72 
 
 73 
 
 64 
 
 49 
 
 39 
 
 45 
 
 44 
 
 52 
 
 83 
 
 55 
 
 
 S. Mis. 94 12 
 
178 
 
 MEMOmS OF THE NATIONAL ACADEMY OF SCIENCES. 
 
 Table A. — Hourly records, drawn from continuous photographic 
 MARCH, 1885. 
 
 Day of montb. 
 
 1 a. m. 
 
 2 a. m. 
 
 3 a. m. 
 
 4 a. m. 
 
 5 a. m. 
 
 6 a.m. 
 
 7 a.m. 
 
 8 a.m. 
 
 9 a.m. 
 
 10 a. m. 
 
 11 a. m. 
 
 12 m. 
 
 1 
 
 75 
 
 25 
 
 100 
 
 10 
 
 30 
 
 60 
 
 —100 
 
 75 
 
 
 
 50 
 
 50 
 
 — 10 
 25 
 
 
 20 
 
 
 25 
 20 
 
 — 10 
 20 
 
 
 
 
 60 
 
 25 
 
 120 
 
 — 10 
 60 
 75 
 
 —100 
 60 
 
 
 50 
 50 
 
 
 
 — 5 
 
 — 10 
 20 
 
 
 25 
 20 
 
 
 20 
 
 — 10 
 
 — 10 
 
 50 
 
 85 
 
 130 
 
 60 
 
 125 
 
 60 
 
 
 
 25 
 
 
 
 50 
 
 60 
 
 
 
 
 
 10 
 
 
 
 
 
 30 
 
 15 
 
 20 
 
 20 
 
 
 
 
 
 50 
 25 
 160 
 10 
 90 
 75 
 
 - 10 
 
 
 
 
 
 50 
 
 50 
 
 — 30 
 
 
 
 30 
 
 —300 
 
 5 
 40 
 25 
 10 
 20 
 
 
 
 
 
 40 
 
 25 
 
 150 
 
 150 
 
 100 
 
 60 
 
 20 
 
 
 
 
 
 40 
 
 50 
 
 — 25 
 
 5 
 30 
 
 — 25 
 10 
 40 
 20 
 10 
 
 
 
 — 20 
 
 
 
 30 
 
 40 
 
 160 
 
 160 
 
 125 
 
 80 
 
 20 
 
 
 
 
 
 50 
 
 60 
 
 — 40 
 
 'I 
 
 — 20 
 50 
 40 
 30 
 10 
 10 
 
 
 
 
 — 60 
 60 
 
 175 
 
 100 
 
 150 
 
 90 
 
 10 
 
 
 
 
 
 100 
 
 30 
 
 — 60 
 
 — 20 
 
 5 
 
 — 20 
 75 
 40 
 20 
 
 
 10 
 20 
 
 — 5 
 
 
 
 60 
 
 200 
 
 10 
 
 110 
 
 60 
 
 100 
 
 
 
 
 
 90 
 
 25 
 
 —100 
 
 
 
 5 
 
 
 
 40 
 
 
 
 25 
 
 
 
 
 
 25 
 
 — 50 
 
 100 
 
 50 
 
 190 
 
 10 
 
 40 
 
 50 
 
 75 
 
 25 
 
 
 
 25 
 
 30 
 
 — 50 
 
 
 
 
 
 
 
 50 
 
 
 
 30 
 
 —300 
 
 
 
 10 
 
 —150 
 
 100 
 
 60 
 
 150 
 
 20 
 
 30 
 
 60 
 
 75 
 
 50 
 
 
 
 
 
 50 
 
 —300 
 
 
 
 — 5 
 
 — 10 
 30 
 
 
 
 30 
 
 200 
 
 
 
 
 
 30 
 
 200 
 
 50 
 
 150 
 
 75 
 
 10 
 
 25 
 
 100 
 
 30 
 
 
 
 10 
 
 60 
 
 
 
 20 
 
 
 
 — 25 
 50 
 
 
 
 50 
 
 
 
 
 
 — 5 
 10 
 
 
 
 50 
 
 130 
 
 75 
 
 
 
 110 
 
 75 
 
 30 
 
 
 
 10 
 
 100 
 
 — 10 
 
 
 25 
 
 — 10 
 30 
 
 
 
 100 
 
 10 
 
 
 
 — 10 
 10 
 
 2 
 
 3 
 
 4 
 
 5 
 
 6 
 
 7 
 
 8 
 
 9 
 
 10 
 
 11 
 
 12 
 
 13 
 
 14 
 
 15 
 
 16 
 
 17 
 
 18 
 
 19 
 
 20 
 
 21 
 
 22 
 
 23 
 
 24 
 
 
 
 
 
 
 
 
 
 
 
 
 
 25 
 
 — 5 
 50 
 
 — 5 
 
 
 
 
 
 
 20 
 
 
 10 
 
 
 — 5 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 26 
 
 27 
 
 28 
 
 
 
 
 
 
 
 
 
 
 
 
 
 29 
 
 
 
 
 
 
 
 
 
 
 
 
 
 30 
 
 110 
 30 
 
 75 
 30 
 
 -75 
 30 
 
 75 
 40 
 
 60 
 75 
 
 75 
 10 
 
 — 5 
 
 10 
 
 125 
 
 60 
 
 175 
 
 75 
 
 125 
 
 75 
 
 150 
 50 
 
 100 
 
 
 31 
 
 
 650 
 26 
 
 540 
 22 
 
 785 
 33 
 
 435 
 18 
 
 825 
 34 
 
 910 
 38 
 
 725 
 32 
 
 785 
 37 
 
 435 
 21 
 
 770 
 37 
 
 1,010 
 
 48 
 
 825 
 39 
 
 Means...... . 
 
 
 APKIXi, 1885. 
 
 1 
 
 — 5 
 150 
 
 15 
 
 — 50 
 60 
 20 
 15 
 
 — 15 
 60 
 40 
 40 
 
 25 
 
 40 
 25 
 — 50 
 50 
 20 
 70 
 5 
 65 
 50 
 50 
 
 30 
 10 
 20 
 — 30 
 70 
 25 
 70 
 10 
 80 
 60 
 70 
 
 30 
 15 
 30 
 — 50 
 200 
 30 
 85 
 10^ 
 80 
 50 
 60 
 
 30 
 25 
 50 
 - 50 
 70 
 45 
 
 100 
 
 
 100 
 50 
 40 
 
 50 
 
 ,to 
 
 40 
 
 - 50 
 
 100 
 
 70 
 
 50 
 
 5 
 
 75 
 
 50 
 
 60 
 
 25 
 
 30 
 
 70 
 
 — 30 
 
 110 
 
 70 
 
 80 
 
 5 
 
 60 
 
 50 
 
 45 
 
 10 
 90 
 80 
 — 15 
 90 
 70 
 70 
 60 
 60 
 50 
 50 
 
 — 10 
 
 
 80 
 
 — 20 
 70 
 60 
 70 
 60 
 60 
 
 100 
 30 
 
 10 
 80 
 50 
 — 25 
 70 
 50 
 100 
 50 
 60 
 85 
 10 
 
 
 
 70 
 
 50 
 
 — 20 
 
 50 
 
 30 
 
 100 
 
 20 
 
 ' 60 
 
 100 
 
 10 
 
 125 
 
 100 
 
 100 
 
 — 20 
 
 50 
 
 30 
 
 50 
 
 
 
 60 
 
 75 
 
 10 
 
 2 
 
 3 
 
 4 
 
 5 
 
 6 
 
 7 
 
 8 
 
 9 
 
 10 
 
 11 
 
 12 
 
 13 
 
 
 
 
 
 
 
 
 
 
 
 
 
 14. 
 
 15 
 10 
 25 
 
 5 
 
 35 
 
 50 
 
 135 
 
 35 
 
 
 
 5 
 25 
 
 
 
 30 
 
 10 
 
 
 
 25 
 
 35 
 
 60 
 
 140 
 
 50 
 
 30 
 
 - 25 
 
 30 
 
 10 
 
 40 
 
 — 10 
 
 — 5 
 30 
 55 
 60 
 
 115 
 50 
 30 
 
 30 
 20 
 
 40 
 25 
 
 40 
 50 
 65 
 100 
 35 
 15 
 50 
 30 
 10 
 
 50 
 30 
 
 25 
 40 
 60 
 50 
 30 
 15 
 15 
 30 
 25 
 
 65 
 50 
 
 
 40 
 50 
 70 
 60 
 50 
 20 
 
 
 50 
 
 
 
 50 
 40 
 
 
 45 
 15 
 60 
 190 
 85 
 30 
 — 50 
 20 
 
 
 
 30 
 
 
 
 
 
 80 
 
 50 
 
 60 
 
 140 
 
 
 
 
 
 
 
 
 
 
 
 30 
 
 
 
 
 
 50 
 
 85 
 
 60 
 
 150 
 
 50 
 
 
 
 60 
 
 
 
 
 
 30 
 
 
 
 
 
 85 
 
 70 
 
 75 
 
 100 
 
 60 
 
 100 
 
 100 
 
 
 
 
 
 40 
 
 25 
 
 
 
 95 
 
 50 
 
 90 
 
 200 
 
 130 
 
 75 
 
 70 
 
 
 
 30 
 
 50 
 75 
 
 
 60 
 50 
 90 
 120 
 60 
 50 
 70 
 
 
 30 
 
 15 
 
 16 
 
 17 
 
 18 
 
 19 
 
 20 
 
 21 
 
 22 
 
 23 
 
 24 
 
 25 
 
 26 
 
 27 
 
 40 
 20 
 75 
 
 50 
 50 
 70 
 
 20 
 50 
 70 
 
 60 
 60 
 70 
 
 50 
 10 
 
 75 
 
 50 
 40 
 70 
 
 50 
 
 50 
 
 
 
 *60 
 
 50 
 
 — 50 
 
 50 
 
 70 
 
 —100 
 
 50 
 
 100 
 
 —100 
 
 50 
 
 80 
 —100 
 
 50 
 
 100 
 
 75 
 
 28 
 
 29 
 
 30 
 
 Sums. -- 
 
 
 
 
 
 
 
 
 
 
 
 
 1,460 
 64 
 
 805 
 31 
 
 915 
 35 
 
 970 
 37 
 
 1,190 
 
 48 
 
 965 
 39 
 
 1,095 
 46 
 
 1,100 
 46 
 
 1,035 
 45 
 
 1,005 
 44 
 
 1,210 
 53 
 
 1,305 
 54 
 
 Means 
 
 
MEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES. 
 
 179 
 
 registration, 0t Baltimore, Md., 1885, 1886, and 1887 — Continued. 
 
 MARCH, 1885. 
 
 1 p.m. 
 
 2 p.m. 
 
 3 p.m. 
 
 4 p. m. 
 
 5 p.m. 
 
 6 p.m. 
 
 7 p.m. 
 
 8 p.m. 
 
 9 p.m. 
 
 10 p. m. 
 
 11 p. m. 
 
 12 mid. 
 
 —100 
 
 — 50 
 
 — 50 
 
 
 
 300 
 
 —100 
 
 — 50 
 
 — 50 
 
 
 
 10 
 
 30 
 
 25 
 
 30 
 
 60 
 
 60 
 
 60 
 
 60 
 
 60 
 
 50 
 
 50 
 
 40 
 
 50 
 
 75 
 
 100 
 
 125 
 
 75 
 
 75 
 
 75 
 
 125 
 
 100 
 
 90 
 
 
 
 — 50 
 
 — 50 
 
 
 
 — 10 
 
 75 
 
 80 
 
 60 
 
 25 
 
 5 
 
 
 
 
 
 
 
 5 
 
 5 
 
 125 
 
 50 
 
 30 
 
 25 
 
 10 
 
 25 
 
 
 
 25 
 
 10 
 
 10 
 
 10 
 
 30 
 
 50 
 
 25 
 
 150 
 
 75 
 
 140 
 
 50 
 
 60 
 
 100 
 
 — 50 
 
 — 20 
 
 — 10 
 
 
 
 30 
 
 30 
 
 50 
 
 60 
 
 60 
 
 40 
 
 75 
 
 — 50 
 
 10 
 
 
 
 20 
 
 30 
 
 30 
 
 20 
 
 50 
 
 60 
 
 50 
 
 40 
 
 30 
 
 30 
 
 30 
 
 30 
 
 25 
 
 20 
 
 10 
 
 5 
 
 50 
 
 40 
 
 40 
 
 40 
 
 40 
 
 25 
 
 ' 50 
 
 50 
 
 50 
 
 50 
 
 50 
 
 50 
 
 20 
 
 30 
 
 30 
 
 30 
 
 30 
 
 25 
 
 
 
 30 
 
 30 
 
 25 
 
 60 
 
 60 
 
 75 
 
 75 
 
 100 
 
 90 
 
 60 
 
 20 
 
 
 
 20 
 
 10 
 
 10 
 
 10 
 
 10 
 
 —100 
 
 — 50 
 
 — 60 
 
 — 20 
 
 — 90 
 
 — 75 
 
 —100 
 
 
 
 100 
 
 75 
 
 25 
 
 
 
 30 
 
 30 
 
 10 
 
 §5 
 
 
 
 20 
 
 
 
 40 
 
 50 
 
 60 
 
 100 
 
 100 
 
 30 
 
 30 
 
 30 
 
 30 
 
 25 
 
 
 
 100 
 
 75 
 
 60 
 
 75 
 
 5 
 
 25 
 
 
 
 — 20 
 
 — 10 
 
 - 60 
 
 
 
 
 
 
 
 
 
 20 
 
 
 
 5 
 
 
 
 25 
 
 25 
 
 25 
 
 — 5 
 
 10 
 
 
 
 
 
 5 
 
 
 
 
 
 5 
 
 20 
 
 
 
 25 
 
 25 
 
 25 
 
 25 
 
 25 
 
 20 
 
 10 
 
 — 20 
 
 25 
 
 25 
 
 10 
 
 50 
 
 — 10 
 
 100 
 
 60 
 
 60 
 
 10 
 
 25 
 
 
 
 — 10 
 
 — 20 
 
 
 
 
 
 20 
 
 20 
 
 20 
 
 20 
 
 20 
 
 20 
 
 
 
 
 
 20 
 
 20 
 
 20 
 
 20 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 — 50 
 
 — 10 
 
 
 
 — 25 
 
 
 
 10 
 
 — 20 
 
 20 
 
 
 
 — 5 
 
 20 
 
 15 
 
 
 
 -20 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 — 25 
 
 — 10 
 
 
 
 
 
 
 
 
 
 
 
 10 
 
 5 
 
 10 
 
 
 
 — 5 
 
 
 
 
 
 100 
 
 
 
 
 
 
 
 
 
 
 
 -10 
 
 — 10 
 
 — 10 
 
 — 25 
 
 '"ioo" 
 
 ""ioo' 
 
 '"'ioo' 
 
 '"'ioo' 
 
 ...... 
 
 """96' 
 
 '""ioo" 
 
 '"iio" 
 
 ""256' 
 
 "m 
 
 """ioo" 
 
 "166" 
 
 50 
 
 100 
 
 75 
 
 100 
 
 100 
 
 50 
 
 125 
 
 75 
 
 75 
 
 30 
 
 20 
 
 30 
 
 25 
 
 10 
 
 20 
 
 
 
 — 5 
 
 20 
 
 —100 
 
 — 20 
 
 — 50 
 
 75 
 
 25 
 
 
 
 735 
 
 780 
 
 1,020 
 
 730 
 
 1,025 
 
 395 
 
 305 
 
 485 
 
 635 
 
 620 
 
 760 
 
 640 
 
 31 
 
 32 
 
 41 
 
 29 
 
 41 
 
 16 
 
 12 
 
 19 
 
 25 
 
 24 
 
 29 
 
 25 
 
 Itemarks. 
 
 SW. fr., rain. 
 NW. fr., rain. 
 S. fr., fair. 
 NW. fr., fair. 
 N. fr., fair. 
 N. It., fair. 
 Var. It., snow. 
 NW. br., snow. 
 SW. br., fair. 
 NW. br., clear. 
 NW. fr., cloudy. 
 SW. It., rain, snow. 
 NE. It., snow. 
 
 Do. 
 S. fr,, rain, fog. 
 S. It., fair. 
 NW. fr., clear. 
 
 Do. 
 NW. br., snow. 
 NW. gen., fair. 
 NW. fr., fair. 
 NW. fr., snow. 
 NW. fr., fair. 
 N. fr., fair. 
 NW. fr., fair. 
 NW. It., fair. 
 Var. It., rain. 
 NW. It., rain, snow. 
 N. fr., snow. 
 W. It., fair. 
 SE. fr., rain. 
 
 APRIL, 1885. 
 
 180 
 50 
 60 
 40 
 .50 
 
 50 
 20 
 80 
 50 
 
 160 
 
 100 
 
 100 
 
 30 
 
 50 
 
 40 
 
 - 20 
 
 — 50 
 75 
 80 
 
 100 
 
 100 
 
 50 
 
 50 
 
 50 
 
 40 
 
 100 
 
 —100 
 
 50 
 
 50 
 
 60 
 100 
 90 
 60 
 50 
 50 
 50 
 —200 
 50 
 50 
 
 
 80 
 60 
 50 
 50 
 70 
 00 
 100 
 40 
 60 
 
 — 40 
 75 
 50 
 60 
 35 
 50 
 25 
 
 — 20 
 50 
 40 
 
 — 25 
 
 50 
 
 — 40 
 50 
 25 
 50 
 
 — 40 
 
 
 50 
 50 
 
 
 40 
 — 50 
 50 
 30 
 60 
 40 
 20 
 50 
 50 
 
 — 30 
 25 
 
 — 90 
 50 
 
 100 
 50 
 20 
 20 
 50 
 25 
 
 - 90 
 25 
 50 
 50 
 35 
 70 
 
 20 
 60 
 60 
 
 75 
 25 
 
 —150 
 50 
 25 
 50 
 
 — 10 
 40 
 50 
 60 
 
 —100 
 25 
 
 —150 
 60 
 
 —200 
 
 50 
 
 
 
 50 
 
 50 
 
 100 
 
 Var. lt„fair, 
 E. fr.,fair. 
 S. fr.,rain. 
 S. It., rain, sleet. 
 NW. fr.,rain. 
 NW. br., clear. 
 E. It., rain. 
 W. lt.,rain, t. s. 
 NW. fr., clear. 
 E. It., cloudy. 
 NW. It., rain, snow. 
 NW. br.,fair. 
 NW. br.,rain. 
 NW. br..fair. 
 Var. It., rain. 
 
 Do. 
 E. It., cloudy. 
 Var. It., fair. 
 E. fir., clear. 
 SE. fr., clear. 
 SE. It., clear. 
 
 Do. 
 SE. fr., clear. 
 SE. fr., cloudy. 
 E. fr., cloudy. 
 SE. fr.,rain. 
 NW. fr., clear. 
 SE. It., rain. 
 NW. gen., clear. 
 W. fr., cloudy. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 '"""50' 
 
 50 
 
 
 
 90 
 
 50 
 
 100 
 
 200 
 
 100 
 
 75 
 
 50 
 
 15 
 
 50 
 
 30 
 
 
 
 110 
 
 85 
 
 150 
 
 170 
 
 100 
 
 100 
 
 70 
 
 — 10 
 
 30 
 
 65 
 
 
 
 25 
 
 130 
 
 95 
 
 200 
 
 150 
 
 
 
 100 
 
 50 
 
 
 
 — 10 
 50 
 
 100 
 
 75 
 
 150 
 
 160 
 
 — 25 
 60 
 70 
 
 — 20 
 
 —150 
 
 50 
 
 
 
 
 
 85 
 
 50 
 
 160 
 
 200 
 
 — 20 
 
 50 
 
 40 
 
 
 
 40 
 
 - 50 
 25 
 60 
 35 
 
 140 
 50 
 
 — 10 
 20 
 25 
 
 
 
 20 
 40 
 —100 
 10 
 50 
 35 
 160 
 25 
 
 — 10 
 
 
 25 
 
 — 30 
 
 20 
 50 
 
 300 
 50 
 30 
 45 
 
 150 
 
 50 
 
 65 
 
 
 
 30 
 
 - 15 
 
 25 
 25 
 
 40 
 75 
 60 
 140 
 15 
 25 
 
 — 5 
 10 
 
 — 5 
 
 25 
 
 ""36" 
 50 
 60 
 60 
 100 
 40 
 25 
 50 
 10 
 
 — 60 
 
 15 
 40 
 —100 
 25 
 60 
 50 
 150 
 50 
 25 
 
 
 30 
 
 
 
 25 
 
 25 
 
 100 
 
 
 
 
 
 50 
 
 120 
 
 50 
 
 5 
 
 5 
 
 30 
 
 10 
 
 "'"56' 
 
 
 30 
 50 
 50 
 
 30 
 
 60 
 
 — 40 
 
 30 
 
 70 
 
 —150 
 
 5 
 
 70 
 40 
 
 
 80 
 60 
 
 5 
 70 
 50 
 
 ...... 
 
 • 50 
 50 
 
 20 
 50 
 20 
 
 
 50 
 50 
 
 40 
 
 5 
 
 75 
 
 35 
 
 50 
 75 
 
 
 
 
 
 
 
 
 50 
 
 75 
 
 100 
 
 80 
 
 —100 
 
 
 
 
 
 
 
 
 1,395 
 67 
 
 1,605 
 67 
 
 1,385 
 55 
 
 920 
 37 
 
 1,120 
 45 
 
 800 
 33 
 
 570 
 22 
 
 1,255 
 
 48 
 
 815 
 31 
 
 850 
 34 
 
 580 
 22 
 
 565 
 22 
 
180 
 
 MEMOIKS OP THE NATIONAL ACADEMY OF SCIENCES. 
 
 Table A. — Hourly records, drawn from continuous photographic 
 MAY, 1885. 
 
 Day of montli. 
 
 1 a. m. 
 
 2 a. m. 
 
 3 a. m. 
 
 4 a, m. 
 
 5 a.m. 
 
 6a.in. 
 
 7a.ni. 
 
 8 a.m. 
 
 9 a.m. 
 
 10 a, m. 
 
 11 a.m. 
 
 12 m. 
 
 1 
 
 —250 
 
 20 
 
 
 
 250 
 
 20 
 
 
 
 50 
 
 20 
 
 
 
 —275 
 
 20 
 
 
 
 
 
 20 
 
 
 
 — 50 
 
 20 
 
 
 
 50 
 
 20 
 
 
 
 -250 
 
 20 
 
 
 
 — 50 
 
 20 
 
 
 
 
 
 20 
 
 
 
 25 
 
 20 
 
 
 
 100 
 
 20 
 
 
 
 2 
 
 3 
 
 4 
 
 5 
 
 
 50 
 — 70 
 60 
 60 
 120 
 40 
 90 
 50 
 
 
 50 
 
 
 
 
 50 
 
 —150 
 20 
 
 - 5 
 80 
 35 
 50 
 80 
 
 -125 
 
 60 
 
 5 
 
 
 150 
 
 20 
 50 
 90 
 35 
 85 
 55 
 50 
 50 
 25 
 
 
 
 100 
 
 5 
 
 40 
 
 
 
 100 
 
 35 
 
 100 
 
 —100 
 
 — 5 
 
 50 
 
 30 
 
 
 
 
 
 25 
 
 25 
 
 10 
 
 105 
 
 35 
 
 75 
 
 -110 
 
 50 
 
 25 
 
 30 
 
 
 
 —100 
 
 —100 
 
 90 
 
 20 
 
 110 
 
 40 
 
 75 
 
 —150 
 
 50 
 
 foo 
 
 
 
 100 
 
 10 
 
 — 50 
 60 
 
 100 
 
 35 
 
 75 
 
 —100 
 
 
 
 50 
 
 — 25 
 
 
 
 120 
 
 —100 
 
 200 
 
 50 
 
 110 
 
 80 
 
 50 
 
 — 50 
 
 
 50 
 
 - 20 
 
 
 
 60 
 
 —200 
 
 
 
 150 
 
 95 
 
 ^^ 
 
 —100 
 
 
 
 50 
 
 10 
 
 
 
 50 
 
 —150 
 
 70 
 
 100 
 
 110 
 
 100 
 
 35 
 
 —200 
 
 
 
 5 
 
 
 
 
 
 130 
 
 —200 
 
 80 
 
 130 
 
 115 
 
 85 
 
 25 
 
 —250 
 
 
 
 5 
 
 
 
 
 
 200 
 
 
 
 80 
 
 120 
 
 110 
 
 50 
 
 25 
 
 —300 
 
 
 
 5 
 
 
 
 6 
 
 7 
 
 8 
 
 9 
 
 10 
 
 11 
 
 12 
 
 13... 
 
 14 
 
 15 
 
 16 
 
 17 
 
 18 
 
 100 
 
 — 15 
 
 
 
 45 
 
 —100 
 
 — 50 
 
 
 
 50 
 
 200 
 
 60 
 
 5 
 75 
 
 — 20 
 —100 
 
 25 
 
 15 
 
 50 
 
 5 
 
 — 50 
 
 — 55 
 
 
 20 
 100 
 50 
 50 
 75 
 20 
 —100 
 
 10 
 
 — 20 
 50 
 50 
 
 
 
 — 50 
 
 
 
 (/ 
 
 100 
 
 50 
 
 50 
 
 65 
 
 
 
 -65 
 
 
 50 
 50 
 60 
 20 
 
 — 45 
 
 
 
 100 
 60 
 50 
 60 
 10 
 
 — 15 
 
 
 
 
 
 50 
 
 5 
 
 —100 
 
 — 45 
 
 
 
 
 
 100 
 
 50 
 
 — 25 
 60 
 
 
 
 
 
 
 
 
 
 
 140 
 
 35 
 
 90 
 
 50 
 
 19. 
 
 20 
 
 50 
 
 50 
 
 —200 
 
 
 
 
 
 
 
 100 
 
 50 
 
 50 
 
 60 
 
 30 
 
 — 25 
 
 — 50 
 50 
 
 —200 
 
 
 
 
 
 
 
 50 
 
 5 
 
 50 
 
 55 
 
 50 
 
 — 25 
 
 15 
 
 75 
 
 —300 
 
 — 20 
 
 
 
 50 
 45 
 65 
 65 
 50 
 
 — 50 
 
 50 
 
 75 
 
 —200 
 
 — 40 
 
 
 
 30 
 50 
 45 
 65 
 20 
 
 — 40 
 
 40 
 
 50 
 
 —200 
 
 — 25 
 
 
 
 30 
 50 
 60 
 60 
 
 — 40 
 
 — 65 
 
 50 
 
 50 
 
 -100 
 
 — 30 
 
 
 100 
 20 
 50 
 85 
 60 
 
 — 50 
 
 — 60 
 
 70 
 30 
 
 — 50 
 
 — 35 
 
 
 75 
 
 
 
 50 
 
 110 
 
 60 
 
 — 50 
 
 — 60 
 
 21 
 
 22 
 
 23 
 
 24 
 
 25 
 
 26 
 
 27 
 
 28 
 
 29 
 
 30 
 
 31 
 
 Sums . 
 
 470 
 
 18 
 
 575 
 22 
 
 920 
 37 
 
 500 
 20 
 
 385 
 17 
 
 310 
 14 
 
 320 
 15 
 
 255 
 12 
 
 390 
 17 
 
 135 
 6 
 
 430 
 19 
 
 660 
 29 
 
 Means .... 
 
 
 1. 
 
 2. 
 3. 
 
 4. 
 
 5. 
 
 6. 
 
 7. 
 
 8. 
 
 9. 
 10. 
 11. 
 12. 
 13. 
 14. 
 15. 
 16. 
 17. 
 18., 
 19.. 
 20. 
 21.. 
 22., 
 23. 
 24. 
 25. 
 26. 
 27., 
 28., 
 29.. 
 30., 
 
 JUNE, 1885. 
 
 - 50 
 60 
 
 100 
 75 
 
 60 
 75' 
 60 
 75 
 70 
 70 
 60 
 65 
 
 - 20 
 
 
 50 
 -100 
 70 
 70 
 65 
 50 
 120 
 50 
 40 
 10 
 
 - 60 
 100 
 
 
 95 
 80 
 
 Sums .. 
 Means . 
 
 1,340 
 45 
 
 - 40 
 75 
 
 100 
 70 
 
 75 
 70 
 60 
 75 
 75 
 40 
 50 
 60 
 
 - 30 
 
 
 50 
 30 
 75 
 50 
 60 
 50 
 125 
 60 
 40 
 
 5 
 
 - 60 
 100 
 
 - 20 
 95 
 80 
 
 1,430 
 47 
 
 — 30 
 60 
 90 
 70 
 
 
 100 
 70 
 60 
 80 
 80 
 70 
 60 
 60 
 
 — 10 
 
 
 50 
 30 
 70 
 50 
 60 
 50 
 125 
 60. 
 10 
 20 
 
 — 60 
 95 
 
 -200 
 
 100 
 
 80 
 
 1,300 
 43 
 
 — 20 
 60 
 
 90 
 70 
 
 90 
 70 
 60 
 80 
 90 
 65 
 60 
 45 
 
 — 10 
 
 
 50 
 50 
 70 
 50 
 50 
 50 
 120 
 70 
 10 
 50 
 
 — 75 
 90 
 
 —300 
 
 100 
 
 85 
 
 1, 220 
 41 
 
 
 75 
 
 100 
 
 70 
 
 
 
 100 
 70 
 60 
 
 105 
 
 100 
 30 
 40 
 50 
 
 10 
 60 
 80 
 70 
 60 
 60 
 35 
 
 115 
 70 
 10 
 50 
 — 56 
 60 
 —300 
 
 100 
 90 
 
 1,315 
 44 
 
 10 
 50 
 
 100 
 
 65 
 
 
 
 100 
 65 
 30 
 
 110 
 75 
 50 
 85 
 50 
 
 15 
 80 
 50 
 65 
 25 
 50 
 40 
 
 115 
 95 
 15 
 30 
 - 55 
 50 
 -250 
 85 
 
 105 
 
 1,305 
 44 
 
 20 
 50 
 
 100 
 50 
 10 
 
 100 
 65 
 25 
 
 150 
 70 
 
 140 
 70 
 50 
 
 20 
 60 
 80 
 90 
 50 
 
 40 
 
 130 
 
 90 
 
 
 
 10 
 
 - 90 
 
 45 
 
 —100 
 
 100 
 
 100 
 
 1, 525 
 51 
 
 110 
 75 
 
 100 
 
 50 
 
 10 
 
 120 
 
 70 
 
 
 
 165 
 
 100 
 
 90 
 
 50 
 
 35 
 
 — 10 
 
 50 
 
 50 
 
 100 
 
 50 
 
 65 
 
 100 
 
 40 
 
 125 
 
 100 
 
 
 
 
 
 —100 
 
 5 
 
 —100 
 
 100 
 
 90 
 
 1,640 
 55 
 
 100 
 100 
 150 
 100 
 
 30 
 130 
 
 55 
 
 - 60 
 200 
 100 
 
 80 
 75 
 50 
 
 - 10 
 60 
 40 
 
 110 
 60 
 50 
 
 100 
 35 
 
 125 
 
 100 
 
 - 10 
 
 - 10 
 
 - 95 
 
 5 
 
 - 50 
 100 
 
 90 
 
 1,810 
 60 
 
 100 
 
 150 
 75 
 
 — 10 
 100 
 
 55 
 
 — 60 
 150 
 110 
 
 85 
 10 
 50 
 
 — 10 
 60 
 25 
 
 110 
 70 
 50 
 
 110 
 25 
 
 135 
 
 100 
 
 — 10 
 
 5 
 
 —105 
 
 40 
 
 
 85 
 15 
 
 1,520 
 52 
 
 155 
 
 100 
 
 
 
 100 
 
 60 
 
 — 25 
 150 
 150 
 110 
 
 
 50 
 
 — 10 
 60 
 25 
 
 105 
 
 50 
 130 
 
 15 
 140 
 100 
 
 - 50 
 
 - 15 
 
 - 90 
 70 
 
 
 
 MO 
 
 50 
 
 1,530 
 
 57 
 
 30 
 
 130 
 100 
 
 - 20 
 90 
 60 
 
 
 
 150 
 
 175 
 
 10 
 
 
 100 
 
 - 10 
 60 
 25 
 
 100 
 
 50 
 
 100 
 
 
 
 130 
 
 80 
 
 — 50 
 
 — 35 
 —100 
 
 60 
 
 
 100 
 
 1,275 
 51 
 
MEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES. 
 
 181 
 
 registration, at Baltimore, Md., 1885, 1886, and 1887— Continued. 
 
 MAY, 1885. 
 
 1 p.m. 
 
 2 p.m. 
 
 3 p.m. 
 
 4 p.m. 
 
 5 p.m. 
 
 6 p.m. 
 
 7 p.m. 
 
 8 p.m. 
 
 9p.m_ 
 
 10 p. m. 
 
 11 p, m. 
 
 12 mid. 
 
 Remarks. 
 
 
 
 / 
 
 
 
 
 100 
 100 
 
 50 
 100 
 
 45 
 100 
 
 35 
 
 »0 
 
 25 
 
 50 
 
 20 
 5 
 
 E.fr,, rain. 
 NW.fr., <air. 
 NW.fr., rain. 
 NW.br., fair. 
 N. It., fair. 
 SE.fr., rain. 
 E.fr., rain. 
 NE.lt., cloudy. 
 SE.fr., cloudy. 
 NW. fr., fair. 
 
 Do. 
 NW. It., fair. 
 NE.fr., rain. 
 NW.fr., rain. 
 N.fr., clear. 
 E.fr., clear. 
 E.fr., rain. 
 Var. It., fair. 
 SE.lt., fair. 
 SE.lt., rain. 
 SE.fr., rain. 
 
 Do. 
 E. It., rain. 
 SE.fr., rain. 
 SE. fr.,rain,t. b. 
 Var. It., rain. 
 NE.lt., rain. 
 
 Do. 
 Var. It. , rain. 
 
 Do. 
 SE. fr.,rain,t. s. 
 
 100 
 
 50 
 
 135 
 
 120 
 
 
 
 
 
 
 
 100 
 
 150 
 
 —250 
 
 50 
 
 120 
 
 15 
 
 50 
 
 150 
 
 
 
 100 
 
 130 
 
 — 10 
 
 50 
 
 160 
 
 100 
 
 75 
 
 170 
 
 0- 
 
 120 
 
 200 
 
 100 
 
 100 
 
 120 
 
 100 
 
 75 
 
 300 
 
 —175 
 
 25 
 
 60 
 
 
 
 200 
 
 260 
 
 — 50 
 
 75 
 
 50 
 
 100 
 
 80 
 
 100 
 
 —125 
 
 25 
 
 45 
 
 
 
 50 
 
 120 
 
 100 
 
 75 
 
 —100 
 
 100 
 
 60 
 
 150 
 
 — 90 
 
 
 
 
 
 
 
 100 
 
 200 
 
 100 
 
 80 
 
 — 10 
 85 
 
 • 55 
 100 
 
 — 60 
 —200 
 
 
 
 
 
 90 
 
 150 
 
 100 
 
 60 
 
 60 
 
 70 
 
 5 
 
 15 
 
 — 50 
 
 10 
 
 50 
 
 
 10 
 200 
 100 
 80 
 60 
 50 
 
 5 
 70 
 80 
 60 
 
 
 
 
 
 
 
 100 
 
 50 
 
 50 
 
 50 
 
 50 
 
 70 
 
 50 
 
 50 
 
 60 
 
 — 75 
 
 
 50 
 60 
 50 
 50 
 60 
 40 
 100 
 50 
 .50 
 50 
 — 15 
 
 
 
 100 
 
 100 
 
 10 
 
 70 
 
 65 
 
 40 
 
 100 
 
 100 
 
 50 
 
 50 
 
 10 
 
 
 
 100 
 
 50 
 
 40 
 
 60 
 
 65 
 
 40 
 
 100 
 
 50 
 
 
 
 50 
 
 a 
 
 70 
 50 
 
 50 
 50 
 
 100 
 
 100 
 
 50 
 
 100 
 
 25 
 
 40 
 
 50 
 200 
 150 
 
 70 
 100 
 
 20 
 
 90 
 
 210 
 
 100 
 
 110 
 
 50 
 
 50 
 
 150 
 
 
 
 160 
 
 40 
 
 -125 
 
 125 
 
 —100 
 
 75 
 
 —200 
 
 100 
 
 200 
 50 
 
 100 
 50 
 40 
 75 
 30 
 
 160 
 
 
 100 
 
 100 
 
 — 75 
 
 20 
 
 300 
 
 50 
 
 150 
 
 70 
 
 170 
 
 50 
 
 25 
 
 75 
 
 
 
 100 
 
 50 
 
 75 
 
 65 
 
 —150 
 
 75 
 
 50 
 
 60 
 
 50 
 
 50 
 
 
 
 15 
 
 - 20 
 
 45 
 
 35 
 
 130 
 
 150 
 
 160 
 
 50 
 
 
 
 50 
 
 60 
 
 45 
 
 40 
 
 50 
 
 
 
 
 
 — 45 
 
 45 
 
 5 
 
 120 
 
 70 
 
 170 
 
 70 
 
 20 
 
 —100 
 
 
 
 60 
 20 
 50 
 50 
 
 — 10 
 
 — 50 
 20 
 20 
 
 100 
 
 100 
 
 110 
 
 105 
 
 25 
 
 —100 
 
 —300 
 
 90 
 10 
 50 
 50 
 
 
 — 50 
 
 
 
 50 
 
 100 
 
 (50 
 
 50 
 
 85 
 
 
 
 —100 
 
 — 60 
 
 50 
 
 30 
 20 
 10 
 
 — 50 
 
 
 
 60 
 
 70 
 
 45 
 
 100 
 
 100 
 
 
 
 —100 
 
 — 50 
 
 50 
 
 
 
 25 
 
 20 
 
 — 15 
 
 — 50 
 
 
 20 
 50 
 40 
 60 
 70 
 
 
 —100 
 
 — 30 
 
 100 
 10 
 20 
 30 
 
 — oO 
 
 — 50 
 
 
 15 
 —200 
 50 
 50 
 70 
 
 — 20 
 —100 
 
 — 30 
 
 '"'ioo' 
 6" 
 
 100 
 
 — 50 
 
 150 
 
 50 
 
 —130 
 150 
 
 
 
 —300 
 
 —300 
 
 920 
 
 4^ 
 
 1,385 
 60 
 
 1,895 
 70 
 
 2, 130 
 79 
 
 1, 3-iO 
 51 
 
 1,285 
 49 
 
 1,250 
 44 
 
 1,065 
 38 
 
 925 
 34 
 
 945 
 35 
 
 910 
 34 
 
 475 
 
 18 
 
 JUNE, 1885. 
 
 
 100 
 
 150 
 
 70 
 200 
 150 
 
 200 
 
 70 
 
 200 
 
 250 
 
 200 
 
 70 
 
 250 
 
 —100 
 
 
 
 
 
 
 50 
 
 25 
 
 60 
 
 
 
 .50 
 
 100 
 
 60 
 
 
 
 NW.fr., clear. 
 Do. 
 Do. 
 
 SE. lt.,rain,t.8. 
 
 100 
 
 250 
 
 — 10 
 
 50 
 
 70 
 
 
 
 50 
 
 100 
 
 10 
 
 20 
 
 100 
 
 
 
 25 
 
 60 
 
 
 
 
 
 
 100 
 
 
 
 50 
 
 —350 
 
 —100 
 
 50 
 
 10 
 
 
 
 10 
 
 30 
 
 , 50 
 
 50 
 
 60 
 
 N. gen., rain, hail, t. s. 
 
 50 
 
 75 
 
 50 
 
 50 
 
 100 
 
 80 
 
 100 
 
 90 
 
 100 
 
 100 
 
 95 
 
 75 
 
 SE. fr., clear 
 
 
 100 
 
 100 
 
 80 
 
 60 
 
 50 
 
 30 
 
 30 
 
 10 
 
 50 
 
 60 
 
 60 
 
 SE. fr., rain, t. s. 
 
 
 
 65 
 
 100 
 
 — 10 
 
 65 
 
 90 
 
 150 
 
 50 
 100 
 150 
 
 50 
 110 
 100 
 
 50 
 150 
 100 
 
 100 
 
 160 
 
 60 
 
 100 
 
 150 
 
 60 
 
 90 
 
 125 
 
 50 
 
 75 
 150 
 100 
 
 65 
 100 
 
 80 
 
 Var. It., rain. 
 NW.fr., clear. 
 Var.lt., fair. 
 
 
 
 
 - 10 
 
 
 100 
 
 100 
 
 100 
 
 60 
 
 50 
 
 60 
 
 100 
 
 100 
 
 80 
 
 85 
 
 60 
 
 S, It., clear. 
 
 100 
 
 150 
 
 130 
 
 110 
 
 100 
 
 100 
 
 50 
 
 110 
 
 95 
 
 70 
 
 70 
 
 70 
 
 S. fr., clear. 
 
 
 
 - 10 
 
 — 10 
 
 - 20 
 
 — 30 
 
 -ao 
 
 5 
 
 5 
 
 
 
 
 
 — 10 
 
 — 15 
 
 S. br., fair. 
 
 
 
 40 
 
 30 
 
 30 
 
 40 
 
 50 
 
 60 
 
 50 
 
 
 
 
 
 
 
 NW. br. thtn'g, lightn'g. 
 
 
 
 - 20 
 
 — 20 
 
 - 50 
 
 - 30 
 
 -125 
 
 —300 
 
 —100 
 
 - 90 
 
 — 50 
 
 30 
 
 50 
 
 N. It., rain, t. s. 
 
 25 
 
 20 
 
 40 
 
 100 
 
 110 
 
 150 
 
 
 
 —200 
 
 — 20 
 
 
 
 30 
 
 
 
 W. fr., rain, t. s. 
 
 10 
 
 75 
 
 50 
 
 100 
 
 100 
 
 100 
 
 70 
 
 70 
 
 95 
 
 55 
 
 70 
 
 65 
 
 N.fr., rain. 
 
 
 
 
 
 
 50 
 100 
 
 100 
 70 
 
 110 
 80 
 
 90, 
 100 
 
 80 
 100 
 
 55 
 
 90 
 
 105 
 75 
 
 SE.fr., clear. 
 Var. It. , clear. 
 
 .50 
 
 50 
 
 80 
 
 ioo 
 
 100 
 
 60 
 
 100 
 
 75 
 
 60 
 
 60 
 
 25 
 
 50 
 
 50 
 
 60 
 
 55 
 
 50 
 
 50 
 
 W. It., fair. 
 
 
 
 50 
 15 
 
 55 
 25 
 
 50 
 25 
 
 100 
 15 
 
 100 
 20 
 
 100 
 15 
 
 110 
 20 
 
 100 
 30 
 
 110 
 40 
 
 110 
 45 
 
 SW.br., fair. 
 W. fr.,/air. 
 
 
 
 15 
 
 20 
 
 25 
 
 30 
 
 40 
 
 50 
 
 40 
 
 
 
 20 
 
 10 
 
 25 
 
 30 
 
 25 
 
 NW.ff., clear. 
 
 
 — 40 
 
 30 
 
 30 
 
 10 
 
 20 
 
 40 
 
 25 
 
 70 
 
 40 
 
 10 
 
 10 
 
 Var. It., fair. 
 
 — 5 
 
 50 
 
 
 
 5 
 
 — 35 
 
 — 30 
 
 — 50 
 
 — 50 
 
 — 90 
 
 — 90 
 
 — 85 
 
 — 90 
 
 Var. It. , rain. 
 
 
 
 100 
 
 100 
 
 100 
 
 110 
 
 150 
 
 135 
 
 145 
 
 140 
 
 115 
 
 95 
 
 95 
 
 S. It., rain. 
 
 150 
 
 — 20 
 
 100 
 
 80 
 
 80 
 
 90 
 
 90 
 
 60 
 
 60 
 
 
 
 50 
 
 30 
 
 E. It., rain. 
 
 
 
 100 
 70 
 
 
 75 
 
 70 
 60 
 
 90 
 
 75 
 
 60 
 
 75 
 
 50 
 
 85 
 
 55 
 
 80 
 
 60 
 70 
 
 90 
 60 
 
 85 
 70 
 
 NE.fr., hvy.rn.(4.47)t.B. 
 NW. fr.,fair. 
 
 
 50 
 
 25 
 
 25 
 
 50 
 
 25 
 
 20 
 
 20 
 
 20 
 
 20 
 
 15 
 
 20 
 
 70 
 
 65 
 
 NW.br., fair. 
 
 485 
 
 1,115 
 
 1,555 
 
 2. 020 
 
 1,870 
 
 1,790 
 
 1,195 
 
 1,365 
 
 1,520 
 
 1,310 
 
 1,605 
 
 1,555 
 
 35 
 
 51 
 
 54 
 
 70 
 
 64 
 
 62 
 
 41 
 
 47 
 
 52 
 
 45 
 
 54 
 
 52 
 
 
182 
 
 MEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES. 
 
 Table A. — hourh/ records, drawn from continuous photographic 
 
 JULY, 1885. 
 
 . Day of mouth. 
 
 1 a. m. 
 
 2 a. m. 
 
 3 a. m. 
 
 4 a. m. 
 
 5 a.m. 
 
 6 a.m. 
 
 7 a.m. 
 
 8 a.m. 
 
 9 a.m. 
 
 10 a. m. 
 
 11 a. m. 
 
 12 m. 
 
 1 
 
 50 
 45 
 
 — 15 
 50 
 50 
 
 — 25 
 45 
 85 
 
 
 
 140 
 50 
 60 
 15 
 • 25 
 55 
 50 
 15 
 20 
 40 
 5 
 40 
 40 
 60 
 50 
 40 
 20 
 15 
 50 
 20 
 40 
 
 60 
 40 
 
 — 5 
 60 
 50 
 
 -25 
 
 50 
 
 100 
 
 — 5 
 
 
 140 
 25 
 60 
 50 
 45 
 60 
 60 
 15 
 20 
 25 
 10 
 40 
 45 
 40 
 50 
 30 
 
 20 
 65 
 20 
 60 
 
 55 
 40 
 
 — 10 
 60 
 55 
 
 — 25 
 50 
 
 110 
 
 — 15 
 20 
 
 135 
 40 
 50 
 50 
 25 
 65 
 60 
 20 
 20 
 25 
 10 
 40 
 30 
 20 
 50 
 30 
 
 25 
 60 
 30 
 65 
 
 55 
 20 
 
 — 15 
 65 
 60 
 
 
 
 50 
 
 200 
 
 — 15 
 20 
 
 130 
 40 
 60 
 —200 
 40 
 65 
 60 
 25 
 20 
 25 
 15 
 40 
 25 
 60 
 60 
 30 
 
 25 
 50 
 40 
 50 
 
 90 
 40 
 
 
 90 
 80 
 
 
 35 
 230 
 — 10 
 20 
 135 
 30 
 50 
 40 
 70 
 90 
 65 
 50 
 20 
 40 
 15 
 50 
 20 
 50 
 60 
 30 
 
 
 75 
 
 
 40 
 30 
 
 100 
 50 
 
 — 30 
 70 
 
 105 
 
 — 20 
 20 
 
 250 
 
 
 
 50 
 
 150 
 40 
 60 
 40 
 
 100 
 90 
 80 
 50 
 30 
 45 
 15 
 30 
 15 
 
 80 
 50 
 
 — 50 
 75 
 75 
 20 
 30 
 
 100 
 10 
 
 — 25 
 
 5 
 110 
 
 — 20 
 10 
 
 250 
 
 5 
 30 
 13b 
 45 
 50 
 50 
 
 
 100 
 45 
 50 
 30 
 25 
 10 
 30 
 
 
 10 
 60 
 50 
 
 
 80 
 75 
 25 
 20 
 
 110 
 10 
 
 — 50 
 30 
 
 110 
 
 — 30 
 
 5 
 
 265 
 
 
 
 30 
 
 110 
 
 60 
 
 75 
 
 50 
 
 50 
 
 70 
 
 110 
 
 40 
 
 30 
 
 25 
 
 10 
 
 30 
 
 
 
 60 
 
 50 
 
 50 
 
 50 
 
 70 
 
 50 
 
 20 
 
 70 
 
 95 
 15 
 
 — 20 
 45 
 
 105 
 
 — 20 
 
 
 250 
 
 — 20 
 30 
 
 110 
 50 
 90 
 50 
 50 
 60 
 50- 
 25 
 30 
 25 
 5 
 50 
 
 
 100 
 40 
 20 
 30 
 60 
 50 
 10 
 
 100 
 
 50 
 
 
 — 20 
 50 
 
 105 
 
 — 20 
 
 — 25 
 - 260 
 
 — 20 
 30 
 
 105 
 55 
 80 
 45 
 25 
 40 
 60 
 25 
 30 
 25 
 5 
 40 
 
 
 130 
 40 
 20 
 60 
 50 
 50 
 5 
 
 100 
 
 60 
 30 
 
 — 20 
 50 
 80 
 
 — 60 
 
 — 45 
 255 
 
 — 15 
 30 
 
 110 
 50 
 85 
 60 
 40 
 40 
 60 
 25 
 30 
 25 
 50 
 50 
 
 100 
 
 100 
 60 
 20 
 50 
 
 100 
 60 
 20 
 90 
 
 50 
 250 
 
 — 30 
 50 
 80 
 
 — 60 
 
 — 50 
 250 
 
 — 10 
 30 
 
 110, 
 50 
 90 
 50 
 50 
 30 
 50 
 25 
 30 
 30 
 60 
 
 "'"50" 
 70 
 50 
 20 
 
 """76" 
 
 100 
 
 30 
 
 20 
 
 2 
 
 3 
 
 4 
 
 5^ 
 
 6 
 
 7. 
 
 8 
 
 9 
 
 10 
 
 11 
 
 12 
 
 13 
 
 14 
 
 15 
 
 16 
 
 17 
 
 18 
 
 19 
 
 ao 
 
 21 
 
 22 
 
 23 
 
 24 
 
 25 
 
 26 
 
 27 
 
 28 
 
 29 
 
 30 
 
 31 
 
 
 1,135 
 37 
 
 1,205 
 39 
 
 1,190 
 38 
 
 1,100 
 35 
 
 1,535 
 
 50 
 
 1,620 
 52 
 
 1,405 
 45 
 
 1,555 
 50 
 
 1,485 
 
 48 
 
 1,400 
 45 
 
 1,590 
 51 
 
 1,545 
 53 
 
 
 
 AUGUST, 1885. 
 
 7. 
 
 8. 
 
 9. 
 10. 
 11. 
 12. 
 13. 
 14. 
 15. 
 16. 
 17. 
 18. 
 19. 
 20. 
 21. 
 22. 
 23. 
 24. 
 25. 
 26. 
 27. 
 28. 
 29. 
 30. 
 31. 
 
 Sums- . 
 Means. 
 
 20 
 20 
 
 -300 
 60 
 
 ■ 30 
 50 
 70 
 20 
 50 
 20 
 85 
 80 
 50 
 30 
 40 
 45 
 50 
 70 
 
 25 
 50 
 25 
 10 
 60 
 65 
 30 
 
 80 
 
 50 
 
 20 
 
 
 
 905 
 31 
 
 20 
 20 
 300 
 70 
 25 
 45 
 90 
 10 
 50 
 20 
 85 
 80 
 50 
 30 
 35 
 40 
 60 
 70 
 15 
 45 
 50 
 40 
 60 
 60 
 50 
 30 
 
 70 
 
 55 
 
 40 
 
 
 
 1,615 
 56 
 
 10 
 15 
 
 50 
 65 
 30 
 40 
 110 
 25 
 60 
 15 
 70 
 80 
 50 
 50 
 35 
 50 
 50 
 80 
 15 
 40 
 45 
 50 
 70 
 60 
 40 
 40 
 
 45 
 
 70 
 
 50 
 
 
 
 1,410 
 49 
 
 50 
 
 50 
 50 
 20 
 50 
 20 
 40 
 70 
 15 
 40 
 70 
 70 
 60 
 40 
 40 
 50 
 90 
 10 
 40 
 60 
 45 
 60 
 60 
 45 
 50 
 30 
 40 
 70 
 40 
 
 
 1,375 
 
 47 
 
 50 
 
 50 
 75 
 50 
 70 
 95 
 30 
 80 
 
 60 
 20 
 50 
 50 
 50 
 30 
 40 
 70 
 15 
 40 
 95 
 50 
 30 
 70 
 50 
 50 
 40 
 55 
 50 
 20 
 
 
 1,435 
 49 
 
 20 
 
 
 
 60 
 
 70 
 
 100 
 
 100 
 
 110 
 
 50 
 
 100 
 
 5 
 
 80 
 
 80 
 
 50 
 
 70 
 
 60 
 
 30 
 
 80 
 
 80 
 
 10 
 
 45 
 
 50 
 
 40 
 
 
 
 90 
 
 50 
 
 70 
 
 50 
 
 60 
 
 100 
 
 50 
 
 
 
 1,760 
 63 
 
 20 
 
 
 100 
 70 
 50 
 20 
 70 
 50 
 110 
 
 5 
 100 
 50 
 ■60 
 60 
 50 
 50 
 - 10 
 50 
 20 
 50 
 50 
 35 
 
 
 70 
 50 
 80 
 60 
 80 
 100 
 100 
 
 
 
 1,600 
 57 
 
 50 
 
 
 -300 
 50 
 50 
 20 
 30 
 50 
 90 
 
 
 70 
 100 
 70 
 70 
 65 
 60 
 70 
 50 
 
 
 60 
 90 
 45 
 
 
 70 
 20 
 80 
 55 
 50 
 70 
 90 
 
 
 
 1,215 
 45 
 
 60 
 
 
 -300 
 50 
 35 
 50 
 
 - 5 
 50 
 90 
 
 80 
 100 
 70 
 70 
 50 
 50 
 
 40 
 
 
 
 50 
 
 50 
 
 30 
 
 
 
 60 
 
 
 
 30 
 
 75 
 
 90 
 
 60 
 
 
 
 1,000 
 40 
 
 60 
 
 
 - 10 
 50 
 30 
 70 
 
 
 
 - 10 
 85 
 
 
 80 
 110 
 60 
 70 
 40 
 50 
 50 
 30 
 
 
 56 
 40 
 40 
 
 
 20 
 
 
 15 
 
 90 
 
 70 
 
 30 
 
 
 
 1,125 
 45 
 
 60 
 
 
 
 10 
 
 50 
 
 30 
 
 60 
 
 - 60 
 
 25 
 
 8.''i 
 
 
 
 100 
 
 100 
 
 50 
 
 60 
 
 25 
 
 50 
 
 00 
 
 
 
 40 
 
 70 
 
 50 
 
 20 
 
 
 
 40 
 
 
 
 5 
 
 100 
 
 110 
 
 
 
 
 
 1,140 
 !>0 
 
 
 
 — 10 
 
 "*30" 
 70 
 
 — 30 
 50 
 
 100 
 
 
 70 
 
 100 
 
 60 
 
 50 
 
 50 
 
 50 
 
 60 
 
 
 
 40 
 
 50 
 
 6U 
 
 10 
 
 
 
 50 
 
 
 
 
 
 100 
 
 100 
 
 
 
 
 
 1,060 
 50 
 
MEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES. 
 
 183 
 
 registration, at Baltimore, Md., 1885, 1886, <md 1887 — Continued* 
 
 JULY, 1885. 
 
 1 p.m. 
 
 2 p.m. 
 
 3 p.m. 
 
 4 p.m. 
 
 5p.m. 
 
 6 p.m. 
 
 7 p.m. 
 
 8 p.m. 
 
 9 p.m. 
 
 10 p. m. 
 
 11p.m. 
 
 12 mia. 
 
 Kemarks. 
 
 40 
 
 35 
 
 40 
 
 40 
 
 25 
 
 35 
 
 2Q 
 
 25 
 
 30 
 
 40 
 
 40 
 
 40 
 
 NW. fr., fair. 
 
 
 —150 
 
 - 30 
 
 — 10 
 
 — 10 
 
 
 
 — 15 
 
 - 10 
 
 - 10 
 
 
 
 5 
 
 - 10 
 
 - 10 
 
 NW. fr., raiD. 
 
 
 
 
 25 
 
 25 
 
 30 
 
 40 
 
 40 
 
 50 
 
 50 
 
 55 
 
 55 
 
 15 
 
 30 
 
 NW. fr., fair. 
 
 
 40 
 
 50 
 
 65 
 
 80 
 
 80 
 
 90 
 
 110 
 
 95 
 
 90 
 
 65 
 
 45 
 
 25 
 
 SW. fr., clear. 
 
 
 — 10 
 
 -300 
 
 -200 
 
 — 30 
 
 -100 
 
 —120 
 
 —120 
 
 - 90 
 
 - 50 
 
 — 50 
 
 — 20 
 
 — 20 
 
 SW. fr., rain, t. s. 
 
 
 20 
 
 20 
 
 100 
 
 100 
 
 100 
 
 120 
 
 100 
 
 80 
 
 80 
 
 50 
 
 50 
 
 60 
 
 SW. fr., rain. 
 
 
 
 
 — 60 
 
 60 
 
 80 
 
 90 
 
 150 
 
 160 
 
 160 
 
 150 
 
 110 
 
 ;io 
 
 110 
 
 Var. It., rain. 
 
 
 
 - 10 
 
 
 
 — 5 
 
 50 
 
 50 
 
 20 
 
 25 
 
 
 
 - 10 
 
 40 
 
 10 
 
 Var. It., clear. 
 
 
 
 10 
 
 50 
 
 50 
 
 60 
 
 60 
 
 80 
 
 100 
 
 80 
 
 60 
 
 
 
 
 
 SW. hi., lightning, 
 
 
 io 
 
 
 
 
 
 20 
 
 20 
 
 15 
 
 20 
 
 40 
 
 50 
 
 60 
 
 150 
 
 145 
 
 NW. fr., rain. 
 
 
 100 
 
 40 
 
 25 
 
 40 
 
 60 
 
 
 
 
 
 50 
 
 15 
 
 40 
 
 40 
 
 40 
 
 Var. fr., fair. 
 
 
 50 
 
 50 
 
 50 
 
 60 
 
 60 
 
 50 
 
 50 
 
 60 
 
 70 
 
 50 
 
 50 
 
 55 
 
 NE. fr., clear. 
 
 
 50 
 
 80 
 
 90 
 
 75 
 
 100 
 
 60 
 
 50 
 
 60 
 
 60 
 
 40 
 
 25 
 
 10 
 
 SE. fr., rain. 
 
 
 50 
 
 50 
 
 40 
 
 25 
 
 
 
 
 
 25 
 
 40 
 
 25 
 
 45 
 
 30 
 
 35 
 
 S. fr., rain. 
 
 
 50 
 
 75 
 
 100 
 
 140 
 
 90 
 
 50 
 
 50 
 
 50 
 
 70 
 
 70 
 
 50 
 
 100 
 
 Var. It., clear. 
 
 
 50 
 
 65 
 
 65 
 
 60 
 
 50 
 
 55 
 
 40 
 
 50 
 
 50 
 
 
 
 50 
 
 25 
 
 S. It., clear. 
 
 
 45 
 
 25 
 
 50 
 
 80 
 
 80 
 
 50 
 
 30 
 
 70 
 
 30 
 
 50 
 
 100 
 
 5)5 
 
 S. It., fair. 
 
 
 20 
 
 20 
 
 20 
 
 60 
 
 30 
 
 10 
 
 - 10 
 
 -100 
 
 
 
 
 
 .%, 20 
 
 20 
 
 N. fr., rain, t. s. 
 
 
 
 30 
 
 30 
 
 35 
 
 35 
 
 10 
 
 50 
 
 25 
 
 20 
 
 20' 
 
 "? 20 
 
 20 
 
 Var. It., fair. 
 
 
 "50 
 
 40 
 
 25 
 
 30 
 
 40 
 
 15 
 
 50 
 
 50 
 
 20 
 
 
 
 
 
 
 
 Do. 
 
 
 60 
 
 60 
 
 80 
 
 80 
 
 —125 
 
 75 
 
 50 
 
 50 
 
 50 
 
 50 
 
 40 
 
 40 
 
 Var. It., lightning. 
 
 
 50 
 
 60 
 
 60 
 
 100 
 
 70 
 
 50 
 
 100 
 
 60 
 
 100 
 
 50 
 
 r 50 
 
 50 
 
 S. It., fair. 
 
 
 50 
 
 75 
 
 100 
 
 115 
 
 100 
 
 60 
 
 100 
 
 60 
 
 65 
 
 80 
 
 60 
 
 85 
 
 SE., It., fair. 
 
 
 —100 
 
 100 
 
 100 
 
 150 
 
 GO 
 
 
 
 
 
 
 
 
 
 20 
 
 20 
 
 40 
 
 S., It., rain, lightnir 
 
 S- 
 
 30 
 
 60 
 
 100 
 
 125 
 
 75 
 
 30 
 
 SO 
 
 30 
 
 25 
 
 60 
 
 50 
 
 50 
 
 Do. 
 
 
 30 
 
 50 
 
 -200 
 
 -350 
 
 —300 
 
 
 
 —200 
 
 
 
 20 
 
 20 
 
 30 
 
 20 
 
 SE. fr., rain, t. B. 
 
 
 15 
 
 50 
 
 50 
 
 90 
 
 50 
 
 50 
 
 50 
 
 50 
 
 30 
 
 40 
 
 25 
 
 15 
 
 E. fr., rain. 
 
 
 70 
 
 50 
 
 50 
 
 90 
 
 100 
 
 50 
 
 75 
 
 60 
 
 130 
 
 100 
 
 70 
 
 70 
 
 Var. It., rain. 
 
 
 —250 
 
 100 
 
 50 
 
 70 
 
 50 
 
 30 
 
 50 
 
 50 
 
 40 
 
 40 
 
 40 
 
 25 
 
 Do. 
 
 
 40 
 
 45 
 
 50 
 
 40 
 
 25 
 
 10 
 
 25 
 
 50 
 
 65 
 
 60 
 
 45 
 
 30 
 
 Var. It., fair. 
 
 
 
 ' 60 
 
 -100 
 
 
 
 20 
 
 100 
 
 60 
 
 20 
 
 30 
 
 20 
 
 20 
 
 
 
 E. It., rain, t. s. 
 
 
 410 
 
 925 
 
 1,175 
 
 1,470 
 
 1,025 
 
 1,180 
 
 1,105 
 
 1,260 
 
 1,390 
 
 1,240 
 
 1,255 
 
 1.145 
 
 15 
 
 30 
 
 38 
 
 47 
 
 33 
 
 38 
 
 36 
 
 41 
 
 45 
 
 40 
 
 40 
 
 37 
 
 
 
 AUGUST, 1885. 
 
 
 50 
 
 50 
 
 50 
 
 40 
 
 30 
 
 30 
 
 
 
 —300 
 
 ■ 
 30 
 
 25 
 
 30 
 
 S. fr., rain, t. s. 
 
 45 
 
 40 
 
 40 
 
 
 
 
 
 
 
 - 30 
 
 — 10 
 
 — 5 
 
 350 
 
 50 
 
 300 
 
 SE. fr., rain, t. s. 
 
 125 
 
 100 
 
 30 
 
 50 
 
 75 
 
 —200 
 
 —200 
 
 5 
 
 30 
 
 65 
 
 60 
 
 40 
 
 Do. 
 
 20 
 
 50 
 
 50 
 
 .50 
 
 70 
 
 70 
 
 95 
 
 70 
 
 100 
 
 50 
 
 40 
 
 40 
 
 SE.fr., rain. 
 
 50 
 
 45 
 
 45 
 
 45 
 
 .55 
 
 50 
 
 50 
 
 45 
 
 55 
 
 20- 
 
 50 
 
 25 
 
 NW. fr., clear. 
 
 65 
 
 50 
 
 55 
 
 55 
 
 20 
 
 15 
 
 10 
 
 15 
 
 70 
 
 100 
 
 65 
 
 100 
 
 N. fr., clear. 
 
 —200 
 
 —350 
 
 —350 
 
 —300 
 
 —100 
 
 —100 
 
 — 90 
 
 — 20 
 
 20 
 
 — 50 
 
 — 50 
 
 - 50 
 
 N. It., rain. 
 
 
 
 15 
 110 
 
 
 135 
 
 75 
 160 
 
 60 
 125 
 
 100 
 150 
 
 50 
 130 
 
 50 
 130 
 
 50 
 170 
 
 50 
 60 
 
 50 
 35 
 
 Var. It., rain. 
 NW.fr., fair. 
 
 100 
 
 ioo 
 
 100 
 
 130 
 
 . 150 
 
 130 
 
 60 
 
 140 
 
 60 
 
 60 
 
 .50 
 
 35 
 
 110 
 
 105 
 
 SE. fr., fair. 
 
 60 
 
 100 
 
 125 
 
 125 
 
 135 
 
 155 
 
 120 
 
 100 
 
 70 
 
 70 
 
 60 
 
 85 
 
 Do. 
 
 60 
 
 —200 
 
 50 
 
 —200 
 
 100 
 
 100 
 
 60 
 
 60 
 
 60 
 
 40 
 
 50 
 
 50 
 
 SE. It., rain, t. 8. 
 
 40 
 
 60 
 
 70 
 
 -100 
 
 —300 
 
 —300 
 
 —200 
 
 
 
 5 
 
 15 
 
 20 
 
 30 
 
 S. It., rain, t. s. 
 
 
 50 
 
 60 
 
 50 
 
 50 
 
 60 
 
 65 
 
 70 
 
 75 
 
 60 
 
 60 
 
 25 
 
 NW.fr., rain. 
 
 25 
 
 20 
 
 50 
 
 35 
 
 25 
 
 — 10 
 
 35 
 
 40 
 
 55 
 
 50 
 
 40 
 
 50 
 
 N. fr., fair. 
 
 50 
 
 ^ 50 
 
 45 
 
 50 
 
 55 
 
 100 
 
 80 
 
 95 
 
 90 
 
 100 
 
 100 
 
 100 
 
 N. fr, clear. 
 
 50 
 
 100 
 
 120 
 
 100 
 
 95 
 
 50 
 
 65 
 
 60 
 
 100 
 
 .50 
 
 60 
 
 55 
 
 SE. It., cloudy. 
 
 30 
 
 30 
 
 30 
 
 45 
 
 50 
 
 40 
 
 
 
 
 
 
 
 
 
 
 
 
 
 SW. fr., fair. 
 
 20 
 
 30 
 
 35 
 
 40 
 
 50 
 
 45 
 
 50 
 
 25 
 
 25 
 
 25 
 
 20 
 
 20 
 
 W. fr., fair. 
 
 50 
 
 70 
 
 65 
 
 80 
 
 50 
 
 45 
 
 — 10 
 
 80 
 
 40 
 
 70 
 
 60 
 
 20 
 
 NW. It., clear. 
 
 50 
 
 55 
 
 50 
 
 80 
 
 85 
 
 80 
 
 30 
 
 30 
 
 
 
 35 
 
 30 
 
 50 
 
 Var. It., rain. 
 
 40 
 
 70 
 
 60 
 
 60 
 
 70 
 
 —100 
 
 —300 
 
 20 
 
 20 
 
 200 
 
 15 
 
 15 
 
 SW. It., rain, t. s. 
 
 
 
 
 40 
 — 5 
 
 50 
 60 
 
 50 
 70 
 
 
 70 
 
 
 60 
 
 50 
 50 
 
 50 
 70 
 
 60 
 40 
 
 70 
 40 
 
 SW. fr., rain, t. s. 
 SW. fr., fair. 
 
 45 
 
 40 
 
 45 
 
 40 
 
 35 
 
 — 50 
 
 —300 
 
 —300 
 
 —300 
 
 —100 
 
 20 
 
 15 
 
 25 
 
 25 
 
 15 
 
 SW. fr., rain, t. s. 
 
 
 
 50 
 60 
 
 45 
 60 
 
 40 
 65 
 
 50 
 70 
 
 45 
 80 
 
 50 
 50 
 
 50 
 80 
 
 70 
 50 
 
 50 
 50 
 
 ■■"eo" 
 
 NW. fr., rain. 
 NW. fr., fair. 
 
 60 
 
 70 
 
 100 
 
 100 
 
 100 
 
 100 
 
 95 
 
 50 
 
 60 
 
 50 
 
 25 
 
 25 
 
 20 
 
 50 
 
 N. fr., clear. 
 
 85 
 
 _110 
 
 100 
 
 70 
 
 100 
 
 — 5 
 
 50 
 
 35 
 
 50 
 
 25 
 
 30 
 
 20 
 
 SW. fr., rain. 
 
 40 
 
 40 
 
 80 
 
 100 
 
 100 
 
 60 
 
 80 
 
 50 
 
 
 
 
 
 
 
 
 
 SW. It., rain, t. s. 
 
 
 
 
 
 50 
 
 50 
 
 50 
 
 20 
 
 15 
 
 50 
 
 60 
 
 50 
 
 Var. It., rain. 
 
 
 
 
 
 1,150 
 
 1,045 
 
 1,340 
 
 690 
 
 1,180 
 
 550 
 
 495 
 
 1,260 
 
 1,075 
 
 1,900 
 
 1,310 
 
 1,470 
 
 46 
 
 39 
 
 46 
 
 23 
 
 38 
 
 18 
 
 16 
 
 41 
 
 36 
 
 63 
 
 44 
 
 51 
 
 
184 
 
 MEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES. 
 
 Table A. — Hourly records, drawn from continuous photographic 
 SEPTEMBER, 1885. 
 
 Day of month. 
 
 la. m. 
 
 2 a. m. 
 
 3 a. m. 
 
 4 a. m. 
 
 5 a. m. 
 
 6 a.m. 
 
 7 a.m. 
 
 8 a.m. 
 
 9 a. m. 
 
 10 a. m. 
 
 11 a. m. 
 
 12 m. 
 
 1 
 
 60 
 25 
 60 
 35 
 
 100 
 75 
 
 120 
 
 80 
 
 —160 
 
 140 
 15 
 40 
 90 
 60 
 30 
 40 
 50 
 50 
 60 
 50 
 35 
 30 
 5 
 50 
 30 
 55 
 55 
 4C 
 25 
 20 
 
 65 
 30 
 70 
 50 
 70 
 70 
 95 
 85 
 50 
 ' 130 
 15 
 70 
 85 
 100 
 40 
 40 
 55 
 60 
 65 
 50 
 35 
 30 
 10 
 50 
 25 
 70 
 70 
 50 
 40 
 70 
 
 50 
 30 
 60 
 
 105 
 90 
 75 
 
 100 
 
 — 5 
 
 50 
 
 100 
 5 
 
 100 
 75 
 90 
 45 
 50 
 50 
 65 
 70 
 40 
 35 
 5 
 25 
 45 
 30 
 75 
 60 
 50 
 60 
 50 
 
 60 
 30 
 
 100 
 50 
 70 
 70 
 
 100 
 50 
 35 
 70 
 10 
 
 100 
 80 
 70 
 50 
 50 
 55 
 10 
 70 
 35 
 35 
 15 
 30 
 70 
 45 
 40 
 60 
 50 
 55 
 70 
 
 50 
 40 
 60 
 50 
 80 
 70 
 100 
 50 
 35 
 80 
 35 
 85 
 75 
 70 
 50 
 70 
 55 
 80 
 70 
 35 
 35 
 20 
 35 
 50 
 20 
 50 
 60 
 .50 
 60 
 60 
 
 . 50 
 
 50 
 
 70 
 
 100 
 
 105 
 
 70 
 
 200 
 
 100 
 
 15 
 
 100 
 
 60 
 
 50 
 
 80 
 
 80 
 
 60 
 
 110 
 
 100 
 
 20 
 
 90 
 
 40 
 
 50 
 
 10 
 
 50 
 
 75 
 
 45 
 
 60 
 
 50 
 
 20 
 
 60 
 
 70 
 
 60 
 
 55 
 
 
 
 100 
 
 100 
 70 
 
 150 
 
 60 
 
 
 
 105 
 70 
 
 130 
 85 
 90 
 70 
 90 
 50 
 — 5 
 50 
 30 
 30 
 60 
 50 
 85 
 10 
 20 
 50 
 25 
 60 
 60 
 
 70 
 
 65 
 
 70 
 
 150 
 
 100 
 
 140 
 
 100 
 
 100 
 
 
 
 110 
 
 75 
 
 140 
 
 70 
 
 50 
 
 70 
 
 60 
 
 60 
 
 20 
 
 60 
 
 35 
 
 50 
 
 50 
 
 60 
 
 50 
 
 
 
 35 
 
 60 
 
 20 
 
 80 
 
 60 
 
 60 
 
 50 
 
 60 
 
 100 
 
 80 
 
 110 
 
 120 
 
 70 
 
 
 
 80 
 
 100 
 
 115 
 
 75 
 
 90 
 
 80 
 
 70 
 
 80 
 
 80 
 
 20 
 
 25 
 
 50 
 
 40 
 
 70 
 
 40 
 
 50 
 
 — 20 
 
 45 
 
 30 
 
 60 
 
 55 
 
 50 
 
 30 
 
 100 
 
 70 
 
 100 
 
 140 
 
 80 
 
 
 
 90 
 
 100 
 
 150 
 
 80 
 
 100 
 
 85 
 
 70 
 
 30 
 
 10 
 
 15 
 
 25 
 
 50 
 
 50 
 
 15 
 
 100 
 
 50 
 
 100 
 
 150 
 
 100 
 
 5 
 
 90 
 
 50 
 
 150 
 
 60 
 
 110 
 
 75 
 
 60 
 
 75 
 
 
 
 
 
 25 
 
 50 
 
 25 
 
 
 
 100 
 
 50 
 100 
 120 
 100 
 
 10 
 
 ""76 
 
 150 
 
 60 
 
 120 
 
 95 
 
 60 
 
 60 
 
 
 
 
 
 25 
 
 '2 
 
 3 
 
 4 
 
 5 
 
 6 
 
 7. 
 
 8.... 
 
 9 
 
 10 .^... 
 
 11 
 
 12 
 
 13 
 
 14... 
 
 15 
 
 16 
 
 17 
 
 18 
 
 19 
 
 20 
 
 21 
 
 22 
 
 30 
 60 
 35 
 100 
 70 
 30 
 50 
 60 
 50 
 
 10 
 50 
 20 
 60 
 80 
 40 
 80 
 100 
 40 
 
 20 
 
 50 
 
 15 
 
 100 
 
 100 
 
 50 
 
 80 
 
 100 
 
 35 
 
 23 
 
 24.. 
 
 25 
 
 26 
 
 27 
 
 28 
 
 29 
 
 30 
 
 Sums .. 
 
 1,375 
 46 
 
 1,745 
 
 58 
 
 1,680 
 56 
 
 1,565 
 52 
 
 1,680 
 56 
 
 2,040 
 68 
 
 1,810 
 ' 62 
 
 2,010 
 69 
 
 1,880 
 65 
 
 1,865 
 67 
 
 1,795 
 66 
 
 1,700 
 68 
 
 
 
 OCTOBEE, 1885. 
 
 1 
 
 50 
 50 
 
 50 
 40 
 
 50 
 30 
 
 50 
 30 
 
 65 
 20 
 
 40 
 25 
 
 30 
 20 
 
 50 
 
 
 50 
 60 
 
 10 
 — 10 
 
 30 
 
 
 25 
 
 
 2 : 
 
 3 
 
 4 
 
 5 
 90 
 60 
 65 
 60 
 40 
 
 100 
 60 
 
 —100 
 25 
 30 
 65 
 75 
 30 
 60 
 60 
 10 
 50 
 75 
 60 
 60 
 75 
 10 
 75 
 50 
 
 —200 
 25 
 
 10 
 
 100 
 
 50 
 
 50 
 
 60 
 
 65 
 
 
 
 110 
 
 65 
 
 —250 
 25 
 30 
 50 
 60 
 75 
 60 
 50 
 25 
 50 
 50 
 60 
 75 
 70 
 50 
 25 
 60 
 
 — 15 
 25 
 
 25 
 ^ 100 
 ■ 30 
 50 
 50 
 80 
 
 95 
 90 
 —350 
 30 
 50 
 50 
 100 
 95 
 50 
 60 
 25 
 50 
 40 
 50 
 75 
 60 
 10 
 50 
 50 
 30 
 25 
 
 30 
 110 
 /O 
 55 
 50 
 25 
 
 
 95 
 75 
 -100 
 30 
 40 
 75 
 50 
 60 
 
 
 60 
 
 
 40 
 40 
 50 
 50 
 60 
 50 
 25 
 50 
 40 
 25 
 
 40 
 105 
 
 — 50 
 55 
 50 
 60 
 
 
 90 
 40 
 
 — 75 
 50 
 50 
 75 
 60 
 65 
 
 
 60 
 —100 
 60 
 75 
 55 
 30 
 60 
 30 
 50 
 35 
 40 
 40 
 
 50 
 125 
 
 — 10 
 75 
 
 
 80 
 
 
 
 100 
 
 80 
 
 — 20 
 85 
 75 
 
 105 
 60 
 
 125 
 
 90 
 
 75 
 
 —300 
 
 95 
 
 100 
 65 
 40 
 50 
 25 
 
 150 
 25 
 50 
 50 
 
 40 
 
 150 
 —300 
 
 100 
 
 —150 
 
 25 
 
 
 
 100 
 
 80 
 
 — 25 
 
 110 
 75 
 
 100 
 65 
 
 125 
 
 10 
 
 80 
 
 —350 
 
 130 
 75 
 75 
 60 
 10 
 75 
 
 100 
 40 
 60 
 50 
 
 40 
 
 50 
 
 —250 
 
 110 
 
 —150 
 
 25 
 
 
 
 140 
 
 80 
 
 
 
 100 
 
 90 
 
 100 
 
 30 
 
 130 
 
 — 50 
 100 
 
 —200 
 90 
 50 
 75 
 100 
 50 
 
 — 50 
 10 
 40 
 50 
 40 
 
 30 
 
 115 
 
 —300 
 
 90 
 —150 
 
 75 
 
 
 
 150 
 
 75 
 
 10 
 100 
 110 
 175 
 
 60 
 
 95 
 105 
 
 90 
 
 — 50 
 80 
 65 
 70 
 
 110 
 
 — 50 
 
 — 25 
 75 
 60 
 70 
 50 
 
 50 
 130 
 
 — 10 
 75 
 
 — 75 
 80 
 
 
 
 150 
 
 75 
 
 25 
 
 90 
 
 90 
 
 160 
 
 60 
 
 80 
 
 110 
 
 85' 
 
 
 
 75 
 
 125 
 
 65 
 
 100 
 
 150 
 
 
 
 95 
 
 50 
 
 30 
 
 45 
 
 65 
 125 
 
 —300 
 80 
 
 75 
 
 25 
 90 
 10 
 75 
 75 
 
 175 
 
 100 
 60 
 
 110 
 80 
 
 50 
 80 
 65 
 95 
 
 140 
 50 
 90 
 
 60 
 40 
 
 50 
 
 125 
 
 
 
 75 
 
 — 20 
 
 60 
 
 
 
 150 
 50 
 25 
 65 
 75 
 
 150 
 
 150 
 60 
 
 110 
 75 
 
 40 
 50 
 60 
 95 
 
 100 
 90 
 80 
 80 
 60 
 50 
 
 5 
 
 6-- 
 
 7 . 
 
 8 
 
 9 :: 
 
 10 
 
 11 
 
 12.. .. 
 
 13 
 
 14 
 
 15 
 
 16 
 
 17 
 
 18-. - 
 
 19 
 
 20 
 
 21 
 
 22 
 
 23 
 
 24 
 
 25 
 
 26 
 
 27 
 
 28 
 
 29..... 
 
 30 
 
 31 
 
 Sums 
 
 1,115 
 38 
 
 1,170 
 40 
 
 1,150 
 40 
 
 1,165 
 40 
 
 1,135 
 39 
 
 1,510 
 52 
 
 960 
 33 
 
 850 
 29 
 
 1, 395 
 48 
 
 1,910 
 
 68 
 
 l,,'-i45 
 57 
 
 1, 930 
 
 71 
 
 
 
MEMOIRS OP THE NATIONAL ACADEMY OF SCIENCES. 
 
 185 
 
 registration, at Baltimore, Md., 1885, 1886, and 1887 — Continued. 
 
 SEPTEMBER, 1885. 
 
 Ip.m. 
 
 2 p. m. 
 
 3 p.m. 
 
 4 p.m. 
 
 5 p.m. 
 
 6 p.m. 
 
 7 p.m. 
 
 8 p.m. 
 
 9 p.m. 
 
 10 p. m. 
 
 11 p. m. 
 
 12 mid. 
 
 Bemarka. 
 
 40 
 
 50 
 
 45 
 
 60 
 
 45 
 
 50 
 
 50 
 
 40 
 
 45 
 
 40 
 
 30 
 
 20 
 
 NW.fr., clear. 
 
 50 
 
 25 
 
 40 
 
 45 
 
 15 
 
 50 
 
 30 
 
 60 
 
 25 
 
 50 
 
 40 
 
 70 
 
 NW. It., clear. 
 
 45 
 
 100 
 
 80 
 
 50 
 
 60 
 
 60 
 
 50 
 
 70 
 
 40 
 
 60 
 
 70 
 
 • 60 
 
 8. It., clear. 
 
 
 
 
 
 
 
 
 
 200 
 
 5 
 
 100 
 
 —300 
 
 -200 
 
 60 
 
 150 
 
 70 
 
 Var. It., rain, t. 8. 
 
 65 
 
 65 
 
 100 
 
 50 
 
 200 
 
 
 
 50 
 
 45 
 
 50 
 
 50 
 
 70 
 
 50 
 
 Var. It., rain. 
 
 100 
 
 100 
 
 100 
 
 85 
 
 100 
 
 100 
 
 150 
 
 170 
 
 100 
 
 100 
 
 100 
 
 140 
 
 Do. 
 
 150 
 
 150 
 
 170 
 
 190 
 
 200 
 
 160 
 
 100 
 
 120 
 
 85 
 
 50 
 
 100 
 
 100 
 
 Var. It., cloudy. 
 
 100 
 
 60 
 
 130 
 
 105 
 
 100 
 
 50 
 
 65 
 
 60 
 
 65 
 
 65 
 
 65 
 
 60 
 
 S. It., rain. 
 
 — 60 
 
 100 
 
 110 
 
 115 
 
 105 
 
 130 
 
 150 
 
 60 
 
 60 
 
 60 
 
 70 
 
 80 
 
 W. fr., rain, lightning. 
 
 
 
 60 
 
 60 
 
 65 
 
 50 
 
 50 
 
 — 20 
 
 15 
 
 20 
 
 15 
 
 30 
 
 
 
 NW. fr.,rain. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 35 
 
 
 
 NE.lt., rain. 
 
 100 
 
 120 
 
 110 
 
 130 
 
 95 
 
 75 
 
 80 
 
 90 
 
 70 
 
 20 
 
 65 
 
 100 
 
 Var.- It., cloudy. 
 
 — 
 
 — 
 
 — 
 
 100 
 
 100 
 
 90 
 
 90 
 
 90 
 
 70 
 
 65 
 
 60 
 
 60 
 
 S.fr.,fair. 
 
 100 
 
 110 
 
 50 
 
 5 
 
 100 
 
 100 
 
 20 
 
 40 
 
 10 
 
 10 
 
 10 
 
 20 
 
 Do. 
 
 70 
 
 75 
 
 70 
 
 55 
 
 60 
 
 70 
 
 90 
 
 70 
 
 50 
 
 40 
 
 40 
 
 30 
 
 W. It., clear. 
 
 50 
 
 55 
 
 60 
 
 '5 
 
 70 
 
 20 
 
 40 
 
 50 
 
 50 
 
 70 
 
 60 
 
 55 
 
 NW. fr., clear. 
 
 100 
 
 120 
 
 50 
 
 100 
 
 130 
 
 135 
 
 100 
 
 70 
 
 60 
 
 60 
 
 80 
 
 50 
 
 NW.lt., clear. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 70 
 
 30 
 
 ■0 
 
 50 
 
 50 
 
 SW.fr., fair. 
 
 50 
 
 65 
 
 55 
 
 55 
 
 120 
 
 50 
 
 60 
 
 70 
 
 40 
 
 25 
 
 50 
 
 50 
 
 Var. It., clear. 
 
 35 
 
 50 
 
 50 
 
 50 
 
 70 
 
 75 
 
 60 
 
 40 
 
 30 
 
 50 
 
 20 
 
 30 
 
 NE. It., fair. 
 
 50 
 
 70 
 
 95 
 
 60 
 
 50 
 
 80 
 
 65 
 
 40 
 
 50 
 
 15 
 
 25 
 
 20 
 
 NE.lt., cloudy. 
 
 50 
 
 —150 
 
 30 
 
 60 
 
 90 
 
 60 
 
 70 
 
 60 
 
 40 
 
 -150 
 
 
 
 
 
 W. fr.,rain. 
 
 15 
 
 50 
 
 65 
 
 50 
 
 65 
 
 60 
 
 60 
 
 75 
 
 50 
 
 55 
 
 50 
 
 46 
 
 NW.br., rain. 
 
 5 
 
 5 
 
 15 
 
 25 
 
 50 
 
 50 
 
 50 
 
 60 
 
 40 
 
 25 
 
 25 
 
 50 
 
 SW.fr., clear. 
 
 100 
 
 120 
 
 70 
 
 100 
 
 120 
 
 100 
 
 50 
 
 ^10 
 
 10 
 
 10 
 
 20 
 
 60 
 
 Var. It., clear. 
 
 110 
 
 110 
 
 120 
 
 100 
 
 110 
 
 90 
 
 50 
 
 70 
 
 20 
 
 25 
 
 40 
 
 40 
 
 Do. 
 
 100 
 
 90 
 
 130 
 
 90 
 
 100 
 
 100 
 
 10 
 
 50 
 
 50 
 
 50 
 
 70 
 
 50 
 
 Var. It., fair. 
 
 70 
 
 70 
 
 100 
 
 100 
 
 70 
 
 40 
 
 10 
 
 40 
 
 40 
 
 50 
 
 45 
 
 40 
 
 Do. 
 
 70 
 
 50 
 
 50 
 
 50 
 
 100 
 
 130 
 
 100 
 
 70 
 
 70 
 
 25 
 
 30 
 
 40 
 
 Var. It., clear. 
 
 
 50 
 
 40 
 
 35 
 
 20 
 
 
 50 
 
 50 
 
 60 
 
 20 
 
 25 
 
 40 
 
 Do. 
 
 
 
 1,565 
 
 1,770 
 
 1,995 
 
 1,925 
 
 2,595 
 
 1,980 
 
 1,780 
 
 1,435 
 
 1,130 
 
 1,015 
 
 1,525 
 
 1,480 
 
 62 
 
 68 
 
 74 
 
 69 
 
 89 
 
 71 
 
 61 
 
 48 
 
 38 
 
 34 
 
 51 
 
 49 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 / 
 
 OCTOBER, 1885. 
 
 50 
 
 90 
 
 60 
 
 60 
 
 65,' 
 
 \ 110 
 
 50 
 
 25 
 
 15 
 
 40 
 
 55 
 
 50 
 
 E. fr., cloudy. 
 E. fr.,rain t. s. 
 Var. It., rain. 
 
 10 
 
 10 
 
 10 
 
 20 
 
 10 
 
 
 
 
 
 6 
 
 — 5 
 
 
 
 
 
 5 
 
 — 
 
 — 
 
 75 
 
 100 
 
 100 
 
 100 
 
 90 
 
 80 
 
 90 
 
 75 
 
 80 
 
 90 
 
 SW.lt., rain. 
 
 65 
 
 60 
 
 75 
 
 70 
 
 60 
 
 75 
 
 100 
 
 110 
 
 75 
 
 85 
 
 90 
 
 60 
 
 SW. It., fair. 
 
 —300 
 
 — 10 
 
 
 
 25 
 
 60 
 
 80 
 
 75 
 
 150 
 
 .75 
 
 75 
 
 90 
 
 60 
 
 Var. It., rain. 
 
 70 
 
 75 
 
 75 
 
 80 
 
 80 
 
 75 
 
 75 
 
 60 
 
 40 
 
 60 
 
 60 
 
 50 
 
 Var. It., fair. 
 
 — 50 
 
 10 
 
 80 
 
 110 
 
 100 
 
 75 
 
 80 
 
 90 
 
 40 
 
 50 
 
 60 
 
 50 
 
 Var. It., rain. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 N. It., cloudy. 
 
 60 
 
 75 
 
 150 
 
 160 
 
 110 
 
 100 
 
 110 
 
 100 
 
 80 
 
 25 
 
 150 
 
 100 
 
 Var. It., clear. 
 
 125 
 
 125 
 
 140 
 
 65 
 
 95 
 
 125 
 
 100 
 
 90 
 
 85 
 
 65 
 
 100 
 
 75 
 
 Var. It., fair. 
 
 75 
 
 90 
 
 75 
 
 60 
 
 10 
 
 
 
 — 10 
 
 —100 
 
 —150 
 
 —200 
 
 — 25 
 
 — 75 
 
 NE.fr., rain. 
 
 25 
 
 30 
 
 110 
 
 125 
 
 120 
 
 75 
 
 60 
 
 60 
 
 50 
 
 50 
 
 60 
 
 40 
 
 E.l)r.,rain. 
 
 65 
 
 60 
 
 65 
 
 60 
 
 60 
 
 60 
 
 
 
 — 50 
 
 30 
 
 30 
 
 40 
 
 40 
 
 SW. fr., rain. 
 
 50 
 
 60 
 
 75 
 
 60 
 
 75 
 
 60 
 
 60 
 
 75 
 
 60 
 
 60 
 
 60 
 
 80 
 
 NW.fr., cloudy. 
 
 150 
 
 150 
 
 160 
 
 200 
 
 200 
 
 120 
 
 100 
 
 75 
 
 50 
 
 
 
 50 
 
 25 
 
 SE.fr., fair. 
 
 150 
 
 150 
 
 150 
 
 150 
 
 150 
 
 50 
 
 — 25 
 
 30 
 
 110 
 
 30 
 
 60 
 
 ,50 
 
 Var. It., fair. 
 
 
 100 
 
 90 
 
 80 
 
 75 
 
 75 
 
 60 
 
 60 
 
 65 
 
 60 
 
 60 
 
 60 
 
 Var. It., fair, fog. 
 
 100 
 
 110 
 
 100 
 
 90 
 
 100 
 
 90 
 
 75 
 
 65 
 
 75 
 
 75 
 
 50 
 
 50 
 
 Var.lt., cloudy, fog. 
 
 75 
 
 75 
 
 60 
 
 65 
 
 , 60 
 
 60 
 
 50 
 
 50 
 
 50 
 
 50 
 
 40 
 
 25 
 
 SE.fr., cloudy. 
 
 20 
 
 25 
 
 25 
 
 60 
 
 .50 
 
 60 
 
 50 
 
 50 
 
 55 
 
 50 
 
 50 
 
 50 
 
 S. fr., rain. 
 
 50 
 
 60 
 
 60 
 
 60 
 
 75 
 
 80 
 
 100 
 
 110 
 
 100 
 
 75 
 
 50 
 
 50 
 
 NW.fr., clear. 
 
 50 
 
 90 
 
 90 
 
 90 
 
 75 
 
 100 
 
 75 
 
 75 
 
 75 
 
 60 
 
 60 
 
 50 
 
 Var. It., rain. 
 
 50 
 
 50 
 
 60 
 
 60 
 
 60 
 
 50 
 
 50 
 
 90 
 
 65 
 
 60 
 
 75 
 
 60 
 
 N. It., fair. 
 
 90 
 
 75 
 
 50 
 
 90 
 
 95 
 
 80 
 
 75 
 
 30 
 
 
 
 50. 
 
 65 
 
 50 
 
 Var. It., clear. 
 
 110 
 
 150 
 
 150 
 
 125 
 
 100 
 
 75 
 
 60 
 
 50 
 
 65 
 
 60 
 
 60 
 
 50 
 
 N. It., clear. 
 
 100 
 
 110 
 
 150 
 
 _ 100 
 
 75 
 
 50 
 
 -110 
 
 
 
 50 
 
 
 
 
 
 10 
 
 60 
 
 Var. It. , fair, fog. 
 
 75 
 
 65 
 
 65 
 
 60 
 
 50 
 
 40 
 
 50 
 
 25 
 
 50 
 
 60 
 
 50 
 
 Var. It., cloudy, fog. 
 
 50 
 
 50 
 
 30 
 
 40 
 
 50 
 
 200 
 
 —200 
 
 
 
 —300 
 
 —200 
 
 —100 
 
 —200 
 
 NE. br., rain, lightning. 
 
 50 
 
 30 
 
 40 
 
 50 
 
 50 
 
 
 
 — 5 
 
 25 
 
 25 
 
 25 
 
 25 
 
 30 
 
 NW.br., rain. 
 
 40 
 
 30 
 
 40 
 
 60 
 
 40 
 
 50 
 
 65 
 
 65 
 
 75 
 
 50 
 
 50 
 
 25 
 
 SW.fr., clear. 
 
 1,355 
 
 1,995 
 
 2,310 
 
 2,390 
 
 2,235 
 
 "2,185 
 
 1,360 
 
 1, 565 
 
 1,020 
 
 910 
 
 1,485 
 
 1,110 
 
 48 
 
 71 
 
 80 
 
 82 
 
 n 
 
 75 
 
 47 
 
 54 
 
 35 
 
 31 
 
 51 
 
 38 
 
 
186 
 
 MEMOIES OP THE NATIONAL ACADEMY OP SCIENCES. 
 
 Table A. — Hourly records, drawn from continuous photographic 
 NOVEMBER, 1885. 
 
 Day of month. 
 
 la. m. 
 
 2 a. m. 
 
 3^. m. 
 
 4 a. m. 
 
 5 a.™. 
 
 6 a.m. 
 
 7 a. m. 
 
 8 a.m. 
 
 9a.m. 
 
 10 a. m. 
 
 11 a. m. 
 
 12 m. 
 
 1 
 
 50 
 
 —300 
 
 50 
 
 75 
 
 130 
 80 
 60 
 — 10 
 10 
 60 
 85 
 
 130 
 60 
 
 100 
 50 
 
 90 
 50 
 40 
 40 
 75 
 
 120 
 
 -250 
 75 
 65 
 40 
 50 
 50 
 40 
 
 60 
 
 
 60 
 125 
 125 
 
 65 
 
 60 
 
 - 20 
 50 
 60 
 
 105 
 125 
 
 75 
 150 
 
 50 
 
 
 90 
 
 — 10 
 50 
 60 
 65 
 
 100 
 
 -125 
 75 
 75 
 50 
 65 
 60 
 35 
 
 60 
 
 — 50 
 60 
 
 150 
 
 125 
 
 75 
 
 75 
 
 
 
 
 
 60 
 
 110 
 
 150 
 
 75 
 
 100 
 
 50 
 
 
 
 90 
 
 10 
 
 50 
 
 50 
 
 75 
 
 75 
 
 —300 
 
 — 50 
 65 
 75 
 60 
 65 
 50 
 40 
 
 30 
 
 
 
 75 
 
 150 
 
 100 
 
 100 
 
 250 
 
 
 
 —100 
 
 60 
 
 100 
 
 110 
 
 80 
 
 150 
 
 50 
 
 
 
 90 
 
 25 
 
 10 
 
 75 
 
 75 
 
 80 
 
 -350 
 
 
 
 65 
 
 60 
 
 60 
 
 75 
 
 50 
 
 40 
 
 25 
 
 50 
 
 75 
 
 175 
 
 110 
 
 100 
 
 —100 
 
 5 
 
 — 50 
 
 65 
 
 100 
 
 125 
 
 95 
 
 125 
 
 60 
 
 
 
 60 
 
 50 
 
 10 
 
 75 
 
 100 
 
 105 
 
 —200 
 
 
 
 90 
 
 65 
 
 65 
 
 75 
 
 50 
 
 50 
 
 40 
 
 80 
 
 110 
 
 175 
 
 60 
 
 100 
 
 50 
 
 5 
 
 
 
 65 
 
 175 
 
 110 
 
 100 
 
 150 
 
 75 
 
 
 
 60 
 
 75 
 
 25 
 
 100 
 
 100 
 
 75 
 
 — 10 
 
 
 
 90 
 
 50 
 
 80 
 
 75 
 
 60 
 
 60 
 
 75 
 90 
 90 
 
 225 
 75 
 90 
 60 
 10 
 
 100 
 75 
 
 aoo 
 
 150 
 50 
 
 100 
 
 80 
 
 
 
 150 
 70 
 50 
 90 
 25 
 60 
 
 
 300 
 
 100 
 60 
 75 
 75 
 75 
 60 
 
 75 
 50 
 90 
 
 200 
 
 180 
 
 105 
 60 
 10 
 
 100 
 80 
 
 180 
 
 100 
 75 
 
 100 
 90 
 
 50 
 90 
 75 
 
 110 
 
 50 
 
 75 
 
 — 50 
 
 
 
 100 
 80 
 
 100 
 
 
 
 60 
 
 50 
 
 80 
 10 
 80 
 100 
 150 
 80 
 50 
 
 — 50 
 100 
 
 80 
 125 
 125 
 
 60 
 150 
 
 80 
 
 
 
 100 
 
 100 
 
 90 
 100 
 
 65 
 
 100 
 
 
 
 300 
 
 100 
 
 75 
 
 90 
 
 — 25 
 75 
 60 
 
 100 
 
 
 60 
 
 90 
 100 
 
 60 
 
 40 
 — 25 
 
 90 
 
 75 
 225 
 125 
 
 25 
 100 
 
 75 
 
 
 
 100 
 
 120 
 
 80 
 100 
 
 50 
 
 100 
 
 
 
 50 
 100 
 
 75. 
 
 50 
 100 
 
 80 
 
 60 
 
 100 
 
 
 
 60 
 
 110 
 50 
 60 
 25 
 
 80 
 60 
 
 250 
 
 125 
 
 100 
 
 160 
 
 75 
 
 
 
 60 
 
 100 
 
 
 100 
 
 
 
 80 
 
 50 
 
 — 50 
 
 100 
 80 
 75 
 
 125 
 50 
 75 
 
 75 
 
 60 
 100 
 75 
 60 
 35 
 
 ""'so' 
 
 50 
 
 150 
 
 125 
 
 10 
 
 100 
 
 60 
 
 
 
 60 
 
 50 
 
 —125 
 
 100 
 
 50 
 
 60 
 
 50 
 
 
 
 100 
 
 80 
 
 80 
 
 110 
 
 50 
 
 75 
 
 2 
 
 3 
 
 4 
 
 5 
 
 6 
 
 7 
 
 8 
 
 9 . 
 
 10 
 
 11 
 
 12 
 
 13 
 
 14 
 
 15 
 
 16 
 
 17 
 
 18 
 
 19 
 
 20 
 
 21 
 
 22 
 
 23 
 
 24 
 
 25 
 
 26 
 
 27 
 
 28 
 
 29 
 
 30 
 
 
 1,215 
 42 
 
 1,670 
 
 58 
 
 1,395 
 
 48 
 
 1,510 
 52 
 
 1,555 
 54 
 
 2,135 
 
 74 
 
 2,660 
 92 
 
 2,285 
 79 
 
 2,450 
 84 
 
 2,205 
 79 
 
 2,100 
 
 75 
 
 1,720 
 64 
 
 Means .. 
 
 
 \ 
 
 
 
 
 DECEl 
 
 tfBEE, 
 
 1885. 
 
 
 
 
 
 
 
 1 
 
 45 
 60 
 60 
 50 
 100 
 60 
 
 
 40 
 70 
 50 
 65 
 100 
 60 
 
 
 65 
 70 
 60 
 65 
 90 
 65 
 
 
 45 
 50 
 60 
 65 
 65 
 70 
 
 
 50 
 20 
 60 
 65 
 10 
 60 
 
 
 25 
 36 
 60 
 70 
 
 
 65 
 
 
 
 15 
 15 
 
 80 
 
 70 
 
 200 
 
 50 
 
 
 
 10 
 50 
 20 
 100 
 50 
 25 
 
 
 — 25 
 65 
 
 5 
 85 
 50 
 20 
 
 
 
 — 70 
 105 
 30 
 60 
 50 
 15 
 
 
 — 30 
 
 100 
 55 
 
 100 
 
 50 
 
 15 
 
 
 
 —200 
 
 100 
 
 50 
 
 100 
 
 20 
 
 15 
 
 
 
 2 
 
 3 
 
 4 
 
 5.. 
 
 6 
 
 7 
 
 8 , 
 
 9 
 
 25 
 
 130 
 
 40 
 
 100 
 
 85 
 
 50 
 
 70 
 
 150 
 
 150 
 
 30 
 
 120 
 
 50 
 100 
 
 40 
 100 
 
 25 
 170 
 100 
 180 
 135 
 
 20 
 110 
 
 20 
 10 
 40 
 
 100 
 20 
 
 100 
 60 
 
 160 
 
 135 
 20 
 
 125 
 
 20 
 10 
 40 
 
 100 
 15 
 
 200 
 90 
 
 210 
 
 150 
 25 
 
 125 
 
 30 
 5 
 35 
 95 
 15 
 
 100 
 90 
 
 230 
 
 150 
 20 
 
 165 
 
 40 
 
 
 40 
 100 
 
 10 
 100 
 100 
 230 
 150 
 5 
 100 
 
 80 
 
 
 45 
 110 
 
 10 
 140 
 110 
 300 
 175 
 
 20 
 100 
 
 60 
 
 20 
 
 50 
 
 80 
 
 10 
 
 150 
 
 130 
 
 300 
 
 140 
 
 — 10 
 
 80 
 
 65 
 
 10 
 
 45 
 
 90 
 
 10 
 
 100 
 
 130 
 
 300 
 
 150 
 
 20 
 
 50 
 
 65 
 
 10 
 
 50 
 
 80 
 
 10 
 
 20 
 
 100 
 
 200 
 
 200 
 
 30 
 
 60 
 
 60 
 
 40 
 
 45 
 
 25 
 
 — 20 
 
 
 
 120 
 
 180 
 
 175 
 
 30 
 
 50 
 
 — 50 
 55 
 25 
 20 
 
 — 50 
 —300 
 
 80 
 
 150 
 
 175 
 
 25 
 
 50 
 
 10 
 
 11 .. . 
 
 12 
 
 13 
 
 14 
 
 15 
 
 16 
 
 17 
 
 18 
 
 19 
 
 20 
 
 21 
 
 
 
 
 
 
 
 
 
 
 
 
 
 22 
 
 40 
 
 100 
 
 40 
 
 40 
 
 20 
 
 15 
 
 
 
 .50 
 
 100 
 
 50 
 
 50 
 120 
 50 
 60 
 20 
 10 
 
 50 
 70 
 65 
 
 55 
 110 
 50 
 55 
 25 
 10 
 
 40 
 85 
 50 
 
 50 
 100 
 55 
 50 
 40 
 15 
 
 
 40 
 85 
 
 
 
 100 
 
 100 
 
 40 
 
 45 
 
 40 
 
 30 
 
 
 
 40 
 
 80 
 
 —300 
 
 70 
 
 130 
 
 30 
 
 55 
 
 60 
 
 10 
 
 
 
 45 
 
 90 
 
 -400 
 
 100 
 
 100 
 
 55 
 
 60 
 
 100 
 
 D 
 
 
 
 
 
 50 
 
 —300 
 
 150 
 
 110 
 
 60 
 
 70 
 
 fO 
 
 
 
 
 
 
 
 — 60 
 
 —300 
 
 110 
 
 120 
 
 60 
 
 80 
 
 
 
 
 
 
 
 
 
 -so 
 
 —100 
 
 150 
 
 100 
 
 55 
 
 70 
 
 — 70 
 
 
 
 
 
 
 
 100 
 
 — 80 
 
 100 
 
 110 
 
 50 
 
 70 
 
 - 60 
 
 
 
 
 
 
 
 110 
 
 — 50 
 
 100 
 
 100 
 
 50 
 
 80 
 
 — 60 
 
 50 
 
 
 
 
 
 100 
 
 
 
 23 
 
 24 
 
 25 
 
 2R 
 
 27 
 
 2d 
 
 20 
 
 30 
 
 31.. 
 
 
 1,780 
 68 
 
 1,910 
 73 
 
 1,685 
 65 
 
 1,775 
 68 
 
 1,375 
 53 
 
 1,220 
 
 47 
 
 1,685 
 70 
 
 1,345 
 56 
 
 1,390 
 
 58 
 
 1.340 
 56 
 
 1,325 
 55 
 
 685 
 29 
 
 Means 
 
 ' _i 
 
MEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES. 
 
 187 
 
 registration, at Baltimore, Md., 1885, 1886, and 1887 — Continued. 
 
 NOVEMBEE. 1885. 
 
 1 p.m. 
 
 2 p.m. 
 
 3 p.m. 
 
 4 p.m. 
 
 5 p.m. 
 
 6 p.m. 
 
 7 p.m. 
 
 8 p.m. 
 
 9 p.m. 
 
 10 p. m. 
 
 11 p. m. 
 
 12 mid. 
 
 Remarks. 
 
 200 
 
 125 
 
 100 
 
 60 
 
 —200 
 
 25 
 
 300 
 
 
 
 —300 
 
 
 
 -300 
 
 —300 
 
 Var. It., rain. 
 
 
 60 
 
 75 
 
 60 
 
 60 
 
 75 
 
 50 
 
 50 
 
 60 
 
 50 
 
 50 
 
 50 
 
 NW. br., rain. 
 
 50 
 
 50 
 
 60 
 
 65 
 
 60 
 
 75 
 
 90 
 
 80 
 
 75 
 
 75 
 
 80 
 
 80 
 
 W. br., cloudy. 
 
 100 
 
 125 
 
 100 
 
 125 
 
 125 
 
 no 
 
 150 
 
 125 
 
 125, 
 
 100 
 
 105, 
 
 110 
 
 W. fr., cloudy. 
 
 60 
 
 50 
 
 50 
 
 75 
 
 110 
 
 125 
 
 100 
 
 75 
 
 60 
 
 75 
 
 60 
 
 
 
 SW. br., rain. 
 
 75 
 
 75 
 
 75 
 
 65 
 
 50 
 
 40 
 
 40 
 
 30 
 
 30 
 
 10 
 
 60 
 
 50 
 
 S. It., rain. 
 
 35 
 
 10 
 
 — 20 
 
 — 5 
 
 — 5 
 
 
 
 5 
 
 5 
 
 5 
 
 5 
 
 5 
 
 5 
 
 Var. It., rain. 
 
 
 
 
 
 
 
 25 
 
 25 
 
 50 
 
 100 
 
 40 
 
 60 
 
 60 
 
 —150 
 
 —100 
 
 S. It., rain. 
 
 75 
 
 75 
 
 75 
 
 75 
 
 75 
 
 75 
 
 60 
 
 60 
 
 60 
 
 60 
 
 60 
 
 60 
 
 NW. fr., rain. 
 
 30 
 
 60 
 
 60 
 
 65 
 
 75 
 
 80 
 
 90 
 
 80 
 
 100 
 
 80 
 
 75 
 
 75 
 
 NW. fr., cloudy. - 
 
 250 
 
 125 
 
 125 
 
 100 
 
 125 
 
 125 
 
 , 150 
 
 125 
 
 175 
 
 250 
 
 200 
 
 150 
 
 W. fr., fair. 
 
 125 
 
 130 
 
 125 
 
 110 
 
 120 
 
 100 
 
 90 
 
 80 
 
 105 
 
 75 
 
 75 
 
 75 
 
 SW. It., fair. 
 
 30 
 
 25 
 
 —100 
 
 10 
 
 
 
 50 
 
 60 
 
 75 
 
 65 
 
 60 
 
 55 
 
 75 
 
 SW. It., rain. 
 
 100 
 
 150 
 
 90 
 
 160 
 
 150 
 
 75 
 
 125 
 
 100 
 
 110 
 
 65 
 
 60 
 
 55 
 
 Vat. It., fair. 
 
 50 
 
 30 
 
 10 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 NW. br., fair. 
 
 60 
 
 60 
 
 65 
 
 75 
 
 65 
 
 90 
 
 90 
 
 100 
 
 95 
 
 100 
 
 80 
 
 60 
 
 NW. fr., clear. 
 
 60 
 
 30 
 
 50 
 
 50 
 
 75 
 
 100 
 
 100 
 
 95 
 
 100 
 
 100 
 
 95 
 
 90 
 
 N. It. fair. 
 
 60 
 
 60 
 
 75 
 
 75 
 
 60 
 
 65 
 
 50 
 
 40 
 
 30 
 
 30 
 
 20 
 
 30 
 
 Var. It., rain. 
 
 — 50 
 
 
 
 — 5 
 
 — 5 
 
 25 
 
 50 
 
 25 
 
 25 
 
 25 
 
 25 
 
 25 
 
 25 
 
 SW. It., rain. 
 
 100 
 
 100 
 
 100 
 
 100 
 
 125 
 
 100 
 
 100 
 
 75 
 
 50 
 
 — 25 
 
 - 20 
 
 20 
 
 N. It., clear. 
 
 100 
 
 80 
 
 75 
 
 75 
 
 30 
 
 75 
 
 100 
 
 125 
 
 110 
 
 75 
 
 80 
 
 75 
 
 Var. It., rain. 
 
 
 
 —150 
 
 — 50 
 
 —150 
 
 — 25 
 
 ' 
 
 —350 
 
 —300 
 
 —250 
 
 —200 
 
 —200 
 
 — 75 
 
 W. It., rain. 
 
 25 
 
 30 
 
 50 
 
 75 
 
 25 
 
 60 
 
 
 
 —100 
 
 —150 
 
 —350 
 
 —150 
 
 —150 
 
 NE. fr., rain^snow. 
 
 50 
 
 75 
 
 30 
 
 50 
 
 60 
 
 75 
 
 75 
 
 60 
 
 60 
 
 50 
 
 65 
 
 65 
 
 NW. fr., rain, snow. 
 
 100 
 
 100 
 
 100 
 
 100 
 
 75 
 
 75 
 
 85 
 
 75 
 
 75 
 
 75 
 
 75 
 
 75 
 
 NW. br., snow. 
 
 80 
 
 80 
 
 75 
 
 50 
 
 75 
 
 80 
 
 80 
 
 75 
 
 75 
 
 60 
 
 50 
 
 40 
 
 NW. fr., cloudy. 
 
 50 
 
 30 
 
 65 
 
 50. 
 
 75 
 
 90 
 
 90 
 
 90 
 
 75 
 
 60 
 
 75 
 
 50 
 
 NW. fr., rain. 
 
 110 
 
 150 
 
 110 
 
 100 
 
 50 
 
 60 
 
 50 
 
 50 
 
 50 
 
 , 50 
 
 50 
 
 50 
 
 NW. It., rain. 
 
 
 
 
 
 
 50 
 
 75 
 
 80 
 
 75 
 
 60 
 
 60 
 
 40 
 
 50 
 
 .50 
 
 NE. It., rain. 
 
 75 
 
 60 
 
 75 
 
 . 75 
 
 75 
 
 50 
 
 40 
 
 30 
 
 50 
 
 25 
 
 30 
 
 30 
 
 N. fr., cloudy. 
 
 2,000 
 
 1,795 
 
 1,640 
 
 1,760 
 
 1,635 
 
 2,055 
 
 2,020 
 
 1,425 
 
 1,175 
 
 1,080 
 
 760 
 
 820 
 
 71 
 
 60 
 
 55 
 
 61 
 
 56 
 
 71 
 
 70 
 
 49 
 
 41 
 
 37 
 
 26 
 
 28 
 
 
 DECEMBER, 1885. 
 
 —250 
 
 — 50 
 
 50 
 
 20 
 
 30 
 
 30 
 
 30 
 
 40 
 
 50 
 
 50 
 
 45 
 
 25 
 
 NE. fr.,rain. 
 
 100 
 
 100 
 
 85 
 
 70 
 
 80 
 
 95 
 
 100 
 
 120 
 
 100 
 
 85 
 
 75 
 
 60 
 
 N. It., clear. 
 
 50 
 
 55 
 
 25 
 
 40 
 
 60 
 
 50 
 
 50 
 
 50 
 
 55 
 
 50 
 
 50 
 
 50 
 
 SE-NW. fr., rain, sleet. 
 
 100 
 
 100 
 
 110 
 
 130 
 
 150 
 
 85 
 
 55 
 
 80 
 
 70 
 
 90 
 
 80 
 
 80 
 
 S. fr., cloudy. 
 
 20 
 
 30 
 
 35 
 
 • 20 
 
 50 
 
 50 
 
 25 
 
 40 
 
 20 
 
 — 30 
 
 30 
 
 50 
 
 S. It., rain. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 SW. br., fair. 
 SW. fr., clear. 
 S. It., cloudy. 
 
 50 
 
 60 
 
 75 
 
 100 
 
 60 
 
 100 
 
 100 
 
 80 
 
 75 
 
 90 
 
 5 
 
 40 
 
 —400 
 
 —200 
 
 100 
 
 200 
 
 150 
 
 95 
 
 150 
 
 50 
 
 100 
 
 80 
 
 40 
 
 40 
 
 Var. It., rain. 
 
 50 
 
 60 
 
 60 
 
 70 
 
 75 
 
 75 
 
 90 
 
 60 
 
 55 
 
 50 
 
 45 
 
 40 
 
 Var. It., fair. 
 
 50 
 
 65 
 
 70 
 
 50 
 
 55 
 
 60 
 
 50 
 
 50 
 
 50 
 
 50 
 
 75 
 
 90 
 
 NW. br., fair. 
 
 25 
 
 90 
 
 150 
 
 120 
 
 180 
 
 90 
 
 100 
 
 130 
 
 130 
 
 100 
 
 120 
 
 100 
 
 NE. fr., clear. 
 
 —400 
 
 —400 
 
 —400 
 
 —250 
 
 80 
 
 110 
 
 200 
 
 230 
 
 240 
 
 150 
 
 —250 
 
 —350 
 
 SE. fr., rain. 
 
 —100 
 
 —300 
 
 —100 
 
 70 
 
 100 
 
 110 
 
 50 
 
 90 
 
 90 
 
 80 
 
 70 
 
 70 
 
 W. fr., rain. 
 
 130 
 
 110 
 
 160 
 
 170 
 
 100 
 
 150 
 
 150 
 
 .145 
 
 160 
 
 150 
 
 150 
 
 145 
 
 NW. br., fair. 
 
 200 
 
 180 
 
 200 
 
 175 
 
 210 
 
 300 
 
 70 
 
 90 
 
 75 
 
 1.50 
 
 150 
 
 150 
 
 Var. gen., fair. 
 
 150 
 
 200 
 
 200 
 
 150 
 
 250 
 
 170 
 
 150 
 
 125 
 
 80 
 
 30 
 
 30 
 
 30 
 
 E. gen., fair. 
 
 100 
 
 110 
 
 130 
 
 140 
 
 150 
 
 200 
 
 150 
 
 135 
 
 115 
 
 no 
 
 50 
 
 100 
 
 Var. gen., fair. 
 W. It., fair. 
 NW. br., fair. 
 W. br. fair. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 6 
 
 
 
 
 
 
 
 50 
 
 50 
 
 50 
 
 50 
 
 50 
 
 45 
 
 100 
 
 50 
 
 75 
 
 80 
 
 75 
 
 150 
 
 200 
 
 160 
 
 150 
 
 20 
 
 20 
 
 100 
 
 W. fr., fair. 
 
 100 
 
 130 
 
 50 
 
 25 
 
 — 10 
 
 — 20 
 
 25 
 
 
 
 10 
 
 50 
 
 25 
 
 50 
 
 SW. fr., rain. 
 
 50 
 
 50 
 
 75 
 
 70 
 
 50 
 
 50 
 
 50 
 
 30 
 
 50 
 
 70 
 
 40 
 
 50 
 
 NW. fr., fair. 
 
 70 
 
 80 
 
 95 
 
 50 
 
 50 
 
 100 
 
 80 
 
 50 
 
 30 
 
 40 
 
 25 
 
 10 
 
 NE. fr., fair. 
 
 —100 
 
 50 
 
 
 
 20 
 
 70 
 
 50 
 
 50 
 
 120 
 
 95 
 
 70 
 
 60 
 
 —100 
 
 Var. It., fair. 
 
 40 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 NW. fr., fair. 
 
 
 50 
 
 60 
 
 45 
 
 30 
 
 35 
 
 25 
 
 30 
 
 30 
 
 30 
 
 30 
 
 35 
 
 W. fr., fair. 
 
 75 
 
 80 
 
 75 
 
 80 
 
 90 
 
 100 
 
 100 
 
 100 
 
 25 
 
 80 
 
 55 
 
 60 
 
 N. It., fair. 
 
 1.50 
 
 200 
 
 170 
 
 130 
 
 150 
 
 110 
 
 90 
 
 95 
 
 100 
 
 100 
 
 100 
 
 70 
 
 SE. It., fair. 
 
 
 360 
 
 50 
 
 70 
 
 70 
 
 65 
 
 80 
 
 50 
 
 40 
 
 40 
 
 60 
 
 60 
 1,230 
 
 70 
 1,110 
 
 Var. It., rain. 
 
 950 
 
 1,620 
 
 1,845 
 
 2,350 
 
 2,525 
 
 2,240 
 
 2,190 
 
 2,045 
 
 1,855 
 
 15 
 
 38 
 
 65 
 
 74 
 
 94 
 
 101 
 
 86 
 
 84 
 
 79 
 
 71 
 
 47 
 
 43 
 
 
188 
 
 MEMOIES OF THE NATIONAL ACADEMY OF SOIBNGES. 
 
 TABLE A.— Hourly records, drawn from continuous photographic 
 JANUAKY, 1886. 
 
 Bay of month. 
 
 1 a.m. 
 
 2 a. m. 
 
 Sam, 
 
 4 a, m. 
 
 5a.iu. 
 
 6 a,]]a. 
 
 7 a^m. 
 
 \ 
 
 8 a. m. 
 
 9 a.m. 
 
 10 a. m. 
 
 11 a.m. 
 
 12 m. 
 
 1 
 
 50 
 
 100 
 
 70 
 
 25 
 
 5 
 
 40 
 
 50' 
 
 90 
 
 150 
 
 — 5 
 
 65 
 
 40 
 
 70 
 
 — 75 
 
 5 
 
 Ij' 40 
 
 l§ 65 
 
 90 
 
 '-J50 
 
 
 
 60 
 
 60 
 
 50 
 
 
 
 15 
 
 45 
 
 60 
 
 70 
 
 —150 
 
 
 
 70 
 70 
 40 
 50 
 10 
 45 
 60 
 70 
 -150 1 
 
 
 60 
 
 70 
 
 10 
 
 — 50 
 
 20 
 
 50 
 
 70 
 
 75 
 
 100 
 
 
 
 80 
 100 
 30 
 10 
 35 
 50 
 85- 
 90 
 
 -go 
 
 
 
 200 
 
 50 
 
 30 
 
 —200 
 
 75 
 
 60 
 
 80 
 
 75 
 
 
 
 
 
 180 
 50 
 50 
 —150 
 75 
 75 
 
 110; 
 
 100 
 30 ' 
 
 
 140 
 
 140 
 
 80 
 
 —100 
 
 75 
 
 55 
 
 70 
 
 100 
 
 50 
 
 
 
 150 
 
 120 
 
 80 
 
 —150 
 
 50 
 
 50 
 
 70 
 
 85 
 
 10 
 
 
 
 120 
 
 100 
 
 110 
 
 —200 
 
 50 
 
 50 
 
 70 
 
 85 
 
 10 
 
 — 50 
 
 100 
 
 110 
 
 50 
 
 — 75 
 50 
 50 
 70 
 80 
 10 
 
 — 50 
 
 2 
 
 3 
 
 4 
 
 5 
 
 6 
 
 7 
 
 8 
 
 9. .. 
 
 10 
 
 11 
 
 12 
 
 
 
 
 
 
 
 
 
 
 
 
 
 13 
 
 
 
 
 
 
 
 
 
 
 
 
 
 14 
 
 
 
 
 
 
 
 
 
 
 
 
 
 15 
 
 
 
 
 
 
 
 
 
 
 
 
 
 16 
 
 
 
 
 
 
 
 
 
 
 
 
 
 17 
 
 
 
 
 
 , 
 
 
 
 
 
 
 
 
 18 
 
 
 
 
 
 
 
 
 
 
 
 
 
 19 
 
 
 
 
 
 
 
 
 
 
 
 
 
 20 
 
 
 
 
 
 
 
 
 
 
 
 
 
 21. . .: 
 
 
 
 
 
 
 
 
 
 - 
 
 
 
 
 
 100 
 
 120 
 
 120 
 
 120 
 
 130 
 
 140 
 
 145 
 
 135 
 
 160 
 
 200 
 
 250 
 
 200 
 
 23 * 
 
 24 
 
 
 
 
 
 
 
 
 
 
 
 
 
 25 .. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 26... 
 
 160 
 120 
 110 
 150 
 50 
 
 
 140 
 130 
 140 
 .75 
 —100 
 
 
 100 
 140 
 100 
 100 
 — 50 
 
 
 85 
 
 135 
 
 90 
 
 120 
 
 -60 
 
 
 
 150 
 
 100 
 
 70 
 
 90 
 
 
 
 
 
 100 
 
 100 
 
 30 
 
 40 
 
 20 
 
 
 
 120 
 
 100 
 95 
 
 
 50 
 
 
 
 110 
 110 
 120 
 
 
 100 
 
 
 
 100 
 130 
 150 
 
 
 59 
 
 
 
 110 
 105 
 160 
 
 
 50 
 
 
 
 130 
 
 —250 
 
 150 
 
 
 
 50 
 
 50 
 
 150 
 
 
 
 150 
 
 
 
 70 
 
 60 
 
 27 
 
 28 
 
 29 
 
 30 
 
 31 
 
 gums , 
 
 1265 
 79 
 
 655 
 44 
 
 720 
 
 48 
 
 755 
 
 50 
 
 945 
 63 
 
 860 
 57 
 
 880 
 63 
 
 1,095 
 
 78 
 
 1,200 
 86 
 
 1,090 
 
 78 
 
 725 
 45 
 
 1,025 
 64 
 
 
 
 FEBEUAKY, 1886. 
 
 i o . 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 g 
 
 80 
 50 
 75 
 
 60 
 
 40 
 
 200 
 
 60 
 
 70 
 250 
 
 45 
 150 
 200 
 
 50 
 
 175 
 
 10 
 
 40 
 
 190 
 
 — 5 
 
 15 
 
 270 
 
 
 
 
 50 
 
 
 
 
 — 2(f 
 
 
 
 45 
 
 — 50 
 
 
 
 25 
 
 — 50 
 
 
 
 
 
 — 35 
 
 
 s 
 
 
 4 
 
 
 5 . 
 
 
 6 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 7 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 C 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 9 
 
 210 
 
 100 
 
 30 
 
 40 
 
 260 
 85 
 50 
 40 
 
 220 
 
 120 
 
 65 
 
 80 
 
 150 
 70 
 50 
 60 
 
 150 
 
 110 
 
 40 
 
 35 
 
 50 
 
 170 
 
 — 10 
 
 30 
 
 10 
 
 200 
 
 —400 
 
 50 
 
 
 
 200 
 
 —400 
 
 60 
 
 
 
 200 
 
 —300 
 
 150 
 
 250 
 
 170 
 
 —400 
 
 120 
 
 20 
 
 150 
 
 —400 
 
 100 
 
 
 
 150 
 
 —350 
 
 110 
 
 
 10 
 
 
 11 
 
 
 ]2 
 
 
 13 
 
 
 14 
 
 
 65 
 45 
 60 
 90 
 30 
 20 
 45 
 
 
 80 
 50 
 50 
 50 
 
 , 
 80 
 60 
 70 
 60 
 45 
 
 ,20 
 50 
 
 100 
 80 
 80 
 65 
 25 
 
 
 
 110 
 
 60 
 
 70 
 
 60 
 
 50 
 
 25 
 
 50 
 
 100 
 
 80 
 
 70 
 
 65 
 
 30 
 
 
 
 60 
 
 
 
 130 
 
 50 
 
 65 
 
 70 
 
 55 
 
 25 
 
 50 
 
 50 
 
 100 
 
 70 
 
 60 
 
 40 
 
 
 
 50 
 
 
 
 140 
 
 65 
 
 60 
 
 100 
 
 25 
 
 25 
 
 50 
 
 60 
 
 120 
 
 65 
 
 50 
 
 30 
 
 
 
 50 
 
 
 
 135 
 
 100 
 
 80 
 
 100 
 
 60 
 
 25 
 
 50 
 
 60 
 
 130 
 
 100 
 
 —200 
 
 
 
 
 
 20 
 
 
 
 50 
 
 120 
 
 90 
 
 120 
 
 100 
 
 25 
 
 90 
 
 75 
 
 140 
 
 200 
 
 
 
 
 
 
 
 
 
 
 
 160 
 
 150 
 
 50 
 
 150 
 
 70 
 
 —100 
 
 75 
 
 80 
 
 120 
 
 120 
 
 
 
 200 
 
 
 
 
 
 
 
 200 
 
 100 
 
 25 
 
 120 
 
 75 
 
 — 70 
 
 90 
 
 70 
 
 135 
 
 105 
 
 
 
 100 
 
 
 
 
 
 
 
 150 
 
 70 
 
 15 
 
 80 
 
 75 
 
 — 40 
 
 60 
 
 70 
 
 100 
 
 110 
 
 
 
 60 
 
 
 
 
 
 6" 
 
 170 
 
 70 
 
 150 
 
 50 
 
 
 
 - 20 
 
 110 
 
 70 
 
 50 
 
 150 
 
 
 
 20 
 
 
 
 
 
 
 160 
 
 """150" 
 
 50 
 
 
 
 — 10 
 
 100 
 
 70 
 
 30 
 
 200 
 
 
 
 
 
 
 
 
 
 
 15 
 
 
 16 
 
 
 17 
 
 
 18 ., 
 
 
 19 
 
 
 20 
 
 
 21 
 
 
 22 1. 
 
 
 23 
 
 \ 
 
 34 
 
 
 -i5 ... . 
 
 
 ■m 
 
 
 i7 
 
 
 'iS 
 
 65 
 
 60 
 
 
 Gumw- _. 
 
 
 1,235 
 62 
 
 1,530 
 76 
 
 1,695 
 
 85 
 
 1,540 
 
 77 
 
 1,410 
 70 
 
 1,125 
 56 
 
 1,155 
 64 
 
 985 
 
 58 
 
 1,000 
 59 
 
 885 
 52 
 
 665 
 42 
 
 625 
 45 
 
 
 
 
 
 
MEMOIRS OF THE IJTATIONAL ACADEMY OP SOIEK^OBS. 
 
 189 
 
 registration, at Baltimore, Md., 1885, 1886, and 1887— Continued. 
 
 JANUAEY, 1886. 
 
 Ip.tn. 
 
 2 p.m. 
 
 3 p.m. 
 
 4 p.m. 
 
 5 p.m. 
 
 6 p.m. 
 
 7 p.m. 
 
 8 p.m. 
 
 9 p.m. 
 
 10 p. m. 
 
 11 p. m. 
 
 12 mid. 
 
 Eemarks. 
 
 90 
 80 
 
 —ioo" 
 
 • 25 
 
 50 
 
 70 
 
 50 
 
 200 
 
 90 
 
 120 
 
 70 
 
 — 70 
 
 65 
 
 35 
 
 85 
 
 100 
 
 aoo 
 
 100 
 
 200 
 
 70 
 
 —100 
 
 70 
 
 50 
 
 - 80 
 
 100 
 
 100 
 
 100 
 
 190 
 
 70 
 
 —100 
 
 50 
 
 50 
 
 80 
 
 100 
 
 50 
 
 120 
 
 70 
 50 
 - 50 
 70 
 50 
 85 
 80 
 30 
 
 100 
 60 
 35 
 — 10 
 50 
 45 
 70 
 30 
 30 
 
 160 
 70 
 25 
 
 50 
 50 
 80 
 — 5 
 15 
 
 140 
 80 
 30 
 
 75 
 50 
 80 
 
 2C0 
 15 
 
 100 
 80 
 20 
 
 — .50 
 50 
 55 
 80 
 
 —200 
 
 - 20 
 
 40 
 90 
 50 
 
 — 5 
 35 
 50 
 85 
 
 —175 
 
 
 100 
 
 90 
 
 55 
 
 
 
 35 
 
 50 
 
 80 
 
 
 
 
 
 100 
 
 90 
 
 40 
 
 
 
 30 
 
 50 
 
 75 
 
 
 
 — 10 
 
 W. It., Clear. 
 E. It., clear. 
 E. It., cloudy. 
 E. gale, rain. 
 W. fr., rain. 
 NW. br., snow. 
 NW. fr., clear. 
 NE. br., snow. 
 NW. br., snow. 
 W. gale, snow 
 NW. gaie, fair. 
 NW. fr., fair. 
 
 Do. 
 Var. It., clear. 
 Var. It., fair. 
 Var. It., rain. 
 W. ft., rain. 
 W. fr., sleet. 
 NW. fr., sleet, rain. 
 Var. It., fair. 
 N. It., rain. ' 
 Var. It., fair. 
 NW. fr., fair. 
 NE. fr., snow. 
 N. fr., rain. 
 N. It., cloudy. 
 N. fr., rain. 
 
 Do. 
 NW. ft., rain. 
 NW. br., rain, snow. 
 NW. fr., snow. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 ....X.. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 175 
 
 210 
 
 220 
 
 200 
 
 160 
 
 150 
 
 150 
 
 130 
 
 100 
 
 80 
 
 100 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 100* 
 110 
 50 
 140 
 100 
 200 
 
 ' 110 
 140 
 
 5C 
 120 
 110 
 
 20 
 
 80 
 50 
 60 
 100 
 120 
 60 
 
 75 
 
 20 
 
 — 10 
 
 140 
 
 120 
 
 50 
 
 100 
 20 
 50 
 50 
 
 115 
 60 
 
 85 
 110 
 
 60 
 150 
 125 
 
 65 
 
 100 
 120 
 
 70 
 100 
 130 
 
 60 
 
 50 
 130 
 
 85 
 120 
 140 
 
 50 
 
 50 
 
 100 
 
 
 
 95 
 
 90 
 
 
 
 50 
 110 
 
 20 
 100 
 
 90 
 
 
 50 
 60 
 
 — 60 
 
 - 50 
 105 
 
 
 
 100 
 
 110 
 
 75 
 
 —100 
 
 100 
 
 
 
 
 
 
 
 
 
 ' 
 
 
 
 
 
 
 1,165 
 83 
 
 1,420 
 89 
 
 1,350 
 
 84 
 
 1,205 
 75 
 
 1,100 
 69 
 
 1, 165 
 73 
 
 1,175 
 73 
 
 1,395 
 
 87 
 
 580 
 39 
 
 640 
 43 
 
 595 
 40 
 
 760 
 51 
 
 FEBEUA.RY, 1886. 
 
 100 
 
 10 
 
 
 
 100 
 100 
 100 
 
 85 
 75 
 50 
 
 80 
 
 60 
 
 — 10 
 
 85 
 
 50 
 
 
 
 80 
 
 65 
 
 — 20 
 
 70 
 
 60 
 
 — 15 
 
 60 
 
 65 
 
 
 
 40 
 
 85 
 
 
 
 50 
 60 
 20 
 
 55 
 50 
 
 70 
 65 
 100 
 
 NW. fr., fair. 
 SW. fr., fair. . 
 NE. fr., snow. 
 NW. br., snow. 
 
 Do. 
 Var. It., snow. 
 NE. It., cloudy. 
 Var. It., cloudy. 
 Var. It., clear. 
 Var. It., rain. 
 NE. fr., rain. 
 NE. It., rain. 
 W. fr., rain. 
 Var. It., fair. 
 SW. gale, rain. 
 NW.br., fair. 
 Var. It., fair. 
 SW. fr., clear. 
 NW.br., iair. 
 NW. galajJair. 
 SW. ft., fair. 
 NW. br., clear. 
 SW. It., lain. 
 SE. It., fair.. 
 NW. br., rain. 
 NW. gale, snow. 
 NW. br., clear. 
 
 Do. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 200 
 210 
 150 
 
 220 
 300 
 200 
 
 80 
 
 300 
 
 160 
 
 — 50 
 
 200 
 
 250 
 
 180 
 
 50 
 
 180 
 210 
 180 
 , 90 
 
 250 
 220 
 150 
 
 40 
 
 60 
 150 
 135 
 
 35 
 
 40 
 
 160 
 
 30 
 
 50 
 
 15 
 
 100 
 50 
 50 
 
 
 
 100 
 
 60 
 
 40 
 
 
 
 100 
 
 60 
 
 50 
 
 150 
 80 
 50 
 60 
 
 
 
 
 
 '""so" 
 
 '"'85" 
 45 
 
 
 
 160 
 
 100 
 
 80 
 
 90 
 
 40 
 
 
 
 200 
 
 100 
 
 80 
 
 60 
 
 40 
 
 70 
 
 — 60 
 
 110 
 
 80 
 
 10 
 
 200 
 
 -200 
 
 —100 
 
 50 
 
 100 
 
 
 250 
 
 85 
 60 
 35 
 30 
 
 — 80 
 70 
 70 
 
 — 50 
 200 
 
 —150 
 
 —100 
 
 50 
 
 100 
 
 
 200 
 
 85 
 95 
 20 
 50 
 
 — 20 
 85 
 60 
 30 
 
 200 
 60 
 
 — 80 
 50 
 60 
 
 
 
 220 
 
 45 
 
 60 
 
 75 
 
 100 
 
 — 10 
 20 
 
 120 
 85 
 55 
 
 220 
 50 
 
 — 50 
 50 
 60 
 
 
 
 130 
 
 50 
 
 50 
 
 90 
 
 80 
 
 50 
 
 25 
 
 100 
 
 160 
 
 60 
 
 200 
 
 110 
 
 — 30 
 
 50 
 
 75 
 
 
 
 130 
 
 50 
 
 80 
 
 75 
 
 70 
 
 40 
 
 30 
 
 100 
 
 120 
 
 60 
 
 140 
 
 100 
 
 — 20 
 
 55 
 
 80 
 
 
 
 200 
 
 50 
 
 60 
 
 70 
 
 80 
 
 70 
 
 35 
 
 1.50 
 
 150 
 
 65 
 
 110 
 
 50 
 
 — 10 
 
 50 
 
 85 
 
 
 
 100 
 
 40 
 
 65 
 
 50 
 
 60 
 
 65 
 
 45 
 
 200 
 
 100 
 
 80 
 
 60 
 
 
 
 — 10 
 
 60 
 
 90 
 
 
 50 
 40 
 65 
 60 
 35 
 60 
 40 
 
 130 
 
 . 60 
 
 60 
 
 60 
 
 150 
 
 — 10 
 
 40 
 
 60 
 
 
 65 
 30 
 90 
 70 
 40 
 40 
 40 
 130 
 85 
 50 
 60 
 —100 
 
 ""50' 
 60 
 
 —100 
 
 ""'70' 
 
 200 
 
 
 — 10 
 
 
 — 50 
 100 
 70 1 
 
 200 
 
 200 
 
 —150 
 
 50 
 
 
 
 950 
 79 
 
 1,910 
 106 
 
 1,540 
 70 
 
 1,380 
 63 
 
 1,690 
 
 77 
 
 1,885 
 86 
 
 1,695 
 
 77 
 
 1,515 
 69 
 
 1,555 
 71 
 
 1,335 
 61 
 
 1,280 
 59 
 
 1,285 
 61 
 
190 
 
 MEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES. 
 
 Table A.— Hourly records, drawn from continuous photographic 
 
 MARCH, 1886. 
 
 Day of month. 
 
 1 a. m. 
 
 2 a. m. 
 
 3 a. m. 
 
 4 a. m. 
 
 5 a. m. 
 
 6 a. m. 
 
 7 a.m. 
 
 8 a.m. 
 
 9 a.m. 
 
 10 a. m. 
 
 11 a. m. 
 
 12 m. 
 
 1 
 
 120 
 
 — 5 
 10 
 
 
 50 
 60 
 50 
 - 60 
 10 
 50 
 70 
 30 
 30 
 25 
 50 
 70 
 80 
 50 
 
 
 
 — 50 
 60 
 50 
 50 
 50 
 95 
 
 
 -300 
 
 — 10 
 60 
 
 — 10 
 ■ 60 
 
 80 
 
 — 5 
 
 
 
 50 
 50 
 40 
 40 
 10 
 50 
 80 
 30 
 10 
 30 
 80 
 80 
 80 
 100 
 
 — 10 
 20 
 50 
 60 
 50 
 50 
 50 
 
 
 
 — 20 
 
 
 60 
 
 — 20 
 20 
 
 90 
 — 5 
 
 
 15 
 50 
 30 
 40 
 40 
 10 
 60 
 75 
 30 
 
 
 30 
 60 
 90 
 80 
 80 
 
 
 60 
 
 
 60 
 75 
 50 
 50 
 
 
 20 
 10 
 45 
 20 
 
 
 
 100 
 
 
 10 
 50 
 50 
 40 
 
 — 5 
 20 
 50 
 70 
 30 
 25 
 30 
 70 
 60 
 90 
 80 
 
 —150 
 45 
 25 
 50 
 60 
 50 
 90 
 
 
 — 50 
 10 
 40 
 30 
 
 — 10 
 
 70 
 
 
 20 
 50 
 50 
 40 
 
 — 50 
 20 
 40 
 70 
 30 
 
 
 30 
 30 
 65 
 95 
 90 
 
 — 20 
 50 
 50 
 50 
 50 
 45 
 70 
 
 
 
 —200 
 
 20 
 
 50 
 
 100 
 
 — 10 
 
 70 
 
 
 25 
 50 
 50 
 45 
 
 — 50 
 30 
 40 
 70 
 30 
 20 
 40 
 60 
 60 
 
 100 
 60 
 
 -200 
 50 
 50 
 55 
 50 
 70 
 50 
 
 
 -250 
 10 
 40 
 75 
 
 — 10 
 
 70 
 
 
 30 
 50 
 50 
 80 
 
 —100 
 40 
 
 80 
 30 
 10 
 50 
 60 
 30 
 100 
 70 
 
 —100 
 60 
 
 70 
 50 
 80 
 40 
 
 — 10 
 —250 
 
 10 
 20 
 
 — 20 
 
 — 10 
 
 70 
 
 
 
 
 
 35 
 
 40 
 
 60 
 
 70 
 
 200 
 
 50 
 
 
 
 85 
 
 30 
 
 
 
 60 
 
 — 5 
 50 
 
 100 
 60 
 
 — 5 
 70 
 60 
 70 
 60 
 
 . 95 
 
 — 10 
 
 — 10 
 —200 
 
 40 
 
 50 
 
 —300 
 
 — 10 
 
 25 
 
 — 10 
 
 — 10 
 25 
 20 
 40 
 50 
 50 
 50 
 
 
 
 80 
 
 —110 
 
 — 10 
 65 
 10 
 60 
 95 
 40 
 
 — 20 
 
 
 75 
 50 
 50 
 70 
 
 
 
 — 20 
 
 — 25 
 40 
 50 
 
 —300 
 
 — 20 
 
 
 
 — 10 
 
 
 
 2.7 
 
 50 
 50 
 50 
 110 
 50 
 
 80 
 
 — 70 
 
 — 10 
 65 
 00 
 30 
 
 110 
 25 
 
 — 10 
 
 — 20 
 90 
 20 
 50 
 50 
 
 — 10 
 —300 
 —100 
 
 25 
 25 
 20 
 
 — 20 
 
 20 
 
 — 5 
 
 — 20 
 25 
 40 
 30 
 50 
 90 
 60 
 
 
 
 80 
 
 —150 
 
 — 20 
 60 
 50 
 25 
 
 100 
 25 
 
 — 15 
 
 — 20 
 90 
 
 
 50 
 30 
 
 — 20 
 —300 
 —100 
 
 20 
 
 40 
 
 100 
 
 — 20 
 
 60 
 
 — 5 
 10 
 25 
 
 40 
 
 30 
 50 
 50 
 60 
 
 20 
 —100 
 
 — 20 
 50 
 60 
 25 
 
 100 
 20 
 
 — 5 
 
 — 25 
 80 
 
 
 
 50 
 
 25 
 
 
 
 —100 
 
 — 25Q 
 
 25 
 
 
 
 100 
 
 — 20 
 
 2 
 
 3 
 
 4 
 
 5 
 
 6 
 
 7 
 
 8 
 
 9 
 
 10 
 
 11 
 
 12 
 
 13 
 
 14 
 
 15 
 
 16 
 
 17 
 
 18 
 
 19 
 
 20 
 
 21 
 
 22 .. 
 
 
 24 
 
 26 
 
 
 28 
 
 
 30 
 
 
 865 
 29 
 
 1,115 
 38 
 
 1, 165 
 40 
 
 960 
 34 
 
 905 
 32 
 
 690 
 25 
 
 590 
 21 
 
 815 
 29 
 
 420 
 14 
 
 425 
 14 
 
 315 
 11 
 
 355 
 13 
 
 
 
 APRIL, 1886. 
 
 1 
 
 20 
 
 ' 
 
 
 
 — 50 
 
 50 
 
 ' 
 
 — 5 
 
 —100 
 
 40 
 
 
 — 10 
 
 — 50 
 
 30 
 
 
 
 — 5 
 
 — 25 
 
 40 
 
 
 
 
 
 — 25 
 
 50 
 
 
 
 — 10 
 
 — 25 
 
 — 10 
 
 
 
 — 30 
 
 o' 
 
 — 10 
 
 
 
 — 60 
 
 
 
 5 
 
 — 5 
 
 — 10 
 
 
 
 5 
 
 — 10 
 
 — 5 
 
 
 5 
 
 — 20 
 
 
 
 
 
 10 
 
 — 20 
 
 - 10 
 
 
 
 2 
 
 3 
 
 4 
 
 5 
 
 6 
 
 —150 
 40 
 35 
 
 
 40 
 40 
 
 —300 
 50 
 35 
 
 —300 
 30 
 35 
 
 —100 
 50 
 35 
 
 — 60 
 50 
 50 
 
 — 1.50 
 50 
 50 
 
 
 
 — 10 
 
 50 
 
 
 10 
 30 
 
 
 30 
 30 
 
 
 30 
 30 
 
 
 
 30 
 30 
 
 7 
 
 8 
 
 9 
 
 10 
 
 100 
 10 
 25 
 
 — 50 
 50 
 80 
 80 
 40 
 
 
 100 
 
 
 25 
 40 
 40 
 
 
 
 — 60 
 25 
 10 
 
 
 50 
 40 
 
 130 
 10 
 25 
 40 
 100 
 80 
 100 
 40 
 
 
 75 
 
 
 40 
 5P 
 
 5 
 
 
 
 - 10 
 
 25 
 
 60 
 
 
 60 
 50 
 
 100 
 20 
 
 5 
 
 40 
 
 100 
 
 50 
 
 100 
 
 40 
 
 
 50 
 
 
 40 
 20 
 30 
 
 
 
 — 10 
 
 25 
 
 
 
 
 50 
 50 
 
 90 
 30 
 
 5 
 
 40 
 
 100 
 
 20 
 
 100 
 
 50 
 
 
 50 
 
 
 40 
 10 
 15 
 
 
 
 — 20 
 
 30 
 
 10 
 
 
 50 
 60 
 
 75 
 30 
 50. 
 40 
 60 
 
 
 
 100 
 
 50 
 
 
 60 
 
 
 30 
 20 
 25 
 
 
 
 — 15 
 
 30 
 
 20 
 
 
 50 
 70 
 
 80 
 25 
 50 
 25 
 60 
 
 
 
 100 
 
 60 
 
 
 100 
 
 
 15 
 30 
 10 
 
 5 
 
 — 15 
 40 
 
 — 5 
 
 
 ,30 
 80 
 
 100 
 10 
 60 
 50 
 60 
 
 
 
 125 
 
 60 
 
 
 60 
 
 
 
 40 
 
 40 
 
 — 20 
 
 
 
 
 50 
 10 
 
 
 25 
 85 
 
 70 
 10 
 40 
 25 
 60 
 
 60 
 10 
 40 
 — 10 
 60 
 
 70 
 
 25 
 
 25 
 
 11 
 
 12 
 
 75 
 50 
 90 
 
 90 
 
 
 
 110 
 
 90 
 
 
 
 120 
 
 13 
 
 14 
 
 15 
 
 16 
 
 150 
 60 
 
 
 70 
 
 
 60 
 30 
 
 
 — 10 
 
 
 60 
 20 
 
 
 
 
 90 
 
 140 
 50 
 
 
 60 
 
 
 80 
 30 
 
 — 10 
 
 — 10 
 
 
 
 —100 
 
 30 
 
 
 
 
 
 95 
 
 100 
 
 50 
 
 
 
 
 
 
 
 80 
 
 15 
 
 — 15 
 
 — 5 
 
 
 — 60 
 
 — 10 
 
 
 
 80 
 
 110 
 
 150 
 
 100 
 
 
 
 
 
 
 
 180 
 
 10 
 
 -^10 
 
 — 5 
 
 — 10 
 40 
 
 — 20 
 
 
 
 80 
 
 100 
 
 150 
 
 75 
 
 
 
 
 
 
 
 180 
 
 25 
 
 
 
 5 
 
 — 5 
 
 "'"56" 
 
 
 
 100 
 
 70 
 
 17 
 
 18 
 
 19 
 
 20 
 
 21 
 
 22 
 
 23 
 
 24 
 
 25 
 
 26 
 
 27 
 
 28 
 
 29 
 
 30 
 
 
 500 
 22 
 
 905 
 39 
 
 475 
 21 
 
 445 
 19 
 
 690 
 30 
 
 745 
 32 
 
 665 
 30 
 
 705 
 34 
 
 555 
 25 
 
 680 
 34 
 
 885 
 47 
 
 935 
 55 
 
 
 
MEMOIRS OF THE NATIONAL ACADEMY OP SCIENCES. 
 
 191 
 
 registration, at Baltimore, Md., 1885, 1886, and 1887 — Continued. 
 
 MABCH, 1886. 
 
 1 p.m. 
 
 2 p.m. 
 
 3 p.m. 
 
 4 p.m. 
 
 5 p.m. 
 
 6 p.m. 
 
 7 p.m. 
 
 8 p.m. 
 
 9 p.m. 
 
 10 p. m. 
 
 11 p. m. 
 
 12 mid. 
 
 Kemarks. 
 
 60 
 
 40 
 
 60 
 
 50 
 
 60 
 
 — 5 
 
 10 
 
 100 
 
 —100 
 
 
 
 — 10 
 
 — 5 
 
 NW. br. , clear. 
 
 — 5 
 
 — 5 
 
 — 60 
 
 — 60 
 
 —100 
 
 — 5 
 
 .50 
 
 20 
 
 25 
 
 
 
 25 
 
 20 
 
 Do. 
 
 5 
 
 20 
 
 15 
 
 . 
 
 20 
 
 15 
 
 20 
 
 25 
 
 20 
 
 20 
 
 
 
 
 
 Do. 
 
 30 
 
 40 
 
 45 
 
 40 
 
 40 
 
 30 
 
 30 
 
 30 
 
 30 
 
 30 
 
 30 
 
 40 
 
 NW. gale, fair. 
 NW.fr., fair. 
 
 40 
 
 45 
 
 50 
 
 50 
 
 50 
 
 50 
 
 50 
 
 75 
 
 60 
 
 100 
 
 110 
 
 90 
 
 40 
 
 40 
 
 40 
 
 45 
 
 40 
 
 40 
 
 80 
 
 100 
 
 10 
 
 80 
 
 80 
 
 60 
 
 N.W.,fr., clear. 
 
 
 60 
 
 ^ 60 
 
 100 
 
 110 
 
 150 
 
 110 
 
 150 
 
 100 
 
 100 
 
 70 
 
 70 
 
 N. It., fair. 
 
 40 
 
 
 
 20 
 
 100 
 
 70 
 
 110 
 
 100 
 
 80 
 
 100 
 
 80 
 
 70 
 
 100 
 
 SE. It., snow. 
 
 50 
 
 70 
 
 70 
 
 65 
 
 80 
 
 90 
 
 80 
 
 90 
 
 90 
 
 50 
 
 100 
 
 90 
 
 NW.'fr., cloudy. 
 
 100 
 
 60 
 
 70 
 
 50 
 
 50 
 
 50 
 
 70 
 
 60 
 
 50 
 
 50 
 
 60 
 
 70 
 
 N. fr., fair. 
 
 70 
 
 75 
 
 60 
 
 70 
 
 80 
 
 90 
 
 100 
 
 150 
 
 100 
 
 70 
 
 20 
 
 10 
 
 NW. fr., clear. 
 
 —300 
 
 —100 
 
 
 
 20 
 
 50 
 
 — 5 
 
 40 
 
 50 
 
 50 
 
 10 
 
 20 
 
 30 
 
 SW. br.,rain. 
 
 30 
 
 50 
 
 35 
 
 50 
 
 50 
 
 50 
 
 40 
 
 40 
 
 40 
 
 30 
 
 30 
 
 30 
 
 NW. br., rain. 
 
 
 40 
 
 60 
 
 ' 50 
 
 100 
 
 70 
 
 80 
 
 80 
 
 60 
 
 70 
 
 70 
 
 60 
 
 SW. It., clear. 
 
 45 
 
 50 
 
 .50 
 
 50 
 
 150 
 
 10 
 
 60 
 
 60 
 
 100 
 
 90 
 
 60 
 
 60 
 
 Do. 
 
 
 
 — 50 
 
 
 
 20 
 
 60 
 
 50 
 
 '60 
 
 60 
 
 50 
 
 55 
 
 60 
 
 , 70 
 
 SW. fr., clear. 
 
 100 
 
 100 
 
 100 
 
 110 
 
 120 
 
 80 
 
 100 
 
 75 
 
 75 
 
 60 
 
 
 
 — 10 
 
 NW. fr., clear. 
 
 
 
 95 
 
 100 
 
 75 
 
 70 
 
 50 
 
 50 
 
 30 
 
 —150 
 
 — 10 
 
 
 
 SW. fr., rain. 
 
 10 
 
 50 
 
 50 
 
 — 5 
 
 10 
 
 
 
 — 10 
 
 — 10 
 
 — 20 
 
 — 5 
 
 — 20 
 
 — 20 
 
 Var. It., rain. 
 
 
 150 
 
 — 10 
 
 — 50 
 
 100 
 
 100 
 
 100 
 
 —150 
 
 —300 
 
 200 
 
 —200 
 
 50 
 
 NE. It., rain. 
 
 50 
 
 70 
 
 70 
 
 50 
 
 50 
 
 25 
 
 25 
 
 100 
 
 —150 
 
 — 60 
 
 60 
 
 50 
 
 SW. br., rain. 
 
 5 
 
 — 10 
 
 20 
 
 50 
 
 25 
 
 60 
 
 60 
 
 70 
 
 50 
 
 70 
 
 60 
 
 50 
 
 NW. br., rain. 
 
 60 
 
 70 
 
 20 
 
 20 
 
 15 
 
 40 
 
 60 
 
 60 
 
 60 
 
 60 
 
 60 
 
 25 
 
 NW. br., cloudy. 
 
 50 
 
 50 
 
 55 
 
 65 
 
 65 
 
 60 
 
 60 
 
 80 
 
 95 
 
 150 
 
 150 
 
 100 
 
 NW. br., fair. 
 
 10 
 
 25 
 
 
 
 — 30 
 
 — 50 
 
 — 50 
 
 
 
 — 20 
 
 — 15 
 
 
 
 -25 
 
 — 50 
 
 SW. fr., fair. 
 
 — 60 
 
 —100 
 
 —100 
 
 —100 
 
 — 25 
 
 — 25 
 
 — 25 
 
 — 20 
 
 150 
 
 —200 
 
 —300 
 
 —200 
 
 Var. It., rain. 
 
 —150 
 
 —300 
 
 —350 
 
 200 
 
 —300 
 
 —350 
 
 —350 
 
 —350 
 
 —250 
 
 —100 
 
 — 40 
 
 — 25 
 
 Do, 
 
 
 75 
 
 60 
 
 60 
 
 60 
 
 60 
 
 50 
 
 60 
 
 60 
 
 90 
 
 90 
 
 80 
 
 E. It., rain. 
 
 
 —100 
 
 —300 
 
 —100 
 
 — 50 
 
 
 
 — 50 
 
 20 
 
 75 
 
 50 
 
 
 
 25 
 
 bo. 
 
 50 
 
 70, 
 
 100 
 
 —300 
 
 —150 
 
 —200 
 
 110 
 
 -200 
 
 —300 
 
 —350 
 
 —100 
 
 50 
 
 Do. 
 
 — 35 
 
 — 40 
 
 — 30 
 
 — 50 
 
 — 50 
 
 — 50 
 
 — 50 
 
 - 35 
 
 — 20 
 
 — 15 
 
 — 5 
 
 10 
 
 SE. high, rain 
 
 295 
 
 545 
 
 355 
 
 720 
 
 805 
 
 610 
 
 1,110 
 
 900 
 
 325 
 
 635 
 
 515 
 
 930 
 
 12 
 
 18 
 
 11 
 
 23 
 
 26 
 
 20 
 
 3G 
 
 29 
 
 10 
 
 21 
 
 17 
 
 30 
 
 , 
 
 APRIL, 1886. 
 
 
 
 10 
 
 20 
 
 10 
 
 — 50 
 
 10 
 
 10 
 
 — 10 
 
 
 
 10 
 
 — 10 
 
 10 
 
 10 
 
 — 60 
 
 30 
 
 10 
 
 — 50 
 
 60 
 
 5 
 
 — 20 
 
 
 
 
 
 — 20 
 
 
 
 — 25 
 
 
 
 
 
 — 25 
 
 
 
 
 
 — 20 
 
 
 
 SW.br., clear. 
 
 NW.br., fair. 
 
 N. It., rain. 
 
 NW. It., rain. 
 
 E.lt., rain, 
 
 NW. fr., rain. 
 
 Var. It., rain. 
 
 NW.fr., fair, 
 
 Var.lt., clear. 
 
 S. It., fair. 
 
 E. br., rain, 
 
 SE.lt., rain, fog. 
 
 SE. It., rain, t. s. 
 
 E. It., clear. 
 
 E. It., fair, fog in a. m. 
 
 E.lt., rain. 
 
 Do. 
 E.lt., clear, 
 N. It., clear. 
 B. It., fair, lightning. 
 Var.lt., cloudy. 
 Var. Ifc., clear. 
 SW. It., clear. 
 W. It., rain, t. 9. 
 W. It., rain. 
 W. It., cloudy. 
 E.lt., cloudy. 
 Var.lt., clQudy. 
 E. fr., fair. 
 E, fr., cloudy. 
 
 — 25 
 
 
 
 
 10 
 30 
 
 50 
 20 
 50 
 
 60 
 20 
 50 
 
 60 
 50 
 50 
 
 — 50 
 15 
 
 — 20 
 
 —150 
 40 
 20 
 
 — 50 
 15 
 10 
 
 - 50 
 
 - 20 
 20 
 
 -150 
 
 
 
 20 
 
 — 20 
 
 
 
 30 
 
 — 20 
 10 
 40 
 
 —200 
 25 
 50 
 
 50 
 
 ""96' 
 
 80 
 
 120 
 
 100 
 
 120 
 
 50 
 
 '"106 
 
 60 
 
 100 
 
 20 
 
 
 
 5 
 
 -■50' 
 
 — 10 
 
 100 
 
 70 
 
 75 
 
 60 
 140 
 
 25 
 120 
 
 80 
 1.50 
 150 
 160 
 100 
 100 
 110 
 
 80 
 100 
 
 20 
 
 — 10 
 
 — 10 
 60 
 60 
 50 
 
 120 
 110 
 110 
 
 60 
 
 120 
 
 40 
 
 130 
 
 150 
 
 200 
 
 200 
 
 150 
 
 100 
 
 100 
 
 130 
 
 140 
 
 120 
 
 100 
 
 
 
 — 10 
 
 70 
 
 60 
 
 75 
 
 130 
 
 100 
 
 100 
 
 • 45 
 130 
 
 40 
 180 
 100 
 200 
 200 
 
 60 
 120 
 100 
 150 
 
 70 
 
 150 
 
 'i 100 
 
 — 10 
 
 — 20 
 
 
 100 
 100 
 150 
 60 
 120 
 
 40 
 105 
 
 50 
 160 
 
 75 
 150 
 200 
 
 85 
 100 
 100 
 150 
 
 80 
 130 
 175 
 
 10 
 
 20 
 
 20 
 150 
 150 
 150 
 
 70 
 120 
 
 30 
 
 70 
 
 40 
 
 40 
 
 105 
 
 200 
 
 180 
 
 120 
 
 100 
 
 75 
 
 100 
 
 140 
 
 80 
 
 100 
 
 5 
 
 —300 
 
 —100 
 
 60 
 
 100 
 
 100 
 
 50 
 
 100 
 
 50 
 
 50 
 
 40 
 
 
 
 100 
 
 200 
 
 140 
 
 100 
 
 50 
 
 70 
 
 70 
 
 170 
 
 100 
 
 40 
 
 — 10 
 
 — 10 
 10 
 50 
 
 — 5 
 100 
 
 50 
 60 
 
 100 
 
 50 
 
 40 
 
 
 
 100 
 80 
 
 130 
 75 
 75 
 
 100 
 50 
 70 
 
 100 
 60 
 10 
 
 25 
 10 
 — 5 
 80 
 50 
 
 110 
 
 120 
 
 50 
 
 10 
 
 
 
 80 
 
 100 
 
 100 
 
 40 
 
 50 
 
 50 
 
 30 
 
 40 
 
 20 
 
 20 
 
 20 
 
 — 50 
 
 25 
 
 
 
 
 
 90 
 
 70 
 
 100 
 
 40 
 
 50 
 10 
 
 — 5 
 80 
 75 
 
 100 
 30 
 25 
 20 
 10 
 30 
 
 — 10 
 
 5 
 
 
 
 50 
 
 20 
 
 40 
 
 
 
 60 
 
 40 
 
 100 
 
 40 
 
 5 
 
 10 
 
 
 
 60 
 
 60 
 
 100 
 
 25 
 
 30 
 
 50 
 
 5 
 
 15 
 
 — 40 
 
 
 
 
 - 20 
 10 
 40 
 
 
 70 
 30 
 70 
 
 90 
 10 
 15 
 —100 
 25 
 80 
 100 
 50 
 
 
 60 
 
 
 
 25 
 
 40 
 
 . 20 
 
 — 5 
 
 
 10 
 40 
 
 
 50 
 30 
 50 
 
 445 
 16 
 
 1,095 
 52 
 
 2,025 
 75 
 
 2,375 
 
 85, 
 
 2,315 
 
 83 
 
 2,235 
 
 80 
 
 1,265 
 45 
 
 1,390 
 50 
 
 1,305 
 47 
 
 815 
 29 
 
 755 
 
 27 
 
 565 
 20 
 
192 
 
 MEMOIRS OF THE NATIONAL ACADEMY OP SCIENCES. 
 
 Table a.— Hourly records, drawn from continuous photographic 
 
 JULY, 1886. 
 
 Day of month. 
 
 1 a. m. 
 
 75 
 30 
 80 
 30 
 50 
 150 
 60 
 25 
 
 
 50 
 30 
 20 
 50 
 70 
 70 
 
 
 50 
 100 
 50 
 25 
 200 
 50 
 30 
 30 
 40 
 50 
 
 5 
 60 
 60 
 
 2 a, m. 
 
 3 a. m. 
 
 4 a. m. 
 
 5 a.m. 
 
 6 a.m. 
 
 7 a.m. 
 
 8 a. m. 
 
 9 a.m. 
 
 10 a.m. 
 
 11 a. m. 
 
 12 m. 
 
 1 
 
 60 
 —100 
 90 
 25 
 50 
 100 
 60 
 30 
 30 
 30 
 30 
 30 
 10 
 — 30 
 60 
 70 
 50 
 90 
 70 
 20 
 150 
 40 
 30 
 30 
 30 
 25 
 15 
 50 
 75 
 
 30 
 
 90 
 35 
 65 
 110 
 75 
 25 
 10 
 20 
 30 
 10 
 50 
 50 
 60 
 90 
 55 
 90 
 80 
 20 
 — 50 
 50 
 30 
 50 
 50 
 25 
 70 
 50 
 60 
 
 40 
 — 60 
 90 
 40 
 80 
 
 110 
 65 
 20 
 10 
 30 
 30 
 20 
 75 
 40 
 50 
 
 110 
 50 
 70 
 
 100 
 10 
 
 350 
 60 
 30 
 40 
 30 
 25 
 15 
 50 
 50 
 
 30 
 —100 
 90 
 20 
 80 
 
 100 
 75 
 20 
 20 
 60 
 30 
 50 
 25 
 
 
 100 
 
 140 
 60 
 75 
 
 110 
 30 
 
 75 
 10 
 50 
 25 
 25 
 50 
 80 
 60 
 
 20 
 
 —200 
 
 90 
 
 
 
 50 
 
 100 
 
 100 
 
 20 
 
 — 5 
 
 — 25 
 50 
 30 
 50 
 50 
 60 
 
 170 
 
 80 
 
 75 
 
 130 
 
 50 
 
 —350 
 
 100 
 
 
 
 25 
 
 25 
 
 
 
 60 
 
 80 
 
 90 
 
 10 
 —500 
 90 
 20 
 65 
 75 
 100 
 
 — 20 
 
 
 75 
 50 
 40 
 10 
 70 
 50 
 
 150 
 90 
 75 
 
 150 
 
 40 
 
 -300 
 
 80 
 
 
 
 10 
 
 — 10 
 10 
 60 
 60 
 90 
 50 
 60 
 
 40 
 —200 
 90 
 50 
 25 
 75 
 25 
 — 10 
 10 
 25 
 10 
 50 
 75 
 70 
 70 
 
 100 
 50 
 
 100 
 
 155 
 20 
 20 
 50 
 
 10 
 
 100 
 10 
 
 100 
 60 
 75 
 50 
 60 
 
 60 
 —450 
 75 
 50 
 40 
 90 
 25 
 
 — 10 
 50 
 25 
 
 
 60 
 
 98 
 
 105 
 
 100 
 
 40 
 
 90 
 
 160 
 
 25 
 
 25 
 
 60 
 
 5 
 
 100 
 
 — 50 
 
 
 
 80 
 
 70 
 
 100 
 
 > 40 
 
 70 
 
 75 
 —500 
 60 
 40 
 60 
 65 
 30 
 
 , 
 25 
 30 
 25 
 50 
 
 350 
 —200 
 90 
 80 
 40 
 65 
 
 125 
 20 
 10 
 50 
 10 
 
 100 
 20 
 
 60 
 70 
 75 
 40 
 80 
 
 90 
 
 —450 
 
 50 
 
 20 
 
 75- 
 
 75 
 
 30 
 
 
 
 50 
 
 -40 
 
 30 
 
 75 
 
 —200 
 
 60 
 
 100 
 
 100 
 
 40 
 
 125 
 
 130 
 
 25 
 
 50 
 
 30 
 
 10 
 
 90 
 
 -200 
 
 
 
 70 
 
 120 
 
 80 
 
 50 
 
 70 
 
 50 
 —300 
 50 
 75 
 90 
 75 
 50 
 
 75 
 
 40 
 
 75 
 
 
 
 -250 
 
 60 
 
 80 
 
 50 
 
 125 
 
 130 
 
 30 
 
 50 
 
 40 
 
 10 
 
 100 
 
 300 
 
 
 
 60 
 
 120 
 
 80 
 
 5U 
 
 JO 
 
 2 
 
 3 
 
 4 
 
 5 
 
 6 
 
 7 
 
 8 .' 
 
 9 
 
 10 
 
 11 
 
 la 
 
 13 
 
 14 
 
 15 
 
 16 
 
 17 
 
 18 
 
 19 
 
 20 
 
 21 
 
 22 
 
 23 --. 
 
 24 
 
 25 
 
 26 
 
 27 
 
 28 
 
 29 
 
 30 
 
 31 
 
 —300 
 
 50 
 
 20 
 
 30 
 
 70 
 
 80 
 
 Sums - 
 
 1,240 
 41 
 
 1,270 
 42 
 
 1,350 
 45 
 
 1,660 
 55 
 
 1,460 
 49 
 
 1,025 
 34 
 
 750 
 24 
 
 1,365 
 44 
 
 1,125 
 38 
 
 1,045 
 35 
 
 835 
 
 28 
 
 1,435 
 
 4« 
 
 MeajUS ............ 
 
 
 AUGUST, 1886. 
 
 1 
 
 75 
 
 105 
 
 125 
 
 60 
 
 60 
 
 40 
 
 
 
 55 
 
 75 
 
 75 
 
 5 
 
 50 
 
 50 
 
 45 
 
 25 
 
 35 
 
 40 
 
 50 
 
 120 
 
 30 
 
 70 
 
 25 
 
 — 50 
 
 100 
 
 100 
 
 65 
 
 ' 50 
 
 60 
 
 10 
 
 60 
 
 75 
 
 'I 
 55 
 5 
 55 
 30 
 60 
 40 
 50 
 140 
 30 
 70 
 20 
 
 — 10 
 70 
 90 
 65 
 40 
 75 
 
 — 20 
 60 
 50 
 75 
 
 5 
 20 
 50 
 75 
 30 
 65 
 15 
 60 
 125 
 20 
 55 
 30 
 
 20 
 30 
 90 
 60 
 50 
 
 
 
 —200 
 
 60 
 
 50 
 
 70 
 
 5 
 45 
 65 
 90 
 30 
 60 
 
 
 60 
 120 
 10 
 60 
 25 
 
 25 
 70 
 90 
 80 
 50 
 50 
 —250 
 60 
 45 
 65 
 10 
 50 
 30 
 75 
 30 
 40 
 20 
 70 
 135 
 10 
 65 
 20 
 
 75 
 90 
 75 
 
 110 
 75 
 60 
 —140 
 65 
 15 
 55 
 10 
 55 
 45 
 55 
 50 
 65 
 30 
 80 
 
 140 
 10 
 45 
 25 
 
 80 
 80 
 90 
 60 
 100 
 60 
 
 -220 
 70 
 
 20 
 10 
 50 
 
 — 5 
 55 
 50 
 20 
 30 
 60 
 140 
 10 
 45 
 40 
 
 75 
 90 
 65 
 65 
 60 
 75 
 —100 
 75 
 25 
 55 
 10 
 50 
 20 
 55 
 55 
 40 
 30 
 70 
 130 
 10 
 50 
 60 
 
 40 
 80 
 50 
 50 
 
 100 
 75 
 — 40 
 50 
 5D 
 70 
 10 
 35 
 70 
 50 
 70 
 45 
 40 
 80 
 
 120 
 
 
 
 55 
 
 50 
 
 50 
 
 90 
 
 75 
 
 50 
 
 100 
 
 105 
 
 — 20 
 
 50 
 
 40 
 
 55 
 
 10 
 
 30 
 
 60 
 
 60 
 
 70 
 
 40 
 
 20 
 
 60 
 
 110 
 
 
 
 45 
 
 35 
 
 65 
 100 
 95 
 60 
 60 
 105 
 — 10 
 50 
 25 
 50 
 10 
 30 
 55 
 60 
 75 
 30 
 20 
 60 
 90 
 
 40 
 50 
 
 50 
 90 
 
 100 
 50 
 50 
 
 130 
 —10 
 50 
 25 
 55 
 40 
 30 
 60 
 60 
 
 ""'26' 
 35 
 
 """65' 
 55 
 50 
 
 2 
 
 3 
 
 4 
 
 5 
 
 6 
 
 7 
 
 8 
 
 9 
 
 10 
 
 11 
 
 12 
 
 13 
 
 14 
 
 15 
 
 16 
 
 17 
 
 18 
 
 19 
 
 20 
 
 21 
 
 22 
 
 23 
 
 24 
 
 
 
 
 
 
 
 
 
 
 
 
 
 25 
 
 
 
 
 
 
 
 
 
 
 
 
 
 26 
 
 
 
 
 
 
 
 
 
 
 
 
 
 27 
 
 
 
 
 
 
 
 
 
 
 
 
 
 28 
 
 , 
 
 
 
 
 
 
 
 
 
 
 
 
 29 
 
 
 
 
 
 
 
 
 
 
 
 
 
 30 
 
 
 
 
 
 
 
 
 
 
 
 
 
 31 
 
 
 
 
 
 
 
 
 
 
 
 
 
 Snms . . 
 
 
 
 
 
 
 
 
 
 
 
 
 
 1,215 
 55 
 
 1,100 
 50 
 
 1,145 
 52 
 
 800 
 36 
 
 840 
 38 
 
 1,090 
 50 
 
 845 
 38 
 
 1,065 
 
 48 
 
 1,150 
 52 
 
 1,135 
 52 
 
 1,120 
 51 
 
 1,005 
 52 
 
 Means ...... . 
 
 
MEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES. 
 
 193 
 
 regisiration, at Baltimore, Md., 1885, 1886, and. 1887 — Continued. 
 
 JULY, 1886. 
 
 1 p.m. 
 
 .2 p.m. 
 
 3 p.m. 
 
 4 p.m. 
 
 5 p.m. 
 
 6 p.m. 
 
 7 p.m. 
 
 8 p.m. 
 
 9 p.m. 
 
 10 p.m. 
 
 11 p.m. 
 
 12 mid. 
 
 Eemarks. 
 
 50 
 
 75 
 
 50 
 
 60 
 
 65 
 
 75 
 
 30 
 
 60 
 
 65 
 
 50 
 
 50 
 
 30 
 
 E. fr., cloudy. 
 
 —250 
 
 —175 
 
 —175 
 
 —225 
 
 —100 
 
 25 
 
 100 
 
 80 
 
 100 
 
 50 
 
 125 
 
 50 
 
 NW. fr., rain. 
 
 30 
 
 25 
 
 10 
 
 
 
 25 
 
 30 
 
 50 
 
 75 
 
 60 
 
 10 
 
 125 
 
 60 
 
 N. It., fair. 
 
 40 
 
 40 
 
 50 
 
 50 
 
 40 
 
 65 
 
 35 
 
 50 
 
 60 
 
 50 
 
 50 
 
 75 
 
 Var. gen., fair. 
 
 75 
 
 60 
 
 40 
 
 60 
 
 75 
 
 75 
 
 65 
 
 60 
 
 75 
 
 25 
 
 20 
 
 75 
 
 SW. It., clear. 
 
 65 
 
 50 
 
 65 
 
 110 
 
 150 
 
 130 
 
 65 
 
 75 
 
 100 
 
 65 
 
 65 
 
 60 
 
 E. It., clear, fog in a. m. 
 
 50 
 
 50 
 
 50 
 
 50 
 
 •30 
 
 20 
 
 50 
 
 100 
 
 65 
 
 40 
 
 40 
 
 25 
 
 SW. fr., clear. 
 
 10 
 
 10 
 
 
 
 5 
 
 — 5 
 
 — 5 
 
 — 40 
 
 10 
 
 
 
 20 
 
 10. 
 
 
 
 N. It., cloudy. 
 
 
 
 75 
 
 100 
 
 100 
 
 100 
 
 75 
 
 40 
 
 75 
 
 50 
 
 40 
 
 65 
 
 60 
 
 SE. It., cloudy. 
 
 60 
 
 60 
 
 60 
 
 60 
 
 60 
 
 60 
 
 — 5 
 
 — 5 
 
 10 
 
 10 
 
 30 
 
 40 
 
 W. It., rain. 
 
 
 40 
 
 50 
 
 30 
 
 30 
 
 35 
 
 30 
 
 50 
 
 75 
 
 30 
 
 30 
 
 20 
 
 N. It., clear. 
 
 50 
 
 60 
 
 40 
 
 75 
 
 50 
 
 60 
 
 30 
 
 50 
 
 110 
 
 '10 
 
 50 
 
 50 
 
 B. It., clear. 
 
 200 
 
 60 
 
 115 
 
 150 
 
 100 
 
 100 
 
 70 
 
 50 
 
 60 
 
 30 
 
 40 
 
 20 
 
 B. It., rain. 
 
 
 
 60 
 
 150 
 
 —300 
 
 100 
 
 — 50 
 
 — 50 
 
 — 20 
 
 80 
 
 60 
 
 60 
 
 65 
 
 B. It., rain, t. «. 
 
 60 
 
 70 
 
 90 
 
 70 
 
 70 
 
 40 
 
 100 
 
 —300 
 
 
 
 —300 
 
 .300 
 
 60 
 
 S. It., rain, t. n. and tor. 
 
 
 50 
 
 60 
 
 60 
 
 50 
 
 60 
 
 50 
 
 50 
 
 60 
 
 50 
 
 60 
 
 70 
 
 Var. It., raiu. 
 
 50 
 
 75 
 
 110 
 
 100 
 
 200 
 
 150 
 
 110 
 
 90 
 
 110 
 
 90 
 
 80 
 
 60 
 
 Var. It., clear. 
 
 120 
 
 130 
 
 130 
 
 130 
 
 125 
 
 150 
 
 70 
 
 140 
 
 155 
 
 —200 
 
 —100 
 
 
 
 S. It., rain, t. s. 
 
 40 
 
 50 
 
 60 
 
 60 
 
 60 
 
 75 
 
 75 
 
 90 
 
 75 
 
 50 
 
 25 
 
 30 
 
 NW. It., clear. 
 
 25 
 
 25 
 
 20 
 
 30 
 
 10 
 
 10 
 
 — 5 
 
 50 
 
 65 
 
 75 
 
 75 
 
 50 
 
 Do. 
 
 20 
 
 
 
 — 10 
 
 10 
 
 60 
 
 60 
 
 20 
 
 100 
 
 100 
 
 90 
 
 90 
 
 60 
 
 NE. It., rain. 
 
 30 
 
 30 
 
 40 
 
 25 
 
 30 
 
 30 
 
 40 
 
 30 
 
 30 
 
 30 
 
 • 30 
 
 30 
 
 W. It., clear. 
 
 20 
 
 30 
 
 20 
 
 50 
 
 25 
 
 
 
 
 
 25 
 
 30 
 
 60 
 
 40 
 
 50 
 
 N. It., cloudy. 
 
 75 
 
 100 
 
 125 
 
 100 
 
 90 
 
 60 
 
 60 
 
 60 
 
 ^ 60 
 
 50 
 
 50 
 
 50 
 
 B. Ic, clear. 
 
 — 50 
 
 50 
 
 50 
 
 30 
 
 30 
 
 50 
 
 20- 
 
 
 
 10 
 
 10 
 
 25 
 
 25 
 
 Var. It., rain. 
 
 30 
 
 50 
 
 —200 
 
 —300 
 
 —200 
 
 300 
 
 -300 
 
 —300 
 
 250 
 
 100 
 
 5 
 
 5 
 
 W. ft., rain, t. a. 
 
 50 
 
 60 
 
 80 
 
 110 
 
 80 
 
 70 
 
 60 
 
 70 
 
 60 
 
 60 
 
 20 
 
 60 
 
 Var. It., rain. 
 
 100 
 
 60 
 
 100 
 
 90 
 
 100 
 
 100 
 
 100 
 
 75 
 
 80 
 
 60 
 
 60 
 
 60 
 
 E. It., clear. 
 Var. It., clear. 
 SW.lt., cloudy, light'g. 
 
 60 
 
 80 
 
 90 
 
 90 
 
 70 
 
 80 
 
 50 
 
 40 
 
 60 
 
 50 
 
 -200 
 
 100 
 
 30 
 
 40 
 
 60 
 
 70 
 
 10 
 
 10 
 
 50 
 
 75 
 
 10 
 
 90 
 
 
 
 50 
 
 W. fr., rain, t. a. 
 
 1, 040 
 
 1,390 
 
 1,430 
 
 940 
 
 1,530 
 
 1,940 
 
 970 
 
 1,005 
 
 2,065 
 
 885 
 
 1,320 
 
 1,390 
 
 37 
 
 46 
 
 48 
 
 31 
 
 51 
 
 65 
 
 32 
 
 34 
 
 69 
 
 30 
 
 44 
 
 46 
 
 
 AUGUST, 1886. 
 
 90 
 60 
 50 
 50 
 80 
 
 
 '""ioo" 
 
 90 
 40 
 30 
 60 
 50 
 
 y""o' 
 
 20 
 30 
 50 
 100 
 45 
 
 —200 
 
 100 
 
 75 
 
 60 
 
 60 
 
 130 
 
 10 
 
 50 
 
 100 
 
 120 
 
 50 
 
 60 
 
 60 
 
 40 
 
 40 
 
 — 5 
 
 30 
 
 40 
 
 55 
 
 100 
 
 65 
 
 
 
 125 
 
 65 
 
 65 
 
 65 
 
 120 
 
 — 10 
 75 
 
 125 
 100 
 55 
 50 
 85 
 40 
 55 
 
 — 10 
 50 
 55 
 75 
 
 100 
 60 
 
 30 
 
 150 
 75 
 75 
 60 
 75 
 20 
 85 
 
 100 
 70 
 50 
 45 
 
 140 
 45 
 75 
 — 20 
 —100 
 55 
 80 
 
 110 
 60 
 
 70 
 130 
 75 
 60 
 75 
 80 
 30 
 70 
 100 
 75 
 50 
 85 
 100 
 40 
 55 
 
 — 30 
 
 — 50 
 65 
 45 
 
 110 
 25 
 
 300 
 140 
 75 
 60 
 60 
 50 
 30 
 70 
 100 
 35 
 60 
 85 
 70 
 25 
 55 
 - 30 
 50 
 70 
 35 
 90 
 40 
 
 — 70 
 150 
 
 75 
 80 
 40 
 .50 
 40 
 60 
 100 
 50 
 60 
 45 
 70 
 20 
 60 
 
 — 50 
 15 
 80 
 25 
 80 
 65 
 
 80 
 125 
 65 
 75 
 30 
 50 
 50 
 115 
 80 
 50 
 55 
 100 
 60 
 15 
 90 
 — 50 
 50 
 85 
 40 
 80 
 70 
 
 105 
 
 160 
 60 
 60 
 
 100 
 40 
 65 
 65 
 
 105 
 
 ""lo 
 
 65 
 40 
 35 
 70 
 — 30 
 20 
 95 
 20 
 70 
 70 
 
 50 
 140 
 60 
 50 
 50 
 20 
 60 
 65 
 95 
 10 
 35 
 60 
 40 
 30 
 80 
 40 
 20 
 105 
 20 
 65 
 70 
 
 130 
 125 
 65 
 10 
 60 
 15 
 50 
 50 
 85 
 25 
 35 
 65 
 50 
 40 
 70 
 40 
 30 
 90 
 50 
 55 
 45 
 
 120 
 
 125 
 
 60 
 
 
 
 50 
 
 55 
 55 
 80 
 5 
 40 
 50 
 55 
 25 
 20 
 40 
 40 
 110 
 50 
 90 
 40 
 
 SE.lt., rain, lightning. 
 NW. fr., rain. 
 NW. fr., clear. 
 
 Do. 
 SW. fr., cloudy. 
 SW. ft,, fair. 
 Var. It., rain. 
 NW. It., clear. 
 S.lt., clear. 
 S. It., cloudy. 
 W.fr.,fair. 
 
 Do. 
 S. It., fair. 
 W. It., rain. 
 Var. It., clear. 
 NE.lt., cloudy. 
 NE. fr., rain, t. s. 
 NE. fr., cloudy. 
 E. fr., clear. 
 
 Do. 
 E. fr., fair. 
 Var. ft. , clear. 
 E. fr., fair. 
 E. It., rain. 
 N. It., clear. 
 E.lt., cloudy. 
 Var. It., clear. 
 SE.lt., clear. 
 S.lt., fair. 
 SE fr., rain, t. s. 
 Var. It., rain. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 945 
 .52 
 
 1,040 
 50 
 
 1,355 
 65 
 
 1,280 
 61 
 
 1,260 
 60 
 
 1,470 
 70 
 
 1,045 
 50 
 
 1,315 
 63 
 
 1,255 
 63 
 
 1,165 
 ' 55 
 
 1,185 
 56 
 
 1,110 
 53 
 
 S. Mis. 94 13 
 
194 
 
 MEMOIRS OF THE I^ATIONAL ACADEMY OF SCIENCES. 
 
 Table A. — Hourly records, drawn from continuous photographic 
 SEPTEMBER, 1886. 
 
 Day of Taonth. 
 
 1 a. m. 
 
 2 a. m. 
 
 3 a. m. 
 
 4 a. m. 
 
 5 a. m. 
 
 6 a. in. 
 
 7 a.m. 
 
 S ELBl. 
 
 9 a.m. 
 
 10 a. m. 
 
 11 a. m. 
 
 12 m. 
 
 1 
 
 
 
 
 
 
 
 
 
 
 
 
 
 2 
 
 
 
 
 
 
 
 
 
 
 
 
 
 3 
 
 
 
 
 
 
 
 
 
 
 
 
 
 4 
 
 
 
 
 
 
 
 
 
 
 
 
 
 5 
 
 
 
 
 
 
 
 
 
 
 
 
 
 6 
 
 
 
 
 
 
 
 
 
 
 
 
 
 7 
 
 
 
 
 
 
 
 
 
 
 
 
 
 8 
 
 
 
 
 
 
 
 
 
 
 
 
 
 9 
 
 
 
 
 
 
 
 
 
 
 
 
 
 10 
 
 
 
 
 
 
 
 
 
 
 
 
 
 11 
 
 
 
 
 
 
 
 
 
 
 
 
 
 12 
 
 
 
 
 
 
 
 
 ' 
 
 
 
 
 
 13 
 
 
 
 
 
 
 
 
 
 
 
 
 
 14 
 
 
 
 
 
 
 
 
 
 
 
 
 
 15 
 
 
 
 
 
 
 
 
 
 
 
 
 —250 
 
 """eo' 
 ""'eo' 
 
 75 
 90 
 10 
 70 
 100 
 
 '"'46' 
 
 95 
 65 
 40 
 
 16 
 
 — 50 
 
 90 
 
 50 
 
 70 
 
 50 
 
 110 
 
 
 
 100 
 
 20 
 
 30 
 
 20 
 
 65 
 
 40 
 
 10 
 
 55 
 
 — 65 
 
 105 
 
 50 
 
 65 
 
 40 
 
 100 
 
 
 
 75 
 
 20 
 
 40 
 
 60 
 
 60 
 
 40 
 
 
 
 35 
 
 — 50 
 105 
 50 
 80 
 40 
 70 
 
 85 
 20 
 50 
 50 
 60 
 55 
 15 
 20 
 
 —300 
 115 
 30 
 60 
 40 
 60 
 
 
 50 
 
 
 50 
 50 
 50 
 30 
 20 
 20 
 
 —200 
 
 110 
 
 60 
 
 80 
 
 40 
 
 100 
 
 5 
 
 50 
 
 
 
 50 
 
 55 
 
 50 
 
 30 
 
 200 
 
 5 
 
 — 75 
 190 
 70 
 85 
 50 
 100 
 10 
 40 
 10 
 55 
 65 
 65 
 10 
 
 —200 
 5 
 
 — 40 
 
 130 
 
 
 
 80 
 
 60 
 
 100 
 
 10 
 
 25 
 
 10 
 
 80 
 
 60 
 
 90 
 
 25 
 
 60 
 
 
 
 40 
 105 
 30 
 85 
 60 
 95 
 20 
 30 
 15 
 90 
 70 
 100 
 60 
 60 
 
 
 
 
 130 
 
 60 
 
 60 
 
 60 
 
 90 
 
 40 
 
 50 
 
 20 
 
 90 
 
 35 
 
 120 
 
 
 
 40 
 
 
 
 — 20 
 
 160 
 
 60 
 
 70 
 
 60 
 
 90 
 
 95 
 
 20 
 
 100 
 
 105 
 
 70 
 
 80 
 
 10 
 
 25 
 
 
 
 60 
 
 100 
 
 80 
 
 60 
 
 60 
 
 75 
 
 150 
 
 
 
 70 
 
 100 
 
 45 
 
 70 
 
 10 
 
 20 
 
 
 
 17 
 
 18 
 
 19 
 
 20 
 
 21 
 
 22 
 
 23 
 
 24 
 
 25 
 
 26 
 
 27 
 
 28 
 
 29 
 
 30 
 
 Sums 
 
 570 
 
 38 
 
 625 
 42 
 
 650 
 43 
 
 275 
 18 
 
 635 
 42 
 
 480 
 32 
 
 690 
 46 
 
 860 
 57 
 
 795 
 53 
 
 925 
 62 
 
 900 
 60 
 
 515 
 ■43 
 
 
 
 
 
 OCTOBER, 1886. 
 
 1 
 
 40 
 
 35 
 
 25 
 
 10 
 
 5 
 
 
 
 
 
 
 
 
 
 
 
 60 
 
 60 
 
 2 
 
 3 
 
 
 
 
 
 
 
 ....... 
 
 
 
 
 
 
 4 
 
 
 
 
 
 
 
 
 
 
 
 
 
 5 
 
 
 
 
 
 
 
 
 
 
 
 
 
 6 
 
 
 
 
 
 
 
 
 
 
 
 
 
 7 
 
 
 
 
 
 
 
 
 
 
 
 
 """45" 
 40 
 
 100 
 60 
 
 110 
 60 
 
 150 
 10 
 60 
 10 
 
 '"70" 
 60 
 65 
 60 
 
 70 
 60 
 
 '""iob" 
 — 20 
 
 25 
 75 
 70 
 45 
 70 
 
 8 
 
 9 
 
 25 
 
 25 
 
 40 
 
 60 
 
 50 
 
 50 
 
 5 
 
 
 
 75 
 
 50 
 
 120 
 
 60 
 
 10 
 
 30 
 
 70 
 
 100 
 
 40 
 
 50 
 
 — 10 
 
 —400 
 
 
 
 90 
 
 55 
 
 50 
 
 25 
 
 50 
 
 40 
 
 60 
 
 50 
 
 50 
 
 5 
 
 
 
 75 
 
 40 
 
 150 
 
 60 
 
 10 
 
 60 
 
 100 
 
 110 
 
 50 
 
 70 
 
 
 
 —300 
 
 
 
 100 
 
 50 
 
 40 
 
 25 
 40 
 40 
 75 
 55 
 50 
 5 
 10 
 75 
 40 
 140 
 40 
 10 
 60 
 100 
 90 
 60 
 75 
 10 
 
 —200 
 10 
 75 
 
 —400 
 20 
 
 25 
 
 50 
 
 40 
 
 65 
 
 60 
 
 60 
 
 
 
 20 
 
 75; 
 
 50 
 
 120 
 
 30 
 
 10 
 
 70 
 
 60 
 
 110 
 
 40 
 
 70 
 
 
 
 —300 
 
 
 
 70 
 
 —200 
 
 30 
 
 30 
 55 
 15 
 
 60 
 
 85 
 
 50 
 
 
 
 '. 20 
 
 , ' 75 
 
 50 
 
 105 
 
 20 
 
 10 
 
 70 
 
 80 
 
 150 
 
 50 
 
 100 
 
 
 
 — 60 
 10 
 
 100 
 
 — 20 
 50 
 
 40 
 50 
 35 
 
 75 
 60 
 45 
 
 20 
 60 
 55 
 
 100 
 
 
 
 
 
 70 
 
 100 
 
 100 
 40 
 
 100 
 20 
 80 
 10 
 60 
 40 
 60 
 
 40 
 
 105 
 
 35 
 
 80 
 
 30 
 
 40 
 
 10 
 
 60 
 
 
 
 60 
 
 100 
 
 — 25 
 
 
 
 —200 
 
 140 
 
 120 
 
 35 
 
 70 
 
 25 
 
 — 5 
 10 
 80 
 60 
 90 
 
 50 
 
 10 
 30 
 95 
 70 
 15 
 5 
 65 
 10 
 90 
 
 100 
 
 
 
 15 
 
 50 
 
 130 
 
 110 
 40 
 
 120 
 
 
 
 20 
 
 40 
 
 105 
 65 
 80 
 
 20 
 
 
 
 40 
 
 70 
 
 120 
 5 
 10 
 75 
 30 
 60 
 
 110 
 60 
 30 
 60 
 
 100 
 90 
 50 
 
 100 
 — 10 
 10 
 50 
 80 
 60 
 80 
 
 20 
 
 
 
 45 
 
 25 
 
 200 
 5 
 20 
 80 
 50 
 65 
 
 110 
 60 
 60 
 60 
 60 
 60 
 50 
 
 100 
 — 10 
 
 70 
 70 
 50 
 60 
 
 30 
 
 
 
 50 
 
 25 
 
 200 
 
 5 
 
 10 
 
 80 
 
 20 
 
 60 
 
 70 
 
 60 
 
 65 
 
 60 
 
 60 
 
 50 
 
 60 
 
 110 
 
 
 
 
 
 65 
 
 60 
 
 60 
 
 75 
 
 10 
 
 11 
 
 12 
 
 13 
 
 14 
 
 15 
 
 16 
 
 17.^. 
 
 18 
 
 19 
 
 20 
 
 21 
 
 22 
 
 23 
 
 24 
 
 25 
 
 26 
 
 27 
 
 28 
 
 29 
 
 30 
 
 31 
 
 Sums . ,.. 
 
 685 
 
 27 
 
 930 
 37 
 
 530 
 21 
 
 565 
 
 23 
 
 1,110 
 44 
 
 1,220 
 49 
 
 960 
 
 38 
 
 1,315 
 53 
 
 1,310 
 52 
 
 1,310 
 52 
 
 1,335 
 53 
 
 1.445 
 60 
 
 Means 
 
 
MEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES, 
 
 195 
 
 registration, at Baltimore, Md., 1885, 1886, and 1887 — Contmued. 
 
 SEPTEMBEE, 1886. 
 
 Ip. m. 
 
 2 p.m. 
 
 3 p.m. 
 
 4 p.m. 
 
 5 p.m. 
 
 Cp.m. 
 
 7 p.m. 
 
 8 p.m. 
 
 9 p.m. 
 
 10 p.m. 
 
 11p.m. 
 
 12 mid. 
 
 Remarks. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 N.fr., clear. 
 NE.fr., clear. 
 E.fr., clear. 
 NE.fr., clear. 
 Var. It., cloudy. 
 
 Do. 
 
 Do. 
 E. It., cloudy. 
 Var.lt., rain. 
 Var, It., cloudy. 
 NW. fr., cloudy. 
 W. fr,,rain, t. s. 
 W. fr,, fair. 
 SW.lt., fair. 
 E. It., rain. 
 Var.lt., rain. 
 S. fr., fair, lightning. 
 Var. It., cloudy. , 
 S. fr., rain, t. s. 
 W. fr., fair. 
 Var. It., rain. 
 E. fr., rain. 
 Var. It., cloudy. 
 SE. gen., clear. 
 8. It., clear. 
 SW. gale, cloudy. 
 SW. It., fair. 
 S. fr., fair. 
 NE. fr., rain. 
 E. fr., fair. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 - 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 70 
 
 "iso 
 
 90 
 
 40 
 
 60 
 
 85 
 
 130 
 
 10 
 
 100 
 
 120 
 
 '"'35' 
 
 85 
 70 
 35 
 
 45 
 160 
 
 aoo 
 
 200 
 
 100 
 
 65 
 
 95 
 
 120 
 
 
 
 100 
 
 170 
 
 — 20 
 
 30 
 
 75 
 
 75 
 
 50 
 
 55 
 
 125 
 
 200 
 
 220 
 
 90 
 
 65 
 
 105 
 
 175 
 
 
 
 150 
 
 180 
 
 10 
 
 85 
 
 150 
 
 70 
 
 50 
 
 40 
 100 
 200- 
 130 
 210 
 
 70 
 100 
 110 
 
 10 
 100 
 
 85 
 
 40 
 105 
 100 
 
 60 
 
 20 
 
 35 
 
 130 
 
 230 
 
 80 
 
 
 
 75 
 
 100 
 
 110 
 
 30 
 
 100 
 
 50 
 
 50 
 
 70 
 
 100 
 
 60 
 
 50 
 
 35 
 80 
 140 
 40 
 60 
 100 
 105 
 60 
 55 
 80 
 30 
 50 
 10 
 80 
 70 
 25 
 
 25 
 85 
 
 160 
 60 
 80 
 80 
 
 130 
 70 
 15 
 
 100 
 30 
 55 
 70 
 65 
 85 
 85 
 
 20 
 85 
 
 170 
 60 
 
 250 
 70 
 90 
 
 110 
 30 
 50 
 40 
 40- 
 75 
 
 100 
 80 
 65 
 
 
 90 
 
 120 
 35 
 
 100 
 70 
 70 
 
 150 
 25 
 50 
 60 
 50 
 55 
 
 120 
 65 
 50 
 
 - 20 
 85 
 70 
 60 
 
 100 
 80 
 45 
 
 150 
 20 
 20 
 70 
 50 
 60 
 
 105 
 40 
 50 
 
 — 30 
 80 
 70 
 80 
 40 
 75 
 35 
 100 
 20 
 10 
 60 
 60 
 60 
 80 
 50 
 50 
 
 — 50 
 75 
 60 
 70 
 40 
 HO 
 
 70 
 10 
 40 
 60 
 60 
 40 
 10 
 55 
 40 
 
 1,080 
 
 77 
 
 1,465 
 91 
 
 1,730 
 108 
 
 1,480 
 92 
 
 1,270 
 79 
 
 1,020 
 64 
 
 1,195 
 
 75 
 
 1,335 
 83 
 
 1,110 
 70 
 
 985 
 62 
 
 840 
 52 
 
 690 
 43 
 
 OCTOBEE, 1886. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 N. W.br., fair. 
 NW.fr., clear. 
 Var. It., clear. 
 S. It., clear. 
 Var. It., clear. 
 N.fr., clear. 
 
 Do. 
 Var. It., clear. 
 
 Do. 
 Var. gen., clear. 
 Var. It., clear. 
 Var. It. , fog, clear. 
 SE.lt., cloudy. 
 SE.br,, rain.' 
 SW.br., clear. 
 NW.fr., fair, 
 NE.fr., fair. 
 Var. It., clear. 
 E. It., cloudy. 
 Var. It., fair. 
 W.fr,,rain. 
 W.fr., clear. 
 Var. It,, clear. 
 E.fr., clear. 
 Var. It., fair. 
 NE. It., rain. 
 
 Do. 
 N. It., rain. 
 Var. It., rain. 
 NW.fr., rain. 
 NW,br,,rain. 
 
 
 
 
 
 
 
 
 
 "* 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 . 
 
 
 
 
 
 
 L 
 
 
 
 
 
 
 
 
 
 50 
 
 60 
 
 100 
 
 "'106' 
 40 
 210 
 20 
 65 
 10 
 
 ""'65' 
 
 100 
 
 100 
 
 50 
 
 65 
 
 100 
 
 'iio' 
 
 60 
 
 25 
 90 
 40 
 
 50 
 90 
 
 100 
 
 110. 
 
 150 
 60 
 
 215 
 15 
 65 
 15 
 
 120 
 90 
 
 100 
 
 120 
 50 
 60 
 
 200 
 70 
 
 150 
 
 -75 
 15 
 30 
 40 
 60 
 
 50 
 
 110 
 
 150 
 
 160 
 
 155 
 
 55 
 
 200 
 
 40 
 
 70 
 
 10 
 
 130 
 
 105 
 
 75 
 
 120 
 
 55 
 
 55 
 
 180 
 
 90 
 
 250 
 
 
 
 10 
 
 50 
 
 20 
 
 35 
 
 65 
 
 35 
 
 160 
 
 160 
 
 160 
 
 200 
 
 50 
 
 230 
 
 40 
 
 70 
 
 40 
 
 140 
 
 250 
 
 100 
 
 90 
 
 60 
 
 55 
 
 200 
 
 100 
 
 300 
 
 60 
 
 60 
 
 50 
 
 25 
 
 
 
 75 
 
 55 
 
 100 
 
 150 
 
 150 
 
 140 
 
 80 
 
 180 
 
 5 
 
 100 
 
 35 
 
 120 
 
 200 
 
 100 
 
 80 
 
 70 
 
 70 
 
 . 200 
 
 90 
 
 100 
 
 —200 
 
 10 
 
 60 
 
 25 
 
 60 
 
 55 
 
 55 
 50 
 60 
 90 
 
 150 
 75 
 
 130 
 
 
 
 95 
 
 35 
 
 95 
 
 160 
 70 
 50 
 60 
 
 110 
 
 100 
 90 
 50 
 
 100 
 80 
 80 
 25 
 55 
 50 
 
 90 
 65 
 35 
 90 
 90 
 90 
 80 
 
 
 100 
 60 
 
 130 
 80 
 40 
 50 
 70 
 
 130 
 50 
 70 
 50 
 
 80 
 70 
 90 
 50 
 50 
 
 40 
 10 
 75 
 90 
 70 
 70 
 60 
 
 
 100 
 65 
 
 240 
 80 
 25 
 50 
 55 
 60 
 35 
 60 
 40 
 —100 
 50 
 70 
 80 
 45 
 75 
 
 65 
 
 — 30 
 60 
 60 
 70 
 60 
 50 
 10 
 
 100 
 70 
 
 100 
 65 
 15 
 40 
 50 
 25 
 50 
 60 
 30 
 
 250 
 
 — 5 
 • 90 
 
 60 
 50 
 80 
 
 60 
 
 60 
 80 
 60 
 55 
 45 
 
 70 
 75 
 90 
 70 
 10 
 30 
 50 
 50 
 40 
 60 
 10 
 —400 
 50 
 100 
 60 
 40 
 .50 
 
 60 
 10 
 55 
 
 100 
 40 
 50 
 20 
 
 80 
 60 
 
 140 
 70 
 10 
 40 
 50 
 60 
 60 
 70 
 
 —300 
 
 — 50 
 90 
 65 
 
 — 60 
 70 
 
 
 20 
 55 
 90 
 40 
 50 
 
 5 
 
 
 
 80 
 
 70 
 
 120 
 
 70 
 
 
 40 
 50 
 50 
 50 
 100 
 
 
 
 —350 
 
 60 
 
 100 
 
 60 
 
 —100 
 
 80 
 
 
 
 1,490 
 71 
 
 2,050 
 86 
 
 2,240 
 90 
 
 2,710 
 108 
 
 2, 035 
 81 
 
 1,915 
 73 
 
 1,710 
 
 68 
 
 1,445 
 58 
 
 1,475 
 59 
 
 815 
 33 
 
 790 
 32 
 
 740 
 30 
 
196 
 
 MEMOIRS OF THE ifATIONAL ACADEMY OP SCIENCES. 
 
 Table A. — Hourly records, drawn from continuous photographic 
 NOVEMBER, 1886. 
 
 Day of month. 
 
 1 a. m. 
 
 2 a. m. 
 
 3 a. m. 
 
 4 a. m. 
 
 5 a. m. 
 
 6 a.m. 
 
 7 a.m. 
 
 8 a. m. 
 
 9a.in. 
 
 10 a.m. 
 
 11 a.m. 
 
 12 m. 
 
 1 -. . 
 
 60 
 
 100 
 
 140 
 
 60 
 
 95 
 
 20 
 
 20 
 
 60 
 
 75 
 
 100 
 
 120 
 
 20 
 
 10 
 
 25 
 
 50 
 
 30 
 
 40 
 
 30 
 
 100 
 
 110 
 
 120 
 
 100 
 
 —100 
 
 70 
 
 50 
 
 50 
 
 100 
 
 140 
 
 90 
 
 110 
 
 65 
 
 110 
 
 140 
 
 60 
 
 90 
 
 30 
 
 30 
 
 75 
 
 100 
 
 80 
 
 150 
 
 15 
 
 10 
 
 30 
 
 40 
 
 50 
 
 50 
 
 40 
 
 90 
 
 100 
 
 130 
 
 100 
 
 —100 
 
 60 
 
 60 
 
 50 
 
 100 
 
 100 
 
 120 
 
 150 
 
 70 
 
 m 
 
 140 
 
 70 
 
 85 
 
 70 
 
 50 
 
 70 
 
 120 
 
 150 
 
 145 
 
 40 
 
 5 
 
 30 
 
 40 
 
 50 
 
 
 
 
 
 100 
 
 90 
 
 125 
 
 60 
 
 —100 
 
 — 25 
 
 65 
 
 50 
 
 90 
 
 120 
 
 120 
 
 50 
 
 70 
 
 95 
 
 140 
 
 70 
 
 80 
 
 60 
 
 55 
 
 100 
 
 100 
 
 100 
 
 140 
 
 25 
 
 
 
 30 
 
 50 
 
 20 
 
 
 
 10 
 
 60 
 
 100 
 
 100 
 
 70 
 
 
 
 
 
 45 
 
 40 
 
 100 
 
 120 
 
 120 
 
 —100 
 
 80 
 
 100 
 
 150 
 
 70 
 
 80 
 
 60 
 
 40 
 
 190 
 
 90 
 
 90 
 
 90 
 
 15 
 
 
 
 40 
 
 .50 
 
 40 
 
 40 
 
 30 
 
 70 
 
 115 
 
 60 
 
 70 
 
 10 
 
 40 
 
 50 
 
 70 
 
 110 
 
 100 
 
 105 
 
 00 
 
 90 
 
 90 
 
 140 
 
 100 
 
 100 
 
 40 
 
 50 
 
 160 
 
 120 
 
 120 
 
 70 
 
 40 
 
 40 
 
 40 
 
 50 
 
 50 
 
 50 
 
 80 
 
 60 
 
 140 
 
 80 
 
 50 
 
 
 
 40 
 
 50 
 
 70 
 
 130 
 
 80 
 
 110 
 
 90 
 
 95 
 
 120 
 
 125 
 
 100 
 
 100 
 
 25 
 
 50 
 
 90 
 
 100 
 
 120 
 
 110 
 
 10 
 
 40 
 
 50 
 
 70 
 
 50 
 
 10 
 
 —100 
 
 160 
 
 100 
 
 85 
 
 60 
 
 50 
 
 50 
 
 60 
 
 80 
 
 160 
 
 75 
 
 115 
 
 90 
 
 105 
 
 120 
 
 190 
 
 100 
 
 120 
 
 10 
 
 50 
 
 100 
 
 100 
 
 140 
 
 120 
 
 
 
 50 
 
 60 
 
 90 
 
 100 
 
 10 
 
 150 
 
 130 
 
 30 
 
 105 
 
 65 
 
 60 
 
 60 
 
 30 
 
 90 
 
 170 
 
 80 
 
 150 
 
 105 
 
 103 
 
 120 
 
 240 
 
 100 
 
 200 
 
 70 
 
 .50 
 
 70 
 
 150 
 
 150 
 
 100 
 
 5 
 
 50 
 
 60 
 
 85 
 
 65 
 
 50 
 
 10 
 
 60 
 
 180 
 
 130 
 
 120 
 
 80 
 
 60 
 
 30 
 
 60 
 
 190 
 
 140 
 
 155 
 
 100 
 
 100 
 
 150 
 
 250 
 
 100 
 
 200 
 
 75 
 
 55 
 
 60 
 
 140 
 
 160 
 
 90 
 
 —100 
 
 45 
 
 60 
 
 60 
 
 70 
 
 100 
 
 30 
 
 60 
 
 150 
 
 100 
 
 120 
 
 80 
 
 50 
 
 50 
 
 90 
 
 150 
 
 130 
 
 150 
 
 100 
 
 130 
 
 110 
 
 240 
 
 100 
 
 140 
 
 110 
 
 70 
 
 50 
 
 150 
 
 190 
 
 90 
 
 
 
 45 
 
 60 
 
 50 
 
 100 
 
 50 
 
 60 
 
 60 
 
 130 
 
 100 
 
 160 
 
 80 
 
 60 
 
 60 
 
 85 
 
 100 
 
 125 
 
 160 
 
 140 
 
 140 
 
 100 
 
 200 
 
 100 
 
 100 
 
 100 
 
 50 
 
 50 
 
 100 
 
 150 
 
 100 
 
 — 60 
 
 40 
 
 60 
 
 80 
 
 90 
 
 50 
 
 60 
 
 .60 
 
 100 
 
 90 
 
 150 
 
 60 
 
 75 
 
 50 
 
 85 
 
 100 
 
 130 
 
 140 
 
 120 
 
 a 
 
 3 
 
 4 
 
 5 
 
 6 
 
 7 
 
 8 
 
 9 
 
 10 
 
 11 
 
 12 
 
 13 
 
 14 
 
 15 
 
 16 
 
 17 
 
 18 
 
 19 
 
 ao 
 
 ai 
 
 as 
 
 23 
 
 94 
 
 25 
 
 26 
 
 27 
 
 :28 
 
 29 
 
 30 
 
 Sams 
 
 1,995 
 67 
 
 3,265 
 76 
 
 2,020 
 67 
 
 1,800 
 60 
 
 2,115 
 
 70 
 
 2,270 
 76 
 
 2,250 
 
 75 
 
 2,690 
 90 
 
 2,985 
 100 
 
 2,875 
 96 
 
 3,005 
 100 
 
 2,670 
 
 89 
 
 
 
 DECEMBER, 1886, 
 
 1 
 
 2 
 
 3 
 
 4 
 
 5 
 
 6 
 
 %.'.'.'.'".'.'. 
 
 9 
 
 10 
 
 11 
 
 12 
 
 13 
 
 14 
 
 15 
 
 16 
 
 IT 
 
 18 
 
 19 
 
 20 
 
 21 
 
 22 
 
 23 
 
 24 
 
 25 
 
 26 
 
 27 
 
 28 , 
 
 29 
 
 30 
 
 31 
 
 Sums . 
 Means 
 
 110 
 60 
 50 
 60 
 
 110 
 50 
 
 — 30 
 100 
 100 
 
 50 
 
 30 
 
 100 
 
 100 
 
 60 
 
 
 
 — 10 
 40 
 80 
 
 100 
 
 85 
 
 
 
 40 
 
 40 
 
 20 
 
 
 
 60 
 
 150 
 
 90 
 
 40 
 
 100 
 
 —250 
 
 1,,595 
 55 
 
 65 
 
 75 
 
 100 
 
 100 
 
 10 
 
 — 20 
 110 
 100 
 
 45 
 45 
 100 
 70 
 50 
 
 
 — 5 
 20 
 
 —200 
 
 150 
 
 65 
 
 120 
 
 50 
 
 50 
 
 75 
 
 
 
 60 
 
 120 
 
 80 
 
 40 
 
 — 10 
 —400 
 
 1,155 
 40 
 
 85 
 60 
 80 
 65 
 
 100 
 
 50 
 
 — 40 
 
 110 
 
 150 
 50 
 65 
 
 100 
 
 70 
 
 60 
 
 
 
 
 
 10 
 
 —100 
 
 160 
 80 
 
 120 
 70 
 50 
 
 100 
 
 
 
 60 
 
 200 
 85 
 50 
 
 120 
 —300 
 
 1,710 
 61 
 
 65 
 70 
 60 
 60 
 120 
 25 
 
 - 30 
 130 
 100 
 
 40 
 
 75 
 
 100 
 
 40 
 
 50 
 
 
 
 
 
 
 
 - 20 
 175 
 100 
 100 
 
 70 
 50 
 
 105 
 
 
 
 65 
 
 130 
 80 
 60 
 
 150 
 -250 
 
 1,720 
 64 
 
 100 
 
 90 
 
 50 
 
 85 
 
 120 
 
 
 
 - 50 
 
 160 
 
 100 
 
 50 
 
 70 
 
 80 
 
 50 
 
 50 
 
 
 
 
 
 
 
 20 
 
 150 
 
 140 
 
 130 
 
 60 
 
 50 
 
 60 
 
 
 
 60 
 
 120 
 
 60 
 
 60 
 
 150 
 
 
 
 2,065 
 79 
 
 150 
 50 
 25 
 40 
 
 100 
 
 
 - CO 
 100 
 100 
 
 70 
 25 
 50 
 60 
 50 
 
 
 - 20 
 
 
 
 60 
 
 150 
 
 160 
 
 150 
 
 70 
 
 50 
 
 75 
 
 
 
 60 
 
 160 
 
 80 
 
 80 
 
 150 
 
 20 
 
 2, 005 
 74 
 
 200 
 40 
 20 
 20 
 50 
 
 
 — 70 
 100 
 
 70 
 
 100 
 
 50 
 
 60 
 
 — 50 
 80 
 
 
 
 15 
 
 
 
 — 60 
 130 
 150 
 160 
 100 
 
 60 
 
 80 
 
 
 65 
 145 
 100 
 110 
 150 
 
 20 
 
 1,895 
 70 
 
 150 
 
 35 
 
 10 
 
 10 
 
 40 
 
 
 
 - 40 
 
 60 
 
 80 
 
 70 
 
 75 
 
 60 
 
 
 
 80 
 
 
 
 5 
 
 
 
 -150 
 
 190 
 
 120 
 
 160 
 
 100 
 
 50 
 
 80 
 
 
 
 70 
 
 200 
 
 90 
 
 130 
 
 100 
 
 20 
 
 1,795 
 66 
 
 250 
 
 35 
 
 
 
 5 
 
 
 
 
 
 - 80 
 
 50 
 
 120 
 
 75 
 
 110 
 
 60 
 
 100 
 
 80 
 
 
 
 
 
 
 
 -200 
 
 120 
 
 100 
 
 160 
 
 100 
 
 60 
 
 120 
 
 
 
 65 
 
 150 
 
 80 
 
 120 
 
 90 
 
 50 
 
 1,820 
 76 
 
 200 
 
 20 
 
 
 
 
 
 
 
 
 
 - 50 
 
 150 
 
 110 
 
 120 
 
 60 
 
 70 
 
 100 
 
 100 
 
 
 
 
 
 
 
 -300 
 
 120 
 
 100 
 
 150 
 
 20 
 
 60 
 
 120 
 
 
 
 85 
 
 200 
 
 50 
 
 100 
 
 100 
 
 65 
 
 750 
 76 
 
 165 
 
 20 
 
 
 
 
 
 
 
 10 
 
 - 10 
 
 250 
 
 150 
 
 120 
 
 100 
 
 60 
 
 150 
 
 100 
 
 
 
 
 
 
 
 -200 
 
 100 
 
 100 
 
 150 
 
 90 
 
 130 
 
 
 
 60 
 
 200 
 
 
 
 IfO 
 
 60 
 
 10 
 
 1, 915 
 83 
 
 120 
 
 
 
 
 
 
 
 50 
 
 200 
 
 — 10 
 
 100 
 
 150 
 
 50 
 
 140 
 
 100 
 
 
 
 
 
 
 
 —200 
 
 100 
 
 100 
 
 150 
 
 90 
 
 150 
 
 
 
 50 
 
 100 
 
 100 
 
 
 
 
 
 1,540 
 86 
 
MEM01E3 OF THE NATIOJ^AL ACADEMY OP SUIENGBS. 
 
 197 
 
 registration, at Baltimore, Md., 1885, 1886, and 1887 — Continued. 
 
 NOVEMBEK, 1886. 
 
 1 p. m. 
 
 2 p.m. 
 
 3 p.m. 
 
 4 p.m. 
 
 5 p.m. 
 
 6 p.m. 
 
 7 p.m. 
 
 8 p.m. 
 
 9 p.m. 
 
 IQp. m. 
 
 11 p. m. 
 
 12 mid. 
 
 Remarks. 
 
 140 
 
 150 
 
 130 
 
 130 
 
 140 
 
 155 
 
 110 
 
 iio 
 
 110 
 
 100 
 
 95 
 
 100 
 
 NW.fr., clear. 
 
 100 
 
 300 
 
 260 
 
 270 
 
 240 
 
 240 
 
 220 
 
 150 
 
 175 
 
 140 
 
 110 
 
 130 
 
 Var. gen., clear. 
 
 140 
 
 200 
 
 250 
 
 175 
 
 140 
 
 120 
 
 100 
 
 100 
 
 80 
 
 80 
 
 80 
 
 60 
 
 S. It., fair. 
 
 100 
 
 120 
 
 125 
 
 120 
 
 170 
 
 120 
 
 150 
 
 120 
 
 80 
 
 100 
 
 100 
 
 100 
 
 NW.fr., fair. 
 
 120 
 
 150 
 
 200 
 
 150 
 
 80 
 
 60 
 
 65 
 
 60 
 
 65 
 
 90 
 
 80 
 
 40 
 
 Var. It., fair. 
 
 140 
 
 50 
 
 - 5 
 
 — 50 
 
 —250 
 
 - 60 
 
 - 20 
 
 —200 
 
 —100 
 
 200 
 
 50 
 
 — 10 
 
 NW. br.,rain. 
 
 
 
 90 
 45 
 
 100 
 55 
 
 6£ 
 50 
 
 70 
 50 
 
 70 
 60 
 
 70 
 
 70 
 
 70 
 100 
 
 65 
 90 
 
 60 
 
 100 
 
 60 
 60 
 
 Do. 
 NW. high, clear. 
 
 50 
 
 65 
 
 100 
 
 95 
 
 150 
 
 180 
 
 120 
 
 230 
 
 160 
 
 180 
 
 190 
 
 100 
 
 75 
 
 75 
 
 NW.fr., clear. 
 
 130 
 
 160 
 
 150 
 
 190 
 
 160 
 
 180 
 
 110 
 
 100 
 
 75 
 
 75 
 
 90 
 
 110 
 
 S. fr.,rain. 
 
 60 
 
 75 
 
 75 
 
 75 
 
 75 
 
 100 
 
 50 
 
 110 
 
 60 
 
 60 
 
 60 
 
 40 
 
 NW.fr., cloudy. 
 
 —200 
 
 —200 
 
 —200 
 
 -ITO 
 
 — 60 
 
 150 
 
 —200 
 
 -200 
 
 —400 
 
 —300 
 
 — 50 
 
 
 
 N. fr.,rain. 
 
 
 
 25 
 
 50 
 
 60 
 
 30 
 
 40 
 
 30 
 
 30 
 
 30 
 
 25 
 
 25 
 
 25 
 
 NW. high, snow. 
 
 
 
 75 
 50 
 
 60 
 
 90 
 
 60 
 60 
 
 65 
 
 50 
 
 65 
 
 45 
 
 50 
 30 
 
 50 
 25 
 
 40 
 30 
 
 30 
 
 50 
 
 50 
 
 40 
 
 NW.br., clear. 
 NW.fr., clear. 
 
 60 
 
 45 
 
 105 
 
 120 
 
 aio 
 
 160 
 
 190 
 
 220 
 
 160 
 
 100 
 
 00 
 
 60 
 
 70 
 
 45 
 
 N.fr.,fair. 
 
 75 
 
 110 
 
 70 
 
 50 
 
 90 
 
 50 
 
 50 
 
 40 
 
 30 
 
 20 
 
 10 
 
 10 
 
 NE.lt., rain. 
 
 60 
 
 60 
 
 60 
 
 65 
 
 50 
 
 50 
 
 50 
 
 50 
 
 55 
 
 100 
 
 no 
 
 120 
 
 SE.br., rain. 
 
 45 
 
 60 
 
 60 
 
 50 
 
 55 
 
 55 
 
 75 
 
 60 
 
 70 
 
 90 
 
 100 
 
 105 
 
 W. br., clear. 
 
 100 
 
 75 
 
 60 
 
 50 
 
 65 
 
 80 
 
 80 
 
 80 
 
 90 
 
 110 
 
 110 
 
 100 
 
 SW.fr.,fair.- 
 
 
 
 140 
 
 100 
 
 150 
 
 100 
 
 105 
 30 
 
 150 
 - 10 
 
 100 
 25 
 
 100 
 50 
 
 100 
 50 
 
 95 
 50 
 
 90 
 
 
 100 
 — 25 
 
 Var.fr., fair. 
 
 N.lt.,raiu. 
 
 140 
 
 140 
 
 60 
 
 100 
 
 110 
 
 100 
 
 120 
 
 100 
 
 100 
 
 60 
 
 
 
 50 
 
 60 
 
 60 
 
 SW.br., rain. 
 
 90 
 
 100 
 
 100 
 
 120 
 
 100 
 
 75 
 
 90 
 
 90 
 
 85 
 
 90 
 
 60 
 
 60 
 
 Do. 
 
 65 
 
 —100 
 
 —400 
 
 —300 
 
 —400 
 
 —250 
 
 20 
 
 50 
 
 50 
 
 50 
 
 50 
 
 50 
 
 NW. high, rain. 
 
 100 
 
 100 
 
 120 
 
 120 
 
 120 
 
 100 
 
 110 
 
 100 
 
 110 
 
 120 
 
 160 
 
 165 
 
 NW.br., clear. 
 
 100 
 
 75 
 
 65 
 
 75 
 
 75 
 
 100 
 
 110 
 
 80 
 
 140 
 
 80 
 
 100 
 
 110 
 
 NW.fr., clear. 
 
 
 
 140 
 150 
 
 IGO 
 110 
 
 100 
 110 
 
 100 
 190 
 
 120 
 175 
 
 120 
 190 
 
 140 
 
 85 
 
 200 
 50 
 
 190 
 
 50 
 
 120 
 100 
 
 S. It., clear. 
 SW.lt., fair. 
 
 100 
 
 130 
 
 100 
 
 —200 
 
 60 
 
 75 
 
 100 
 
 130 
 
 135 
 
 120 
 
 95 
 
 95 
 
 95 
 
 100 
 
 E.fr.,rain. 
 
 2,080 
 
 2,005 
 
 2,490 
 
 2,520 
 
 1,990 
 
 2,710 
 
 2,415 
 
 2,070 
 
 1,770 
 
 2,155 
 
 2,210 
 
 2,100 
 
 80 
 
 77 
 
 83 
 
 84 
 
 66 
 
 90 
 
 80 
 
 69 
 
 59 
 
 72 
 
 73 
 
 70 
 
 
 DECEMBER, 1886. 
 
 120 
 
 100 
 
 100 
 
 95 
 
 100 
 
 100 
 
 80 
 
 85 
 
 85 
 
 85 
 
 85 
 
 60 
 
 NW.fr., cloudv. 
 
 — 50 
 
 20 
 
 25 
 
 50 
 
 , 50 
 
 60 
 
 60 
 
 50 
 
 50 
 
 50 
 
 60 
 
 50 
 
 NW. high, fair. 
 
 5 
 
 20 
 
 25 
 
 30 
 
 30' 
 
 60 
 
 50 
 
 55 
 
 60 
 
 60 
 
 65 
 
 70 
 
 Do. 
 
 
 
 10 
 
 50 
 
 55 
 
 50 
 
 50 
 
 30 
 
 60 
 
 40 
 
 100 
 
 65 
 
 — 20 
 
 N. br., snow. 
 
 200 
 
 50 
 
 — 50 
 
 - 20 
 
 -100 
 
 — 60 
 
 — 50 
 
 10 
 
 20 
 
 50 
 
 50 
 
 50 
 
 NE. fr., snow. 
 
 65 
 
 100 
 
 60 
 
 60 
 
 20 
 
 50 
 
 
 
 
 
 
 
 
 
 — 5 
 
 — 30 
 
 NW.fr., snow, rain. 
 
 100 
 
 100 
 
 100 
 
 75 
 
 90 
 
 105 
 
 90 
 
 110 
 
 110 
 
 90 
 
 100 
 
 100 
 
 NE. br., snow. 
 
 190 
 
 160 
 
 150 
 
 150 
 
 160 
 
 240 
 
 . 200 
 
 200 
 
 160 
 
 100 
 
 130 
 
 100 
 
 W.fr., clear. 
 
 
 
 200 
 
 200 
 
 210 
 
 200. 
 
 100 
 
 75 
 
 80 
 
 80 
 
 100 
 
 60 
 
 60 
 
 Var. It., clear. 
 
 150 
 
 , 160 
 
 165 
 
 165 
 
 165 
 
 60 
 
 50 
 
 50 
 
 — 50 
 
 
 
 
 
 40 
 
 Do. 
 
 160 
 
 240 
 
 200 
 
 160 
 
 130 
 
 110 
 
 140 
 
 100 
 
 100 
 
 100 
 
 90 
 
 100 
 
 Var.lt., fair. 
 
 
 
 60 
 150 
 
 ""m 
 
 100 
 130 
 
 140 
 200, 
 
 100 
 180 
 
 75 
 170 
 
 75 
 160 
 
 5 
 160 
 
 15 
 200 
 
 100 
 140 
 
 Var.lt., raiu. 
 Var. fr., rain. 
 
 140 
 
 100 
 
 
 
 
 100 
 - 50 
 
 60 
 300 
 
 180 
 250 
 
 205 
 —100 
 
 160 
 -200 
 
 60 
 160 
 
 40 
 150 
 
 -- 20 
 
 
 
 — 20 
 
 SW.br., cloudy. 
 Var.fr., rain, snow. 
 
 v!00 
 
 60 
 
 70 
 
 50 
 
 —100 
 
 60 
 
 50 
 
 65 
 
 110 
 
 110 
 
 90 
 
 60 
 
 60 
 
 50 
 
 50 
 
 NW. br., snow. 
 
 
 
 
 
 
 
 80 
 100 
 
 80 
 60 
 
 90 
 100 
 
 60 
 100 
 
 60 
 120 
 
 60 
 130 
 
 SW. fr., cloudy. 
 SW. fr., rain. 
 
 100 
 
 — 20 
 
 — 80 
 
 —300 
 
 — ioo 
 
 -200 
 
 
 
 100 
 
 110 
 
 no 
 
 100 
 120 
 
 120 
 150 
 120 
 
 120 
 110 
 100 
 
 90 
 130 
 100 
 
 130 
 130 
 100 
 
 110 
 
 100 
 60 
 
 130 
 
 100 
 
 60 
 
 90 
 
 — 10 
 
 40 
 
 NW. gen., fog, fair. 
 NW. fr., clear. 
 Var. It., clear. 
 
 
 
 130 
 
 160 
 
 200 
 
 200 
 
 
 
 
 —100 
 
 —160 
 
 — 50 
 
 
 
 50 
 
 50 
 
 50 
 
 30 
 
 20 
 
 NW. gen., rain. 
 
 60 
 
 100 
 
 50 
 
 50 
 
 30 
 
 60 
 
 80 
 
 70 
 
 60 
 
 50 
 
 60 
 
 25 
 
 NE.fr., rain. 
 
 100 
 
 120 
 
 120 
 
 100 
 
 120 
 
 100 
 
 
 
 —210 
 
 —200 
 
 • 
 
 
 
 
 
 Var.fr., rain. 
 
 
 
 65 
 
 80 
 
 80 
 
 75 
 
 75 
 
 50 
 
 85 
 
 120 
 
 100 
 
 60 
 
 65 
 
 NW. br., clear. 
 
 
 
 
 100 
 100 
 
 200 
 
 85 
 
 -20 
 
 85 
 
 
 80 
 
 
 65 
 
 
 100 
 
 200 
 110 
 
 160 
 110 
 
 2il0 
 100 
 
 NE. fr., snow. 
 NW.fr., fair. 
 
 120 
 
 100 
 
 130 
 
 120 
 
 110 
 
 110 
 
 100 
 
 150 
 
 160 
 
 120 
 
 120 
 
 160 
 
 150 
 
 100 
 
 60 
 
 Var. It., cloudy. 
 
 100 
 
 100 
 
 100 
 
 100 
 
 95 
 
 80 
 
 75 
 
 50 
 
 20 
 
 30 
 
 — 20 
 
 120 
 
 N. fr., snow. 
 
 10 
 
 50 
 
 10 
 
 10 
 
 20 
 
 50 
 
 
 
 — 10 
 
 — 5 
 
 — 50 
 
 20 
 
 25 
 
 NE. fr., snow. 
 
 
 
 — 5 
 
 60 
 
 75 
 
 40 
 
 40 
 
 60 
 
 —400 
 
 300 
 
 300 
 
 300 
 
 —450 
 
 NE.fr., snow, rain. . 
 
 1,370 
 69 
 
 2,000 
 83 
 
 2,245 
 86 
 
 1,925 
 69 
 
 2,435 
 81 
 
 2,525 
 
 84 
 
 2,195 
 71 
 
 1,375 
 44 
 
 2,325 
 75 
 
 2,520 
 
 84 
 
 2, 275 
 76 
 
 1,325 
 46 
 
198 
 
 MEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES. 
 
 Table A. — Hourly records, drawn from continuous photograpMc 
 
 JANUARY, 1887. 
 
 Day of month. 
 
 1 a. m. 
 
 2 a. m. 
 
 3 a. <h. 
 
 4 a. m. 
 
 5 a.m. 
 
 6 a.m. 
 
 7 a.m. 
 
 8 a.m. 
 
 9 a.m. 
 
 10 a. m. 
 
 11 a. m. 
 
 12 m. 
 
 1 
 
 150 
 
 
 —100 
 
 
 100 
 
 
 120 
 
 
 130 
 
 
 100 
 
 
 —300 
 
 
 —150 
 
 
 
 
 
 
 
 
 
 60 
 
 
 50 
 
 
 
 2 
 
 •-i 
 
 4 
 
 
 
 
 
 
 
 
 
 
 
 
 
 5 
 
 
 
 
 
 
 
 
 
 
 
 
 
 g 
 
 
 
 
 
 
 
 
 
 
 
 
 
 7 
 
 
 
 
 
 
 
 
 
 
 
 
 
 H 
 
 
 
 
 
 
 
 
 
 
 
 
 120 
 
 60 
 
 — 20 
 
 
 
 '"''ioo' 
 
 '—'56' 
 
 "'iso' 
 
 
 50 
 
 6 
 
 100 
 40 
 140 
 100 
 200 
 
 ""uo 
 
 9 
 
 150 
 
 135 
 
 90 
 
 110 
 
 200 
 
 —250 
 
 270 
 
 100 
 
 95 
 
 95 
 
 30 
 
 120 
 
 75 
 
 • 20 
 
 70 
 
 140 
 
 120 
 
 80 
 
 90 
 
 100 
 
 75 
 
 130 
 
 100 
 
 120 
 
 100 
 
 110 
 
 100 
 
 300 
 
 —100 
 
 260 
 
 140 
 
 95 
 
 95 
 
 30 
 
 110 
 
 30 
 
 110 
 
 50 
 
 65 
 
 120 
 
 80 
 
 80 
 
 80 
 
 75 
 
 130 
 
 120 
 
 120 
 
 12^ 
 
 105 
 
 95 
 
 200 
 
 50 
 
 250 
 
 175 
 
 90 
 
 95 
 
 25 
 
 100 
 
 25 
 
 25 
 
 60 
 
 205 
 
 130 
 
 80 
 
 75 
 
 100 
 
 60 
 
 135 
 
 130 
 
 120 
 
 130 
 
 105 
 
 120 
 
 160 
 
 45 
 
 230 
 
 160 
 
 70 
 
 90 
 
 25 
 
 100 
 
 20 
 
 
 
 55 
 
 300 
 
 140 
 
 95 
 
 50 
 
 110 
 
 100 
 
 100 
 
 110 
 
 120 
 
 150 
 
 80 
 
 60 
 
 240 
 
 
 
 140 
 
 110 
 
 85 
 
 90 
 
 25 
 
 100 
 
 25 
 
 30 
 
 50 
 
 100 
 
 170 
 
 100 
 
 25 
 
 90 
 
 100 
 
 100 
 
 110 
 
 125 
 
 155 
 
 60 
 
 90 
 
 160 
 
 100 
 
 170 
 
 120 
 
 100 
 
 100 
 
 25 
 
 110 
 
 40 
 
 20 
 
 45 
 
 100 
 
 210 
 
 105 
 
 15 
 
 100 
 
 100 
 
 100 
 
 135 
 
 135 
 
 195 
 
 50 
 
 110 
 
 175 
 
 100 
 
 90 
 
 120 
 
 60 
 
 50 
 
 40 
 
 140 
 
 90 
 
 20 
 
 30 
 
 — 60 
 
 220 
 
 100 
 
 10 
 
 110 
 
 70 
 
 150 
 
 100 
 
 100 
 
 100 
 
 40 
 
 110 
 
 150 
 
 140 
 
 60 
 
 125 
 
 60 
 
 40 
 
 30 
 
 150 
 
 65 
 
 50 
 
 15 
 
 —300 
 
 210 
 
 — 50 
 
 5 
 
 100 
 
 35 
 
 100 
 
 100 
 
 70 
 
 70 
 
 30 
 
 120 
 
 290 
 
 150 
 
 50 
 
 125 
 
 75 
 
 35 
 
 20 
 
 160 
 
 50 
 
 50 
 
 5 
 
 —300 
 
 190 
 
 — 50 
 
 
 110 
 
 — 50 
 100 
 110 
 
 70 
 
 60 
 
 20 
 
 120 
 
 250 
 
 120 
 
 40 
 
 120 
 
 10 
 
 30 
 
 5 
 
 100 
 
 50 
 
 60 
 
 
 
 -200 
 
 160 
 
 40 
 
 
 
 100 
 
 —200 
 
 140 
 
 110 
 
 60 
 
 
 
 30 
 
 120 
 
 200 
 
 100 
 
 40 
 
 125 
 
 10 
 
 20 
 
 
 
 100 
 
 
 
 80 
 
 
 
 —400 
 
 140 
 
 45 
 
 
 
 100 
 
 300 
 
 60 
 
 120 
 
 10 
 
 11 
 
 12 
 
 13 
 
 14 
 
 15 
 
 16 
 
 17 
 
 18 
 
 19 
 
 20 
 
 21 
 
 22 
 
 23 
 
 24 
 
 25 
 
 26 
 
 27 
 
 28 
 
 29 
 
 30 
 
 31 
 
 Sums 
 
 2,295 
 96 
 
 2,190; 
 91: 
 
 2,555 
 106 
 
 2, 555 
 106 
 
 2,230 
 93 
 
 2,385 
 99 
 
 1,805 
 75 
 
 1,285 
 54 
 
 1,410 
 61 
 
 1,205 
 55 
 
 1,310 
 59 
 
 1,280 
 85 
 
 Means ._.. 
 
 
 FEBRUARY, 1887. 
 
 1 
 
 2 
 
 3 
 
 4 
 
 5 
 
 6 
 
 7 
 
 8 
 
 9 
 
 10 
 
 11 
 
 12 
 
 13 
 
 14 
 
 15 
 
 16 
 
 17 
 
 18 
 
 19... 
 
 20 
 
 21 
 
 22 
 
 23 
 
 24 
 
 25 
 
 26 
 
 27 
 
 28 
 
 Sums 
 Means 
 
 70 
 
 40 
 
 55 
 
 10 
 
 80 
 
 50 
 
 
 
 85 
 
 60 
 
 120 
 
 50 
 
 25 
 
 40 
 
 105 
 
 -350 
 10 
 30 
 50 
 30 
 70 
 60 
 80 
 70 
 
 - 50 
 
 70 
 
 120 
 
 70 
 
 60 
 
 1,110 
 41 
 
 90 
 25 
 45 
 
 70 
 25 
 
 80 
 45 
 
 160 
 25 
 40 
 40 
 
 110 
 
 -250 
 
 10 
 
 40 
 
 75 
 
 
 
 75 
 
 60 
 
 80 
 
 70 
 
 -250 
 
 75 
 
 120 
 70 
 G5 
 
 995 
 
 38 
 
 90 
 30 
 
 
 
 
 75 
 35 
 
 
 
 70 
 
 60 
 
 165 
 
 30 
 
 50 
 
 40 
 
 100 
 
 -200 
 
 50 
 
 ^0 
 
 50 
 
 
 90 
 60 
 80 
 65 
 - 20 
 80 
 130 
 70 
 70 
 
 1,320 
 51 
 
 80 
 
 100 
 
 - 10 
 
 
 
 65 
 10 
 
 
 50 
 50 
 125 
 40 
 40 
 40 
 80 
 -150 
 
 
 70 
 55 
 
 
 60 
 60 
 60 
 .50 
 ,50 
 80 
 140 
 (i.'i 
 60 
 
 1,270 
 49 
 
 85 
 
 100 
 
 25 
 
 
 
 60 
 
 20 
 
 
 
 60 
 
 50 
 
 150 
 
 20 
 
 60 
 
 20 
 
 65 
 
 —200 
 
 30 
 
 70 
 
 40 
 
 25 
 
 60 
 
 100 
 
 70 
 
 50 
 
 40 
 
 100 
 
 300 
 
 70 
 
 40 
 
 ,510 
 58 
 
 110 
 
 —300 
 
 85 
 
 
 
 70 
 
 20 
 
 
 
 85 
 
 50 
 
 140 
 20 
 60 
 20 
 90 
 — 20 
 60 
 
 100 
 45 
 30 
 60 
 90 
 80 
 80 
 60 
 
 100 
 
 
 
 80 
 
 25 
 
 1,240 
 
 48 
 
 50 
 
 — 50 
 125 
 
 
 
 70 
 
 60 
 
 
 
 100 
 50 
 
 120 
 25 
 65 
 10 
 
 130 
 25 
 
 — 20 
 100 
 
 — 20 
 50 
 60 
 
 100 
 60 
 50 
 60 
 110 
 300 
 80 
 20 
 
 1,730 
 
 67 
 
 90 
 
 — 50 
 200 
 
 
 
 60 
 
 100 
 
 
 
 110 
 
 55 
 
 130 
 
 40 
 
 40 
 
 
 
 160 
 
 — 20 
 60 
 80 
 
 
 60 
 90 
 
 IM) 
 
 100 
 90 
 50 
 
 100 
 —300 
 
 100 
 20 
 
 1,545 
 
 59 
 
 90 
 
 - 25 
 165 
 
 
 
 100 
 
 80 
 
 
 
 75 
 
 55 
 
 150 
 
 40 
 
 
 
 
 
 100 
 
 - 30 
 50 
 80 
 
 
 50 
 80 
 
 160 
 90 
 90 
 70 
 90 
 
 100 
 80 
 20 
 
 1,760 
 73 
 
 95 
 
 
 
 145 
 
 
 
 90 
 
 85 
 
 
 
 100 
 
 35 
 
 180 
 
 40 
 
 
 
 
 
 TO 
 
 - 25 
 
 50 
 
 60 
 
 
 
 50 
 
 80 
 
 120 
 
 50 
 
 100 
 
 85 
 
 110 
 
 100 
 
 90 
 
 10 
 
 1,720 
 
 75 
 
 no 
 
 
 
 
 
 
 175 
 
 150 
 
 
 
 
 
 60 
 
 70 
 
 50 
 
 
 
 
 
 
 150 
 
 
 ;» 
 
 60 
 
 100 
 
 60 
 
 
 
 50 
 
 
 
 
 
 
 
 
 
 50 
 
 
 — 30 
 
 — 30 
 
 100 
 
 90 
 
 ' 60 
 
 50 
 
 — 20 
 
 
 50 
 
 50 
 
 80 
 
 100 
 
 120 
 
 100 
 
 50 
 
 6(1 
 
 100 
 
 
 80 
 
 f?ll 
 
 100 
 
 
 
 
 
 
 80 
 
 70 
 
 10 
 
 100 
 
 1,505 
 
 1,140 
 
 65 
 
 71 
 
MB510IB3 OF THE NATIONAL AOADBMY OF SCIENCES. 
 
 199 
 
 registraiion, at Baltimore, Md., 1885, 1886, and 1887 — Continued. 
 
 JANUARY, 1887. 
 
 Ip.m. 
 
 2 p.m. 
 
 3 p.m. 
 
 4 p.m. 
 
 5 p.m. 
 
 6 p.m. 
 
 7 p.m. 
 
 8 p.m. 
 
 9 p.m. 
 
 10 p. m. 
 
 lip. m. 
 
 12 mid. 
 
 Eemarks.. 
 
 60 
 
 90 
 
 80 
 
 30 
 
 70 
 
 60 
 
 55 
 
 50 
 
 50 
 
 50 
 
 50 
 
 30 
 
 NW.br., rain, snow. 
 NW.br., clear. 
 
 Do. 
 NW.lt., cloudy. 
 N. It., snow. 
 N. It., fair. 
 NW.lt., cloudy. 
 NE.fr., clear. 
 NE., fr., snow, sleet. 
 NW. br., snow, clear. 
 NW.fr., cloudy. 
 SW.fr., fair. 
 Var. It., rain. | 
 Var. It., rain, fog. ! 
 NW.br., fog, fair. 
 Var. fr., cloudy. 
 Var. It., rain. 
 NW. high, clear. 
 NW.fr., cloudy. 
 Var. fr., cloudy. 
 SW.fr., cloudy. 
 SW.fr., fair. 
 S.br.,fair. 
 NW. br. , rain, snow. 
 NW.br., fair. 
 W. br., rain, snow. 
 NW.fr., clear. 
 SW.br., cloudy. 
 SW.fr., rain. 
 W.fr., cloudy. 
 E. fr,, clear. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 120 
 
 60 
 
 — 15 
 
 150 
 
 '"ieo" 
 
 150 
 
 120 
 160 
 20 
 130 
 160 
 190 
 290 
 120 
 
 135 
 
 140 
 
 — 30 
 
 125 
 
 200 
 160 
 175 
 140 
 150 
 100 
 
 40 
 
 70 
 120 
 
 60 
 15p 
 110 
 100 
 
 60 
 100 
 220 
 145 
 —300 
 160 
 115 
 
 140 
 
 120 
 
 25 
 
 100 
 
 130 
 
 100 
 
 200 
 
 150 
 
 200 
 
 —200 
 
 40 
 
 80 
 
 80 
 
 10 
 
 105 
 
 150 
 
 60 
 
 10 
 
 IHO 
 
 240 
 
 110 
 
 —200 
 
 150 
 
 105 
 
 120 
 130 
 
 25 
 175 
 175 
 
 85 
 220 
 125 
 140 
 
 — 50 
 45 
 75 
 
 9r> 
 
 50 
 110 
 180 
 
 80 
 
 
 
 140 
 
 180 
 
 200 
 
 — 50 
 140 
 100 
 
 160 
 125 
 
 20 
 140 
 200 
 
 60 
 190 
 125 
 125 
 
 60 
 
 90 
 
 75 
 110 
 
 40 
 
 80 
 160 
 
 85 
 
 
 
 120 
 
 130 
 
 160 
 
 50 
 120 
 
 85 
 
 145 
 
 100 
 
 5 
 
 140 
 
 250 
 
 65 
 160 
 100 
 100 
 
 60 
 
 60 
 
 80 
 100 
 
 25 
 
 20 
 
 160 
 
 100 
 
 
 
 90 
 130 
 
 90- 
 
 50 
 120 
 
 85 
 
 130 
 85 
 60 
 
 145 
 
 300 
 —300 
 
 220 
 
 100 
 
 120 
 70 
 50 
 80 
 
 100 
 
 — 60 
 
 50 
 
 120 
 
 80 
 
 
 
 95 
 
 130 
 95 
 30 
 
 120 
 75 
 
 150 
 
 100 
 
 60 
 
 150 
 
 300 
 
 — 50 
 
 200 
 
 100 
 
 140 
 
 75 
 
 30 
 
 90 
 
 70 
 
 85 
 
 60 
 
 140 
 
 95 
 
 
 
 140 
 
 100 
 
 105 
 
 25 
 
 90 
 
 80 
 
 160 
 
 110 
 
 75 
 
 130 
 
 150 
 
 20 
 
 280 
 
 85 
 
 90 
 
 75 
 
 20 
 
 90 
 
 75 
 
 60 
 
 70 
 
 140 
 
 80 
 
 80 
 
 100 
 
 100 
 
 100 
 
 60 
 
 150 
 
 150 
 
 100 
 
 120 
 
 105 
 
 100 
 
 210 
 
 40 
 
 2(i0 
 
 100 
 
 95 
 
 75 
 
 30 
 
 95 
 
 80 
 
 45 
 
 95 
 
 120 
 
 75 
 
 75 
 
 140 
 
 80 
 
 no 
 
 95 
 160 
 140 
 
 175 
 
 l.'iO 
 
 100 
 
 110 
 
 240 
 
 —300 
 
 220 
 
 100 
 
 100 
 
 75 
 
 30 
 
 100 
 
 50 
 
 30 
 
 60 
 
 145 
 
 100 
 
 70 
 
 120 
 
 80 
 
 90 
 
 140 
 
 140 
 
 100 
 
 140 
 50 
 60 
 
 190 
 30 
 
 100 
 
 -266' 
 
 140 
 
 
 
 250 
 
 105 
 
 —400 
 
 50 
 
 75 
 
 65 
 210 
 
 60 
 130 
 
 60 
 150 
 140 
 
 80 
 
 250 
 
 130 
 
 —300 
 
 155 
 
 145 
 
 1,305 
 -65 
 
 2,525 
 110 
 
 2,530 
 101 
 
 2,165 
 
 87 
 
 2,560 
 102 
 
 2,570 
 103 
 
 2,290 
 89 
 
 1,945 
 
 78 
 
 2,385 
 55 
 
 2,500 
 100 
 
 2,655 
 105 
 
 2,255 
 90 
 
 FEBRUARY, 1887 
 
 
 110 
 
 100 
 
 60 
 
 30 
 
 60 
 
 65 
 
 50 
 
 50 
 
 55 
 
 60 
 
 45 
 
 Var. fr. , cloudy. ]^ rain. 
 
 25 
 
 30 
 
 10 
 
 60 
 
 90 
 
 100 
 140 
 
 —100 
 
 — 60 
 
 50 
 
 10 
 
 100 
 
 50 
 
 NE. fr., snow, sleet, 
 
 100 
 
 160 
 
 75 
 
 —200 
 
 185 
 
 130 
 
 105 
 
 95 
 
 60 
 
 25 
 
 20 
 
 Var. It., rain. 
 
 90 
 
 90 
 
 95 
 
 90 
 
 100 
 
 100 
 
 100 
 
 100 
 
 130 
 
 150 
 
 130 
 
 105 
 
 NW. fr., cloudy. 
 
 70 
 
 115 
 
 .55 
 
 — 40 
 
 20 
 
 25 
 
 60 
 
 40 
 
 40 
 
 45 
 
 40 
 
 50 
 
 N. fr. , snow, sleet, rain. 
 
 
 140 
 
 160 
 
 190 
 
 175 
 
 140 
 
 100 
 
 50 
 
 10 
 
 
 
 
 
 
 
 N. fr.,raiii. 
 
 100 
 
 100 
 
 100 
 
 70 
 
 95 
 
 150 
 
 25 
 
 .50 
 
 60 
 
 50 
 
 95 
 
 100 
 
 NE.fr., rain, fog. 
 
 75 
 
 110 
 
 50 
 
 100 
 
 130 
 
 120 
 
 10 
 
 - 10 
 
 150 
 
 120 
 
 60 
 
 70 
 
 E. It., rain, fog. 
 
 60 
 
 75 
 
 50 
 
 55 
 
 45 
 
 70 
 
 80 
 
 65 
 
 90 
 
 80 
 
 110 
 
 110 
 
 NW.fr., fair. 
 
 60 
 
 100 
 
 95 
 
 110 
 
 100 
 
 — 60 
 
 —150 
 
 75 
 
 70 
 
 60 
 
 40 
 
 60 
 
 Var. It., rain. 
 
 40 
 
 
 
 
 
 
 
 0, 
 
 
 
 
 
 
 
 
 
 
 
 
 
 40 
 
 NW. high, rain. 
 
 40 
 
 55 
 
 40 
 
 40 
 
 45 
 
 45 
 
 40 
 
 40 
 
 50 
 
 50 
 
 50 
 
 50 
 
 NW. br., cloudy. 
 
 50 
 
 55 
 
 55 
 
 55 
 
 60 
 
 50 
 
 65 
 
 70 
 
 60 
 
 60 
 
 80 
 
 80 
 
 NW.fr., clear. 
 
 100 
 
 105 
 
 125 
 
 80 
 
 60 
 
 70 
 
 90 
 
 40 
 
 40 
 
 25 
 
 10 
 
 —100 
 
 NE. fr., snow, rain. 
 
 50 
 
 70 
 
 100 
 
 100 
 
 60 
 
 40 
 
 50 
 
 — 25 
 
 5 
 
 70 
 
 90 
 
 
 
 NE.fr., rain. 
 
 100 
 
 95 
 
 95 
 
 100 
 
 70 
 
 40 
 
 50 
 
 50 
 
 40 
 
 35 
 
 40 
 
 30 
 
 NE.fr., cloudy. 
 
 50 
 
 50 
 
 60 
 
 50 
 
 120 
 
 100 
 
 100 
 
 75 
 
 25 
 
 60 
 
 50 
 
 60 
 
 NW.lt., clear. 
 
 —150 
 
 10 
 
 60 
 
 20 
 
 200 
 
 — 10 
 
 -200 
 
 
 
 30 
 
 40 
 
 50 
 
 30 
 
 SW.fr., rain, t.d. 
 
 60 
 
 50 
 
 50 
 
 50 
 
 40 
 
 70 
 
 ■- 60 
 
 50 
 
 60 
 
 50 
 
 50 
 
 60 
 
 NW.fr., clear, [sleet. 
 
 
 300 
 
 70 
 
 40 
 
 60- 
 
 100 
 
 200 
 
 50 
 
 100 
 
 120 
 
 60 
 
 50 
 
 NE. fr., rain, snow, 
 
 60 
 
 65 
 
 90 
 
 150 
 
 140 
 
 150 
 
 120 
 
 60 
 
 60 
 
 70 
 
 80 
 
 80 
 
 E.fr.,rain. 
 
 55 
 
 70 
 
 60 
 
 60 
 
 60 
 
 70 
 
 60 
 
 50 
 
 65 
 
 60 
 
 70 
 
 ' 70 
 
 Var. It., fair. 
 
 200 
 
 180 
 
 190 
 
 180 
 
 190 
 
 140 
 
 80 
 
 60 
 
 100 
 
 60 
 
 70 
 
 100 
 
 Var. It., snow, rain. 
 
 60 
 
 80 
 
 85 
 
 80 
 
 70 
 
 60 
 
 60 
 
 60 
 
 60 
 
 60 
 
 60 
 
 70 
 
 SW.NW.br., rain. 
 
 75 
 
 90 
 
 60 
 
 80 
 
 65 
 
 100 
 
 100 
 
 140 
 
 75 
 
 140 
 
 ■ 120 
 
 100 
 
 NW.fr., fair. 
 
 —200 
 
 20 
 
 —175 
 
 — 50 
 
 200 
 
 150 
 
 
 
 —100 
 
 — 50 
 
 ^0 
 
 40 
 
 70 
 
 N. fr.,snow,rair. 
 
 75 
 
 60 
 
 55 
 
 60 
 
 40 
 
 50 
 
 60 
 
 100 
 
 80 
 
 50 
 
 50 
 
 60 
 
 NW. gale, clear. 
 
 90 
 
 70 
 
 70 
 
 70 
 
 70 
 
 70 
 
 70 
 
 70 
 
 70 
 
 70 
 
 80 
 
 95 
 
 NW, high, clear. 
 
 1,335 
 
 2,455 
 
 1,880 
 
 1,660 
 
 2,520 
 
 2,140 
 
 1,325 
 
 1,255 
 
 1,685 
 
 1,700 
 
 1,710 
 
 1,555 
 
 53 
 
 91 
 
 70 
 
 61 
 
 93 
 
 79 
 
 49 
 
 49 
 
 62 
 
 66 
 
 67 
 
 60 
 
 
200 
 
 MEMOIRS OP THE NATIONAL ACADEMY OP SCIENCES. 
 
 Table A. — Rourly records, drawn from continuous photographic 
 MARCH, 1887. 
 
 Day of montli. 
 
 1 a. m. 
 
 2 a. m. 
 
 3 a. m. 
 
 4 a.m. 
 
 5 a.m. 
 
 6 a.m. 
 
 7 a.m. 
 
 8 a.m. 
 
 9 a.m. 
 
 10 a. m. 
 
 11 a.m. 
 
 12 m. 
 
 1 
 
 100 
 
 35 
 
 40 
 
 
 
 30 
 
 — 50 
 100 
 150 
 
 50 
 75 
 65 
 50 
 90 
 
 40 
 45 
 60 
 60 
 60 
 40 
 110 
 
 - 
 50 
 60 
 50 
 70 
 30 
 
 
 
 50 
 
 50 
 
 100 
 
 55 
 35 
 30 
 
 60 
 
 
 100 
 
 100 
 
 , 50 
 
 60 
 
 50 
 
 50 
 
 100 
 50 
 40 
 40 
 60 
 60 
 60 
 45 
 
 110 
 
 60 
 80 
 50 
 50 
 30 
 
 30 
 50 
 
 100 
 
 70 
 40 
 30 
 
 50 
 50 
 75 
 
 140 
 60 
 75 
 50 
 50 
 
 100 
 50 
 50 
 50 
 60 
 50 
 60 
 40 
 
 120 
 
 200 
 50 
 70 
 50 
 60 
 25 
 —300 
 20 
 50 
 60 
 
 60 
 40 
 25 
 
 50 
 
 100 
 75 
 
 150 
 70 
 50 
 50 
 50 
 
 100 
 25 
 55 
 50. 
 60 
 50 
 50 
 45 
 
 110 
 
 200 
 40 
 60 
 50 
 40 
 25 
 
 40 
 50 
 60 
 
 100 
 
 25 
 
 26 
 
 
 
 50 
 
 150 
 20 
 
 130 
 
 100 
 50 
 60 
 50 
 
 100 
 25 
 55 
 55 
 70 
 50 
 50 
 50 
 
 100 
 
 200 
 AO 
 70 
 50 
 40 
 20 
 50 
 50 
 70 
 50 
 
 60 
 
 40 
 
 25 
 
 
 
 60 
 
 60 
 
 — 50 
 
 150 
 
 100 
 
 100 
 
 80 „ 
 
 50 
 
 150 
 
 25 
 
 , 70 
 
 55 
 
 90 
 
 60 
 
 50 
 
 55 
 
 150 
 
 —400 
 
 55 
 
 50 
 
 50 
 
 50 
 
 25 
 
 40 
 
 40 
 
 70 
 
 10 
 
 140 
 
 80 
 
 45 
 
 
 
 75 
 
 110 
 
 100 
 
 150 
 
 100 
 
 75 
 
 60 
 
 
 
 150 
 
 5 
 
 50 
 
 50 
 
 85 
 
 125 
 
 50 
 
 60 
 
 150 
 
 300 
 
 50 
 
 50 
 
 50 
 
 50 
 
 • 25 
 
 50 
 
 40 
 
 70 
 
 10 
 
 100 
 
 65 
 
 50 
 
 
 
 eo 
 
 150 
 
 
 
 < 125 
 
 150 
 75 
 50 
 
 — 80 
 90 
 10 
 50 
 
 
 
 
 
 200 
 
 50 
 
 . 65 
 
 75 
 
 —400 
 
 50 
 
 50 
 
 50 
 
 50 
 
 25 
 
 70 
 
 — 70 
 60 
 
 —100 
 
 160 
 
 60 
 
 25 
 
 
 
 70 
 
 105 
 
 
 120 
 
 150 
 50 
 60 
 
 — 80 
 100 
 
 50 
 
 50 
 
 
 
 
 
 100 
 50 
 50 
 
 200 
 
 CO 
 50 
 25 
 50 
 25 
 70 
 
 — 10 
 70 
 
 —100 
 
 180 
 
 5 
 
 30 
 
 
 
 70 
 
 75 
 
 
 
 100 
 
 200 
 
 50 
 
 50 
 
 — 40 
 100 
 
 50 
 40 
 5 
 60 
 40 
 50 
 50 
 
 200 
 
 —100 
 
 60 
 
 100 
 20 
 40 
 40 
 80 
 
 — 20 
 60 
 
 — 50 
 
 70 
 
 20 
 
 20 
 
 
 
 75 
 
 20 
 
 150 
 
 100 
 
 200 
 
 50 
 
 45 
 
 20 
 
 100 
 
 60 
 
 40 
 
 
 
 75 
 
 50 
 
 25 
 
 50 
 
 200 
 
 50 
 
 60 
 
 50 
 
 50 
 
 25 
 
 
 
 65 
 
 50 
 
 120 
 
 •100 
 
 150 
 
 50 
 
 50 
 
 25 
 
 100 
 
 50 
 
 50 
 
 5 
 
 100 
 
 100 
 
 25 
 
 50 
 
 220 
 
 60 
 
 60 
 
 2 
 
 3 
 
 4 
 
 5 
 
 6 
 
 7 
 
 H 
 
 9 
 
 10 
 
 11 
 
 12 
 
 la 
 
 14.. 
 
 15 
 
 16 . .. 
 
 17 
 
 18 
 
 19 
 
 ao 
 
 21 
 
 22 
 
 as 
 
 24 
 
 25 
 
 
 50 
 25 
 60 
 10 
 60 
 —100 
 
 45 
 50 
 
 ""'eo' 
 
 70 
 
 60 
 
 100 
 
 26 
 
 27 
 
 38 
 
 29 
 
 ao 
 
 31 
 
 
 1,610 
 54 
 
 1,605 
 54 
 
 1, 555 
 52 
 
 1,890 
 63 
 
 1, 955 
 65 
 
 1,390 
 46 
 
 2, 345 
 
 78 
 
 1,070 
 36 
 
 1,560 
 52 
 
 1,545 
 52 
 
 1,605 
 55 
 
 1,940 
 69 
 
 Means.. ... 
 
 
 APRIL, 1887. 
 
 1. 
 
 2. 
 
 3. 
 
 4. 
 
 5. 
 
 6. 
 
 7. 
 
 8. 
 
 9. 
 10. 
 11. 
 12. 
 13. 
 14. 
 15. 
 16. 
 17. 
 18. 
 19. 
 20. 
 21. 
 22. 
 23. 
 24. 
 25. 
 26. 
 27. 
 28. 
 29. 
 30. 
 
 Sums.. 
 Means. 
 
 - 50 
 100 
 
 60 
 30' 
 10 
 50 
 10 
 25 
 30 
 50 
 40 
 10 
 20 
 
 10 
 
 - 50 
 
 
 20 
 
 
 70 
 50 
 50 
 30 
 40 
 50 
 50 
 80 
 50 
 30 
 20 
 
 31 
 
 - 25 
 luO 
 
 60 
 40 
 25 
 50 
 25 
 25 
 40 
 30 
 50 
 20 
 10 
 10 
 20 
 
 - 50 
 
 
 20 
 
 5 
 90 
 50 
 50 
 30 
 40 
 70 
 
 - 50 
 90 
 70 
 40 
 25 
 
 960 
 33 
 
 — 15 
 
 100 
 , 60 
 30 
 25 
 60 
 40 
 50 
 50 
 
 
 50 
 20 
 10 
 
 
 15 
 50 
 
 
 20 
 
 — 5 
 80 
 50 
 25 
 10 
 40 
 
 100 
 —300 
 50 
 80 
 40 
 50 
 
 785 
 27 
 
 - 20 
 100 
 
 40 
 30 
 30 
 55 
 20 
 20 
 50 
 30 
 50 
 20 
 20 
 10 
 40 
 20 
 
 
 - 15 
 
 
 60 
 40 
 60 
 30 
 50 
 100 
 30 
 50 
 70 
 40 
 50 
 
 1,080 
 37 
 
 - 10 
 100 
 
 40 
 15 
 40 
 60 
 
 - 5 
 30 
 50 
 40 
 
 100 
 10 
 15 
 5 
 20 
 50 
 
 
 -100 
 50 
 80 
 50 
 40 
 60 
 50 
 100 
 50 
 
 -100 
 30 
 40 
 50 
 
 960 
 33 
 
 - 50 
 100 
 
 50 
 50 
 40 
 60 
 10 
 30 
 50 
 40 
 70 
 5 
 10 
 10 
 10 
 
 - 50 
 
 
 
 - 70 
 50 
 70 
 50 
 50 
 60 
 50 
 
 120 
 90 
 
 - 10 
 70 
 50 
 50 
 
 1,115 
 38 
 
 - 5 
 110 
 
 60 
 
 - 5 
 30 
 60 
 
 5 
 30 
 50 
 25 
 50 
 10 
 
 
 
 100 
 
 10 
 
 - 20 
 
 
 
 - 20 
 50 
 90 
 50 
 70 
 
 
 60 
 
 100 
 60 
 20 
 
 100 
 50 
 60 
 
 1,205 
 42 
 
 20 
 
 110 
 
 60 
 
 10 
 
 
 60 
 
 
 20 
 40 
 30 
 70 
 20 
 
 
 
 100 
 
 60 
 
 10 
 
 
 20 
 50 
 90 
 50 
 90 
 90 
 60 
 80 
 60 
 60 
 100 
 20 
 60 
 
 1,440 
 50 
 
 10 
 70 
 50 
 25 
 10 
 60 
 10 
 40 
 50 
 30 
 60 
 50 
 20 
 
 100 
 50 
 10 
 
 20 
 50 
 90 
 
 100 
 70 
 
 100 
 60 
 
 100 
 60 
 70 
 
 150 
 20 
 50 
 
 1, ,585 
 
 
 
 80 
 
 50 
 
 20 
 
 
 
 60 
 
 
 
 60 
 
 75 
 
 15 
 
 15 
 
 80 
 
 30 
 
 80 
 
 60 
 
 10 
 
 
 
 
 
 40 
 
 70 
 
 105 
 70 
 60 
 60 
 
 100 
 65 
 70 
 
 120 
 30 
 50 
 
 ,470 
 51 
 
 
 
 — 10 
 
 60 
 
 70 
 
 60 
 
 60 
 
 10 
 
 
 
 10 
 
 10 
 
 60 
 
 60 
 
 20 
 
 20 
 
 90 
 
 90 
 
 100 
 
 100 
 
 30 
 
 30 
 
 25 
 
 30 
 
 80 
 
 85 
 
 50 
 
 30 
 
 105 
 
 80 
 
 60 
 
 50 
 
 10 
 
 
 
 
 
 
 
 
 
 —200 
 
 40 
 
 60 
 
 70 
 
 70 
 
 110 
 
 150 
 
 60 
 
 60 
 
 80 
 
 80 
 
 60 
 
 
 150 
 
 130 
 
 65 
 
 70 
 
 60 
 
 60 
 
 130 
 
 80 
 
 
 
 — 20 
 
 30 
 
 30 
 
 1,605 
 55 
 
 1,275 
 46 
 
MEMOIRS OP TEE NATIONAL ACADEMY OF SCIENCES. 
 
 20 i 
 
 registration, at Baltimore, Md., 1885, 1886, and 1887 — Continued. 
 
 MARCH, 1887. 
 
 1 p.m. 
 
 2 p.m. 
 
 3 p.m. 
 
 4 p.m. 
 
 5 p.m. 
 
 6 p. m. 
 
 7 p.m. 
 
 8 p.m. 
 
 9 p.m. 
 
 10 p.m. 
 
 il p. m. 
 
 12 mid. 
 
 Eemarks. 
 
 90 
 
 65 
 
 70 
 
 100 
 
 120 
 
 70 
 
 60 
 
 70 
 
 50 
 
 60 
 
 60 
 
 50 
 
 Var. It. , cloudy^ 
 
 40 
 
 60 
 
 50 
 
 80 
 
 80 
 
 30 
 
 60 
 
 60 
 
 30 
 
 60 
 
 40 
 
 40 
 
 E. It., cloudy. 
 
 10 
 
 25 
 
 20 
 
 20 
 
 
 
 15 
 
 25 
 
 15 
 
 
 
 
 
 
 
 
 
 E. It., rain, sleet. 
 
 100 
 
 60 
 
 40 
 
 65 
 
 70 
 
 70 
 
 80 
 
 15 
 
 10 
 
 60 
 
 60 
 
 20 
 
 NE. br.,rain, snow. 
 
 100 
 
 50 
 
 — 75 
 
 —100 
 
 —200 
 
 —150 
 
 
 
 .50 
 
 50 
 
 25 
 
 40 
 
 50 
 
 E. fr., snow, sleet, rain. 
 
 
 80 
 
 20 
 
 15 
 
 40 
 
 —100 
 
 50 
 
 60 
 
 150 
 
 150 
 
 100 
 
 110 
 
 Var. It., rain. 
 
 80 
 
 150 
 
 150 
 
 150 
 
 150 
 
 150 
 
 140 
 
 80 
 
 150 
 
 175 
 
 200 
 
 .200 
 
 Do. 
 
 100 
 
 100 
 
 100 
 
 90 
 
 100 
 
 100 
 
 90 
 
 75 
 
 120 
 
 80 
 
 70 
 
 10 
 
 Var. It., clear. 
 
 
 
 —200 
 
 —175 
 
 ' 5 
 
 —100 
 
 —100 
 
 
 
 — 75 
 
 — 50 
 
 
 
 50 
 
 25 
 
 E. It., rain. 
 
 50 
 
 65 
 
 60 
 
 60 
 
 50 
 
 60 
 
 50 
 
 50 
 
 70 
 
 90 
 
 50 
 
 50 
 
 NW. br.,rain, clear. 
 
 45 
 
 50 
 
 45 
 
 45 
 
 50 
 
 50 
 
 50 
 
 50 
 
 55 
 
 45 
 
 40 
 
 45 
 
 NW. br., clear. 
 
 50 
 
 50 
 
 50 
 
 50 
 
 50 
 
 50 
 
 50 
 
 50 
 
 50 
 
 60 
 
 60 
 
 70 
 
 1)0. 
 
 
 100 
 
 75 
 
 80 
 
 80 
 
 80 
 
 75 
 
 90 
 
 80 
 
 —400 
 
 -400 
 
 50 
 
 Var. It., rain. 
 
 40 
 
 55 
 
 65 
 
 50 
 
 
 
 50 
 
 50 
 
 40 
 
 50 
 
 40 
 
 40 
 
 40 
 
 NW. br., cloudy. 
 
 50 
 
 45 
 
 50 
 
 60 
 
 60 
 
 50 
 
 50 
 
 50 
 
 50 
 
 50 
 
 45 
 
 45 
 
 Do. 
 
 — 20 
 
 25 
 
 25 
 
 25 
 
 
 
 50 
 
 50 
 
 50 
 
 50 
 
 50 
 
 50 
 
 60 
 
 NW.fr., fair. 
 
 50 
 
 100 
 
 100 
 
 50 
 
 50 
 
 50 
 
 100 
 
 60 
 
 150 
 
 170 
 
 170 
 
 170 
 
 NW. br.,8now. 
 
 50 
 
 40 
 
 50 
 
 20 
 
 20 
 
 50 
 
 50 
 
 50 
 
 50 
 
 50 
 
 50 
 
 50 
 
 NW. fr., cloudy. 
 
 50 
 
 .^0 
 
 50 
 
 50 
 
 50 
 
 25 
 
 30 
 
 40 
 
 50 
 
 45 
 
 45 
 
 50 
 
 NW. It., cloudy. 
 
 
 100 
 
 100 
 
 100 
 
 100 
 
 100 
 
 110 
 
 115 
 
 120 
 
 100 
 
 100 
 
 120 
 
 NW. fr.,fair. 
 
 120 
 
 100 
 
 2U0 
 
 200* 
 
 200 
 
 —250 
 
 -200 
 
 —200 
 
 —250 
 
 
 
 —300 
 
 
 
 N. fr.,rain, snow. 
 
 45 
 
 . 60 
 
 50 
 
 50 
 
 50 
 
 50 
 
 .50 
 
 50 
 
 60 
 
 45 
 
 45 
 
 55 
 
 NW. high, snow, rain. 
 
 45 
 
 .65 
 
 60 
 
 50 
 
 50 
 
 50 
 
 70 
 
 60 
 
 65 
 
 60 
 
 50 
 
 50 
 
 NW.br., fair. 
 
 100 
 
 220 
 
 180 
 
 160 
 
 100 
 
 80 
 
 90 
 
 80 
 
 60 
 
 50 
 
 50 
 
 45 
 
 Var. It., rain. 
 
 45 
 
 50 
 
 60 
 
 50 
 
 50 
 
 60 
 
 60 
 
 60 
 
 90 
 
 50 
 
 100 
 
 50 
 
 NW. br.,fair. 
 
 50 
 
 50 
 
 50 
 
 65 
 
 50 
 
 25 
 
 50 
 
 50 
 
 40 
 
 20 
 
 30 
 
 40 
 
 N. fr.,fair. - 
 
 
 50 
 
 40 
 
 — 20 
 
 30 
 
 40 
 
 - 20 
 
 100 
 
 70 
 
 —200 
 
 —300 
 
 
 
 E. fr.,rain. 
 
 90 
 
 40 
 
 25 
 
 100 
 
 —100 
 
 50 
 
 50 
 
 50 
 
 40 
 
 40 
 
 50 
 
 50 
 
 NNW.fr., rain, snow. 
 
 — 20 
 
 — 5 
 
 15 
 
 — 15 
 
 — 5 
 
 — 10 
 
 50 
 
 40 
 
 40 
 
 50 
 
 20 
 
 50 
 
 NW. high, cloudy. 
 
 50 
 
 50 
 
 45 
 
 40 
 
 40 
 
 40 
 
 60 
 
 60 
 
 70 
 
 60 
 
 75 
 
 100 
 
 NW.fr., fair. 
 
 —100 
 
 l.TO 
 
 150 
 
 
 
 
 
 100 
 
 100 
 
 120 
 
 80 
 
 120 
 
 100 
 
 60 
 
 NW. fr.,8now. 
 
 1,310 
 
 1,900 
 
 1.745 
 
 1, 695 
 
 1,235 
 
 935 
 
 1,530 
 
 1,465 
 
 1,650 
 
 1,205 
 
 790 
 
 1,705 
 
 49 
 
 61 
 
 56 
 
 55 
 
 40 
 
 30 
 
 49 
 
 47 
 
 55 
 
 40 
 
 26 
 
 57 
 
 
 APEIL, 1887. 
 
 — 20 
 
 40 
 
 40 
 
 70 
 
 70 
 
 50 
 
 50 
 
 90 
 
 60 
 
 40 
 
 60 
 
 100 
 
 NW.fr., snow. 
 
 70 
 
 70 
 
 60 
 
 60 
 
 40 
 
 50 
 
 50 
 
 70 
 
 40 
 
 20 
 
 50 
 
 60 
 
 NW. fr. , sno w, fair. 
 
 
 60 
 
 60 
 
 65 
 
 80 
 
 80 
 
 80 
 
 50 
 
 50 
 
 50 
 
 50 
 
 25 
 
 SW.fr.,t!lear. 
 
 5 
 
 5 
 
 
 
 5 
 
 5 
 
 10 
 
 
 
 5 
 
 30 
 
 30 
 
 — 50 
 
 —300 
 
 SW.br., rain. 
 
 
 
 — 5 
 
 — 5 
 
 10 
 
 - 10 
 
 ' , 5 
 
 50 
 
 25 
 
 50 
 
 50 
 
 50 
 
 ^0 
 
 NW.br., snow. 
 
 60 
 
 60 
 
 50 
 
 45 
 
 40 
 
 .;. 30 
 
 40 
 
 100 
 
 100 
 
 60 
 
 50 
 
 — 5 
 
 NW.br., fair. 
 
 
 
 25 
 
 25 
 
 25 
 
 
 
 ■ 50 
 
 20 
 
 60 
 
 50 
 
 50 
 
 10 
 
 25 
 
 E. It., cloudy. 
 
 100 
 
 110 
 
 90 
 
 90 
 
 100 
 
 80 
 
 90 
 
 70 
 
 45 
 
 45 
 
 50 
 
 25 
 
 Do.- 
 
 100 
 
 120 
 
 150 
 
 140 
 
 90 
 
 50 
 
 50 
 
 30 
 
 30 
 
 50 
 
 40 
 
 50 
 
 Var. It., clear. 
 
 
 60 
 
 60 
 
 50 
 
 ' 60 
 
 50 
 
 50 
 
 50 
 
 60 
 
 40 
 
 40 
 
 40 
 
 Do. 
 
 60 
 
 65 
 
 50 
 
 50 
 
 30 
 
 30 
 
 30 
 
 20 
 
 20 
 
 25 
 
 15 
 
 10 
 
 W.fr., clear. 
 
 65 
 
 110 
 
 120 
 
 100 
 
 90 
 
 75 
 
 80 
 
 50 
 
 50 
 
 25 
 
 25 
 
 25 
 
 E. It., clear. 
 
 40 
 
 30 
 
 40 
 
 60 
 
 30 
 
 20 
 
 20 
 
 10 
 
 20 
 
 20 
 
 5 
 
 10 
 
 E. It., fair. 
 
 90 
 
 120 
 
 105 
 
 50 
 
 105 
 
 105 
 
 60 
 
 40 
 
 10 
 
 10 
 
 20 
 
 10 
 
 SE.lt., fair. 
 
 60 
 
 100 
 
 100 
 
 80 
 
 70 
 
 70 
 
 25 
 
 - 20 
 
 —100 
 
 —100 
 
 —300 
 
 —250 
 
 SE.fr.,rain,t.8. 
 
 
 
 — 5 
 
 — 20 
 
 — 10 
 
 — 5 
 
 
 
 10 
 
 10 
 
 
 
 
 
 
 
 
 
 NW.br., rain. 
 
 50 
 
 40 
 
 40 
 
 50 
 
 40 
 
 30 
 
 30 
 
 30 
 
 30 
 
 15 
 
 — 10 
 
 5 
 
 NW.fr., rain. 
 
 —350 
 
 
 
 10 
 
 10 
 
 —200 
 
 200 
 
 50 
 
 
 
 
 
 
 
 10, 
 
 
 
 NE. fr. , rain. 
 
 15 
 
 30 
 
 40 
 
 50 
 
 60 
 
 60 
 
 80 
 
 100 
 
 120 
 
 100 
 
 110 
 
 100 
 
 N.fr.,rain. 
 
 60 
 
 120 
 
 100 
 
 140 
 
 120 
 
 80 
 
 70 
 
 90 
 
 130 
 
 100 
 
 100 
 
 50 
 
 N. It., fair. 
 
 100 
 
 150 
 
 120 
 
 150 
 
 1.50 
 
 100 
 
 80 
 
 60 
 
 70 
 
 50 
 
 50 
 
 90 
 
 S. It., clear. 
 
 80 
 
 70 
 
 120 
 
 —150 
 
 —150 
 
 —300 
 
 .-200 
 
 — 50 
 
 
 
 10 
 
 10 
 
 20 
 
 Var. It., rain. 
 
 60 
 
 50 
 
 80 
 
 70 
 
 40 
 
 100 
 
 — 70 
 
 40 
 
 40 
 
 —100 
 
 50 
 
 40 
 
 SE.fr., rain. 
 
 
 100 
 
 100 
 
 90 
 
 80 
 
 100 
 
 100 
 
 105 
 
 100 
 
 100 
 
 60 
 
 60 
 
 NW.fr., clear. 
 
 100 
 
 — 50 
 
 — 50 
 
 —100 
 
 —250 
 
 —300 
 
 —300 
 
 200 
 
 —150 
 
 -100 
 
 — 10 
 
 —100 
 
 NE.fr., rain. 
 
 70 
 
 80 
 
 70 
 
 60 
 
 70 
 
 50 
 
 50 
 
 50 
 
 60 
 
 50 
 
 50 
 
 60 
 
 W.fr., Tain. 
 
 60 
 
 60 
 
 60 
 
 60 
 
 170 
 
 50 
 
 50 
 
 100 
 
 100 
 
 100 
 
 30 
 
 40 
 
 Var. It., rain. 
 
 100 
 
 120 
 
 —200 
 
 —100 
 
 —100 
 
 
 
 10 
 
 30 
 
 40 
 
 30 
 
 40 
 
 30 
 
 S. ft., rain. 
 
 20 
 
 20 
 
 20 
 
 30 
 
 30 
 
 30 
 
 —100 
 
 
 
 — 10 
 
 10 
 
 10 
 
 20 
 
 NW.br., rain. 
 
 
 
 20 
 
 25 
 
 — 50 
 
 — 20 
 
 — 20 
 
 50 
 
 50 
 
 60 
 
 60 
 
 40 
 
 40 
 
 NW.br., cloudy. 
 
 995 
 
 1,775 
 
 1,420 
 
 1,200 
 
 835 
 
 935 
 
 605 
 
 1,515 
 
 1,105 
 
 840 
 
 645 
 
 330 
 
 37 
 
 59 
 
 47 
 
 40 
 
 28 
 
 31 
 
 20 
 
 50 
 
 38 
 
 29 
 
 22 
 
 11 
 
 
202 
 
 MEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES. 
 
 Table A. — Hourly records, drawn from continuous photographic 
 
 MAY, 1887. 
 
 Day of month. 
 
 1 a.m. 
 
 2 a.m. 
 
 3 a.m. 
 
 4 a.m. 
 
 5a.m. 
 
 a a.m. 
 
 7 a.m. 
 
 8 a. m. 
 
 9 a.m. 
 
 10 a.m. 
 
 11 a, m. 
 
 12 m. 
 
 1 
 
 55 
 50 
 
 
 10 
 
 5 
 10 
 15 
 10 
 40 
 65 
 10 
 
 
 10 
 20 
 30 
 
 5 
 — 5 
 10 
 10 
 20 
 60 
 20 
 90 
 50 
 50 
 50 
 40 
 40 
 
 
 
 60 
 60 
 10 
 10 
 
 
 10 
 15 
 10 
 70 
 60 
 100 
 
 
 20 
 
 
 20 
 
 5 
 
 
 10 
 10 
 30 
 60 
 20 
 90 
 30 
 40 
 50 
 20 
 50 
 
 
 
 50 
 30 
 10 
 15 
 
 
 
 15 
 
 - 50 
 
 10 
 
 
 
 65 
 
 120 
 
 
 20 
 10 
 20 
 
 5 
 
 
 40 
 10 
 40 
 60 
 40 
 90 
 50 
 30 
 60 
 20 
 55 
 
 
 
 55 
 50 
 10 
 15 
 
 
 10 
 70 
 — 10 
 10 
 50 
 150 
 
 
 15 
 30 
 15 
 
 
 
 
 20 
 10 
 40 
 75 
 40 
 90 
 30 
 SO 
 50 
 30 
 55 
 
 
 
 60 
 
 50 
 
 
 
 15 
 
 
 
 
 
 — 10 
 
 — 5 
 
 — 10 
 50 
 
 110 
 
 
 — 5 
 30 
 15 
 
 
 
 
 35 
 
 5 
 35 
 80 
 30 
 90 
 35 
 30 
 100 
 30 
 50 
 
 
 
 65 
 50 
 
 
 10 
 
 
 15 
 — 20 
 10 
 20 
 15 
 110 
 
 
 
 
 20 
 20 
 
 
 
 
 20 
 
 5 
 50 
 90 
 50 
 90 
 35 
 60 
 105 
 30 
 25 
 
 
 
 80 
 
 60 
 
 
 
 5 
 
 20 
 
 
 
 — 20 
 30 
 70 
 25 
 
 '100 
 
 
 
 
 
 20 
 
 20 
 
 
 
 — 10 
 10 
 10 
 50 
 80 
 50 
 60 
 35 
 60 
 60 
 40 
 20 
 
 
 
 90 
 
 65 
 
 
 
 30 
 5 
 
 15 
 —100 
 
 - 50 
 35 
 
 100 
 
 
 
 
 
 15 
 
 10 
 
 5 
 
 — 50 
 30 
 
 5 
 90 
 80 
 60 
 50 
 85 
 60 
 20 
 40 
 
 
 
 90 
 
 90 
 
 5 
 
 8^0 
 10 
 30 
 
 — 70 
 —100 
 
 100 
 
 100 
 
 
 
 — 5 
 20 
 10 
 70 
 
 — 60 
 30 
 10 
 90 
 80 
 60 
 70 
 40 
 60 
 30 
 80 
 
 
 
 
 90 
 
 '— "io' 
 
 10 
 
 100 
 
 15 
 
 20 
 
 — 60 
 60 
 10 
 60 
 60 
 
 — 50 
 20 
 10 
 80 
 
 
 
 10 
 75 
 60 
 60 
 70 
 
 — 50 
 50 
 60 
 60 
 
 
 
 
 100 
 
 100 
 
 120 
 
 10 
 
 100 
 
 70 
 
 30 
 
 15 
 
 
 
 
 
 60 
 
 120 
 
 60 
 
 20 
 
 20 
 
 80 
 
 110 
 
 10 
 
 10 
 
 70 
 
 70 
 
 60 
 
 70 
 
 — 50 
 
 50 
 
 60 
 
 40 
 
 
 
 
 
 100 
 
 100 
 
 110 
 
 10 
 
 60 
 
 75 
 
 50 
 
 — 20 
 
 '"iso 
 
 70 
 
 60 
 
 20 
 
 
 
 100 
 
 10 
 
 5 
 
 
 
 70 
 
 60 
 
 70 
 
 100 
 
 50 
 
 60 
 
 30 
 
 
 
 
 
 2 
 
 3 
 
 4 
 
 5 
 
 6 
 
 7 
 
 8 
 
 9 
 
 10 
 
 11 
 
 12 
 
 13 
 
 14 
 
 15 
 
 IH 
 
 17 
 
 18 
 
 19 
 
 20, 
 
 31 
 
 22 
 
 23 
 
 24 
 
 25 
 
 26 : 
 
 27 
 
 28 
 
 29 
 
 30 
 
 31 
 
 105 
 
 80 
 
 100 
 
 70 
 
 80 
 
 60 
 
 70 
 
 60 
 
 
 
 
 
 
 
 
 
 
 875 
 31 
 
 945 
 34 
 
 915 
 33 
 
 1,010 
 36 
 
 900 
 32 
 
 935 
 33 
 
 945 
 34 
 
 700 
 26 
 
 925 
 36 
 
 810 
 31 
 
 1,405 
 52 
 
 1,340 
 56 
 
 
 
 JUNE, 1887. 
 
 1 
 
 2 
 
 3 
 
 4 
 
 5 
 
 6 
 
 7 
 
 8 
 
 9 
 
 10 
 
 11 
 
 \-l 
 
 13 
 
 14 ;... 
 
 15. 
 
 10 
 
 17 
 
 18 
 
 19 
 
 SiO 
 
 21 
 
 22 
 
 23 
 
 24 
 
 25 
 
 yfi 
 
 27 
 
 30 , 
 
 Sums. 
 Means 
 
 —220 
 
 — 50 
 
 
 
 10 
 
 30 
 
 .30 
 
 100 
 
 120 
 
 120 
 
 80 
 
 70 
 
 90 
 
 60 
 
 70 
 
 85 
 
 80 
 
 70 
 
 —150 
 
 70 
 
 120 
 
 100 
 
 110 
 
 150 
 
 60 
 
 
 
 
 
 
 
 60 
 
 70 
 
 70 
 
 40 
 
 50 
 
 60 
 
 70 
 
 80 
 
 
 50 
 
 50 
 
 50 
 
 50 
 
 60 
 
 70 
 
 70 
 
 50 
 
 40 
 
 40 
 
 40 
 
 40 
 
 70 
 
 100 
 
 50 
 
 50 
 
 50 
 
 50 
 
 60 
 
 65 
 
 60 
 
 60 
 
 70 
 
 70 
 
 55 
 
 60 
 
 60 
 
 60 
 
 - 30 
 
 30 
 
 70 
 
 -350 
 
 —300 
 
 —150 
 
 
 100 
 
 10 
 
 20 
 
 
 
 — 20 
 
 — 30 
 
 
 
 — 10 
 
 — 40 
 
 20 
 
 20 
 
 10 
 
 
 
 40 
 
 30 
 
 30 
 
 40 
 
 50 
 
 30 
 
 40 
 
 100 
 
 100 
 
 70 
 
 110 
 
 120 
 
 80 
 
 80 
 
 60 
 
 40 
 
 55 
 
 55 
 
 50 
 
 50> 
 
 40 
 
 40 
 
 30 
 
 40 
 
 30 
 50 
 
 20 
 50 
 
 40 
 50 
 
 60 
 10 
 
 50 
 60 
 
 50 
 60 
 
 50 
 50 
 
 60 
 60 
 
 
 
 
 60 
 — 10 
 
 40 
 
 — 60 
 
 — 60 
 
 50 
 
 50 
 
 40 
 
 30 
 
 30 
 
 30 
 
 30 
 
 30 
 
 20 
 
 20 
 
 20 
 
 
 70 
 
 60 
 
 60 
 
 50 
 
 60 
 
 70 
 
 fiO 
 
 50 
 
 35 
 
 
 
 15 
 
 20 
 
 
 
 
 
 " 
 
 — 10 
 
 20 
 
 30 
 
 
 
 
 
 20 
 
 — 10 
 
 — 10 
 
 50 
 
 
 
 
 
 
 
 
 
 10 
 
 20 
 
 50 
 
 40 
 
 50 
 
 50 
 
 50 
 
 40 
 
 90 
 
 90 
 
 60 
 
 60 
 
 60 
 
 60 
 
 70 
 
 60 
 
 50 
 
 60 
 
 60 
 
 60 
 
 30 
 
 10 
 
 
 
 
 
 
 
 10 
 
 
 
 
 
 
 
 — 10 
 
 — 20 
 
 30 
 
 10 
 
 40 
 
 60 
 
 50 
 
 60 
 
 50 
 
 40 
 
 30 
 
 40 
 
 50 
 
 50 
 
 
 15 
 
 
 
 20 
 
 50 
 
 30 
 
 40 
 
 80 
 
 70 
 
 50 
 
 50 
 
 40 
 
 
 80 
 
 80 
 
 90 
 
 70 
 
 110 
 
 160 
 
 110 
 
 110 
 
 80 
 
 200 
 
 100 
 
 
 70 
 200 
 
 60 
 60 
 
 100 
 70 
 
 130 
 
 80 
 
 130 
 
 80 
 
 120 
 
 80 
 
 130 
 80 
 
 110 
 110 
 
 210 
 120 
 
 180 
 50 
 
 180 
 60 
 
 130 
 
 70 
 
 160 
 
 —175 
 
 — 5 
 
 40 
 
 50 
 
 no 
 
 110 
 
 110 
 
 100 
 
 100 
 
 170 
 
 200 
 
 100 
 
 70 
 
 70 
 
 80 
 
 70 
 
 110 
 
 105 
 
 90 
 
 105 
 
 80 
 
 70 
 
 .'■>0 
 75 
 
 30 
 
 40 
 
 40 
 
 40 
 
 50 
 
 60 
 
 60 
 
 50 
 
 05 
 
 50 
 
 60 
 
 60 
 
 70 
 
 65 
 
 75 
 
 60 
 
 70 
 
 80 
 
 90 
 
 75 
 
 60 
 
 60 
 
 10 
 
 10 
 
 15 
 
 10 
 
 10 
 
 30 
 
 50 
 
 50 
 
 50 
 
 30 
 
 40 
 
 40 
 60 
 50 
 80 
 
 75 
 
 75 
 
 70 
 
 " 50 
 
 65 
 
 80 
 
 80 
 
 60 
 
 60 
 
 60 
 
 40 
 
 50 
 
 60 
 
 60 
 
 50 
 
 45 
 
 40 
 
 55 
 
 60 
 
 65 
 
 60 
 
 60 
 
 50 
 
 50 
 
 40 
 
 40 
 
 60 
 
 50 
 
 70 
 
 50 
 
 50 
 
 80 
 
 80 
 
 1,035 
 34 
 
 1,250 
 42 
 
 1, 325 
 44 
 
 1,345 
 45 
 
 1,505 
 50 
 
 1, 515 
 50 
 
 1,850 
 62 
 
 1,495 
 50 
 
 53 
 
 1,520 
 fl2 
 
 1,655 
 59 
 
 1,465 
 61 
 
MEMOIRS OP THE NATIONAL ACADEMY OF SCIENCES. 
 
 203 
 
 registration, at Baltimore, Md., 1885, 1886, and 1887 — Continued. 
 
 MAY, 1887. 
 
 1 p.m. 
 
 2 p.m. 
 
 3 p.m. 
 
 4 p.m. 
 
 6 p.m. 
 
 6 p.m. 
 
 7 p.m. 
 
 8 p.m. 
 
 9 p.m. 
 
 10 p. m. 
 
 11 p. m. 
 
 12 mid.^ 
 
 Remarks. 
 
 70 
 
 90 
 
 100 
 
 65 
 
 65 
 
 60 
 
 60 
 
 60 
 
 80 
 
 80 
 
 60 
 
 60 
 
 Var.lt., rain. 
 
 XOO 
 
 100 
 
 100 
 
 100 
 
 110 
 
 70 
 
 40 
 
 35 
 
 35 
 
 20 
 
 20 
 
 20 
 
 SE. ft., fair. 
 
 70 
 
 105 
 
 110 
 
 50 
 
 25 
 
 
 
 50 
 
 50 
 
 50 
 
 — 10 
 
 10 
 
 10 
 
 Do. 
 
 5 
 
 15 
 
 100 
 
 100 
 
 110 
 
 120 
 
 50 
 
 10 
 
 15 
 
 15 
 
 25 
 
 5 
 
 SE. fr., fair, lightning. 
 
 75 
 
 120 
 
 25 
 
 25 
 
 25 
 
 25 
 
 — 10 
 
 — 10 
 
 10 
 
 10 
 
 10 
 
 10 
 
 E. It., rain. 
 
 90 
 
 110 
 
 60 
 
 
 
 —300 
 
 70 
 
 40 
 
 50 
 
 30 
 
 10 
 
 
 
 10 
 
 SE. fr., rain, t, s. 
 
 
 
 150 
 
 60 
 
 70 
 
 —200 
 
 — 50 
 
 10 
 
 15 
 
 30 
 
 25 
 
 
 
 10 
 
 SW. fr., rain, t. s. 
 
 
 200 
 
 —100 
 
 —200 
 
 60 
 
 —100 
 
 —200 
 
 — 5 
 
 
 
 
 
 15 
 
 15 
 
 NE. fr.,rain, t. a. 
 
 80 
 
 30 
 
 45 
 
 15 
 
 90 
 
 100 
 
 100 
 
 20 
 
 50 
 
 50 
 
 50 
 
 65 
 
 E. fr.,rain. 
 
 100 
 
 100 
 
 110 
 
 110 
 
 90 
 
 75 
 
 80 
 
 90 
 
 90 
 
 70 
 
 100 
 
 100 
 
 Do. 
 
 
 200 
 
 105 
 
 
 
 150 
 
 70 
 
 80 
 
 65 
 
 60 
 
 
 
 
 
 
 
 SE.fr., clear. 
 
 150 
 
 160 
 
 80 
 
 60 
 
 30 
 
 100 
 
 100 
 
 10 
 
 — 10 
 
 10 
 
 30 
 
 15 
 
 E.fr., clear. 
 
 70 
 
 160 
 
 170 
 
 170 
 
 150 
 
 
 
 - 50 
 
 — 50 
 
 
 
 
 
 25 
 
 40 
 
 Do. 
 
 100 
 
 100 
 
 100 
 
 90 
 
 90 
 
 70 
 
 70 
 
 100 
 
 30 
 
 30 
 
 30 
 
 40 
 
 NE.fr., clear. 
 
 5 
 
 10 
 
 30 
 
 30 
 
 60 
 
 60 
 
 60 
 
 65 
 
 10 
 
 5 
 
 10 
 
 10 
 
 SE. fr., clear. 
 
 100 
 
 160 
 
 90 
 
 105 
 
 110 
 
 60 
 
 50 
 
 - 20 
 
 5 
 
 
 
 
 
 
 
 SE.lt., clear. 
 
 110 
 
 160 
 
 100 
 
 130 
 
 80 
 
 25 
 
 
 
 10 
 
 
 
 60 
 
 — 20 
 
 10 
 
 NE.fr., hazy. 
 
 10 
 
 10 
 
 100 
 
 130 
 
 150 
 
 130 
 
 70 
 
 50 
 
 50 
 
 10 
 
 30 
 
 10 
 
 NE.fr., cloudy. 
 
 10 
 
 100 
 
 100 
 
 120 
 
 120 
 
 80 
 
 60 
 
 50 
 
 10 
 
 20 
 
 20 
 
 20 
 
 E. It. , clear. 
 
 fi 
 
 
 
 
 
 
 
 
 
 60 
 
 . 70 
 
 70 
 
 60 
 
 75 
 
 75 
 
 50 
 
 Var.lt., hazy. 
 
 80 
 
 105 
 
 105 
 
 70 
 
 80 
 
 60 
 
 50 
 
 .50 
 
 50 
 
 30 
 
 30 
 
 30 
 
 Var.lt., cloudy. 
 
 35 
 
 60 
 
 65 
 
 70 
 
 60 
 
 60 
 
 70 
 
 80 
 
 90 
 
 80 
 
 90 
 
 80 
 
 Var.lt., fog, clear. 
 
 100 
 
 i;^o 
 
 110 
 
 75 
 
 90 
 
 50 
 
 50 
 
 50 
 
 50 
 
 50 
 
 50 
 
 50 
 
 S. It., fair. 
 
 110 
 
 150 
 
 100 
 
 100 
 
 -200 
 
 —300 
 
 —200 
 
 60 
 
 
 
 50 
 
 50 
 
 70 
 
 Var. It., rain. 
 
 105 
 
 180 
 
 180 
 
 110 
 
 —300 
 
 100 
 
 
 
 80 
 
 60 
 
 60 
 
 50 
 
 40 
 
 Var.br., rain, t. s. 
 
 50 
 
 60 
 
 70 
 
 50 
 
 200 
 
 
 
 - 30 
 
 60 
 
 40 
 
 40 
 
 50 
 
 70 
 
 NW.br.,rain,t.8. 
 
 50 
 
 40 
 
 40 
 
 60 
 
 150 
 
 50 
 
 50 
 
 50 
 
 50 
 
 50 
 
 45 
 
 40 
 
 NW.fr., rain. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 Do. 
 N.fr.,fair. 
 SE.fr., clear. 
 
 220 
 
 275 
 
 230 
 
 210 
 
 170 
 
 140 
 
 140 
 
 120 
 
 150 
 
 150 
 
 130 
 
 iio 
 
 60 
 
 100 
 
 100 
 
 80 
 
 80 
 
 — 50 
 
 —100 
 
 —250 
 
 —300 
 
 —250 
 
 —300 
 
 — 50 
 
 E. br.,rain. 
 
 1,955 
 
 3,170 
 
 2,485 
 
 1,995 
 
 2, 420 
 
 1,135 
 
 760 
 
 965 
 
 795 
 
 740 
 
 685 
 
 940 
 
 72 
 
 109 
 
 86 
 
 69 
 
 83 
 
 39 
 
 26 
 
 33 
 
 27 
 
 26 
 
 24 
 
 32 
 
 
 JUNE, 1887. 
 
 110 
 
 130 
 
 160 
 
 200 
 
 180 
 
 110 
 
 100 
 
 80 
 
 70 
 
 70 
 
 60 
 
 60 
 
 Var. 11., rain, lightning. 
 
 150 
 
 120 
 
 110 
 
 170 
 
 160 
 
 120 
 
 200 
 
 -300 
 
 100 
 
 —300 
 
 60 
 
 70 
 
 SW. br., rain, t. 8. 
 
 40 
 
 55 
 
 50 
 
 45 
 
 65 
 
 65 
 
 60 
 
 60 
 
 50 
 
 50 
 
 50 
 
 40 
 
 NW.fr., rain. 
 
 30 
 
 70 
 
 50 
 
 50 
 
 20 
 
 40 
 
 100 
 
 100 
 
 100 
 
 100 
 
 70 
 
 70 
 
 NW. fr., fair. 
 
 70 
 
 70 
 
 60 
 
 65 
 
 50 
 
 40 
 
 40 
 
 35 
 
 40 
 
 30 
 
 50 
 
 50 
 
 E.fr., cloudy. 
 
 60 
 
 120 
 
 110 
 
 110 
 
 120 
 
 90 
 
 85 
 
 60 
 
 65 
 
 40 
 
 50 
 
 —150 
 
 E. Ir., rain. 
 
 50 
 
 35 
 
 40 
 
 40 
 
 55 
 
 50 
 
 55 
 
 50 
 
 60 
 
 50 
 
 25 
 
 60 
 
 Do. 
 
 80 
 
 90 
 
 100 
 
 120 
 
 80 
 
 80 
 
 80 
 
 100 
 
 80 
 
 80 
 
 80 
 
 80 
 
 Var.lt., cloudy. 
 
 50 
 
 60 
 
 —200 
 
 — 70 
 
 
 
 100 
 
 20 
 
 50 
 
 50 
 
 50 
 
 40 
 
 40 
 
 W.fr., cloudy, t.s. 
 
 40 
 
 100 
 
 100 
 
 90 
 
 70 
 
 50 
 
 50 
 
 50 
 
 60 
 
 50 
 
 50 
 
 , 40 
 
 NE. fr., cloudy. 
 
 — 20 
 
 — 50 
 
 20 
 
 50 
 
 50 
 
 50 
 
 60 
 
 40 
 
 60 
 
 40 
 
 30 
 
 50 
 
 E.br., clear. 
 
 
 50 
 
 50 
 
 70 
 
 40 
 
 50 
 
 30 
 
 30 
 
 .60 
 
 50 
 
 70 
 
 70 
 
 NE. fr., clear. 
 
 20 
 
 20 
 
 35 
 
 40 
 
 20 
 
 40 
 
 40 
 
 50 
 
 50 
 
 30 
 
 20 
 
 10 
 
 N. fr., clear. 
 
 50 
 
 50 
 
 40 
 
 40 
 
 140 
 
 110 
 
 70 
 
 60 
 
 40 
 
 50 
 
 40 
 
 10 
 
 NE.lt., clear. 
 
 60 
 
 70 
 
 150 
 
 160 
 
 130 
 
 110 
 
 90 
 
 90 
 
 130 
 
 100 
 
 100 
 
 100 
 
 E.fr., clear. 
 
 50 
 
 70 
 
 80 
 
 60 
 
 50 
 
 45 
 
 60 
 
 50 
 
 — 10 
 
 10 
 
 20 
 
 50 
 
 SW. It., clear. 
 
 — 20 
 
 — r, 
 
 - 5 
 
 
 
 - 10 
 
 
 
 5 
 
 10 
 
 10 
 
 
 
 10 
 
 
 
 W. It., fair, lightning. 
 
 30 
 
 40 
 
 40 
 
 —200 
 
 —200 
 
 - 10 
 
 20 
 
 — 5 
 
 10 
 
 
 
 
 
 —110 
 
 Var. br. , rain, hail, t. s. 
 
 
 150 
 
 1.50 
 
 150 
 
 160 
 
 100 
 
 70 
 
 200 
 
 200 
 
 160 
 
 80 
 
 70 
 
 Var.br., rain, t.s. 
 
 90 
 
 100 
 
 120 
 
 110 
 
 130 
 
 200 
 
 200 
 
 150 
 
 120 
 
 lOO 
 
 80 
 
 70 
 
 W. br., rain, t.s. 
 
 100 
 
 155 
 
 200 
 
 140 
 
 115 
 
 120 
 
 
 
 10 
 
 30 
 
 50 
 
 —100 
 
 
 
 S. br,, rain, t. a. 
 
 60 
 
 200 
 
 —200 
 
 60 
 
 70 
 
 110 
 
 300 
 
 -200 
 
 300 
 
 
 
 —200 
 
 —800 
 
 Var. br., rain, t. s. 
 
 100 
 
 140 
 
 160 
 
 160 
 
 200 
 
 ISO 
 
 205 
 
 15u 
 
 160 
 
 120 
 
 125 
 
 105 
 
 Var.lt., rain. 
 
 70 
 
 80 
 
 90 
 
 70 
 
 60 
 
 50 
 
 60 
 
 50 
 
 50 
 
 30 
 
 25 
 
 20 
 
 W.fr., fair. 
 
 70 
 
 100 
 
 105 
 
 110 
 
 80 
 
 60 
 
 75 
 
 100 
 
 30 
 
 60 
 
 60 
 
 60 
 
 N.fr., fair. 
 
 
 70 
 
 50 
 
 60 
 
 70 
 
 70 
 
 25 
 
 60 
 
 30 
 
 30 
 
 20 
 
 10 
 
 Var. It., fair. 
 
 40 
 
 60 
 
 70 
 
 75 
 
 120 
 
 160 
 
 130 
 
 160 
 
 80 
 
 80 
 
 80 
 
 80 
 
 Do. 
 
 40 
 
 150 
 
 80 
 
 150 
 
 160 
 
 140 
 
 80 
 
 120 
 
 90 
 
 80 
 
 80 
 
 60 
 
 Do. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 60 
 
 120 
 
 130 
 
 80 
 
 70 
 
 40 
 
 SW.tr., clear. 
 
 70 
 
 90 
 
 90 
 
 95 
 
 80 
 
 80 
 
 80 
 
 80 
 
 120 
 
 100 
 
 100 
 
 90 
 
 S. It., clear. 
 
 1,490 
 
 1,390 
 
 1,905 
 
 2,215 
 
 2,265 
 
 2,410 
 
 2,450 
 
 1,610 
 
 2,365 
 
 1,390 
 
 1,245 
 
 945 
 
 55 
 
 46 
 
 64 
 
 74 
 
 76 
 
 80 
 
 82 
 
 54 
 
 79 
 
 47 
 
 42 
 
 32 
 
 
204 
 
 MEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES. 
 
 Table A. — Hourly records, drawn from continuous photographic 
 JULY, 1887. 
 
 Day of month. 
 
 1 a. m. 
 
 2 a. m. 
 
 3 a. m. 
 
 4 a.m. 
 
 5 a.m. 
 
 6 a.m. 
 
 7 a.m. 
 
 8 a.m. 
 
 9 3.m. 
 
 10 a. m. 
 
 11 a. m. 
 
 12 m. 
 
 1 
 
 100 
 90 
 80 
 
 100 
 60 
 90 
 
 105 
 80 
 
 130 
 
 100 
 50 
 40 
 50 
 40 
 40 
 30 
 30 
 20 
 
 — 10 
 
 
 70 
 
 — 5 
 60 
 
 
 70 
 80 
 60 
 100 
 40 
 40 
 70 
 
 110 
 90 
 80 
 90 
 60 
 70 
 70 
 80 
 90 
 70 
 50 
 40 
 50 
 40 
 30 
 30 
 30 
 30 
 20 
 
 90 
 — 5 
 50 
 50 
 75 
 80 
 80 
 100 
 40 
 60 
 70 
 
 90 
 80 
 
 . 80 
 90 
 50 
 70 
 70 
 70 
 60 
 70 
 50 
 50 
 50 
 50 
 50 
 30 
 30 
 30 
 200 
 
 60 
 
 — 10 
 50 
 6ft 
 75 
 80 
 70 
 40 
 40 
 30 
 80 
 
 90 
 80 
 60 
 
 100 
 —100 
 
 105 
 70 
 
 100 
 40 
 80 
 50 
 60 
 50 
 50 
 30 
 25 
 30 
 30 
 
 300 
 
 60 
 — 10 
 50 
 40 
 75 
 70 
 
 100 
 50 
 10 
 30 
 80 
 
 100 
 
 100 
 
 70 
 
 100 
 
 —200 
 
 100 
 
 100 
 
 70 
 
 50 
 
 100 
 
 00 
 
 70 
 
 40 
 
 55 
 
 20 
 
 40 
 
 30 
 
 30 
 
 — 10 
 
 
 40 
 
 — 10 
 40 
 25 
 75 
 90 
 70 
 50 
 30 
 20 
 80 
 
 80 
 
 100 
 
 65 
 
 100 
 
 -250 
 
 100 
 
 140 
 
 70 
 
 60 
 
 100 
 
 70 
 
 90 
 
 50 
 
 60 
 
 30 
 
 25 
 
 30 
 
 70 
 
 
 
 
 
 
 
 — 15 
 
 
 
 20 
 
 80 
 
 120 
 
 110 
 
 50 
 
 10 
 
 50 
 
 100 
 
 100 
 110 
 
 70 
 120 
 —300 
 80 
 70 
 60 
 
 no 
 
 90 
 
 60 
 
 60 
 
 30 
 
 50 
 
 40 
 
 
 
 25 
 
 50 
 
 
 
 
 
 60 
 
 — 15 
 
 
 
 20 
 
 80 
 
 100 
 
 110 
 
 50 
 
 30 
 
 15 
 
 100 
 
 140 
 
 100 
 80 
 
 130 
 -200 
 
 100 
 70 
 80 
 
 100 
 85 
 40 
 40 
 40 
 50 
 . 50 
 
 20 
 20 
 
 — 30 
 
 
 70 
 
 — 20 
 15 
 30 
 50 
 
 120 
 140 
 35 
 30 
 50 
 70 
 
 130 
 
 130 
 
 60 
 
 70 
 
 150 
 
 70 
 
 70 
 
 100 
 
 200 
 
 80 
 
 40 
 
 60 
 
 50 
 
 50 
 
 60 
 
 
 
 15 
 
 30 
 
 
 
 
 
 80 
 
 - 20 
 
 10 
 
 30 
 
 50 
 
 100 
 
 100 
 
 30 
 
 25 
 
 150 
 
 70 
 
 125 
 
 160 
 
 60 
 
 90 
 
 50 
 
 100 
 
 65 
 
 130 
 
 300 
 
 80 
 
 20 
 
 50 
 
 50 
 
 50 
 
 40 
 
 30 
 
 10 
 
 40 
 
 
 
 80 
 
 200 
 
 60 
 
 80 
 
 30 
 
 60 
 
 100 
 
 100 
 
 30 
 
 25 
 
 190 
 
 70 
 
 160 
 
 160 
 
 50 
 
 90 
 
 70 
 
 120 
 
 80 
 
 150 
 
 300 
 
 80 
 
 ""bO 
 
 50 
 
 60 
 
 70 
 
 30 
 
 10 
 
 
 
 — 10 
 
 80 
 
 
 
 75 
 
 80 
 
 30 
 
 200 
 
 140 
 
 100 
 
 50 
 
 70 
 
 200 
 
 .70 
 
 '"ioo" 
 
 50 
 90 
 70 
 
 120 
 80 
 
 150 
 
 80 
 30 
 50 
 50 
 60 
 75 
 30 
 
 — 5 
 40 
 
 — 20 
 
 6' 
 
 ""■SO 
 200 
 
 "ioo 
 
 40 
 70 
 
 40 
 70 
 
 2 
 
 3 
 
 4 
 
 5 
 
 6 
 
 7 
 
 8 
 
 9 
 
 10 
 
 XI 
 
 12 
 
 13 
 
 14 
 
 15 
 
 16.. .< 
 
 17 
 
 18 
 
 19 
 
 20 
 
 21 
 
 aa 
 
 23 
 
 24 
 
 a5 
 
 26 
 
 27 
 
 28 
 
 29 
 
 30 
 
 31 
 
 Sums.- . -. 
 
 1,810 
 60 
 
 1,810 
 60 
 
 1,845 
 62 
 
 1,805 
 60 
 
 1,435 
 
 48 
 
 1,515 
 50 
 
 1,375 
 46 
 
 1,505 
 50 
 
 1,990 
 66 
 
 2, 475 
 80 
 
 2,605 
 87 
 
 1,615 
 62 
 
 Means .. ... 
 
 
MEMOIRS OP THE NATIONAL ACADEMY OF SCIlfiNCEB. 
 
 205 
 
 registration, at Baltimore, Md., 1885, 1886, and 1887 — CoDtinued. 
 
 JULY, 1887. 
 
 1 p.m. 
 
 2 p.m. 
 
 3 p.m. 
 
 4 p.m. 
 
 6 p.m. 
 
 6 p.m. 
 
 7 p.m. 
 
 8 p. m. 
 
 9 p.m. 
 
 10 p. m. 
 
 H p. m. 
 
 12 mid. 
 
 Kemarka. 
 
 200 
 
 140 
 
 100 
 
 150 
 
 170 
 
 120 
 
 120 
 
 80 
 
 110 
 
 105 
 
 100 
 
 100 
 
 S.fr., clear. 
 
 100 
 
 200 
 
 180 
 
 150 
 
 90 
 
 90 
 
 80 
 
 75 
 
 90 
 
 80 
 
 70 
 
 80 
 
 Do. 
 
 
 
 
 140 
 
 80 
 
 110 
 90 
 
 70 
 90 
 
 80 
 90 
 
 80 
 70 
 
 90 
 
 eo 
 
 80 
 70 
 
 . 80 
 60 
 
 110 
 
 60 
 
 S.fr., fair. 
 SE.br., fair. 
 
 '"ioo" 
 
 "ioh 
 
 "'"60 
 
 60 
 
 
 
 -200 
 
 50 
 
 150 
 
 120 
 
 170 
 
 100 
 
 —250 
 
 100 
 
 60 
 
 100 
 
 NW. fr.,raiti,t.8. 
 
 80 
 
 120 
 
 250 
 
 —250 
 
 150 
 
 100 
 
 90 
 
 80 
 
 90 
 
 90 
 
 100 
 
 90 
 
 S. It., rain, lightning. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 100 
 
 70 
 
 70 
 
 S.fr., rain. 
 
 120 
 
 160 
 
 160 
 
 200 
 
 200 
 
 210 
 
 60 
 
 100 
 
 200 
 
 150 
 
 110 
 
 150 
 
 8. fr., cloudy. 
 
 100 
 
 120 
 
 —200 
 
 100 
 
 140 
 
 140 
 
 130 
 
 110 
 
 100 
 
 100 
 
 110 
 
 100 
 
 S. fr.,rain,t. 8. 
 
 
 
 
 
 
 
 60 
 
 60 
 
 50 
 
 50 
 
 50 
 
 50 
 
 W. br. , clear. 
 
 " "36 
 
 """36' 
 
 ""m 
 
 '""eo' 
 
 ""eo' 
 
 '"eo' 
 
 70 
 
 80 
 
 80 
 
 60 
 
 50 
 
 40 
 
 Do. 
 
 50 
 
 60 
 
 60 
 
 60 
 
 60 
 
 60 
 
 70 
 
 70 
 
 120 
 
 60 
 
 60 
 
 50 
 
 Do. 
 
 50 
 
 65 
 
 65 
 
 70 
 
 70 
 
 75 
 
 80 
 
 90 
 
 60 
 
 65 
 
 50 
 
 50 
 
 W.fr.,fair, 
 
 50 
 
 55 
 
 45 
 
 10 
 
 10 
 
 10 
 
 30 
 
 30 
 
 30 
 
 40 
 
 40 
 
 30 
 
 Var.fr., clear. 
 
 150 
 
 120 
 
 130 
 
 100 
 
 150 
 
 80 
 
 20 
 
 50 
 
 50 
 
 50 
 
 35 
 
 30 
 
 Var. fr.,fair. 
 
 
 
 
 
 
 
 25 
 
 30 
 
 20 
 
 30 
 
 40 
 
 40 
 
 40 
 
 30 
 
 30 
 
 Var.lt., fair. 
 
 
 
 -300 
 
 -300 
 
 300 
 
 10 
 
 10 
 
 300 
 
 — 5 
 
 20 
 
 20 
 
 30 
 
 30 
 
 NW. fr.,rain, t. s. 
 
 40 
 
 60 
 
 —200 
 
 — 50 
 
 —300 
 
 200 
 
 200 
 
 —200 
 
 
 
 —150 
 
 — 10 
 
 — 10 
 
 N. fr.,rain,t. 8. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 Var. lt.,rain,t. H. 
 
 60 
 
 60 
 
 80 
 
 80 
 
 100 
 
 25 
 
 40 
 
 40 
 
 60 
 
 50 
 
 60 
 
 60 
 
 K. fr.,rain. 
 
 
 
 70 
 
 45 
 
 40 
 
 40 
 
 
 
 
 
 
 
 
 
 
 
 
 
 — 5 
 
 Var. It., rain, t. 8. 
 
 100 
 
 130 
 
 130 
 
 160 
 
 150 
 
 100 
 
 70 
 
 50 
 
 50 
 
 50 
 
 50 
 
 60 
 
 Var. It., fair, lightning. 
 
 70 
 
 140 
 
 140 
 
 - 20 
 
 —300 
 
 —200 
 
 
 
 
 
 
 
 20 
 
 100 
 
 —200 
 
 S. fr.,rain, t. 8. 
 
 
 110 
 
 110 
 
 120 
 
 125 
 
 90 
 
 80 
 
 75 
 
 —100 
 
 75 
 
 80 
 
 80 
 
 SE.fr., rain. 
 
 "'iso' 
 
 240 
 
 250 
 
 250 
 
 250 
 
 170 
 
 100 
 
 100 
 
 100 
 
 60 
 
 . 60 
 
 80 
 
 SE. fr., rain, lightning. 
 
 1.50 
 
 200 
 
 150 
 
 
 
 150 
 
 100 
 
 —100 
 
 
 
 -300 
 
 
 
 200 
 
 50 
 
 SE. fr.,rain, t. 8. 
 
 60 
 
 130 
 
 
 
 140 
 
 150 
 
 120 
 
 80 
 
 140 
 
 110 
 
 100 
 
 100 
 
 100 
 
 Var. fr.,rain. 
 
 100 
 
 • 210 
 
 160 
 
 —300 
 
 — 300 
 
 130 
 
 150 
 
 100 
 
 50 
 
 60 
 
 50 
 
 50 
 
 SE, It., fog, fair, hazy. 
 
 60 
 
 100 
 
 200 
 
 200 
 
 200 
 
 200 
 
 100 
 
 60 
 
 80 
 
 60 
 
 70 
 
 50 
 
 SE.fr.,rain,t.s. 
 
 100 
 
 130 
 
 150 
 
 150 
 
 120 
 
 110 
 
 90 
 
 60 
 
 70 
 
 100 
 
 110 
 
 70 
 
 S. It., clear. [ning. 
 
 lOl 
 
 110 
 
 120 
 
 110 
 
 110 
 
 120 
 
 110 
 
 100 
 
 60 
 
 60 
 
 100 
 
 100 
 
 SW. It., cloudy, light- 
 
 2, 205 
 
 2, 855 
 
 1,745 
 
 1,525 
 
 2,275 
 
 2,420 
 
 2,100 
 
 1,940 
 
 1,425 
 
 1,745 
 
 2,065 
 
 1,655 
 
 85 
 
 106 
 
 65 
 
 54 
 
 81 
 
 86 
 
 72 
 
 67 
 
 49 
 
 60 
 
 71 
 
 57 
 
 
206 
 
 MBMOIES OF THE NATIONAL ACADEMY OF SCIENCES. 
 
 Table A. Hourly records^ drawn from continuous photographic 
 
 MONTHLY MEANS. 
 
 Month. 
 
 1 a.lii. 
 
 2 a. m. 
 
 3 ». m. 
 
 4 a. m. 
 
 5 a. m. 
 
 6 a. m. 
 
 7 a. m. 
 
 8 a. in. 
 
 9 a. m. 
 
 10 3.ni. 
 
 11 a. m. 
 
 12 m. 
 
 
 48 
 55 
 26 
 31 
 18 
 45 
 37 
 31 
 46 
 38 
 42 
 68 
 
 57 
 39 
 23 
 35 
 22 
 47 
 39 
 56 
 58 
 40 
 58 
 73 
 
 49 
 27 
 33 
 37 
 37 
 43 
 38 
 49 
 56 
 40 
 48 
 65 
 
 62 
 25 
 18 
 48 
 20 
 41 
 35 
 47 
 52 
 40 
 52 
 68 
 
 58 
 18 
 34 
 39 
 17 
 44 
 50 
 49 
 56 
 39 
 54 
 53 
 
 59 
 30 
 38 
 46 
 14 
 44 
 52 
 63 
 68 
 52 
 74 
 47 
 
 58 
 33 
 32 
 46 
 15 
 51 
 45 
 .57 
 62 
 33 
 92 
 70 
 
 42 
 45 
 37 
 45 
 12 
 55 
 50 
 45 
 69 
 29 
 79 
 56 
 
 32 
 
 28 
 21 
 44 
 17 
 
 60 
 48 
 40 
 65 
 
 48 
 84 
 58 
 
 30 
 36 
 37 
 53 
 6 
 52 
 45 
 45 
 67 
 68 
 79 
 56 
 
 29 
 28 
 48 
 54 
 19 
 .57 
 51 
 50 
 66 
 57 
 75 
 55 
 
 31 
 
 40 
 39 
 64 
 29 
 51 
 53 
 50 
 68 
 71 
 64 
 29 
 
 February, 1885 
 
 March. 1885 
 
 Anril 1885 
 
 May 1885 
 
 June, 1885 
 
 Julv 1885 
 
 Aiia-nat 1885 - 
 
 September, 1885 
 
 October. 1885 
 
 November, 1885 
 
 December, 1885 
 
 495 
 
 41 
 
 546 
 
 ■46 
 
 522 
 44 
 
 508 
 42 
 
 511 
 43 
 
 587 
 49 
 
 594 
 50 
 
 564 
 
 47 
 
 545 
 45 
 
 574 
 
 48 
 
 589 
 49 
 
 589 
 49 
 
 Meaus 
 
 January, 1886 
 
 79 
 62 
 29 
 22 
 
 a . . 
 
 44 
 76 
 38 
 39 
 
 48 
 85 
 40 
 21 
 
 50 
 77 
 34 
 19 
 
 63 
 70 
 32 
 30- 
 
 57 
 
 56 
 
 =. 25 
 
 t^.- 32 
 
 63 
 64 
 21 
 30 
 
 78 
 58 
 29 
 34 
 
 86 
 59 
 14 
 25 
 
 78 
 52 
 14 
 34 
 
 45 
 42 
 11 
 
 47 
 
 64 
 45 
 13 
 55 
 
 February, 1886 
 
 March. 1886 
 
 April. 1886 
 
 Mo Tr 1 fl*?fi * 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 Julv 1886 
 
 41 
 55 
 38 
 27 
 67 
 55 
 
 42 
 50 
 42 
 37 
 76 
 40 
 
 45 
 52 
 43 
 21 
 67 
 61 
 
 55 
 36 
 
 18 
 23 
 60 
 64 
 
 49 
 38 
 42 
 44 
 70 
 79 
 
 34 
 50 
 32 
 49 
 76 
 74 
 
 24 
 38 
 46 
 38 
 75 
 70 
 
 44 
 48 
 57 
 53 
 90 
 66 
 
 38 
 52 
 53 
 52 
 100 
 76 
 
 35 
 52 
 62 
 52 
 96 
 76 
 
 28 
 51 
 60 
 53 
 100 
 83 
 
 48 
 52 
 43 
 60 
 89 
 86 
 
 August, 1886 
 
 September, 1886 
 
 October 1886 
 
 NoTcmber, 1886 
 
 December, 1886 
 
 Sums 
 
 475 
 48 
 
 484 
 48 
 
 483 
 48 
 
 436 
 44 
 
 517 
 52 
 
 485 
 
 48 
 
 469 
 47 
 
 557 
 56 
 
 555 
 56 
 
 551 
 55 
 
 520 
 52 
 
 555 
 56 
 
 
 96 
 41 
 54 
 31 
 31 
 34 
 60 
 
 91 
 38 
 54 
 33 
 34 
 42 
 60 
 
 106 
 51 
 52 
 27 
 33 
 44 
 62 
 
 106 
 49 
 63 
 37 
 36 
 45 
 60 
 
 93 
 58 
 65 
 33 
 32 
 50 
 48 
 
 99 
 48 
 46 
 38 
 33 
 50 
 50 
 
 75 
 67 
 78 
 42 
 34 
 62 
 46 
 
 54 
 59 
 36 
 50 
 26 
 50 
 50 
 
 61 
 73 
 52 
 55 
 36 
 53 
 66 
 
 55 
 75 
 52 
 51 
 31 
 52 
 80 
 
 59 
 65 
 55 
 55 
 52 
 59 
 87 
 
 85 
 71 
 69 
 46 
 56 
 61 
 62 
 
 February, 1887 
 
 March 1887 
 
 AtJril. 1887 - 
 
 May,1887 v 
 
 June, 1887 
 
 Julv.1887 
 
 Sums. .--....... 
 
 347 
 50 
 
 352 
 50 
 
 375 
 54 
 
 396 
 57 
 
 379 
 54 
 
 364 
 52 
 
 404 
 
 58 
 
 325 
 46 
 
 396 
 
 57 
 
 396 
 57 
 
 432 
 62 
 
 450 
 64 
 
 
 
 * No record. 
 
MEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES. 
 
 207 
 
 registration, at Baltimore, Md., 1885, 1886, and 1887 — Continued. 
 
 MONTHLY MEANS. 
 
 Ip. m. 
 
 2 p.m. 
 
 3 p.m. 
 
 4 p.m. 
 
 5 p. m. 
 
 6 p.m. 
 
 7 p.m. 
 
 8 p.m. 
 
 9 p.m. 
 
 10 p. m. 
 
 11 p. m. 
 
 12 mid. 
 
 Means. 
 
 59 
 
 89 
 
 96 
 
 93 
 
 87 
 
 66 
 
 77 
 
 78 
 
 76 
 
 54 
 
 52 
 
 54 
 
 60 
 
 65 
 
 77 
 
 72 
 
 73 
 
 64 
 
 49 
 
 39 
 
 45 
 
 44 
 
 52 
 
 83 
 
 55 
 
 47 
 
 31 
 
 32 
 
 41 
 
 29 
 
 41 
 
 16 
 
 12 
 
 19 
 
 25 
 
 24 
 
 29 
 
 25 
 
 30 
 
 67 
 
 67 
 
 55 
 
 37 
 
 45 
 
 33 
 
 22 
 
 48 
 
 31 
 
 34 
 
 22 
 
 22 
 
 43 
 
 44 
 
 60 
 
 70 
 
 79 
 
 51 
 
 49 
 
 44 
 
 38 
 
 34 
 
 35 
 
 34 
 
 18 
 
 33 
 
 35 
 
 51 
 
 54 
 
 70 
 
 64 
 
 62 
 
 41 
 
 47 
 
 52 
 
 45 
 
 54 
 
 52 
 
 51 
 
 15 
 
 30 
 
 38 
 
 47 
 
 33 
 
 38 
 
 36 
 
 41 
 
 45 
 
 40 
 
 40 
 
 37 
 
 41 
 
 46 
 
 39 
 
 46 
 
 23 
 
 38 
 
 18 
 
 16 
 
 41 
 
 36 
 
 63 
 
 44 
 
 51 
 
 43 
 
 62 
 
 68 
 
 74 
 
 69 
 
 89 
 
 71 
 
 61 
 
 48 
 
 38 
 
 34 
 
 51 
 
 49 
 
 60 
 
 48 
 
 71 
 
 80 
 
 82 
 
 77 
 
 75 
 
 47 
 
 54 
 
 35 
 
 31 
 
 51 
 
 38 
 
 55 
 
 71 
 
 60 
 
 55 
 
 61 
 
 56 
 
 71 
 
 70 
 
 49 
 
 41 
 
 37 
 
 26 
 
 28 
 
 59 
 
 15 
 
 38 
 
 65 
 
 74 
 
 94 
 
 101 
 
 86 
 
 84 
 
 79 
 
 71 
 
 47 
 
 43 
 
 62 
 
 558 
 
 682 
 
 746 
 
 737 
 
 739 
 
 649 
 
 551 
 
 592 
 
 536 
 
 520 
 
 533 
 
 472 
 
 584 
 
 46 
 
 57 
 
 62 
 
 61 
 
 62 
 
 54 
 
 46 
 
 49 
 
 45 
 
 43 
 
 44 
 
 39 
 
 49 
 
 83 
 
 89 
 
 84 
 
 75 
 
 69 
 
 73 
 
 73 
 
 87 
 
 39 
 
 43 
 
 40 
 
 51 
 
 65 
 
 79 
 
 106 
 
 70 
 
 63 
 
 77 
 
 86 
 
 77 
 
 69 
 
 71 
 
 61 
 
 59 
 
 61 
 
 68 
 
 12 
 
 18 
 
 11 
 
 23 
 
 ■Z6 
 
 20 
 
 36 
 
 29 
 
 10 
 
 21 
 
 17 
 
 30 
 
 23 
 
 52 
 
 75 
 
 85 
 
 83 
 
 80 
 
 45 
 
 50 
 
 47 
 
 29 
 
 27 
 
 20 
 
 16 
 
 42 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 37 
 
 46 
 
 48 
 
 31 
 
 51 
 
 65 
 
 32 
 
 34 
 
 69 
 
 30 
 
 44 
 
 46 
 
 42 
 
 52 
 
 50 
 
 65 
 
 61 
 
 60 
 
 70 
 
 50 
 
 63 
 
 63 
 
 55 
 
 56 
 
 53 
 
 53 
 
 77 
 
 91 
 
 108 
 
 92 
 
 79 
 
 64 
 
 75 
 
 83 
 
 70 
 
 62 
 
 52 
 
 43 
 
 60 
 
 71 
 
 86 
 
 90 
 
 108 
 
 81 
 
 73 
 
 68 
 
 58 
 
 59 
 
 33 
 
 32 
 
 30 
 
 54 
 
 80 
 
 77 
 
 83 
 
 84 
 
 66 
 
 90 
 
 80 
 
 69 
 
 59 
 
 72 
 
 73 
 
 70 
 
 78 
 
 69 
 
 83 
 
 86 
 
 69 
 
 81 
 
 84 
 
 71 
 
 44 
 
 75 
 
 84 
 
 76 
 
 46 
 
 71 
 
 612 
 
 721 
 
 730 
 
 689 
 
 670 
 
 670 
 
 612 
 
 583 
 
 544 
 
 488 
 
 * 469 
 
 446 
 
 556 
 
 61 
 
 72 
 
 73 
 
 69 
 
 67 
 
 67 
 
 61 
 
 58 
 
 54 
 
 49 
 
 47 
 
 45 
 
 56 
 
 65 
 
 110 
 
 101 
 
 87 
 
 102 
 
 103 
 
 89 
 
 78 
 
 55 
 
 100 
 
 105 
 
 90 
 
 86 
 
 53 
 
 91 
 
 70 
 
 61 
 
 93 
 
 79 
 
 49 
 
 49 
 
 62 
 
 66 
 
 67 
 
 60 
 
 62 
 
 49 
 
 61 
 
 56 
 
 55 
 
 40 
 
 30 
 
 49 
 
 47 
 
 55 
 
 • 40 
 
 26 
 
 57 
 
 52 
 
 37 
 
 59 
 
 47 
 
 40 
 
 28 
 
 31 
 
 20 
 
 50 
 
 38 
 
 29 
 
 22 
 
 11 
 
 38 
 
 72 
 
 109 
 
 86 
 
 69 
 
 83 
 
 39 
 
 26 
 
 33 
 
 27 
 
 26 
 
 24 
 
 32 
 
 44 
 
 55 
 
 46 
 
 64 
 
 74 
 
 76 
 
 80 
 
 82 
 
 54 
 
 79 
 
 47 
 
 42 
 
 32 
 
 55 
 
 85 
 
 106 
 
 65 
 
 54 
 
 81 
 
 86 
 
 72 
 
 67 
 
 49 
 
 60 
 
 71 
 
 57 
 
 66 
 
 416 
 
 582 
 
 489 
 
 440 
 
 503 
 
 448 
 
 387 
 
 378 
 
 365 
 
 368 
 
 357 
 
 339 
 
 403 
 
 59 
 
 83 
 
 70 
 
 63 
 
 72 
 
 64 
 
 55 
 
 54 
 
 52 
 
 53 
 
 51 
 
 48 
 
 58 
 
208 
 
 MEMOIRS OP THE NATIONAL ACADEMY OF SOIENOBS. 
 
 Table B. — Daily observations with hourly, daily, monthly, and annual means, Ithaca, N. Y. 
 
 JULY, 1886, TO SEPTEMBEE, 1887, INCLUSIVE. 
 [An asterisk (*) indicates "beyond the range of tlie electrometer, " usaally accompanied by sparking between needle and quadrants.] 
 
 JULY, 1886. 
 
 
 
 
 
 
 
 
 
 Day of montb. 
 
 9 a. m. 
 
 11 a. m. 
 
 1 p. m. 
 
 3 p. m. 
 
 Means. 
 
 Remarks, 
 
 1 
 
 115 
 65 
 40 
 75 
 85 
 88 
 
 — 16 
 65 
 
 145 
 
 122 
 65 
 
 135 
 34 
 57 
 76 
 
 110 
 
 — 3 
 95 
 10 
 24 
 58 
 90 
 87 
 20 
 85 
 
 133 
 65 
 
 — 12 
 85 
 75 
 
 — 20 
 
 80 
 
 70 
 
 60 
 
 112 
 
 46 
 
 70 
 
 21 
 
 80 
 
 95 
 
 25 
 
 83 
 
 43 
 
 35 
 
 —220 
 
 230 
 
 114 
 
 — 49 
 77 
 
 (t) 
 
 — 3 
 73 
 
 118 
 
 95 
 
 180 
 
 118 
 
 148 
 
 90 
 
 75 
 
 86 
 
 85 
 
 35 
 
 80 
 53 
 80 
 
 102 
 30 
 72 
 30 
 50 
 82 
 65 
 75 
 63 
 50 
 —198 
 60 
 30 
 30 
 —480 
 13 
 48 
 84 
 
 152 
 60 
 
 135 
 88 
 
 146 
 
 120 
 85 
 
 120 
 72 
 98 
 
 70 
 82 
 108 
 90 
 43 
 85 
 25 
 75 
 67 
 94 
 68 
 62 
 50 
 45 
 63 
 62 
 27 
 
 -a 
 
 92 
 
 106 
 
 180 
 
 102 
 
 121 
 
 72 
 
 168 
 
 133 
 
 70 
 
 131 
 
 126 
 
 155 
 
 86 
 68 
 72 
 95 
 51 
 79 
 15 
 68 
 97 
 76 
 73 
 76 
 42 
 —79 
 
 107 
 79 
 1 
 —103 
 29 
 40 
 80 
 
 135 
 86 
 
 114 
 91 
 
 149 
 
 102 
 54 
 
 105 
 89 
 67 
 
 N.lt., clear. 
 SW.lt., fair. 
 
 Do. 
 NW. It., clear. 
 
 Do. 
 NW. It., fair. 
 
 NW. fr., fair, threatening, 
 NW.br., clear. 
 S. It., fair. 
 NW.. It., fair. 
 NW. br., fair. 
 NW.lt., clear. 
 S. br., threatening. 
 SE.br., cloudy, rain. 
 Var.fr., cloudy. 
 SW. gen., cloudy. 
 NW. IL, cloudy, rain, t. s. 
 SW. fr., cloudy, rain, t. s. 
 Cloudy. 
 W. It., cloudy. 
 Cloudy. 
 Clear. 
 
 Do. 
 
 Do. 
 S.fr., fair. 
 
 SW. it., cloudy, rain. 
 W. fr., cloudy. 
 Fair. 
 
 Cloudy, rain. 
 Cloudy. 
 W.fr., fair. 
 
 NW. It., cloudy. 
 
 t.s. 
 
 2 
 
 3 
 
 4 
 
 5 
 
 6 
 
 7 
 
 8 
 
 9 : 
 
 10 
 
 11 
 
 12 . 
 
 13 
 
 14 
 
 15 
 
 16 
 
 17 . 
 
 18 
 
 19 
 
 20 
 
 21 
 
 22 
 
 23 
 
 24 
 
 25 
 
 26 - 
 
 27 
 
 28 
 
 29 
 
 30 
 
 31 
 
 Sums -- . 
 
 2,053 
 66 
 
 2,072 
 69 
 
 1, 495 
 48 
 
 2,637 
 
 88 
 
 2,044 
 66 
 
 
 
 AUGUST, 1886. 
 
 1 
 
 2 
 
 3 
 
 4 
 
 5 
 
 6 
 
 7 
 
 8 
 
 9 
 
 10 
 
 11 
 
 12 
 
 13 
 
 14......... 
 
 15 
 
 16 
 
 17 
 
 18 
 
 19 
 
 20 
 
 21 
 
 22 
 
 23 
 
 24 
 
 25 
 
 26 
 
 27 
 
 28 
 
 29 
 
 30 
 
 31 
 
 Sums- 
 Means 
 
 53 
 
 117 
 
 95 
 
 HO 
 
 
 
 68 
 
 80 
 
 75 
 
 3 
 
 — 12 
 
 75 
 
 90 
 
 140 
 
 — 14 
 
 75 
 
 45 
 
 45 
 
 110 
 
 65 
 
 85 
 
 105 
 
 45 
 
 160 
 
 157 
 
 70 
 
 70 
 
 3 
 
 120 
 
 TO 
 
 70 
 
 12 
 
 — 41 
 
 70 
 
 55 
 
 100 
 
 110 
 
 160 
 
 80 
 
 120 
 
 105 
 
 50 
 
 95 
 
 97 
 
 100 
 
 105 
 
 108 
 
 110 
 
 90 
 
 110 
 
 190 
 
 80 
 
 78 
 
 95 
 
 85 
 
 95 
 
 100 
 
 115 
 
 75 
 
 39 
 
 - 10 
 
 180 
 
 195 
 
 2,577 
 
 2,551 
 
 83 
 
 82 
 
 115 
 
 80 
 
 65 
 
 60 
 
 28 
 
 130 
 
 141 
 
 45 
 
 102 
 
 120 
 
 125 
 
 177 
 
 113 
 
 115 
 
 100 
 
 -220 
 
 60 
 
 105 
 
 80 
 
 105 
 
 100 
 
 110 
 
 105 
 
 108 
 
 109 
 
 85 
 
 102 
 
 95 
 
 71 
 
 90 
 
 190 
 
 3,811 
 91 
 
 133 
 
 104 
 
 95 
 
 95 
 
 95 
 
 57 
 
 75 
 
 72 
 
 98 
 
 29 
 
 120 
 
 104 
 
 107 
 
 94 
 
 85 
 
 62 
 
 118 
 
 94 
 
 115 
 
 96 
 
 88 
 
 91 
 
 135 
 
 157 
 
 158 
 
 103 
 
 160 
 
 100 
 
 145 
 
 96 
 
 1,101 
 
 213 
 
 45 
 
 35 
 
 125 
 
 110 
 
 88 
 
 102 
 
 100 
 
 108 
 
 135 
 
 95 
 
 118 
 
 106 
 
 100 
 
 104 
 
 100 
 
 102 
 
 115 
 
 131 
 
 125 
 
 92 
 
 145 
 
 l07 
 
 90 
 
 95 
 
 105 
 
 92 
 
 255 
 
 94 
 
 125 
 
 175 
 
 4, 509 
 
 3,115 
 
 145 
 
 100.5 
 
 S. br., fair, t. s. 
 NW.br., fair. 
 NW. high, cloudy. 
 W. It., fair. 
 W. It., cloudy, rain. 
 Fair. 
 
 Cloudy, rain. 
 Clear. 
 
 SW.fr., clear. 
 S.fr., fair. 
 
 SW. fr., cloudy, rain. 
 NW. It., fair. 
 SE.fr., fair, t.s. 
 NW. br., cloudy. 
 NW. It., clear. 
 S. br., cloudy, rain. 
 W.fr., cloudy. 
 Clear. 
 
 W. It., clear. 
 SW. It., fair. 
 SW. br., fair. 
 SW. fr., clear. 
 SW.fr., cloudy. 
 SW.fr., fair. 
 NW.fr., fair. 
 N. It., clear. 
 Clear. 
 Do. 
 SW. fr., fair. 
 SW. br., cloudy, rain. 
 NW. fr., hazy. 
 
 SW.fr., fair. 
 
 t Omitted. 
 
MEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES. 
 
 209 
 
 Table B — Daily observations with hourly, daily, monthly, and annual means, Ithaca, N. Y. — Cont'd. 
 
 JULY, 1886, TO'SEPTEMBEE, 1887, INCLUSIVE. 
 [An asterisk (') indicates "beyond the range of the electrometer," usually aocompaniod by sparking between needle and tiuadrants.) 
 
 SEPTEMBER, 1886. 
 
 Day of month. 
 
 Oa. m. 
 
 11 a. m. 
 
 1p.m. 
 
 3 p.m. 
 
 Means. 
 
 Kemarks. 
 
 1 
 
 70 
 
 83 
 
 120 
 
 125 
 
 100 
 
 107 
 
 90 
 
 98 
 
 57 
 
 ' 110 
 
 84 
 
 30 
 
 250 
 
 20 
 
 52 
 
 —235 
 
 55 
 
 40 
 
 155 
 
 65 
 
 42 
 
 120 
 
 125 
 
 175 
 
 103 
 
 — 25 
 
 25 
 
 52 
 
 145 
 
 120 
 
 80 
 
 92 
 
 120- 
 
 80 
 
 105 
 
 125 
 
 115 
 
 120 
 
 60 
 
 120 
 
 73 
 
 — 76 
 
 110 
 
 99 
 
 85 
 
 45 
 
 41 
 
 31 
 
 220 
 
 95 
 
 71 
 
 75 
 
 130 
 
 122 
 
 90 
 
 70 
 
 140 
 
 90 
 
 35 
 
 110 
 
 105 
 
 130 
 
 150 
 
 138 
 
 115 
 
 110 
 
 105 
 
 130 
 
 76 
 
 77 
 
 55 
 
 333 
 
 90 
 
 128 
 
 87 
 
 58 
 
 35 
 
 45 
 
 43 
 
 85 
 
 75 
 
 85 
 
 101 
 
 120 
 
 152 
 
 70 
 
 160 
 
 55 
 
 103 
 
 130 
 
 110 
 
 115 
 
 150 
 
 152 
 
 130 
 
 118 
 
 85 
 
 118 
 
 60 
 
 100 
 
 70 
 
 - 20 
 
 77 
 
 78 
 
 85 
 
 83 
 
 75 
 
 80 
 
 167 
 
 75 
 
 75 
 
 123 
 
 147 
 
 150 
 
 50 
 
 65 
 
 92 
 
 25 
 
 95 
 
 140 
 
 91 
 
 105 
 
 135 
 
 124 
 
 112 
 
 115 
 
 99 
 
 116 
 
 63 
 
 102 
 
 70 
 
 67 
 
 133 
 
 81 
 
 77 
 
 —12 
 
 52 
 
 49 
 
 146 
 
 80 
 
 66 
 
 101 
 
 126 
 
 142 
 
 <19 
 
 45 
 
 104 
 
 56 
 
 94 
 
 125 
 
 NW.fr., fair. 
 
 W.fr., fair. 
 SW.fr., cloudy. 
 W. ft., cloudy. 
 W.fr., hazy. 
 
 Do. 
 SW.fr., clear. 
 SW.fr., fair. 
 
 Do. 
 NW.fr., clear. 
 SE. It., cloudy, rain. 
 NW.br., fair. 
 SW. br., rain, cloudy. 
 SE.fr., cloudy. 
 S. fr., rain, cloudy. 
 SW.br., fair. 
 Clear. 
 
 SW. high, raiu, cloudy. 
 NW.fr., fair.' - 
 
 Do. 
 NW. It., cloudy. 
 NE.lt., fair. 
 Cloudy. 
 SW.fr., cloudy. 
 S W. br. , rain, cloudy. 
 Cloudy. 
 Var. It. , cloudy. 
 NW.fr., fair. 
 W.br,, clear. 
 
 SW.fr., cloudy. 
 
 2 
 
 3 
 
 4 
 
 5 
 
 6 
 
 ^::::::.:::::::::::::: 
 
 9 ., 
 
 10 ?. 
 
 n 
 
 12 
 
 13 
 
 14 
 
 15 
 
 16 
 
 17 
 
 18 
 
 19 
 
 20 
 
 21 
 
 22 
 
 23 
 
 24 
 
 25 
 
 26 
 
 27 „ 
 
 28 
 
 29 
 
 30 
 
 
 2,358 
 
 79 
 
 2,673 
 
 89 
 
 3,145 
 105 
 
 ■ 2,870 
 96 
 
 2,762 
 92.1 
 
 Meati ... 
 
 
 
 
 
 OCTOBER, 1886. 
 
 
 
 1 
 
 50 
 
 58 
 
 105 
 
 105 
 
 - 10 
 90 
 
 195 
 80 
 142 
 198 
 85 
 82 
 15 
 
 - 39 
 67 
 85 
 
 130 
 
 85 
 
 230 
 
 150 
 
 45 
 
 150 
 
 180 
 
 105 
 
 110 
 
 83 
 
 34 
 
 280 
 
 - 31 
 190 
 
 40 
 
 55 
 65 
 95 
 95 
 35 
 97 
 
 235 
 
 165 
 92 
 
 175 
 75 
 88 
 
 110 
 
 — 59 
 90 
 
 110 
 
 95 
 
 65 
 
 135 
 
 220 
 
 95 
 
 160 
 
 370 
 
 90 
 
 235 
 
 74 
 
 - 1 
 117 
 
 4 
 25 
 70 
 
 42 
 
 85 
 
 88 
 
 150 
 
 50 
 
 131 
 
 200 
 
 160 
 
 109 
 
 145 
 
 60 
 
 103 
 
 35 
 
 — 95 
 20 
 65 
 
 —712 
 200 
 140 
 195 
 
 60 
 165 
 370 
 
 50 
 195 
 
 69 
 
 26 
 182 
 
 — 43 
 70 
 
 125 
 
 47 
 
 105 
 
 100 
 
 140 
 
 110 
 
 155> 
 
 125 
 
 133 
 
 150 
 
 130 
 
 65 
 
 290 
 
 98 
 
 13 
 
 70 
 
 65 
 
 — 72 
 210 
 175 
 220 
 100 
 175 
 260 
 
 60 
 
 130 
 
 —107 
 
 — 6 
 131 
 
 —494 
 215 
 120 
 
 48 
 
 78 
 
 97 
 
 122 
 
 46 
 
 118 
 
 189 
 
 134 
 
 123 
 
 162 
 
 71 
 
 141 
 
 64 
 
 —45 
 
 62 
 
 81 
 
 —140 
 
 140 
 
 170 
 
 196 
 
 75 
 
 162 
 
 295 
 
 76 
 
 168 
 
 30 
 
 13 
 
 178 
 
 —141 
 
 125 
 
 - 89 
 
 NW.br., cloudy. 
 
 Do. 
 N. It., clear. 
 SW.fr., cloudy. 
 NW. It., hazy, cloudy. 
 W. It., haze. 
 Hazy, clear. 
 W. It., hazy, clear. 
 W. fr., hazy, clear. 
 W. It., hazy, clear. 
 SW. fr., hazy, clear. 
 SW. It., cloudy, rain. 
 Clondy. 
 
 SW. high, cloudy, rain. 
 NW. br., clondy, rain. 
 NW. br., clondy. 
 S W. fr. , fair, snow, raiu, sleet. 
 NW.lt., cloudy. 
 W.fr., cloudy. 
 W. br., clear, hazy, cloudy. 
 NW.br., fair. 
 NW.lt.. clear. 
 W.fr., clear. 
 S. br., clear, cloudy. 
 SW.fr., clondy. 
 N.fr., cloudy. 
 Kain,fog, cloudy. 
 Bain, fog. 
 Clondy, rain. 
 N. fr., clondy, rain. 
 
 Do. 
 
 NW.fr., cloudy. 
 
 / 
 
 2 
 
 3 
 
 4 
 
 5 
 
 6 
 
 7 
 
 8 
 
 9 
 
 10 
 
 11 
 
 12 
 
 13 
 
 14 
 
 15 
 
 16 
 
 17 
 
 18 
 
 19 
 
 20 
 
 21 
 
 22 
 
 23 
 
 24 
 
 25 
 
 26 
 
 27 
 
 28 
 
 29 
 
 30 
 
 31 
 
 
 3,089 
 100 
 
 3,277 
 106 
 
 2, 440 
 79 
 
 2,913 
 94 
 
 2,927 
 94.4 
 
 Mean --- ...... 
 
 
 
 
 S. Mis. 94 14= 
 
210 
 
 MEMOIRS OP THE JSTATIONAL ACADEMY OF SCIENCES. 
 
 Table B. — Daily observations with hourly, daily, monthly, and annual means, Ithaoa, W. Y. — Cont'd. 
 
 JULY, 1886, TO SEPTEMBER, 1887, INCLUSIVE. 
 [An asterisk (*) Indicates " bejond the range of the electrometer," usually accompanied by sparking between needle and qnadrants.J 
 
 NOVEMBER, 1886. 
 
 Day of month. 
 
 1 
 
 2 
 
 3 
 
 4 
 
 5 
 
 6 
 
 7 
 
 8 
 
 9 
 
 10 
 
 11 
 
 12 
 
 13 
 
 14 
 
 15 
 
 16 
 
 17 
 
 18 , 
 
 19 
 
 20 
 
 21 
 
 22 , 
 
 23 
 
 24 
 
 25 
 
 26 , 
 
 27 
 
 28 
 
 29 
 
 30 
 
 Sums. 
 Means 
 
 9 a. m. 
 
 1 1 a, m. 
 
 1 p.m. 
 
 3 p.m. 
 
 Means. 
 
 263 
 
 253 
 
 210 
 
 163 
 
 222 
 
 298 
 
 195 
 
 130 
 
 148 
 
 193 
 
 142 
 
 140 
 
 99 
 
 110 
 
 123- 
 
 190 
 
 105 
 
 155 
 
 120 
 
 142 
 
 113 
 
 146 
 
 162 
 
 141 
 
 140 
 
 — 81 
 
 18 
 
 — 15 
 
 500 
 
 106 
 
 23 
 
 88 
 
 98 
 
 160 
 
 92 
 
 105 
 
 5'i 
 
 55 
 
 60 
 
 68 
 
 105 
 
 170 
 
 200 
 
 210 
 
 171 
 
 50 
 
 22- 
 
 174 
 
 
 82 
 
 39 
 
 103 
 
 39 
 
 — 30 
 
 38 
 
 15 
 
 — 156 
 
 —115 
 
 280 
 
 6 
 
 1,100 
 
 1,100 
 
 ._-. .... 
 
 1,800 
 
 1,333 
 
 — 203 
 
 — 310 
 
 —340 
 
 6 
 
 ^ 212 
 
 135 
 
 185 
 
 85 
 
 —120 
 
 71 
 
 220 
 
 260 
 
 240 
 
 280 
 
 250 
 
 — 590 
 
 — 740 
 
 —270 
 
 —480 
 
 — 520 
 
 — 6 
 
 90 
 
 —215 
 
 50 
 
 — 20 
 
 50 
 
 180 
 
 267 
 
 187 
 
 171 
 
 166 
 
 225 
 
 240 
 
 60 
 
 173 
 
 132 
 
 120 
 
 125 
 
 — 25 
 
 88 
 
 145 
 
 212 
 
 180 
 
 170 
 
 177 
 
 — 6 
 
 17 
 
 125 
 
 84 
 
 55 
 
 
 
 — 180 
 
 — 15 
 
 15 
 
 — 45 
 
 — 31 
 
 — 712 
 
 450 
 
 —690 
 
 — 246 
 
 115 
 
 110 
 
 170 
 
 215 
 
 152 
 
 148 
 
 185 
 
 205 
 
 178 
 
 179 
 
 68 
 
 108 
 
 125 
 
 48 
 
 87 
 
 25 
 
 125 
 
 140 
 
 65 
 
 89 
 
 98 
 
 109 
 
 — 31 
 
 490 
 
 166 
 
 2,828 
 
 2,220 
 
 2,673 
 
 4,195 
 
 3,331 
 
 94 
 
 74 
 
 92 
 
 145 
 
 111 
 
 'Remarks. 
 
 Clear. 
 
 Fair. 
 
 S. fr., fair, hazy. 
 
 WNW. br., fair. 
 
 SW. high, cloudy. 
 
 NNW". It., cloudy, rain, snow. 
 
 NNW. br., cloudy, snow. 
 
 NW. br., cloudy, snow. 
 
 SW. ft., cloudy. 
 
 SE. ft., cloudy. 
 
 SW. It., olomdy, rain. 
 
 Cloudy, snow. 
 
 N. fr., snow. 
 
 NW. ft., clear. 
 
 W. ft., fair. 
 
 Clear, cloudy. 
 
 SE. br., rain. 
 
 W. br.,rain, fair. 
 
 SW. high, cloudy, snow. 
 
 SW. ft., cloudy. 
 
 W. fr., clear. 
 
 S. It., fair. 
 
 W. br., rain, cloudy. 
 
 NWW. ft., cloudy. 
 
 SE. ft., snow. 
 
 W. br., clear. 
 
 W. br., fair. 
 
 S. fr., cloudy. 
 
 SW. ijr., cloudy. 
 
 NW. It., snow. 
 
 W. fr., cloudy. 
 
 DECEMBER, 1886. 
 
 1 
 
 2 
 
 3 
 
 4 
 
 5 
 
 6 
 
 7 
 
 8 
 
 9 
 
 10 
 
 11 
 
 12 
 
 13 
 
 14 
 
 15 
 
 16 
 
 17 
 
 18...: 
 
 19 
 
 20 
 
 21 
 
 22 
 
 23 
 
 24 
 
 25 
 
 26 
 
 27 
 
 28 
 
 29 
 
 30 
 
 31 
 
 Sums. 
 Means 
 
 110 
 
 175 
 
 210 
 
 195 
 
 172 
 
 — 165 
 
 — 495 
 
 134 
 
 500 
 
 — 6 
 
 522 
 
 — 183 
 
 — 388 
 
 —301 
 
 — 88 
 
 1,500 
 
 330 
 
 130 
 
 —160 
 
 450 
 
 — 150 
 
 — 5 
 
 — 527 
 
 —343 
 
 — 256 
 
 — 185 
 
 127 
 
 255 
 
 387 
 
 146 
 
 — 250 
 
 — 130 
 
 — 16 
 
 — 85 
 
 — 120 
 
 255 
 
 130 
 
 110 
 
 96 
 
 148 
 
 — 16 
 
 60 
 
 2 
 
 136 
 
 46 
 
 290 
 
 35 
 
 270 
 
 225 
 
 205 
 
 65 
 
 275 
 
 130 
 
 110 
 
 145 
 
 230 
 
 285 
 
 240 
 
 120 
 
 219 
 
 — 50 
 
 — 110 
 
 68 
 
 52 
 
 — 10 
 
 — 302 
 
 — 80 
 
 22 
 
 75 
 
 — 71 
 
 2,050 
 
 1,700 
 
 350 
 
 700 
 
 1,200 
 
 21 
 
 — 250 
 
 75 
 
 — 75 
 
 — .57 
 
 172 
 
 170 
 
 263 
 
 268 
 
 218 
 
 — 180 
 
 — 80 
 
 — 625 
 
 — 65 
 
 — 238 
 
 — 170 
 
 — 50 
 
 25 
 
 —125 
 
 — 80 
 
 30 
 
 100 
 
 175 
 
 200 
 
 126 
 
 155 
 
 190 
 
 245 
 
 200 
 
 198 
 
 205 
 
 r5 
 
 250 
 
 190 
 
 170 
 
 280 
 
 180 
 
 172 
 
 —125 
 
 127 
 
 180 
 
 250 
 
 • 250 
 
 75 
 
 189 
 
 450 
 
 — 250 
 
 — 355 
 
 —625 
 
 — 195 
 
 210 
 
 1,350 
 
 1,520 
 
 100 
 
 795 
 
 1,300 
 
 550 
 
 100 
 
 -280 
 
 418 
 
 — 10 
 
 .50 
 
 150 
 
 1.50 
 
 85 
 
 950 
 
 385 
 
 66 
 
 — 40 
 
 340 
 
 — 55 
 
 237 
 
 305 
 
 245 
 
 183 
 
 410 
 
 215 
 
 57 
 
 187 
 
 217 
 
 7,852 
 
 5,196 
 
 3,663 
 
 1,988 
 
 4,676 
 
 253 
 
 168 
 
 118 
 
 64 
 
 151 
 
 SW. It., cloudy. 
 
 W. br., cloudy, snow. 
 
 NW. br., snow, fair, cloudy. 
 
 NNW. ft., snow, fair, cloudy. 
 
 Cloudy, snow. 
 
 NW. It., snow, clear. 
 
 Fog, cloudy, snow. 
 
 SE.lt., fair, cloudy. 
 
 Cloudy, fair. 
 
 SE. ft., clear. 
 
 Var. It., clear. 
 
 Cloudy, fair. 
 
 S. fr., rain, cloudy. 
 
 NW. br., cloudy. 
 
 NW. br., suow. 
 
 NNW. fr., cloudy, snow. 
 
 WSW.fr., cloudy.. 
 
 SE. fr., cloudy, rain. 
 
 N. It,, snow, cloudy. 
 
 Cloudy. 
 
 W. ft,, fair, clear. 
 
 S. It.., snow. 
 
 SE. br., cloudy, 
 
 SES.br., cloudy. 
 
 N W. br., snow, cloudy. 
 
 SE. br., suow, cloudy. 
 
 WNW. br. , cloudy, suow. 
 
 NW.lt., fair, 
 
 NW. br,,8now. 
 
 Snow. 
 
 S, ft., snow, cloudy. 
 
 NW. br,, snow, cloudy. 
 
MEMOIRS OP THE NATIONAL ACADEMY OF SCIENCES. 
 
 211 
 
 Table B.— Daily observations with hourly, daily, monthly, and annual means, Ithaca, N. T.— Cont'd. 
 
 JULY, 1886, TO SEPTEMBER, 1887, INCLUSIVE. 
 [An asterisk (*) indicates " beyond the range of tie electrometer," usually accompanied by sparking between needle and quadrants.] 
 
 JANUARY, 1887.- 
 
 Day of luontli. 
 
 9 a.m. 
 
 n a.m. 
 
 Ip. ai. 
 
 3 p. m. 
 
 Moans. 
 
 Remarks. 
 
 1 
 
 1,795 
 1,345 
 220 
 582 
 317 
 127 
 120 
 182 
 
 (t) 
 
 — 130 
 - 205 
 
 90 
 2 
 
 — 20 
 
 — 7 
 107 
 
 — 10 
 1,600 
 
 — 40 
 67 
 20 
 
 110 
 
 (+) 
 
 — 55 
 257 
 430 
 171 
 
 — 425 
 
 — 5 
 15 
 
 — 680 
 
 450 
 1,545 
 70 
 220 
 320 
 132 
 237 
 297 
 
 (t) 
 
 40 
 
 315 
 
 65 
 
 -^ 32 
 
 ft) • 
 
 — 35 
 67 
 85 
 
 157 
 
 — ,52 
 
 — 27 
 
 5 
 
 — 10 
 
 -'\ 
 
 12 
 
 55 
 
 100 
 
 — 10 
 60 
 
 110 
 
 — 352 
 
 830 
 
 1.675 
 
 120 
 
 70 
 300 
 
 67 
 130 
 
 22 
 (t) 
 
 90 
 265 
 122 
 
 — 2 
 20 
 
 — 17 
 45 
 
 — 18 
 900 
 
 47 
 
 — 20 
 
 — 12 
 10 
 
 (t) 
 
 — 47 
 55 
 17 
 90 
 45 
 
 165 
 45 
 
 — 165 
 
 65 
 225 
 295 
 310 
 307 
 265 
 1,790 
 417 
 (t) 
 
 92 
 250 
 
 22 
 
 — 10 
 12 
 
 — 20 
 95 
 
 — 8 
 735 
 117 
 
 — 27 
 
 — 112 
 227 
 
 (t) 
 
 — 562 
 150 
 
 1,7.50 
 42 
 
 — 7 
 167 
 117 
 
 — 77 
 
 785 
 
 1,198 
 
 176 
 
 296 
 
 311 
 
 148 
 
 569 
 
 230 
 
 (t) 
 
 23 
 
 259 
 
 75 
 
 — 10 
 
 4 
 
 — 20 
 78 
 12 
 
 848 
 18x 
 
 — 2 
 
 — 25 
 84 
 
 (t) 
 
 — 179 
 118 
 563 
 101 
 
 — 99- 
 97 
 72 
 
 — 318 
 
 NW. fr., snow. 
 
 NW. br., cloudy. 
 
 NW. It., fair. 
 
 NW. fr., fair. 
 
 S. It., snow, cloudy. 
 
 Cloudy. 
 
 NW.lt., clear, snow. 
 
 NW.lt., clear. 
 
 NW. br., snow, fair. 
 SE. fr., clear. 
 SESW.br., cloudy, snow. 
 S. It., cloudy, snow. 
 Bain, cloudy. 
 NW. fr., snow. 
 SE.lt., snow, cloudy. 
 S. fr., cloudy, rain. 
 NW.br., snow, cloudy. 
 S. br., cloudy. 
 
 Do. 
 SW. fr., cloudy, snow. 
 SE. br., fair. 
 
 - W. br., rain, snow, ploudy. 
 SE. br., cloudy, fair. 
 N. fr., snow. 
 S. It., clear. 
 S. br., cloudy. 
 Snow, cloudy. 
 W. fr., snow, cloudy. 
 NW.lt., cloudy, snow. 
 
 NW. br., snow, cloudy. 
 
 2 
 
 3 
 
 4 „ 
 
 5 
 
 6 : 
 
 7 
 
 8 
 
 9 
 
 10 
 
 11 
 
 12 ^ 
 
 13 
 
 14 
 
 15 : 
 
 16 
 
 17 
 
 18 
 
 19 
 
 20 
 
 21 
 
 22 
 
 23 
 
 24 
 
 25 
 
 26 
 
 27: 
 
 28 
 
 29 
 
 30 
 
 31 
 
 Sums. ...... 
 
 6,390 
 220 
 
 3, 772 
 135 
 
 4,849 
 167 
 
 6,627 
 229 
 
 5,412 
 
 187 
 
 Means ...... ...... 
 
 
 FEBRUARY, 1887. 
 
 1 
 
 560 
 1,300 
 
 — 100 
 
 52 
 
 ,- 138 
 
 63 
 
 — 177 
 
 60 
 
 — 352 
 150 
 
 — 85 
 
 — 480 
 
 55 
 ^ 33 
 
 — 48 
 64 
 
 — 127 
 1,312 
 
 127 
 30 
 
 161 
 
 15 
 
 75 
 
 
 
 105 
 
 450 
 
 65 
 
 1,500- 
 
 50 
 
 — 150 
 
 — 325 
 363 
 290 
 
 23 
 -1,215 
 
 — 352 
 
 — 145 
 280 
 
 — 535 
 
 — 572 
 
 — 231 
 
 — 80 
 
 7 
 30 
 
 — 67 
 663 
 
 — 137 
 
 — 41 
 
 — '335 
 
 — 85 
 - 183 
 
 132 
 
 — 37 
 627 
 222 
 149 
 
 55 
 
 — 600 
 
 — 78 
 
 — 200 
 232 
 
 82 
 
 — 308 
 
 52 
 
 — 247 
 200 
 
 — 300 
 
 — 185 
 413 
 
 15 
 
 — 3 
 37 
 
 — 192 
 
 93 
 
 — 45 
 
 — 120 
 
 — 242 
 
 — 142 
 
 97 
 77 
 
 — 48 
 1,035 
 
 (t) 
 
 — 75 
 
 135 
 
 — 420 
 100 
 
 — ' 75 
 270 
 112 
 
 — 805 
 
 37 
 
 — 275 
 
 90 
 
 24 
 
 175 
 
 — 438 
 
 45 
 19 
 45 
 45 
 141 
 
 — 12 
 
 — 168 
 
 — 300 
 
 — 100 
 
 60 
 105 
 
 — 273 
 557 
 
 ^^^60 
 
 200 
 
 32 
 
 -101 
 
 35 
 
 232 
 
 70 
 
 —476 
 
 — 51 
 -255 
 
 180 
 —224 
 —266 
 
 — 50 
 
 — 13 
 
 — 6 
 44 
 
 — 85 
 552 
 
 — 17 
 
 — 75 
 —179 
 
 — 78 
 104 
 
 78 
 
 — 63 
 667 
 144 
 408 
 
 N. It., snow, cloudy. 
 
 ES. fr., snow, cloudy. 
 
 S. It., rain, cloudy. 
 
 NWN.fr., snow, cloudy. 
 
 Fair. 
 
 Clondy, rain. 
 
 Cloudy, snow,- rain. 
 
 S. br., clondy. 
 
 NW. br., fair. 
 
 S. fr., clear, cloudy. 
 
 NW. It., fog, rain, cloudy. 
 
 NW. fr., cloudy, snow. 
 
 NW. fr., fair. 
 
 S.br., clear.. 
 
 S. It., cloudy. 
 
 Cloudy. 
 
 NW. It., cloudy, clear. 
 
 S. high, snow, cloudy. 
 
 Cloudy, snow. 
 
 N. It., cloudy. 
 
 Cloudy. 
 
 Var.lt., 'snow, cloudy. 
 
 S. fr., cloudy. 
 
 NW. high, cloudy, snow. 
 
 NW. It., cloudy, clear. 
 
 S. high, snow. 
 
 W.fr., cloudy, snow. 
 
 NW.br., fair. 
 
 NW. It., cloudy,. snow. 
 
 « 
 
 2 
 
 3 
 
 4 
 
 5 
 
 6 
 
 7 
 
 8 
 
 9 
 
 10 
 
 11 
 
 12 
 
 13 , 
 
 14 
 
 15 
 
 16 
 
 17 
 
 18 
 
 19 
 
 20 
 
 21 
 
 22 
 
 23 
 
 24 
 
 25 
 
 26 
 
 27 
 
 28 
 
 
 4,880 
 174 
 
 * ■ 
 
 — 1, 288 
 — 46 
 
 — 397 
 
 — 15 
 
 - 246 
 
 — 9 
 
 807 
 29 
 
 Means • 
 
 t Omitted. 
 
212 
 
 MEMOIRS OP THE NATIONAL ACADEMY OP SCIENCES. 
 
 Table B.— Daily observations with hourly, daily, monthly, and annual means Ithaca, W. T.— Cont'd. 
 
 JULY, 1886, TO SEPTEMBER, 1887, INCLUSIVE. 
 (An asterisk (*) iadioatea "beyond the range of the electrometer," nanally accompanied by sparking between needle and quadrants.] 
 
 MARCH, 1887. 
 
 Day of month. 
 
 9 a. m. 
 
 11 a. m. 
 
 1p.m. 
 
 3p'm. 
 
 Means. 
 
 Bemarks. 
 
 1 
 
 22 
 
 92 
 120 
 
 17 
 150 
 
 — 830 
 147 
 
 — 20 
 140 
 
 — 385. 
 287 
 
 55 
 225 
 
 — 150 
 650 
 
 15 
 
 1,000 
 
 225 
 
 50 
 
 80 
 
 55 
 
 100 
 
 — 225 
 110 
 
 (t) 
 
 70 
 
 — 280 
 
 (') 
 212 
 290 
 
 — 35 
 90 
 
 — 102 
 
 37 
 
 17 
 
 —1,250 
 
 207 
 
 — 42 
 62 
 
 — 77 
 
 — 300 
 
 55 
 305 
 
 — 155 
 265 
 
 — 150 
 500 
 210 
 
 — 65 
 185 
 165 
 500 
 
 — 45 
 (t) 
 (t) 
 
 85 
 95 
 
 — 30 
 2,900 
 
 196 
 270 
 
 — 130 
 
 87 
 
 — 60 
 
 — 40 
 
 — 60 
 
 — 537 
 110 
 
 — 10 
 45 
 
 — 207 
 
 62 
 45 
 35 
 
 — 230 
 
 80 
 
 65 
 
 170 
 
 220 
 
 10 
 
 85 
 
 55 
 
 1,500 
 
 25 
 
 105 
 
 — 35 
 65 
 20 
 
 — 155 
 2,300 
 
 115 
 . 285 
 
 
 95 
 
 — 150 
 
 30 
 250 
 
 — 20 
 30 
 
 — 365 
 
 
 
 — 150 
 
 (t) 
 
 20 
 
 20 
 
 1,075 
 
 180 
 
 130 
 
 130 
 
 400 
 
 — 95 
 65 
 
 150 
 1,300 
 50. 
 160 
 
 — 140 
 - 80 
 
 80 
 
 — 35 
 1,260 
 
 97 
 200 
 
 — 36 
 91 
 
 — 46 
 11 
 89 
 
 — 659 
 124 
 
 — 109 
 
 62 
 
 — 205 
 
 16 
 44 
 146 
 135 
 294 
 15 
 450 
 264. 
 
 — 25 
 104 
 106 
 850 
 
 — 49 
 125 
 
 — 88 
 57 
 66 
 
 — 125 
 2,153 
 
 155 
 261 
 
 SW. fr., cloudy. 
 
 S. fr., hazy. 
 
 Cloudy. 
 
 Fair. 
 
 SSE. fr., cloudy, snow. 
 
 S. ft., rain, snow, cloudy. 
 
 Cloudy. 
 
 N. It., clear. 
 
 S. br., clear. 
 
 NW.fr., cloudy. 
 
 NW. br., snow. 
 
 NW.fr., clear. 
 
 S. It., fair, cloudy. 
 
 NW.fr., br., sleet, cloudy, snow. 
 
 NW. fr., snow. 
 
 NW.fr., cloudy, snow. 
 
 Do. 
 
 Do. 
 NW.fr., cloudy. 
 Var.lt., cloudy. 
 S. It., cloudy. 
 N. br., snow. 
 W. br., cloudy, fair. 
 E. br., cloudy, hazy. 
 NW. br., fair. 
 N. ft., snow, fair. 
 S.fr., cloudy. 
 W. It., rain, cloudy. 
 W. fr. , sno w. 
 NW. br., fdir. 
 E.lt., clear. 
 
 NW.fr., cloudy. 
 
 2 
 
 3 
 
 4 
 
 5 
 
 6 
 
 7 
 
 8 
 
 9 
 
 10 
 
 11 
 
 12 
 
 13 
 
 14 
 
 15 
 
 16 
 
 17 
 
 18 
 
 19 
 
 20 
 
 21 
 
 22 
 
 23 ' 
 
 24 
 
 25 
 
 26 . . . , 
 
 27 
 
 28 
 
 29 
 
 30 
 
 31 
 
 
 2,222 
 
 77 
 
 3,893 
 134 
 
 4,030 
 130 
 
 4,847 
 162 
 
 4,276 
 138 
 
 Mean 
 
 
 t Omitted. 
 APRIL, 1887. 
 
 1 
 
 2 
 
 3v- 
 
 4 
 
 5 
 
 6 
 
 7 
 
 8 
 
 9 
 
 10 
 
 11 
 
 12 
 
 13 
 
 14 
 
 15 
 
 16 
 
 17 
 
 18 
 
 19 
 
 20 
 
 21 
 
 22 
 
 23 
 
 24 
 
 25 
 
 26 
 
 27 
 
 28 
 
 29 
 
 30 
 
 i 
 
 Sums 
 
 Mean 
 
 —157 
 
 35 
 
 —137 
 
 127 
 
 — 33 
 
 127 
 
 177 
 
 43 
 
 67 
 
 104- 
 
 170 
 
 92 
 
 123 
 
 112 
 
 124 
 
 7 
 
 52 
 
 23 
 
 —322 
 
 — 60 
 
 15 
 
 17 
 
 984 
 
 75 
 
 273 
 
 —106 
 
 -119 
 
 —124 
 
 -225 
 
 —144 
 
 72 
 
 —310 
 
 —245 
 
 —200 
 
 —171 
 
 217 
 
 250 
 
 200 
 
 140 
 
 202 
 
 167 
 
 167 
 
 147 
 
 15 
 
 124 
 
 147 
 
 105 
 
 27 
 
 
 
 70 
 
 —187 
 
 —145 
 
 — 42 
 
 115 
 
 — 64 
 
 —350 
 
 —205 
 
 —167 
 
 —262 
 
 —246 
 
 — 8 
 
 32 
 
 34 
 
 81 
 
 35 
 
 25 
 
 95 
 
 81 
 
 65 
 
 66 
 
 11 
 
 (*) 
 
 —122 
 
 9 
 
 — 34 
 
 —155 
 
 —162 
 
 —372 
 
 —265 
 
 —238 
 
 —293 
 
 — 70 
 
 —100 
 
 —322 
 
 —196 
 
 732 
 
 450 
 
 175 
 
 30 
 
 347 
 
 —213 
 
 —145 
 
 
 
 —105 
 
 —116 
 
 157 
 
 217 
 
 180 
 
 95 
 
 162 
 
 87 
 
 115 
 
 106 
 
 72 
 
 95 
 
 167 
 
 162 
 
 140 
 
 122 
 
 148 
 
 85 
 
 85 
 
 57 
 
 38 
 
 66 
 
 — 72 
 
 — 60 
 
 —240 
 
 — 57 
 
 —107 
 
 126 
 
 104 
 
 90 
 
 106 
 
 106 
 
 - 88 
 
 —128 
 
 150 
 
 41 
 
 — 6 
 
 124 
 
 -121 
 
 —237 
 
 — 52 
 
 — 72 
 
 135 
 
 120 
 
 65 
 
 11 
 
 83 
 
 — 16 
 
 -220 
 
 —157 
 
 —203 
 
 —149 
 
 — 66 
 
 22 
 
 — 50 
 
 275 
 
 45 
 
 860 
 
 612 
 
 632 
 
 —417 
 
 414 
 
 29 
 
 21 
 
 21 
 
 — 14 
 
 14 
 
 Fair. 
 
 N. It., clear. 
 
 Fair. 
 
 S. It., cloudy, rain. 
 
 NW. br., cloudy, snow. 
 
 NW.lt., fair. 
 
 Do. 
 Clear. 
 
 SW.lt., hazy. 
 Hazy. 
 
 NW. It., hazy, rain. 
 Cloudy. 
 
 NE. It., cloudy, rain. 
 NE. br., cloudy. 
 E. br., rain. 
 W. br., rain. 
 W. It., fair. 
 SE.lt., snow. 
 Fair. 
 
 SW. It., clear. 
 W. fr., clear. 
 W. fr, , hazy, rain. 
 SW. br., cloudy, rain. 
 NW.lt., fair. 
 SW.lt., fair. 
 W. It., cloudy. 
 Cloudy. 
 SW.br., raiu. 
 W. It., rain. 
 NW. br., cloudy. 
 
 WNW. It., cloudy, rain. 
 
MEMOIRS OP THE NATIONAL ACADEMY OP SCIENCES. 
 
 213 
 
 Table B. — Daily observations with hourly, daily, monthly, and annual means, Ithaca, N. Y. — Cont'd. 
 
 JULY, 1886, TO SEPTEMBEE, 1887, INCLUSIVE. 
 [An asterisk (*) indicates "beyond the range of the eleotrometer," usually accompanied by sparliing between needle and quadrants.] 
 » MAY, 1887. 
 
 Bay of month. 
 
 9 a.m. 
 
 11 a. m. 
 
 1p.m. 3 p.m. 
 
 ^Remarks, 
 
 1 
 
 2 
 
 3 
 
 4 
 
 5 
 
 6 
 
 7 
 
 8 
 
 9 
 
 10 
 
 11 
 
 12 
 
 13 
 
 14 
 
 15 
 
 16 
 
 17 
 
 18 
 
 19 
 
 20 
 
 21 
 
 22 
 
 23 
 
 24 
 
 25 
 
 26 
 
 27 
 
 28 
 
 29 
 
 30 
 
 31 
 
 Sums . 
 Means 
 
 -220 
 
 121 
 
 143 
 
 132 
 
 11 
 
 110 
 
 148 
 
 137 
 
 -132 
 
 -181 
 
 -132 
 
 - 55 
 99 
 
 -242 
 
 - 93 
 71 
 
 
 
 -160 
 
 44 
 
 66 
 
 - 38 
 44 
 
 137 
 
 - 33 
 137 
 
 27 
 5 
 
 (*) 
 
 - 16 
 192 
 
 99 
 
 247 
 
 105 
 
 110 
 
 —187 
 
 —148 
 
 110 
 
 137 
 
 88 
 
 71 
 
 — 77 
 82 
 
 — 77 
 143 
 
 27 
 
 50 
 
 5 
 
 — 55 
 
 — 55 
 
 — 77 
 105 
 
 16 
 44 
 121 
 44 
 . 33 
 22 
 .55 
 
 — 33 
 
 — 66 
 105 
 154 
 
 421 
 14 
 
 1,099 
 35 
 
 -137 
 111 
 
 - 11 
 -160 
 -110 
 
 99 
 105 
 
 99 
 137 
 
 - 33 
 93 
 
 - U 
 115 
 
 - 11 
 
 - 6 
 55 
 
 
 
 55 
 
 5 
 
 121 
 
 27 
 
 44 
 
 126 
 
 - 66 
 88 
 27 
 
 - 44 
 
 - 16 
 
 - 16 
 140 
 110 
 
 — 77 
 99 
 
 — 27 
 —160 
 —203 
 
 105 
 
 88 
 
 93 
 
 —105 
 
 
 
 - 
 
 187 
 
 110 
 
 — 55 
 
 — 11 
 115 
 
 77 
 
 
 
 3 
 
 I 77 
 
 55 
 
 (t) 
 88 
 11 
 55 
 71 
 66 
 
 — 25 
 
 — 77 
 110 
 
 936 
 - 30 
 
 675 
 22 
 
 - 47 
 109 
 
 54 
 
 -94 
 
 -112 
 
 106 
 
 120 
 
 104 
 
 - 7 
 
 - 73 
 11 
 11 
 
 117 
 
 - 70 
 
 - 15 
 62 
 
 6 
 
 - 40 
 
 - 6 
 92 
 
 2 
 
 47 
 
 128 
 
 8 
 67 
 33 
 22 
 
 6 
 
 - 31 
 90 
 
 118 
 
 818 
 26 
 
 NW. It., fair. 
 
 Var.lt., fair. 
 
 SW.lt., hazy. 
 
 W. It., fair. 
 
 W. It., cloudy. 
 
 W. fr., cloudy. 
 
 NW. br., cloudy, rain. 
 
 E. It., cloudy. 
 
 Cloudy. 
 
 N W. fr. , clear. 
 Hazy. 
 
 NW.lt., clear. 
 W. It., clear. 
 Clear. 
 N. It., fair. 
 Hazy. 
 
 Cloudy, rain. 
 Hazy. 
 Do. 
 Clear. 
 
 SW.lt.,bazy. 
 S.fr., fair. 
 
 SW. br., cloudy, rain. 
 NW.fr., rain. 
 NE. It , rain, cloudy. 
 W. It., rain. 
 NW. fr., rain, cloudy. 
 SW.lt., clear. 
 S. It. , clear. 
 SW.lt., cloudy. 
 
 NW.lt., cloudy. 
 
 f Omitted. 
 JUNE, 1887. 
 
 1 
 
 203 
 38 
 
 — 44 
 66 
 
 137 
 154 
 
 — 11 
 115 
 
 38 
 
 — 60 
 99 
 
 143 
 27 
 
 115 
 44 
 61 
 19 
 
 181 
 99 
 
 146 
 83 
 
 88 
 
 -181 
 
 11 
 
 2 
 
 84 
 
 137 
 
 46 
 
 22 
 
 — 3 
 
 — 22 
 82 
 44 
 68 
 
 148 
 
 115 
 55 
 88 
 71 
 44 
 
 132 
 57 
 71 
 
 137 
 44 
 66 
 88 
 93 
 88 
 82 
 88 
 
 14 
 
 258 
 
 11 
 
 82 
 
 71 
 
 57 
 
 33 
 
 19 
 
 110 
 
 33 
 
 101 
 
 47 
 
 71 
 
 148 
 
 126 
 
 38 
 
 — 22 
 27 
 82 
 93 
 71 
 
 159 
 123 
 
 — 44 
 11 
 82 
 
 167 
 91 
 82 
 66 
 
 139 
 95 
 82 
 13 
 
 126 
 
 137 
 44 
 38 
 
 104 
 55 
 88 
 
 ,47 
 65 
 11 
 93 
 44 
 28 
 
 110 
 93 
 77 
 66, 
 
 116 
 93 
 13 
 88 
 88 
 
 148 
 
 131 
 99 
 88 
 
 111 
 
 52 
 
 
 
 41 
 
 104 
 
 121 
 
 28 
 
 48 
 
 62 
 
 2 
 
 92 
 
 70 
 
 58 
 
 106 
 
 94 
 
 50 
 
 28 
 
 97 
 
 80 
 
 112 
 
 69 
 
 115 
 
 117 
 
 8 
 
 48 
 
 70 
 
 130 
 
 121 
 
 106 
 
 84 
 
 W. br., cloudy, rain. 
 S. It., rain, cloudy. 
 Cloudy. 
 W.fr., clear. 
 S. It. , cloudy. 
 SW.lt., rain. 
 Cloudy. 
 W.lt.,clondy. 
 NW. fr., cloudy, rain. 
 N. It., cloudy. " 
 SENW.fr., fair. 
 NW.lt., clear. 
 N. It., fair. 
 NW.fr., clear. 
 SW.fr., fair. 
 SW.fr., cloudy. 
 NW. It., cloudy, rain. 
 NE.lt., cloudy. 
 NW. fr., cloudy, rain. 
 NW.lt., fair. 
 S.fr,, cloudy. 
 S. ]t.,rain, t. s. 
 S.fr., fair. 
 N. It., cloudy, rain. 
 NW.lt., fair. 
 NW. ft., fair. 
 NW.lt., cloudy. 
 NW.fr., fair, 
 NW.fr., clear. 
 NW.lt., clear. 
 
 NW.lt., cloudy. 
 
 2 
 
 3 
 
 4 
 
 5 
 
 6 
 
 7 
 
 8 
 
 9 
 
 10 , 
 
 11 
 
 12 
 
 13 
 
 14 
 
 15 
 
 16 
 
 17 
 
 18 
 
 19 
 
 30 -. 
 
 21 
 
 22 
 
 23 
 
 lis 
 
 17 
 
 27 
 
 22 
 
 114 
 
 183 
 
 160 
 
 81 
 
 24 
 
 25 
 
 26 
 
 27 
 
 28 
 
 39 
 
 30 
 
 SuniB -.-- ------ 
 
 2,371 
 
 82 
 
 1,845 
 62 
 
 2,207 
 
 74 
 
 2,349 
 
 78 
 
 2,221 
 
 74 
 
 MfifliOfl ..-- ------ 
 
 
214 
 
 MEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES. 
 
 Table B. — Daily observations with hourly, daily, monthly, and annual means, Ithaca, N. ¥. — Cont'd. 
 
 JULY, 1886, TO SEPTEMBER, 1887, INCLUSIVE. 
 [An asterisk (*) indicates "beyond the range of the electrometer," agually accompanied by -sparking between needle and quadrants.] 
 
 JULY, 1887. 
 
 Day of month. 
 
 1 
 
 2 
 
 3 
 
 4 
 
 5 ., 
 
 (i 
 
 7 
 
 8 
 
 9 
 
 ■10 
 
 11 
 
 12 
 
 13 
 
 14 
 
 15 
 
 16 
 
 17 
 
 18 
 
 19 
 
 20 
 
 21 
 
 22 
 
 23 
 
 24 
 
 25 
 
 26 
 
 27 
 
 28 
 
 29 
 
 30 
 
 31 
 
 Sums. 
 Means 
 
 1. 
 2. 
 
 3. 
 
 4. 
 
 5. 
 
 6. 
 
 7. 
 
 8- 
 
 9. 
 10. 
 11. 
 12. 
 13. 
 14. 
 15. 
 16. 
 17. 
 18. 
 19. 
 20. 
 21. 
 22.. 
 23.. 
 24.. 
 25.. 
 26.. 
 27.. 
 28.. 
 29.. 
 30.. 
 31.. 
 
 9 a.m. 
 
 H a.m. 
 
 110 
 
 104 
 
 66 
 
 71 
 
 77 
 
 15 
 
 45 
 
 ■ 50 
 
 (t) 
 
 (t) 
 
 (t) 
 
 (t) 
 
 125 
 
 72 
 
 115 
 
 150 
 
 140 
 
 210 
 
 95 
 
 190 
 
 120 
 
 85 
 
 • 60 
 
 30 
 
 215 
 
 55 
 
 75 
 
 125 
 
 25 
 
 100 
 
 -85 
 
 2,610 
 
 97 
 
 104 
 
 104 
 
 82 
 
 77 
 
 6 
 
 30 
 
 60 
 
 75 
 
 ft) 
 
 (t) 
 
 (t) 
 
 (t) 
 
 125 
 
 80 
 
 125 
 
 95 
 
 125 
 
 65 
 
 80 
 
 105 
 
 70 
 
 - (*) 
 
 60 
 30 
 
 - (') 
 
 20 
 70 
 90 
 50 
 80 
 70 
 
 1p.m. 
 
 1,878 
 75 
 
 99 
 132 
 
 77 
 
 60 
 
 —115 
 
 50 
 
 60 
 
 85 
 
 (t) 
 
 (t) 
 
 (t) 
 
 (t) 
 
 112 
 
 110 
 
 155 
 
 — 65 
 
 90 
 
 110 
 
 75 
 
 95 
 
 10 
 
 50 
 
 45 
 
 55 
 
 - (*) 
 60 
 85 
 
 100 
 
 85 
 
 3 p.m. 
 
 1,780 
 68 
 
 104 
 143 
 
 79 
 82 
 - 35 
 2,100 
 65 
 ft) 
 (t) 
 (t) 
 
 (n 
 (t) 
 
 112 
 
 120 
 
 115 
 
 145 
 
 100 
 
 80 
 
 110 
 
 , 25 
 
 125 
 
 75 
 
 80 
 
 70 
 
 - n 
 
 10 
 
 80 
 100 
 100' 
 155 
 
 90 
 
 Means. 
 
 4,230 
 169 
 
 104 
 
 121 
 
 76 
 
 72 
 
 — 17 
 
 549 
 5r! 
 70 
 (t) 
 (t) 
 (t) 
 (t) 
 
 118 
 95 
 
 127 
 81 
 
 114 
 
 116 
 90 
 
 104 
 61 
 70 
 61 
 46 
 
 215 
 36 
 77 
 99 
 64 
 
 109 
 82 
 
 2,818 
 104 
 
 t Omitted. 
 AUGUST, 1887. 
 
 Slims. . 
 Means. 
 
 50 
 80 
 
 — 10 
 40 
 85 
 95 
 70 
 
 125 
 80 
 65 
 35 
 55 
 65 
 
 125 
 60 
 35 
 85 
 
 140 
 45 
 
 — 30 
 75 
 
 
 155 
 135 
 135 
 135 
 
 — 15 
 35 
 
 — 25 
 105 
 145 
 
 2, 175 
 
 70 
 
 25 
 
 55 
 
 20 
 
 60 
 
 90 
 
 55 
 
 70 
 
 75 
 
 80 
 
 50 
 
 80 
 
 115 
 
 105 
 
 85 
 
 50 
 
 40 
 
 105 
 
 75 
 
 75 
 
 70 
 
 85 
 
 10 
 
 140 
 
 135 
 
 100 
 
 115 
 
 90 
 
 30 
 
 100 
 
 150 
 
 100 
 
 3, 4S5 
 79 
 
 55 
 42 
 60 
 75 
 40 
 80 
 65 
 115 
 80 
 40 
 
 (') 
 
 75 
 
 110 
 
 85 
 
 80 
 
 70 
 
 85 
 
 25 
 
 65 
 
 125 
 
 155 
 
 190 
 
 115 
 
 80 
 
 150 
 
 135 
 
 120 
 
 35 
 
 88 
 
 85 
 
 105 
 
 2, 630 
 
 88 
 
 85 
 
 65 
 
 65 
 
 65 
 
 50 
 
 105 
 
 60 
 
 110 
 
 95 
 
 150 
 
 5 
 
 110 
 
 105 
 
 55 
 
 90 
 
 65 
 
 125 
 
 80 
 
 70 
 
 135 
 
 120 
 
 135 
 
 105 
 
 90 
 
 125 
 
 150 
 
 120 
 
 50 
 
 105 
 
 60 
 
 2,835 
 91 
 
 54 
 
 60 
 
 34 
 
 60 
 
 66 
 
 84 
 
 66 
 
 106 
 
 84 
 
 76 
 
 40 
 
 89 
 
 96 
 
 87 
 
 70 
 
 52 
 
 100 
 
 80 
 
 64 
 
 75 
 
 109 
 
 84 
 
 129 
 
 110 
 
 127 
 
 134 
 
 79 
 
 37 
 
 67 
 
 100 
 
 109 
 
 2,528 
 
 82 
 
 Kemarks. 
 
 SW. fr., fair. 
 SW. fr., fair, rain. 
 SE. It., clear. 
 SW. br., fair. 
 SE. br., clouay, rain. 
 SW.fr., rain. 
 NW. ft., clear. 
 NW. lb., cloudy. 
 
 NW. It., fair. 
 
 NW. fr., cloudy. 
 
 W. It., rain. - 
 
 W. br., fair, rain. 
 
 W. It., rain, fair. 
 
 NW. fr., cloudy, rain. 
 
 NW. fr., fair. 
 
 W. fr., fair. 
 
 SE. fr., cloudy, rain. 
 
 W. fr., cloudy, rain. 
 
 NW.fr,, cloudy. 
 
 Fair. 
 
 Kaln. 
 
 NW. fr., cloudy. 
 
 NW. It., clear. 
 
 W. It., clear. 
 
 NW. fr., cloudy, rain. 
 
 SW. fr., fair. 
 
 W, It., clear. 
 
 NW.fr., rain, cloudy. 
 
 Fair. 
 
 NW. It., cloudy. 
 
 NW. fr., cloudy. 
 
 S. fr., cloudy. 
 
 SW. fr., cloudy, rain. 
 
 NW. fr., cloudy, rain. 
 
 NW.fr., clear. 
 
 S. It., clear. 
 
 SW.fr., fair. 
 
 S. It., cloudy, rain. 
 
 Cloudy, rain. 
 
 NW. fr., clear. 
 
 NW.lt., clear. 
 
 Fair. 
 
 SW. Ir., cloudy. 
 
 NW.fr., cloudy, rain. 
 
 W. fr., cloudy, rain. 
 
 NW. Ir., cloudy, rain. 
 
 NW.fr., cloudy. 
 
 NW. fr., fair. 
 
 NW.lt., liazy, rain. 
 
 NW. It., cloudy, riiiu. 
 
 NW.br., cloudy, rain. 
 
 NW.fr., cloudy, rain. 
 
 NW. sale, fair. 
 
 Do. 
 NW. br., fair. 
 NW.fr., fair. 
 NW.fr., clear. 
 
 Do. 
 Clear. 
 
 NW.fr., cloudy, rain. 
 
MEMOIRS OF THE NATIONAL AOADEMY OP SCIENCES. 
 
 215 
 
 Table B. — Daily observations with hourly, daily, monthly, and annual means, Ithaca, N. Y. — Cont'd. 
 
 JULY, 1886, TO SEPTEMBEE, 1887, INCLUSIVE. 
 [An asterisk (*) indicates " beyond the range of the electrometer," usnally accompanied hy sparking between needle and qaadrants.] 
 
 SEPTEMBEE, 1887. 
 
 V 
 
 Day of month. 
 
 9 a.m. 
 
 11 a. m. 
 
 1 p.m. 
 
 3 p.m. 
 
 Means. 
 
 Eemarks. 
 
 1 
 
 120 
 30 
 70 
 60 
 
 100 
 
 110 
 80 
 70^ 
 
 115 
 50 
 - 135 
 85 
 - 35 
 75 
 50 
 
 115 
 30 
 
 (+) 
 50 
 60 
 190 
 
 85 
 
 45 
 
 60 
 
 35 
 
 210 
 
 70 
 
 110 
 
 120 
 
 110 
 
 105 
 
 70 
 
 90 
 
 115 
 
 145 
 
 (t) 
 
 190 
 150 
 
 (t) 
 80 
 85 
 60 
 90 
 45 
 —2,250 
 
 (t) 
 115 
 60 
 95 
 
 120 
 70 
 105 
 70 
 (t) 
 (t) 
 70 
 190 
 150 
 
 (t) 
 
 150 
 
 100 
 
 65 
 
 90 
 
 so" 
 
 80 
 90 
 85 
 95 
 — 35 
 40 
 85' 
 85 
 H5 
 (t) 
 (t) 
 100 
 185 
 
 120 
 92 
 85 
 57 
 85 
 63 
 —470 
 73 
 
 107 
 79 
 
 109 
 39 
 49 
 80 
 89 
 
 104 
 30 
 
 '% 
 156 
 163 
 
 Clear. 
 
 W. It., cloudy, rain. 
 NW. fr., cloudy. 
 NW. It., clear. 
 W.fr.. clear. 
 S.fr., cloudy. 
 8W. br., cloudy, rain. 
 NW.fr., fair. 
 SW.br., cloudy. 
 NW.-fr., cloudy. 
 E. It., cloudy. 
 SW. It., cloudy. 
 S. fr., rain, cloudy. 
 NW.fr., fair. 
 Cloudy, rain. 
 N. It., cloudy, rain. 
 N. It., clear. 
 
 N. fr., clear. 
 NW.lt:, clear. 
 S. It., hazy. 
 
 NW. It., cloudy. 
 
 • 
 
 2 
 
 3 
 
 4 
 
 5 
 
 6 
 
 7 
 
 8 
 
 9 
 
 10 
 
 11 
 
 12 
 
 13. 
 
 14 
 
 15 
 
 16 
 
 17 
 
 18 
 
 19 
 
 20 
 
 21 
 
 22 
 
 23 . . 
 
 
 
 
 
 
 24 
 
 
 
 
 
 
 25 
 
 
 
 
 
 
 26 
 
 
 
 
 
 
 27 •, 
 
 
 
 
 
 
 28 
 
 
 
 
 
 
 29 
 
 
 
 
 
 
 30 
 
 
 
 
 
 
 Sums ......... 
 
 1,560 
 
 78 
 
 
 
 
 
 1,900 
 106 
 
 — 845 
 
 — 50 
 
 1,380 
 86 
 
 1,180 
 59 
 
 Means .... ...... 
 
 
 t Omitted. 
 SUMMARY. 
 
 July, 1886 
 
 August, 1886.... 
 September, 1886 
 October, 1886... 
 November, 1886. 
 December, 1886. 
 January, 1887 .. 
 February, 1887 . 
 
 March, 1887 
 
 Ap]:il,1887 
 
 May, 1887 
 
 June, 1887 
 
 July, 1887 
 
 August, 1887 ... 
 September, 1887 
 
 Sums 
 
 Means 
 
 66 
 
 69 
 
 48 
 
 88 
 
 68 
 
 83 
 
 82 
 
 91 
 
 145 
 
 100 
 
 79 
 
 
 105 
 
 96 
 
 92 
 
 100 
 
 106 
 
 79 
 
 94 
 
 95 
 
 94 
 
 74 
 
 92 
 
 145 
 
 101 
 
 253 
 
 168 
 
 118 
 
 64 
 
 151 
 
 220 
 
 135 
 
 167 
 
 229 
 
 188 
 
 174 
 
 — 46 
 
 — 15 
 
 — 9 
 
 ' 26 
 
 77 
 
 134 
 
 130 
 
 162 
 
 126 
 
 29 
 
 21 
 
 21 
 
 — 14 
 
 14 
 
 14 
 
 35 
 
 30 
 
 22 
 
 25 
 
 82 
 
 62 
 
 74 
 
 78 
 
 74 
 
 97 
 
 75 
 
 68 
 
 169 
 
 102 
 
 70 
 
 79 
 
 88 
 
 91 
 
 82- 
 
 78 
 
 106 
 
 — 50 
 
 86 
 
 55 
 
 1.516 
 
 1,189 
 
 1.046 
 
 1,446 
 
 1,299 
 
 101 
 
 79 
 
 70 
 
 96 
 
 87 
 
 NW.lt., cloudy. 
 SW. fr., fair. 
 SW. fr., cloudy. 
 NW. fr., cloudy. 
 W.fr., cloudy. 
 NW. br., cloudy, snow. 
 NW.br., snow, cloudy. 
 NW. It., snow, cloudy. 
 NW. fr., cloudy. 
 NW.lt., cloudy, rain.- 
 NW.lt;., cloudy. 
 
 Do. 
 NW.fr., rain, cloudy. 
 NWrfr., cloudy, rain. 
 NW.lt., cloudy. 
 
216 
 
 MEMOIES OF THE iJfATIONAL ACADEMY OF SCIENCES. 
 
 Table B. — Daily observations with hourly, daily, monthly, and annual means, Ithaca-, JV. Y. — Cont'd. 
 
 OCTOBEE, 1887, TO AUGUST, 1888, INCLUSIVE. 
 [An asterisk (*) iadicates " beyond the range of the electrometer," nsaally accompanied by sparking between needle and quadrants.] 
 
 OCTOBEE, 1887. 
 
 Day of month. 
 
 9 a.m. 
 
 11 a. m. 
 
 1 p. m. 
 
 3 p. m. 
 
 5 p. m. 
 
 Means. 
 
 Kemarks. 
 
 1 
 
 
 
 
 
 
 
 W. fr., It. rain. 
 W. ]t., cloudy. 
 W. It., fair. 
 SW. It., fair. 
 
 NW. ht., fair. 
 NW. It., clear. 
 SW. fr., fair. 
 S. fr., cloudy. 
 SW. br., cloudy. 
 NW. fr., fair. 
 S. br., cloudy, fog. 
 SW.br., It. rain. 
 W. br., It. suow, 
 W. br., cloudy. 
 NW. br., cloudy. 
 W. fr., cloudy. 
 W. It., fair. 
 SE. fr., cloudy. 
 NW. gen., fair. 
 S. fr., cloudy. 
 W.fr., cloudy, snow. 
 SW. gen., clear. 
 
 W. fr., cloudy. 
 
 2 
 
 
 
 
 
 
 
 3 
 
 
 
 
 ' 
 
 
 
 4 
 
 
 
 
 
 
 
 5 
 
 292 
 403 
 540 
 375 
 
 143 
 
 278 
 210 
 342 
 
 — 68 
 
 (t) 
 210 
 243 
 
 55 
 
 275 
 235 
 
 40 
 242 
 281 
 270 
 
 92 
 303 
 303 
 293 
 
 6 
 
 7 
 
 8- 
 
 9 
 
 10 
 
 
 
 
 
 
 
 11 
 
 
 
 
 
 
 
 12 
 
 
 
 
 
 
 
 13... : 
 
 
 
 
 
 
 
 14 
 
 364 
 546 
 382 
 418 
 150 
 636 
 -(*) 
 
 80 
 
 — 72 
 
 499 
 
 722 
 
 1,197 
 
 72 
 
 36a 
 
 / 270 
 
 88 
 
 455 
 
 210 
 400 
 236 
 450 
 132 
 108 
 —736 
 125 
 80 
 115 
 364 
 644 
 950 
 110 
 385 
 258 
 121 
 368 
 
 167 
 362 
 150 
 216 
 105 
 22 
 100 
 150 
 — 45 
 135 
 264 
 510 
 725 
 55 
 204 
 229 
 251 
 330 
 
 249 
 308 
 164 
 199 
 120 
 161 
 201 
 150 
 
 48 
 165 
 
 88 
 425 
 766 
 197 
 214 
 236 
 302 
 317 
 
 268 
 398 
 173 
 152 
 250 
 180 
 154 
 318 
 105 
 198 
 16 
 505 
 680 
 121 
 214 
 185 
 348 
 367 
 
 252 
 403 
 221 
 287 
 151 
 221 
 — 70 
 186 
 
 54 
 137 
 246 
 561 
 563 
 
 82 
 277 
 236 
 222 
 367 
 
 15 
 
 16 
 
 17 
 
 18 
 
 19 
 
 20 
 
 21 
 
 22 
 
 23 
 
 24 
 
 25 
 
 26.. .. 
 
 27 
 
 28 
 
 29 
 
 30 
 
 31 
 
 
 6,225 
 311 
 
 5,293 
 241 
 
 4,315 
 206 
 
 4,875 
 232 
 
 5,365 
 244 
 
 5,392 
 247 
 
 
 
 1. 
 
 2. 
 3. 
 
 4. 
 
 5. 
 
 6. 
 
 7. 
 
 8. 
 
 9. 
 10. 
 11. 
 12. 
 13. 
 14. 
 15. 
 16. 
 17. 
 18. 
 19. 
 20. 
 21. 
 22. 
 23. 
 24. 
 25. 
 26.: 
 27., 
 28.. 
 29. 
 30., 
 
 Sums.. 
 Means. 
 
 NOVEMBEE, 1887. 
 
 264 
 434 
 330 
 311 
 180 
 331 
 425 
 150 
 391 
 266 
 1,321 
 
 — 53 
 256 
 269 
 
 76 
 
 — 33 
 70 
 
 506 
 
 -135 
 
 485 
 
 104 
 
 134 
 
 129 
 
 105 
 
 294 
 
 348 
 
 82 
 
 -576 
 
 151 
 
 530 
 
 430 
 
 435 
 
 330 
 
 125 
 
 513 
 
 450 
 
 546 
 
 55 
 
 443 
 
 -269 
 
 !,390 
 
 200 
 
 310 
 
 399 
 
 91 
 
 76 
 
 373 
 
 570 
 
 -336 
 
 415 
 
 130 
 
 340 
 
 29 
 
 62 
 
 -228 
 
 615 
 
 -148 
 
 -139 
 
 -482 
 
 132 
 
 6,985 
 233 
 
 9,461 
 262 
 
 312 
 300 
 355 
 - 76 
 210 
 205 
 426 
 185 
 335 
 
 21 
 628 
 134 
 140 
 246 
 
 48 
 100 
 180 
 219 
 
 40 
 149 
 127 
 48] 
 134 
 201 
 
 91 
 
 504 
 
 —272 
 
 —550 
 
 -1, 073 
 
 349 
 
 6,196 
 141 
 
 249 
 
 315 
 
 ' 353 
 
 27 
 
 300 
 
 260 
 
 244 
 
 300 
 
 340 
 
 
 
 2,063 
 155 
 218 
 242 
 63 
 166 
 195 
 286 
 591 
 198 
 255 
 376 
 201 
 196 
 200 
 260 
 176 
 
 — 95 
 157 
 .'■>77 
 
 8,935 
 
 29,". 
 
 fOmitted. 
 
 304 
 
 312 
 
 NW.br., clear. 
 
 343 
 
 365 
 
 N. gen., clear. 
 S. ft., fair. 
 
 370 
 
 348 
 
 90 
 
 95 
 
 NW.br., cloudy. 
 
 774 
 
 395 
 
 NW. high, fair. 
 
 410 
 
 371 
 
 S.lt., clear. 
 
 299 
 
 388 
 
 S. br., hazy. 
 
 336 
 
 205 
 
 NW. br., cloudy. 
 
 330 
 
 368 
 
 E. gen., clear. 
 
 43 
 
 14 
 
 s. hish, rain. 
 
 1,588 
 
 1, 598 
 
 NW. high, snow. 
 
 195 
 
 126 
 
 NW. high, cloudy. 
 
 361 
 
 257 
 
 NW.lt., fair. 
 
 76 
 
 246 
 
 SE.fr., cloudy. 
 
 20 
 
 60 
 
 NW. br,, cloudy, rain. 
 
 113 
 
 g4 
 
 NW.fr., cloudy. 
 
 180 
 
 200 
 
 W.high, fair. 
 
 177 
 
 352 
 
 W. br., clear. 
 
 329 
 
 98 
 
 SE.br., snow, sleet. 
 
 206 
 
 291 
 
 SW.br., cloudy. 
 
 264 
 
 176 
 
 Do. 
 
 603 
 
 387 
 
 E.gen., hazy. 
 
 389 
 
 176 
 
 S. gen., ha&v. 
 
 200 
 
 154 
 
 NW. gen., snow, rain, sleet. 
 
 38 
 
 61 
 
 S. gen., cloudy. 
 
 164 
 
 379 
 
 Do. 
 
 117 
 
 — 21 
 
 S. fr., clear. 
 
 —130 
 
 —298 
 
 NW.fr., fair, sleet. 
 
 —455 
 
 -340 
 
 NW. fr., clear. 
 
 150 
 
 428 
 
 N, br., cloudy, snow. 
 
 8,469 
 
 7,934 
 
 263 
 
 242 
 
 NW.br., cloudy. 
 
MEMOIRS OF THE NATIONAL ACADEMY OP SCIENCES. 
 
 217 
 
 Table B. — Daily observations with hourly, daily, monthly, and annual means, Ithaca, N. Y. Cont'd. 
 
 OCTOBER, 1887, TO AUGUST, 1888, INCLUSIVE. 
 [An asterisk (*) indicates " beyond tlie, range of ttie electrometer," usually accompanied bysparking between needle and quadrants.] 
 
 DECEMBEB, 1887. 
 
 Day of month. 
 
 9 a.m. 11a.m. 1p.m. 3 p.m. 6 p.m. Means, 
 
 Kemarks. 
 
 1 
 
 2 
 
 3 
 
 4 
 
 5 
 
 6 
 
 7 
 
 8- 
 
 9 
 
 10 
 
 11 
 
 12 
 
 13 
 
 14 
 
 15 , 
 
 16 ,.-. 
 
 17 :... 
 
 18 , 
 
 19 , 
 
 20 
 
 21 
 
 22 , 
 
 23 
 
 24......... 
 
 25 
 
 26 
 
 27 
 
 28 , 
 
 29 , 
 
 30 , 
 
 31 
 
 Sums . 
 Means 
 
 1,053 
 
 —117 
 
 126 
 
 —120 
 
 5 
 
 590 
 
 910 
 
 350 
 
 940 
 
 —547 
 
 714 
 
 —433 
 
 300 
 
 760 
 
 610 
 
 — .92 
 
 1,050 
 
 1,937 
 
 141 
 
 780 
 
 —109 
 
 630 
 
 407. 
 
 817 
 
 305 
 
 447 
 
 ,450 
 
 637 
 
 (') 
 
 (*) 
 
 585 
 
 1,131 
 
 101 
 
 599 
 
 — 30 
 
 —322 
 
 380 
 
 734 
 
 185 
 
 830 
 
 821 
 
 630 
 
 51 
 
 560 
 
 880 
 
 410 
 
 —412 
 
 1,176 
 
 1,929 
 
 127 
 
 1,012 
 
 -295 
 
 425 
 
 392- 
 
 785 
 
 320 
 
 755 
 
 826 
 
 1,101 
 
 (') 
 2,330 
 3,040 
 
 1,195 
 
 —130 
 
 652 
 
 —210 
 
 — 139 
 
 149 
 
 659 
 
 352 
 
 784 
 
 1,133 
 
 600 
 
 100 
 
 800 
 
 970 
 
 245 
 
 —180 
 
 987 
 
 1,938 
 
 201 
 
 1,700 
 
 —360 
 
 —238 
 
 705 
 
 896 
 
 335 
 
 798 
 
 912 
 
 —238 
 
 (*) 
 
 (") 
 
 120 
 
 537 
 213 
 
 585 
 
 — 98 
 
 —218 
 
 256 
 
 450 
 
 274 
 
 740 
 
 567 
 
 473 
 
 175 
 
 680 
 
 780 
 
 122 
 
 —114 
 
 950 
 
 1,970 
 
 377 
 
 1,114 
 
 -413 
 
 42 
 
 375 
 
 575 
 
 235 
 
 1,075 
 
 919 
 
 421 
 
 (*> 
 
 318 
 
 n 
 
 874 
 139 
 537 
 
 — 63 
 —200 
 
 440 
 300 
 550 
 820 
 484 
 211 
 264 
 791 
 640 
 58 
 
 — 50 
 846 
 
 1,792 
 156 
 
 2,002 
 
 -190 
 426 
 485 
 490 
 303 
 
 1,090 
 
 720 
 
 62 
 
 (*) 
 300 
 907 
 
 958 
 
 41 
 
 500 
 
 —104 
 
 —175 
 
 363 
 
 611 
 
 342 
 
 823 
 
 492 
 
 526 
 
 31 
 
 626 
 
 806 
 
 289 
 
 —170 
 
 1,002 
 
 1,913 
 
 200 
 
 1,322 
 
 —273 
 
 257 
 
 473 
 
 713 
 
 300 
 
 833 
 
 765 
 
 397 
 
 (*) 
 
 983 
 
 1,163 
 
 13,126 
 453 
 
 20,471 
 682 
 
 14, 736 
 508 
 
 13, 378 
 461 
 
 15, 184 
 506 
 
 16, 007 
 534 
 
 E. It., clear. 
 
 S.fr., cloudy. 
 
 S. gen., cloudy. 
 
 S.fr., cloudy. 
 
 W. br. , cloudy, snow. 
 
 Var. It., clear. 
 
 SE.fr., cloudy. 
 
 N. fr., cloudy. 
 
 E. br. , fair. 
 
 SE.br., rain. 
 
 SW.lt., cloudy. 
 
 NW. br.,8now. 
 
 Var. It , clear. 
 
 SE.fr., fair. 
 
 SW.lt., cloudy. 
 
 NW. br. , cloudy. 
 
 SE.fr., cloudy. 
 
 NW. br. , snow. 
 
 NW.fr., cloudy. 
 
 S. It., cloudy. 
 
 NW. fr. , threatening. 
 
 SW. br. , cloudy, snow, fair. 
 
 S. It., snow, fair. 
 
 SE.fr., cloudy. 
 
 Var. It., cloudy. 
 
 SE. fr., cloudy, snow. 
 
 SB.fr., clear. 
 
 NW. br., snow, cloudy. 
 
 NW. gale, snow. 
 
 NW. high, snow, fair. 
 
 SE.br., snow. 
 
 NWSE.fr., cloudy. 
 
 JANUARY, 1888. 
 
 1 
 
 13 
 
 —310 
 
 550 
 
 230 
 
 — 50 
 
 170 
 
 —356 
 
 —600 
 
 300 
 
 763 
 
 284 
 
 900 
 
 210 
 
 104 
 
 250 
 
 249 
 
 859 
 
 420 
 
 1,4.50 
 
 3,501 
 
 200 
 
 1,062 
 
 860 
 
 110 
 
 3,000 
 
 (') 
 
 (t) 
 
 880 
 
 700 
 
 530 
 
 150 
 280 
 -605 
 600 
 360 
 
 -(') 
 
 670 
 
 202 
 
 —144 
 
 —148 
 
 3,512 
 
 1,005 
 
 1,674 
 
 220 
 
 — 43 
 
 . 545 
 
 (*) 
 546 
 
 3,754 
 650 
 
 4,112 
 795 
 730 
 
 2,220 
 350 
 (•) 
 (*) 
 (+) 
 630 
 340 
 395 
 
 — 5 
 515 
 
 —1,013 
 
 500 
 
 50 
 
 -n 
 
 185 
 —128 
 
 — 24 
 22 
 
 769 
 670 
 680 
 700 
 —119 
 640 
 
 (*) 
 
 866 
 
 1,339 
 
 570 
 
 811 
 
 650 
 
 1,600 
 
 1,750 
 
 1,305 
 
 (') 
 
 -a 
 
 252 
 300 
 560 
 
 —198 
 550 
 176 
 92 
 350 
 150 
 
 ' 338 
 89 
 
 -300 
 185 
 422 
 820 
 815 
 690 
 940 
 
 —210 
 ' 3,436 
 770 
 575 
 635 
 830 
 500 
 
 2,725 
 
 (*) 
 2,352 
 
 (*) 
 (*) 
 
 295 
 219 
 630 
 
 —500 
 300 
 
 - 18 
 695 
 450 
 150 
 300 
 
 —110 
 
 ^900 
 150 
 206 
 680 
 810 
 700 
 
 —104 
 
 —290 
 —2,990 
 
 2,366 
 403 
 785 
 750 
 680 
 
 2,290 
 735 
 
 2,590 
 C) 
 
 n 
 (t) 
 
 480 
 410 
 450 
 
 —138 
 
 332 
 
 —354 
 
 487 
 
 148 
 
 83 
 
 333 
 
 — 61 
 
 —394 
 
 102 
 
 1,134 
 
 692 
 
 976 
 
 504 
 
 156 
 
 187 
 
 232 
 
 1,081 
 
 1,298 
 
 818 
 
 2,001 
 
 555 
 
 1,681 
 
 1,391 
 
 1,341 
 
 3,000 
 
 (*) 
 
 (t) 
 
 507 
 
 394 
 
 513 
 
 S. br.. threatening. 
 
 NW. fr., snow, cloudy. 
 
 NW. fr., snow. 
 
 SE. fr., suow, cloudy. 
 
 N.fr.,fair. 
 
 SE. br., sleet. 
 
 Var. br., cloudy. 
 
 N. br., cloudy. 
 
 N. It., snow. 
 
 W.br., snow, fair. 
 
 NW. br. , snow, fair. 
 
 SE.fr., clear. 
 
 S. br. , clear, snow. 
 
 Var. fr. , clear. 
 
 W.br., snow, rain. 
 
 Var. It. , cloudy. 
 
 SE. high, snow. 
 
 NW.br., snow. 
 
 Do. 
 NW.fr., fair. 
 NW. high, fair, snow. 
 NW. fr., snow, fair. 
 S. fr., cloudy. 
 NW. br., snow, fair. 
 SE.br., fair. 
 NW. high, snow. 
 NW. high, fair. 
 NW. gale, fair. 
 NW.fr., cloudy. 
 NW.lt., cloudy. 
 NW.fr., cloudy. 
 
 NW.br., snow. 
 
 2 
 
 3 
 
 4 
 
 5 
 
 6 
 
 7 
 
 8 
 
 9 
 
 10 
 
 11...., 
 
 12 
 
 13 
 
 14 
 
 15 
 
 16 
 
 17 • 
 
 18 
 
 19 
 
 20 
 
 21 
 
 22 
 
 23 
 
 24 
 
 25 
 
 26 
 
 27 , 
 
 28 
 
 29 
 
 30 
 
 31 
 
 Sums 
 
 16,279 
 581 
 
 22, 800 
 
 877 
 
 13, 445 
 517 
 
 17, 176 
 636 
 
 11,468 
 410 
 
 18,999 
 655 
 
 
 t Omitted. 
 
218 
 
 MEMOIRS OP THE NATIONAL ACADEMY OP SCIENCES. 
 
 Table B.— Daily observations with hourly, daily, monthly,and annual means, Ithaca, F. I. — Cont'd. 
 
 OCTOBER, 1887, TO AUGUST, 1888, INCLUSIVE. 
 [An asterisk (*) indicates " beyond the range of the electrometer," nsuaUy accompanied by sparking between needle and qnadranta.] 
 
 FEBRUARY, 1888. 
 
 Day of month. 
 
 9 a.m. 
 
 11 a.m. 
 
 Ip. m. 
 
 3 p.m. 
 
 6 p.m. 
 
 Mefbiis. 
 
 Kemarks. 
 
 1 
 
 522 
 
 216 
 
 550 
 
 -1,039 
 
 260 
 
 315 
 
 639 
 
 800 
 
 575 
 
 1,010 
 
 1,000 
 
 915 
 
 950 
 
 810 
 
 ^'3^0 
 202 
 643 
 .■525 
 
 — 742 
 
 — 240 
 
 — 371 
 640 
 320 
 
 —2,046 
 534 
 
 -1,690 
 
 2,442 
 
 308 
 
 270 
 198 
 120 
 —2, 605 
 245 
 330 
 814 
 
 (*) 
 300 
 350 
 380 
 1,210 
 915 
 540 
 
 n 
 
 380 
 400 
 656 
 690 
 321 
 
 — 170 
 
 — 160 
 500 
 400 
 
 —2, 601 
 799 
 
 — 138 
 779 
 278 
 
 20.^ 
 332 
 155 
 
 — 520 
 250 
 310 
 740 
 
 (*) 
 205 
 61 
 885 
 890 
 815 
 365 
 
 520 
 518 
 330 
 741 
 380 
 
 — 871 
 
 — 110 
 550 
 360 
 165 
 220 
 
 —1,049 
 150 
 
 — 538 
 
 430 
 
 210 
 
 550 
 
 —2, 610 
 
 310 
 
 290 
 
 1,679 
 
 490 
 
 50 
 
 — 175 
 1,400 
 
 895 
 650 
 400 
 
 (*) 
 '620 
 532 
 476 
 612 
 260 
 80 
 
 — 640 
 408 
 600 
 
 80 
 370 
 
 —1,278 
 205 
 
 — 1, 050 
 
 305 
 
 250 
 
 350 
 
 — 2,629 
 
 525 
 
 180 
 
 150 
 
 450 
 
 250 
 
 2,003 
 
 1,004 
 
 970 
 
 500 
 
 170 
 
 (*) 
 260 
 483 
 560 
 420 
 205 
 160 
 — 1, 050 
 370 
 430 
 250 
 207 
 
 — 941 
 
 — 566 
 173 
 
 346 
 241 
 345 
 — 1, 881 
 318 
 285 
 804 
 580 
 276 
 650 
 1,034 
 976 
 766 
 457 
 
 (*) 
 422 
 427 
 .533 
 598 
 85 
 
 — 208 
 
 — 466 
 494 
 422 
 
 — 830 
 426 
 
 —1,028 
 602 
 
 — 166 
 
 Var. gen., snow. 
 
 NW. It., cloudy. 
 
 N. fir., cloudy. 
 
 SE.br., sleet, rain. 
 
 N. fr., threatening. 
 
 NW. fr. , cloudy. 
 
 SE. br. , cloudy, snow. 
 
 N. fr., cloudy, snow. 
 
 NW.fr., cloudy. 
 
 SE. br. , cloudy. 
 
 NW.fr., cloudy. 
 
 SE.fr., fair. 
 
 S.fr., clear. 
 
 SW.fr., fair. 
 
 NW. high, snow. 
 
 SW.fr., fair. ' 
 
 NW. fr. , cloudy. 
 
 N. It. , snow, fog, cloudy. 
 
 SE. br. , cloudy. 
 
 S. br., cloudy. 
 
 N. fr. , cloudy. 
 
 NW. fr.. snow, clear. 
 
 S.fr., fair. 
 
 Do. 
 SE. br , sleet, rain, cloudy. 
 S.fr., fair. 
 
 NW. fr., snow, cloudy. 
 NW. fr., cloudy. 
 N. gen., cloudy. 
 
 NW.fr., cloudy. 
 
 2 
 
 3 
 
 4 
 
 5 
 
 6 
 
 7 
 
 8 
 
 9 
 
 10 
 
 11 .- 
 
 12 
 
 13 
 
 14 
 
 15 
 
 16 ." 
 
 17 
 
 18 
 
 19 
 
 20 
 
 21 
 
 22 
 
 23 
 
 24 
 
 25, 
 
 26 
 
 27 
 
 28 
 
 29 
 
 
 8,377 
 299 
 
 5,701 
 211 
 
 6,014 
 223 
 
 5,844 
 209 
 
 5,439 
 194 
 
 6, 508 
 232 
 
 
 
 MARCH, 1888. 
 
 1 708 
 
 2 —1,535 
 
 3 (*) 
 
 4 1,191 
 
 5 895 
 
 6 550 
 
 7 671 
 
 8 156 
 
 9 610 
 
 10 1,640 
 
 11 685 
 
 12 C) 
 
 13 -(") 
 
 14 : 980 
 
 15 160 
 
 16 321 
 
 17 1,979 
 
 18 909 
 
 19 877 
 
 20 350 
 
 21 — 135 
 
 22 -2,238 
 
 23 33 
 
 24 260 
 
 25 .'. 316 
 
 26 53 
 
 27 1,110 
 
 28 689 
 
 29 —1,274 
 
 30 — 340 
 
 31 — 225 
 
 Sums 
 
 Means 
 
 9,396 
 336 
 
 478 
 623 
 957 
 
 2,428 
 760 
 410 
 471 
 527 
 600 
 
 1,031 
 800 
 C) 
 
 1,110 
 
 93 
 
 146 
 
 2,098 
 
 870 
 
 1,250 
 
 186 
 
 106 
 
 —1,913 
 
 — 341 
 
 — 341 
 537 
 
 -(') 
 
 980 
 
 248 
 
 — 1, 687 
 
 —2, 709 
 
 — 136 
 
 9,582 
 342 
 
 - 539 
 589 
 
 1,423 
 1,953 
 590 
 125 
 430 
 980 
 850 
 765, 
 708 
 (") 
 
 -C) 
 
 640 
 254 
 
 - 89 
 382 
 830 
 880 
 350 
 
 - 610 
 
 (*) 
 
 - 329 
 
 - 942 
 239 
 
 -C) 
 
 649 
 
 554 
 
 -1, 234 
 
 - 778 
 
 - 671 
 
 7,999 
 296 
 
 400 
 
 ■ 601 
 
 1,106 
 
 1,700 
 
 680 
 
 150 
 
 430 
 
 765 
 
 750 
 
 947 
 
 82 
 
 (*) 
 
 -(*) 
 
 215 
 
 410 
 
 150 
 
 600 
 
 740 
 
 810 
 
 - 71 
 
 - 350 
 -1, 105 
 
 - 189 
 — 221 
 
 478 
 648 
 600 
 435 
 1,465 
 18 
 574 
 
 7,538 
 260 
 
 170 
 
 - 43 
 
 (•) 
 2,099 
 410 
 350 
 246 
 400 
 760 
 600 
 
 (*) 
 
 (*) 
 
 410 
 609 
 103 
 717 
 601 
 1,030 
 259 
 -1, 489 
 108 
 
 - 530 
 
 - 513 
 491 
 216 
 460 
 
 39 
 
 - 579 
 238 
 
 - 235 
 
 6,927 
 257 
 
 243 
 
 193 
 
 1,162 
 
 1,874 
 
 667 
 
 315 
 
 450 
 
 566 
 
 714 
 
 997 
 
 596 
 
 (*) 
 
 ■(") 
 
 671 
 
 305 
 
 126 
 
 1,155 
 
 790 
 
 969 
 
 215 
 
 - 496 
 ■1,287 
 
 - 271 
 
 - 351 
 412 
 306 
 758 
 393 
 
 —1,248 
 
 — 714 
 
 — 368 
 
 8,756 
 302 
 
 N. It. , cloudy, snow. 
 SE. br., rain. 
 NW. high, snow. 
 NW.br., fair. 
 N. fr., cloudy. 
 NW. fr., cloudy. 
 
 Do. 
 NW.br., cloudy, snow. 
 N.fr., clear. 
 S. br., cloudy. 
 S. br., rain, snow. 
 N. high, suow. 
 
 Do. 
 N. br., snow, cloudy. 
 N.fr., cloudy. 
 NW., fr., cloudy, snow. 
 N.fr,, fair, snow. 
 N. It. , clear. 
 SE. br., clear. 
 S. br., cloudy. 
 NW.. high, cloudy. 
 NW. br., cloudy, snow. 
 NW. high, fair. 
 NW. br., fair. 
 SE. fr. , clear. 
 SE. high, rain, cloudy. 
 SE. br., cloudy. 
 SE.fr., cloudy. 
 NW.fr., fair. 
 SE. fr., rain, snow, fair. 
 NW, br., fair. 
 
 NW. br., cloudy. 
 
MEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES. 
 
 219 
 
 Table B.— Daily observations with hourly, daily, monthly., and annual means, Ithaca, N. r.— Cont'd. 
 
 OCTOBER, 1887, TO AUGUST, 1888, INCLUSIVE. 
 [An asterisk (*) indicates "beyond the range of the electrometer," usually accompanied by sparking between needle and qaadrants.l ■" 
 
 APRIL, 1888. 
 
 Day of month. 
 
 1 
 
 2 
 
 3 
 
 4 
 
 5 
 
 6 
 
 7 
 
 8 
 
 9 
 
 10 
 
 11 
 
 12 
 
 13 
 
 14 
 
 15 
 
 16 
 
 17 
 
 18 , 
 
 19 , 
 
 20....- 
 
 21 
 
 22 
 
 23 
 
 24 
 
 25 
 
 26 
 
 27 , 
 
 28 
 
 29 , 
 
 30 
 
 Sums. 
 Means 
 
 9 a.m. 
 
 575 
 
 1,296 
 
 459 
 
 72 
 
 1,420 
 
 1,090 
 402 
 
 1,190 
 312 
 199 
 430 
 170 
 422 
 240 
 649 
 103 
 746 
 
 1,786 
 162 
 
 1,308 
 311 
 124 
 444 
 287 
 262 
 276 
 250 
 46 
 111 
 
 1,851 
 
 -10,069 
 - 336 
 
 1,378 
 868 
 
 1,060 
 487 
 
 (') 
 1,925 
 2,382 
 1,432 
 164 
 1,109 
 351 
 
 76 
 338 
 369 
 810 
 
 27 
 598 
 480 
 512 
 
 42 
 
 97 
 583 
 844 
 148 
 
 62 
 166 
 179 
 
 89 
 200 
 920 
 
 -14,636 
 - 505 
 
 1p.m. 
 
 — 1 
 
 — 1 
 
 50 
 955 
 852 
 302 
 
 (•) 
 750 
 768 
 476 
 148 
 697 
 195 
 316 
 616 
 523 
 020 
 
 29 
 751 
 
 75 
 704 
 458 
 010 
 425 
 303 
 
 35 
 710 
 617 
 300 
 119 
 145 
 
 15 
 
 -11,562 
 - 399 
 
 3 p.m. 
 
 64 
 
 - 910 
 
 - 366 
 1,015 
 
 1 
 
 - ,548 
 
 - 462 
 
 - 662 
 219 
 
 - 200 
 
 - 340 
 
 92 
 
 - 743 
 
 - 600 
 
 - 745 
 
 4 
 
 - 473 
 124 
 
 - 885 
 
 - 248 
 
 - 325 
 
 - 297 
 
 37 
 
 - 42 
 
 - 976 
 
 - 252 
 
 - 121 
 244 
 125 
 
 - 245 
 
 -9,555 
 - 318 
 
 5 p.m. 
 
 (") 
 360 
 
 1,635 
 531 
 
 1,430 
 17 
 
 1,058 
 690 
 255 
 116 
 388 
 724 
 224 
 740 
 295 
 333 
 
 1,638 
 
 1,238 
 
 1,150 
 
 990 
 
 165 
 
 268 
 
 79 
 
 140 
 
 681 
 
 20 
 
 270 
 
 350 
 
 208 
 
 50 
 
 -10, 179 
 - 351 
 
 Means. 
 
 Remarks. 
 
 485 
 878 
 874 
 481 
 950 
 868 
 1,014 
 890 
 220 
 538 
 341 
 171 
 379 
 494 
 704 
 
 46 
 845 
 499 
 618 
 592 
 302 
 339 
 117 
 
 57 
 513 
 
 90 
 
 56 
 151 
 158 
 610 
 
 -11,250 
 - 375 
 
 SE. fr., cloudy, rain. 
 NW. fr., fog, rain. 
 NW.fr., lair. 
 NW. fr., clear. 
 SE. br., rain, cloudy. 
 NW. br. , clear. 
 
 Do. 
 NW. fr., clear. 
 SE.fr., clear. 
 SE. high, rain. 
 NW. br., cloudy. 
 N. br., cloudy, suow. 
 NW. fr., clear. 
 NW. fr., rain. 
 NW. fr., cloudy. 
 NW. fr., clear. 
 NW. It., fair. 
 NW. br., fair. 
 NW. It., fair, hazy. 
 NW. br., cloudv, snow. 
 
 Do. 
 NW. fr, fair, clear. 
 NW. br., fair, cloudy. 
 NW. br., cloudy. 
 N. It., clear. 
 NW. It., clear. 
 
 Do. 
 
 Do. 
 NW.fr., clear. 
 NW.fr,, hazy. 
 
 NW . fr. , clear. 
 
 
 
 
 MAY, 
 
 1888. 
 
 
 
 
 1 
 
 — 266 
 185 
 260 
 208 
 241 
 330 
 255 
 138 
 212 
 260 
 305 
 101 
 
 — 225 
 
 — 669 
 
 — 468 
 120 
 
 22 
 210 
 202 
 160 
 
 — 327 
 250 
 406 
 330 
 389 
 270 
 153 
 
 — 124 
 
 242 
 230 
 
 — 161 
 
 19 
 
 445 
 206 
 
 282 
 
 — ^^^93 
 
 — 541 
 ' 450 
 
 260 
 320 
 
 — 247 
 
 — 304 
 
 — 680 
 
 — 576 
 220 
 186 
 
 — 261 
 
 — 163 
 120 
 
 — 343 _ 
 389 
 360 
 320 
 397 
 265 
 
 — 30 
 742 
 
 21 
 190 
 117 
 
 — 636 
 300 
 280 
 320 
 
 — 18 
 
 — 372 
 270 
 150 
 350 
 316 
 300 
 
 — 70 
 
 — 142 
 —1,650 
 
 — 267 
 349 
 180 
 201 
 
 — 506 
 130 
 
 18 
 355 
 331 
 350 
 321 
 200 
 
 — 72 
 280 
 200 
 120 
 .315 
 
 — 214 
 100 
 335 
 168 
 
 68 
 140 
 133 
 428 
 330 
 
 — 588 
 325 
 
 — 238 
 
 — 260 
 
 — 275 
 
 — 86 
 
 — 759 
 
 72 
 482 
 
 — 862 
 168 
 
 — 247 
 325 
 141 
 242 
 272 
 
 90 
 
 40 
 
 230 
 
 120 
 
 160 
 
 1,464 
 
 — 350 
 100 
 203 
 250 
 
 — 150 
 321 
 
 65 
 409 
 240 
 494 
 280 
 1,035 
 
 — 159 
 —1, 076 
 
 — 71 
 328 
 
 - 133 
 234 
 
 — 178 
 246 
 
 — 540 
 514 
 156 
 246 
 
 .36 
 39 
 
 — 140 
 258 
 
 40 
 
 230 
 
 1,380 
 
 — 325 
 
 87 
 305 
 230 
 
 85 
 105 
 203 
 117 
 316 
 148 
 306 
 116 
 
 — 218 
 
 — 870 
 
 — 294 
 
 52 
 
 65 
 
 173 
 
 — 301 
 165 
 
 — 293 
 367 
 279 
 308 
 283 
 173 
 
 — 10 
 378 
 
 51 
 188 
 701 
 
 NW.fr., cloudy. 
 
 N. br., cloudy, fair. 
 
 S. fr., fair. 
 
 S. high, fair, clear. 
 
 W. fr., fair, cloudy, 
 
 N.fr,, clear. 
 
 NW. fr., cloudy. 
 
 SE. br., cloudy, raiu. 
 
 S.fr., fair. 
 
 SW. It,, cloudy, rain. 
 
 S. br., cloudy. 
 
 SSE. fr., cloudy. 
 
 SW. fr., falr,^lear, cl'y. 
 
 N.fr., rain, cloudy, 
 
 NW. It., cloudy, rain. 
 
 NW. It,, rain, cloudy, 
 
 N,fr,,fair. [fair. 
 
 SE.fr,, rain. 
 
 NW. fr., cloudy. 
 
 NW. br., cloudy, fair. 
 
 NW. fr., clear. 
 
 SSW. fr., clear, fair, 
 
 ESE. fr,, fair, c!oudj , 
 
 E,fr., cloudy, 
 
 SE, fr,, cloudy, rain, 
 
 SE, fr., cloudy. 
 
 SE, It., cloudy. 
 
 S. br,, cloudy, rain. 
 
 N. It., cloudy, rain, fair. 
 
 NW.lt., cloudy, fair. 
 
 S, It,, fair, cloudy, rain. 
 
 S.fr., cloudy. 
 
 2 
 
 3 
 
 4 
 
 5 
 
 6 
 
 7 
 
 8 
 
 9 
 
 10 
 
 11 
 
 12 
 
 13 
 
 14 
 
 15 
 
 16 . 
 
 17 . 
 
 18 
 
 19 - 
 
 20 
 
 21 
 
 22 
 
 23 ... 
 
 24 ... 
 
 25 
 
 26 ... 
 
 27 
 
 28 . 
 
 29 
 
 30 : 
 
 31 
 
 
 3,400 
 113 
 
 2,296 
 
 77 
 
 1,903 
 61 
 
 2,301 
 74 
 
 4,307 
 139 
 
 2,890 
 93 
 
 
 
 t Omitted, 
 
220 
 
 MEMOIRS OF THE ITATIOIS^AL ACADEMY OP SCIENCES. 
 
 Table B, — Daily observations with hourly , daily ^ mo nthly^ and anmuU means, Ithaca^ N. Y. — Cont'd. 
 
 OCTOBER, 1887, TO AUGUST, 1888, INCLUSIVE. 
 [An asterisk (*) indicates *'beyond the range of the electrometer," ueuaUy accompanied by sparking between needle and quadrants.] 
 
 \ JUNE, 1888. 
 
 Day of month. 
 
 ] p.m. 
 
 3 p.m. 
 
 5 p.m. 
 
 Means. 
 
 Semarks. 
 
 - — \— 
 
 1 
 
 2 
 
 3 
 
 4 
 
 5 
 
 6 
 
 7 
 
 8 
 
 9 
 
 10 
 
 11 
 
 12 
 
 13 
 
 14. 
 
 15 
 
 16 
 
 17 
 
 18 
 
 19 
 
 20 
 
 21 
 
 22 
 
 23 
 
 24 
 
 25 
 
 26 
 
 27 
 
 28 
 
 29 
 
 30 , 
 
 Sums 
 Mean 
 
 1. 
 2. 
 3. 
 4. 
 
 5. 
 
 6. 
 
 7. 
 
 8. 
 
 9. 
 10. 
 11. 
 12. 
 13. 
 14. 
 15. 
 16.. 
 17. 
 18.. 
 19.. 
 20.. 
 21.. 
 22.. 
 23. 
 24.. 
 25.. 
 26.. 
 27.. 
 28.. 
 29.. 
 30.. 
 31.. 
 
 26 
 269 
 164 
 290 
 250 
 250 
 - 49 
 280 
 275 
 209 
 240 
 
 20 
 230 
 310 
 100 
 100 
 
 95 
 130 
 230 
 210 
 140 
 210 
 200 
 242 
 210 
 
 49 
 190 
 130 
 
 80 
 
 82 
 
 97 
 
 —433 
 
 190 
 
 —108 
 
 300 
 
 240 
 
 — 40 
 149 
 230 
 200 
 
 — 90 
 112 
 
 68 
 200 
 250 
 
 15 
 126 
 350 
 S95 
 180 
 186 
 240 
 
 82 
 210 
 141 
 191 
 321 
 140 
 110 
 
 — 24 
 
 162 
 42 
 140 
 110 
 350 
 210 
 110 
 210 
 280 
 170 
 140 
 44 
 199 
 120 
 200 
 61 
 95 
 145 
 220 
 150 
 124 
 180 
 !,486 
 184 
 198 
 142 
 200 
 170 
 66 
 142 
 
 - 230 
 
 - (*) 
 190 
 
 70 
 280 
 175 
 2 
 270 
 250 
 210 
 
 - 95 
 96 
 
 180 
 200 
 140 
 154 
 
 90 
 220 
 260 
 280 
 160 
 210 
 136 
 3,068 
 203 
 216 
 255 
 100 
 
 70 
 182 
 
 - 672 
 954 
 265 
 120 
 180 
 1,115 
 
 87 
 110 
 230 
 110 
 100 
 160 
 180 
 160 
 190 
 230 
 120 
 282 
 310 
 280 
 241 
 261 
 110 
 
 75 
 
 58 
 230 
 157 
 
 90 
 100 
 106 
 
 -188 
 187 
 190 
 96 
 272 
 398 
 
 - 23 
 204 
 253 
 180 
 3 
 86 
 171 
 198 
 176 
 112 
 105 
 225 
 263 
 220 
 170 
 220 
 803 
 756 
 162 
 166 
 225 
 126 
 85 
 99 
 
 5,162 
 172 
 
 3,932 
 131 
 
 7,142 
 238 
 
 7,338 
 253 
 
 6,079 
 203 
 
 5,940 
 198 
 
 NW.br., clear. 
 NW. fr., cloudy, rain. 
 NW. ft., clear. 
 
 Do. 
 SW.fr., clear. 
 S. ft., fair. 
 NW.fr., cloudy. 
 NW.lt., clear. 
 S. br., clear. 
 S. fr., cloudy, fair. 
 NW. br., cloudy, rain, clear. 
 N. ft., fair. 
 S. br., fair, cloudy. 
 N and S. ft., cloudy, fair. 
 W. br., rain, fair. 
 N. fr., clear. 
 NW.lt., clear. 
 NW.br., fair. 
 NW.lt., clear. 
 NW. ft., fair. . 
 NE. It., clear, cloudy. 
 W. It., fair. 
 
 S. It. , fair, rain, cloudy. 
 NW.lt., fair, rain, cloudy. 
 NW.fr., clear. 
 NW. fr. , rain , fair. 
 NW.fr., clear. 
 SE. br., rain. 
 NW. It., rain, cloudy. 
 NW.fr., cloudy. 
 
 NW.fr., clear. 
 
 JULY, 1888. 
 
 Sums 
 Mean 
 
 100 
 178 
 205 
 215 
 465 
 330 
 240 
 100 
 200 
 70 
 320 
 .578 
 202 
 491 
 90 
 110 
 60 
 60 
 180 
 165 
 242 
 160 
 145 
 135 
 20 
 90 
 102 
 127 
 110 
 100 
 170 
 
 ,760 
 186 
 
 103 
 148 
 205 
 220 
 140 
 350 
 249 
 72 
 251 
 360 
 194 
 560 
 260 
 358 
 
 — 8 
 200 
 115 
 
 60 
 
 8 
 
 120 
 
 110 
 
 180 
 
 90 
 108 
 
 — 30 
 85 
 
 258 
 120 
 130 
 145 
 135 
 
 5,326 
 172 
 
 60 
 
 ■ 140 
 
 162 
 
 113 
 
 128 
 
 210 
 
 115 
 
 156 
 
 197 
 
 200 
 
 227 
 
 207 
 
 160 
 
 168 
 
 160 
 
 185 
 
 —769 
 
 110 
 
 165 
 
 22 
 
 230 
 
 210 
 
 295 
 
 283 
 
 264 
 
 218 
 
 214 
 
 237 
 
 —160 
 
 — 74 
 
 —110 
 
 ^— 34 
 
 116 
 
 61 
 
 47 
 
 135 
 
 190 
 
 228 
 
 320 
 
 234 
 
 - 90 
 
 —212 
 
 234 
 
 89 
 
 562 
 
 380 
 
 262 
 
 468 
 
 215 
 
 188 
 
 190 
 
 211 
 
 222 
 
 232 
 
 195 
 
 300 
 
 20 
 
 145 
 
 210 
 
 91 
 
 150 
 
 150 
 
 170 
 
 156 
 
 108 
 
 110 
 
 60 
 
 91 
 
 —150 
 
 — 72 
 
 !578 
 
 95 
 
 185 
 
 
 
 74 
 
 89 
 
 165 
 
 188 
 
 225 
 
 173 
 
 107 
 
 120 
 
 185 
 
 153 
 
 215 
 
 . 145 
 
 90 
 
 158 
 
 160 
 
 170 
 
 160 
 
 145 
 
 166 
 
 230 
 
 220 
 
 172 
 
 95 
 
 lOH 
 
 156 
 
 70 
 
 95 
 
 110 
 
 50 
 
 86 
 
 164 
 
 210 
 
 230 
 
 193 
 
 90 
 
 40 
 
 80 
 
 91 
 
 100 
 
 110 
 
 170 
 
 124 
 
 125 
 
 155 
 
 270 
 
 159 
 
 130 
 
 —188 
 
 155 
 
 80 
 
 3, 300 
 
 3, 780 
 
 5, 559 
 
 4,732 
 
 106 
 
 122 
 
 179 
 
 153 
 
 NW.br., fair. 
 
 N. It., fair. 
 
 S.fr., clear. 
 
 SW.br.. clear. 
 
 S. fr., cloudy, rain, clear. 
 
 NW.fr., clear. 
 
 NW.br., clear. 
 
 NW. fr., clear, hazy. 
 
 NW.lt., cloudy. 
 
 NW.lt., clear. 
 
 SW. br., clear, fair. 
 
 W.br., clear. 
 
 NW. br., cloudy, fair. 
 
 NW.fr., clear. 
 
 NW. ft., hazy, clear. 
 
 NW. fr., clear. 
 
 SW. br., hazy, fair. 
 
 S. br., cloudy, rain. 
 
 S. fr., cloudy, rain. 
 
 NW.fr., clear. 
 
 Do. 
 NW.lt., clear. 
 NW. ft., fair. 
 NW. br., clear. 
 NW.fr., clear. 
 S.fr., cloudy, rain. 
 NW.fr., fair. 
 
 Do. 
 NW. fr., clear. 
 8E. fr., hazy, clear. 
 SW. and NW. fr., cloudy, rain 
 
 NW.fr., clear. 
 
MEMOIRS Ol^ THE NATIONAL ACADEMY OF SCIENCES. 
 
 221 
 
 Table B — Daily observations with hourly, daily, monthly, and annual means, Ithaca, N.Y. — Cont'd. 
 
 OCTOBER, 1887, TO AUGUST, 1888, INCLUSIVE. 
 [An asterisk (*) indicates "beyond the range of the electrometer," usually accompanied by sparking between needle and quadrants.] 
 
 AUGUST, 1888. 
 
 Day of mouth. 
 
 9 a.m. 
 
 11a.m. 
 
 1 p.m. 
 
 3 p.m. 
 
 5 p.m. 
 
 Means. 
 
 Bemarks. 
 
 1 
 
 350 
 
 - 8 
 160 
 360 
 160 
 110 
 160 
 190 
 150 
 210 
 280 
 
 - 45 
 —170 
 
 340 
 60 
 190 
 190 
 100 
 215 
 185 
 200 
 50 
 160 
 300 
 
 - 15 
 190 
 115 
 280 
 290 
 390 
 365 
 
 100 
 200 
 140 
 
 70 
 220 
 120 
 190 
 140 
 155 
 200 
 
 60 
 100 
 265 
 — 10 
 140 
 100 
 180 
 
 90 
 220 
 200 
 200 
 
 90 
 175 
 265 
 
 75 
 160 
 148 
 270 
 310 
 395 
 310 
 
 100 
 200 
 120 
 120 
 140 
 170 
 190 
 140 
 200 
 225 
 110 
 125 
 160 
 110 
 180 
 60 
 190 
 120 
 , 200 
 210 
 180 
 120 
 — 10 
 190 
 120- 
 100^ 
 160 
 , 220 
 ■ 230 
 240 
 255 
 
 190 
 240 
 200 
 170 
 
 — 90 
 200 
 140 
 160 
 255 
 230 
 280 
 195 
 250 
 100 
 270 
 180 
 145 
 130 
 230 
 200 
 180 
 140 
 140 
 180 
 200 
 130 
 220 
 230 
 280 
 360 
 
 —110 
 
 210 
 260 
 210 
 
 —395 
 190 
 210 
 150 
 150 
 220 
 165 
 225 
 205 
 270 
 20 
 210 
 165 
 190 
 180 
 270 
 175 
 110 
 170 
 160 
 190 
 130 
 92 
 260 
 370 
 395 
 340 
 
 — 70 
 
 190 
 178 
 146 
 65 
 124 
 162 
 166 
 156 
 156 
 204 
 191 
 116 
 155 
 112 
 172 
 139 
 179 
 124 
 227 
 194 
 174 
 134 
 125 
 225 
 102 
 134 
 183 
 274 
 301 
 345 
 150 
 
 NW. fr., clear. 
 
 Do. - 
 SW.fr., fair. 
 SEN.fr., fair. 
 NW. fr., cloudy. 
 NW. It., fair. 
 NW. fr., clear. 
 SW. fr., fair. 
 NW.fr.. clear. 
 
 Do. 
 NW. It., cloudy, rain. 
 NW.fr., rain, cloudy. 
 NW. high, rain, cloudy, fair. 
 NW. It., clear, fair. 
 SW.fr., cloudy, hazy. 
 SWNW.fr., fair. 
 SNW.fr., rain, cloudy, fair. 
 NW. fr., cloudy. 
 S. fr. , clear. 
 N. fr., cloudy. 
 S. fr., cloudy, rain. 
 NW. fr., rain, cloudy. 
 NW. fr., fair, rain, cloudy. 
 WSW.fr., clear, 
 W. fr., clear. 
 SW. fr., clear. 
 NW. ft., fair. 
 N. fr., clear. 
 NW.fr., clear. 
 SW.fr., fair. 
 S, fr., cloudy. 
 
 NW.fr., clear. 
 
 2 
 
 3 
 
 4 
 
 5 
 
 6 :.... 
 
 7 
 
 8 
 
 9 
 
 10 
 
 11 
 
 la 
 
 13 
 
 14 
 
 15 
 
 16 
 
 17 
 
 18 
 
 19 
 
 20 
 
 21 
 
 22 
 
 23 
 
 24. 
 
 25 
 
 86 
 
 27 
 
 28.., , 
 
 29... 
 
 30 
 
 31 
 
 Sniiia 
 
 5,512 
 178 
 
 6,270 
 170 
 
 4,795 
 155 
 
 5,625 
 181 
 
 5,427 
 175 
 
 5,303 
 171 
 
 
 
 SUMMARY. 
 
 ' Months. 
 
 9 a.m. 
 
 11a.m. 
 
 Ip. m. 
 
 '3 p.m. 
 
 5 p.m. 
 
 Means. 
 
 Remarks. 
 
 October, 1887 . 
 
 311 , 
 233 ' 
 453 
 581 
 299 
 336 
 —336 
 113 
 172 
 186 
 178 
 
 241 
 
 " 262 
 
 682 
 
 877 
 
 211 
 
 342 
 
 —505 
 
 77 
 
 131 
 
 172 
 
 170 
 
 206 
 141 
 508 
 517 
 223 
 296 
 —399 
 61 
 238 
 106 
 155 
 
 232 
 295 
 461 
 636 
 209 
 260 
 —318 
 74 
 253 
 122 
 181 
 
 , *244 
 263 
 506 
 410 
 194 
 257 
 
 —351 
 139 
 203 
 179 
 175 
 
 247 
 242 
 534 
 655 
 232 
 302 
 —375 
 93 
 198 
 153 
 171 
 
 W. ft., cloudy. 
 NW.br., cloudy. 
 NWSE.fr., cloudy. 
 NW. br., snow. 
 NW. fr., cloudy. 
 NW. br., cloudy. 
 NW.fr., clear. 
 S. fr., cloudy. 
 NW.fr., clear. 
 
 Do. 
 
 Do. V 
 
 NW.fr., cloudy. 
 
 November, 1887 
 
 December, 1887 
 
 February, 1888 
 
 March, 1888 
 
 April, 1888 
 
 Mav 1888 
 
 June, 1888 
 
 Julv, 1888 
 
 August, 1888 
 
 Siims . ---- 
 
 2,526 
 229 
 
 2,660 
 242 
 
 2,052 
 
 187 
 
 2,405 
 219 
 
 2,219 
 202 
 
 2,452 
 223 
 
 
 
222 
 
 MEMOIRS OP THE NATIONAL ACADEMY OF SCIENCES. 
 
 Table 0. — Daily observations with hourly, daily, monthly, and annual means. New Haven, Conn., 
 
 August 1, 1886, to July 31, 1887. 
 
 AUGUST, 1886. 
 
 Bate. 
 
 9 a.m. 
 
 11a.m. 
 
 1 p.m. 
 
 3 p.m. 
 
 Means. 
 
 Bemarks. 
 
 2 
 
 4.3 
 10.8 
 10.6 
 21.2 
 23.2 
 
 9.8 
 11.5 
 14.0 
 
 1.7 
 
 —15.3 
 
 13.9 
 
 4.0 
 15.2 
 
 6.7 
 19.3 
 10.1 
 
 6.9 
 11.0 
 10.3 
 32.6 
 16.9 
 12.9 
 19.6 
 18.2 
 
 3.0 
 13.4 
 10.5 
 
 9.8 
 11.7 
 10.6 
 11.5 
 
 0.2 
 
 11.4 
 
 ■ 7.2 
 
 9.7 
 18.6 
 
 2.6 
 20.9 
 12.8 
 
 8.4 
 
 6.5 
 
 — 0.6 
 14.3 
 
 - 0.6 
 9.6 
 
 11.4 
 
 12.3 
 
 6.2 
 13.5 
 
 3.2 
 
 21.9 
 
 —20.5 
 
 54.3 
 
 15.4 
 
 8.5 
 10.7 
 
 4.7 
 24.1 
 
 1.2 
 10.9 
 14.2 
 
 + 5.9 
 
 9.8 
 
 10.4 
 
 16.7 
 
 20. a 
 
 1.2 
 
 26.6 
 
 15.1 
 
 5.4 
 
 3.8 
 
 7.1 
 
 13. '0 
 
 6.9 
 
 9.4 
 
 14.1 
 
 10.1 
 
 NW. It., cloudy, rain, 12.25-12.58 
 
 W. It. , cloudy. [p.m. 
 
 W. It., fair. 
 
 S. It., cloudv, 
 
 SE.lt., cloudy. 
 
 NE. It., cloudy. 
 
 SW.lt., clear. 
 
 SW.lt., fair. 
 
 SW.lt., cloudy. 
 
 NW. It., cloudy. 
 
 S,,fair. 
 
 W.,fair. 
 
 N.,f»ir. 
 NE., cloudy. 
 
 3 
 
 4 
 
 5 
 
 6 
 
 7 
 
 9 
 
 10 
 
 11 
 
 12 
 
 13 . 
 
 14 
 
 16 
 
 17 
 
 18 
 
 19 
 
 
 
 
 
 161.0 
 10.1 
 
 198. 9- 
 13.3 
 
 132.4 
 
 8.8 
 
 180.6 
 12.0 
 
 175. 7 
 11.0 
 
 
 
 SEPTEMBEK, 1886. 
 
 20 : 
 
 8.3 
 13*. 6 
 17.9 
 80.0 
 36.4 
 35.7 
 4.0 
 2.7 
 10.4 
 
 4.5 
 10.6 
 16.5 
 
 5.3 
 51.5 
 16.6 
 
 2.4 
 
 7.6 
 14.0 
 
 8.5 
 
 5.7 
 
 22.9 
 
 60.3 
 
 10.6 
 
 2.3 
 
 5.4 
 
 25.0 
 
 5.2 
 
 7.6 
 
 10.9 
 
 25.9 
 
 36.6 
 
 ""{'.¥ 
 
 3.0 
 
 22.5 
 
 6.0 
 10.1 
 12.6 
 .33.5 
 46.2 
 21.01 
 2.6 
 4.7 
 18.0 
 
 NW.,fair. 
 
 Do. 
 SW., cloudy. 
 Var. , cloudy. It. rain, 
 Var. , fair. 
 ' E., cloudy. 
 SW., cloudy. 
 NE., cloudy. 
 NW., It, rain, cloudy. 
 
 • 
 
 21 
 
 22 
 
 23 
 
 24 
 
 25 
 
 27 
 
 28 
 
 29 ; 
 
 Sums 
 
 209.0 
 23.2 
 
 139.0 
 14.3 
 
 140.7 
 17.6 
 
 113.4 
 14.2 
 
 154.9 
 17.2 
 
 Means 
 
 
 OCTOBEE, 1886. 
 
 1 
 
 4 
 
 5 
 
 6 
 
 7 
 
 8...: 
 
 9 
 
 11 
 
 12. 
 
 13 
 
 14 
 
 15 
 
 16 
 
 18 
 
 19 
 
 20 
 
 21 
 
 22 
 
 23 
 
 25 
 
 26 
 
 27 
 
 28 
 
 29 
 
 30.. 
 
 Sums. . 
 Means. 
 
 41.5 
 
 37.3 
 
 , 9.1 
 
 16.7 
 
 26.2 
 
 41.8 
 
 20.0 
 
 38.5 
 
 29.2 
 
 32.4 
 
 33.7 
 
 10.4 
 
 10,6 
 
 7.0 
 
 15.4 
 
 13.3 
 
 10.9 
 
 10.7 
 
 8.6 
 
 10.9 
 
 1.7 
 
 2.9 
 
 3.3 
 
 
 2.6 
 
 16.2 
 
 17.4 
 
 12.5 
 
 
 15.4 
 
 31.8 
 
 9.6 
 
 9.9 
 
 9.7 
 
 15.2 
 
 18.6 
 
 10.4 
 
 22.4 
 
 11.8 
 
 . 1,5.8 
 
 10.8 
 
 24.7 
 
 33.9 
 
 15.7 
 
 21.3 
 
 19.3 
 
 20.2 
 
 
 10.8 
 
 16.8 
 
 9.8 
 
 12.6 
 
 10.3 
 
 11.3 
 
 11.0 
 
 11.8 
 
 10.9 
 
 6.8 
 
 7.8 
 
 9.3 
 
 9.9 
 
 U. 1 
 
 9.6 
 
 
 10.2 
 
 — 1.7 
 
 24.5 
 
 19.0 
 
 21.0 
 
 15.7 
 
 21.6 
 
 20.7 
 
 27.6 
 
 16.9 
 
 21.7 
 
 39.4 
 
 21.4 
 
 32.0 
 
 27.7 
 
 30.1 
 
 10.0 
 
 18.1 
 
 14.2 
 
 - 3.6 
 
 9.7 
 
 16.4 
 
 14.1 
 
 17.5 
 
 15.4 
 
 15.8 
 
 38.6 
 
 17.8 
 
 14.0 
 
 
 23.5 
 
 9.7 
 
 7.7 
 
 17.5 
 
 13.1 
 
 12.0 
 
 - 11.3 
 
 6.9 
 
 10.3 
 
 2.7 
 
 2.2 
 
 —146. 8 
 
 6.3 
 
 61.9 
 
 
 —26. 2 
 
 17.5 
 
 34.7 
 
 9.3 
 
 12.7 
 
 18.6 
 
 15.5 
 
 11.6 
 
 U.l 
 
 9.5 
 
 11.9 
 
 2.7 
 
 5.7 
 
 0.7 
 
 1.3 
 
 2.6 
 
 271.8 
 
 387.9 
 
 412.7 
 
 245. 3 
 
 340.1 
 
 10.8 
 
 15.5 
 
 17.2 
 
 12.3 
 
 13.6 
 
 NW.,fair. 
 SW., clear. 
 NE., clear. 
 NE.,fair. 
 NE., clear. 
 Var., clear. 
 S., clear. 
 
 Do. 
 W., clear. 
 E., cloudy. 
 SE., cloudy. 
 W., cloudy. 
 W.,fair. 
 
 W.,hvy. rain, cloudy. 
 S., cloudy. 
 S., fair. 
 
 NW., It. rain, clear. 
 W., clear. 
 Var., clear. 
 SW., cloudy. 
 NE., cloudy. 
 NE., It. rain. 
 NE. , cloudy. It. rain. 
 NE., cloudy. 
 NE. , threatening. 
 
 NE., cloudy. 
 
MEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES. 
 
 223 
 
 Table O. — Daily observations with hourly^ daily, monthly, and annual means, New Haven, Conn., 
 " August 1, 1886, to July 31, 1887— Continued. 
 
 NOVEMBEE, 1886. 
 
 Day of month. 
 
 9 a.m. 
 
 11 a. m. 
 
 Ip.m. 
 
 3 p.m. 
 
 Means. 
 
 Eemarks. 
 
 1 . . ... 
 
 28.1 
 55.0 
 13.5 
 25.4 
 77.1 
 70.0- 
 11.9 
 13.4 
 28.4 
 32.9 
 9.0 
 6.2 
 10.0 
 12.3 
 
 -6.7 
 23.9 
 11.7 
 25.5 
 19.2 
 
 —116. 
 17.2 
 17.5 
 18.1 
 65.9 
 41.2 
 30.9 
 
 50.7 
 39.0 
 26.8 
 13.5 
 31.1 
 
 - 17.5 
 12.0 
 14.6 
 
 - 18.4 
 26.3 
 11.9 
 
 1.3 
 8.9 
 41.2 
 41.3 
 26.7 
 19.7 
 
 "'i8.'7' 
 12.4 
 12.9 
 9.4 
 22.0 
 57.9 
 30.6 
 19.4 
 
 54.3 
 37.3 
 53.3 
 
 9.7 
 17.2 
 15.3 
 18.5 
 17.0 
 
 3.7 
 20.0 
 
 5.3 
 
 1.0 
 
 9.5 
 15.9 
 24.9 
 
 0.2 
 23.1 
 33.2 
 19.3 
 
 8.0 
 27.2 
 
 5.8 
 17.6 
 18.4 
 
 2o;o 
 
 29.3 
 
 29.3 
 77.3 
 32.7 
 
 6.6 
 27.3 
 24.7 
 12.6 
 17.2 
 27.9 
 11.4 
 — 39.4 
 
 2.5 
 14.4 
 14.0 
 33.1 
 
 9.5 
 24.3 
 28.2 
 15.4 
 14.3 
 16.4 
 
 7.8 
 15.6 
 11.8 
 21.2 
 27.4 
 
 40.6 
 52.2 
 31.6 
 13.8 
 38.2 
 23.1 
 13.8 
 15.6 
 10.4 
 22.7 
 
 -3.3 
 2.8 
 10.7 
 20.8 
 23.2 
 15.1 
 19.7 
 28.9 
 18.2 
 
 —20.3 
 18.4 
 10.1 
 18.3 
 38.5 
 28.2 
 26.7 
 
 N., clear. 
 
 N., fair. 
 
 S.,fair. 
 
 NW.,fair. 
 
 S., clear. 
 
 S., It. rain, cloudy. 
 
 W.,fair. 
 
 SW., clear. 
 
 SW. , cloudy. It. rain . 
 
 W.,fair. 
 
 N., cloudy. It. rain. 
 
 N., cloudy. 
 
 NW., clear. 
 
 NW., fair. 
 
 NE., It. rain. 
 
 W., cloudy, rain. 
 
 W., cloudy, fair. 
 
 SW., clear. 
 
 NW., clear. 
 
 E., It. rain. 
 
 W., fair. 
 
 NE., cloudy. It. rain. 
 
 W., clear, cloudy. 
 
 SW., clear. 
 
 SW.,fair. 
 
 NE., cloudy. 
 
 W., cloudy. 
 
 2 
 
 3 
 
 4 
 
 5 
 
 6 
 
 8 
 
 9 
 
 10 , 
 
 11 
 
 12 
 
 13 
 
 15 
 
 16 : 
 
 17 
 
 18 
 
 19 
 
 20 
 
 22. 
 
 23 
 
 24 
 
 25 
 
 26 ...1. 
 
 27 
 
 29 
 
 30 
 
 Sums .. 
 
 541.5 
 20.8 
 
 512.4 
 20.5 
 
 504.9 
 19.4 
 
 484.5 
 18.6 
 
 518.0 
 19.9 
 
 Means 
 
 
 DECEMBER, 1886. 
 
 1 
 
 24.6 
 11.8 
 26.8 
 28.4 
 9.9 
 
 — 8.8 
 38.1 
 56.0 
 67.0 
 37.5 
 24.6 
 40.6 
 17.6 
 
 1,307.0 
 61.0 
 
 — 39.0 
 71.0 
 30.9 
 75.6 
 66.0 
 60.0 
 11.0 
 21.9 
 27.2 
 
 ^ 24.6 
 # 88.9 
 
 — 67.6 
 
 15.3 
 66.8 
 13.6 
 22.9 
 11.1 
 
 — 7.0 
 33.0 
 46.0 
 52.5 
 
 "2i.'5' 
 
 28.7 
 
 7.8 
 
 957.0 
 
 102.0 
 
 -108.5 
 
 21.6 
 
 59.4 
 
 27.9- 
 
 37.0 
 
 22.5 
 
 14.7 
 
 18.2 
 
 17.4 
 
 31.7 
 
 85.0 
 
 — 53.4 
 
 26.3 
 
 '"'39.'8 
 10.6 
 14.4 
 25.7 
 44.8 
 28.3 
 65.4 
 40.6 
 
 — 57.0 
 30.8 
 
 — 5.1 
 295.0 
 
 34.0 
 , 50.3 
 17.9 
 49.8 
 81.8 
 41.8 
 22.6 
 11.8 
 33.7 
 17.4 
 14.9 
 88.8 
 
 — 69.6 
 
 32.9 
 10.8 
 36.8 
 
 "'u'.i' 
 
 540.0 
 5.8 
 38.2 
 53.4 
 40.4 
 19.3 
 25.4 
 
 — 68.8 
 30.9 
 
 - 50.6 
 
 '"is." 9' 
 
 47.5 
 38.2 
 28.2 
 22.7 
 13.1 
 8.5 
 16.4 
 10.2 
 31.6 
 -125.0 
 
 24.8 
 39.8 
 29.2 
 20.6 
 12.5 
 137.5 
 30.4 
 42.1 
 59.6 
 39.5 
 2.1 
 31.4 
 
 —12.1 
 
 647.5 
 
 61.9 
 
 —32.4 
 32.3 
 46.9 
 55.9 
 43.2 
 31.9 
 12.6 
 20.6 
 19.6 
 20.3 
 73.6 
 
 —78.9 
 
 W., cloudy. 
 
 NW., clear. 
 Do. 
 
 NW.,fair. 
 
 N., cloudy. 
 
 NE., snow. 
 
 NW., clear. 
 Do. 
 
 W. , clear. 
 Do. 
 
 NE.lt., rain. 
 
 NW.,fair. 
 
 W. It., rain. 
 
 N., snow, fair. 
 
 SW., clear. 
 
 SW. It. ,rain. 
 
 N., fair. 
 
 W., clear. 
 
 N., cloudy. 
 
 NE.,fair. 
 
 SE.. fog. It. rain. 
 
 NW., clear. 
 W., snow, clear. 
 W.,fair. 
 W., cloudy. 
 NE.lt., snow. 
 NE., sleet, rain. 
 
 W., cloudy. 
 
 2 
 
 3 
 
 4 
 
 6 : 
 
 7 
 
 8 
 
 9 
 
 10 
 
 11 
 
 13 
 
 14 
 
 15 
 
 16 
 
 17 
 
 18 
 
 ao 
 
 21 
 
 22 
 
 23 
 
 24 
 
 25 
 
 27 
 
 28 
 
 29 
 
 30 
 
 31 
 
 
 2,112.6 
 78.2 
 
 1,544.7 
 59.4 
 
 954.8 
 36.7 
 
 940.7 
 37.6 
 
 1402.4 
 51.9 
 
 
 
224 
 
 MBMOIES OF THE NATIONAL ACADEMY OF SCIENCES. 
 
 Table 0. — Daily observations with hourly, daily, monthly, and annual means, New Haven, Conn., 
 
 August 1, 1886 to July 31, 1887^0ontinued. 
 
 JANUARY, 1837. 
 
 •• Day of montli. 
 
 9a.ln. 
 
 11 a. m. 
 
 1 p.m. 
 
 3 p.m. 
 
 Means. 
 
 '" Bemarks. 
 
 1 
 
 16.4 
 36.0 
 55.7 
 
 ■ 56.6 
 30.9 
 49.3 
 12.8 
 35.2 
 28.0 
 24.7 
 51.4 
 
 —39.9 
 20.1 
 
 —22.3 
 67.7 
 42.6 
 32.4 
 45.9 
 7.2 
 
 —10.7 
 43.7 
 27.0 
 26.2 
 54.4 
 13.7 
 28.8 
 
 — 96.6 
 32.6 
 76.9 
 46.0 
 45.7 
 27.5 
 14.5 
 27.8 
 32.2 
 25.9 
 33.2 
 27.7 
 13.4 
 
 —146. 2 
 44.4 
 34.9 
 87.1 
 34.0 
 18.4 
 
 — 57.0 
 44.3 
 11.3 
 28.5 
 27.7 
 11.0 
 15.4 
 
 3.3 
 31.5 
 69.7 
 38.9 
 40.7 
 20.0 
 24.4 
 15.9 
 ■28.5 
 25.9 
 22.6 
 39.9 
 27.6 
 9.0 
 21.7 
 28.2 
 57.1 
 16.2 
 28.1 
 
 —96.6 
 54.4 
 
 —77.2 
 26.9 
 24.3 
 
 —44.8 
 16.0 
 
 19.4 
 34.4 
 40.6 
 31.1 
 21.6 
 17.0 
 38.3 
 6.2 
 10.2 
 38.8 
 66.9 
 2.2 
 23.7 
 28.3 
 39.4 
 22.0 
 43.9 
 16.0 
 34.7 
 2.4 
 31.8 
 37.6 
 28.1 
 25.5 
 —.52. 8 
 17.2 
 
 —14.4 
 33.6 
 58.2 
 40.6 
 " 34.7 
 28.4 
 22.5 
 21.3 
 24.7 
 28.8 
 43.5 
 7.5 
 21. 2 
 
 —32.8 
 43.3 
 31.9 
 55.1 
 28.0 
 22.1 
 
 —40.5 
 43.6 
 
 —00.3 
 27.4 
 33.0 
 
 —18.2 
 19.3 
 
 NE., rain, fog. 
 NW., clear. 
 NE., clear. 
 NE., cloudy, sno-w. 
 NW.,falr, 
 
 Do. 
 NE., clear, hazy. 
 NW.,fair. 
 W., clear. 
 SW., fair. 
 W., hazy, clear. 
 N. , rain, cloudy. 
 NE., cloud V, snow. 
 NE.,lt. rain. 
 W. , clear. 
 W. , clear, cloudy. 
 Var. , cloudy. 
 W.,fair. 
 NE. , cloudy. 
 SW., It. rain, hvy. rain. 
 S. , cloudy. 
 N., cloudy, snow. 
 NW., clear. 
 SW., cloudy. 
 SW., cloudy, hvy. rain. 
 NW.,fair. 
 
 NE., cloudy. 
 
 3 
 
 4 . 
 
 5 
 
 6 
 
 7 
 
 8 
 
 10 
 
 11 
 
 12 
 
 13 
 
 14 
 
 15 
 
 17 
 
 18 
 
 19 
 
 20... . 
 
 21 
 
 22 
 
 24 
 
 25 
 
 26 
 
 27 
 
 28 
 
 29 
 
 31 
 
 
 733.8 
 28.2 
 
 460 6 
 
 ii9 Q 
 
 614.5 
 23.6 
 
 662. 5 
 21.6 
 
 Means 
 
 17' 7 17' n 1 
 
 
 
 
 1 
 
 9. 
 10. 
 11. 
 12. 
 14. 
 15. 
 16. 
 17. 
 18. 
 19. 
 21. 
 22. 
 23. 
 24.. 
 25. 
 26., 
 27.. 
 28.. 
 
 Sums-- 
 Means . 
 
 FEBEUARY, 1887. 
 
 12.0 
 —394. 3 
 11.6 
 17.6 
 29.9 
 
 - 3.5 
 
 - 1.1 
 16.9 
 82.8 
 93.0 
 14.2 
 22.5 
 
 - 53.7 
 79.4 
 33.2 
 91.3 
 10.7 
 22.6 
 
 198.0 
 40.8 
 20.8 
 12.1 
 20.4 
 13.0 
 66.0 
 
 153. 9 
 6.2 
 
 17.9 
 402.9 
 16.3 
 19.2 
 34.4 
 4.9 
 
 - 11.8 
 16.8 
 32.4 
 23.8 
 13.6 
 28.5 
 10.7 
 27.0 
 13.6 
 9.4 
 13.0 
 20.2 
 
 -111.0 
 19.8 
 14.3 
 16.6 
 20.4 
 
 37.8 
 
 680.7 
 28.4 
 
 26.6 
 27.6 
 19.7 
 16.8 
 40.1 
 11.4 
 7.9 
 14.2 
 16.6 
 20.0 
 12.4 
 24.5 
 18.0 
 26.4 
 11.6 
 81.6 
 20.9 
 28.6 
 13.0 
 18.2 
 10.7 
 12.7 
 65.2 
 11.2 
 15.8 
 
 2g.6 
 
 10.6 
 
 2.0 
 
 31.7 
 -24.8 
 25.4 
 17.0 
 36.4 
 9.2 
 17.0 
 18.6 
 30.1 
 15.4 
 11.8 
 -14.2 
 15.2 
 31.8 
 13.6 
 22.2 
 13.6 
 16.6 
 41.6 
 
 11.8 
 
 561.7 
 22.5 
 
 378.2 
 16.4 
 
 20.5 
 11.7 
 12.4 
 17.9 
 34.0 
 
 — 3.0 
 5.1 
 16.2 
 42.0 
 36.5 
 14.3 
 23.5 
 1.3 
 37.0 
 17.6 
 
 -3.6 
 15.0 
 25.8 
 28.4 
 25. •> 
 14.8 
 14.5 
 36.9 
 12.1 
 32.8 
 
 488.9 
 19.6 
 
 N. , cloudy. 
 NE.,snow^ cloudy. 
 N., cloudy, snow, rain. 
 NW.,fair. 
 N.,fair. 
 
 NE., cloudy, sleet. 
 E. It., rain. 
 NW., clear. 
 SW., fair. 
 
 SW., foggy, threatening. 
 NW., clear. 
 NE., clear. 
 
 SW., hvy. rain. It. rain. 
 NW., cloudy. 
 NW.,tair. 
 
 E., sleet, cloudy. It. rain. 
 W., clear. 
 N. , cloudy. 
 
 SE., hvy. snow. It, rain. 
 NE., cloudy. 
 W., It., rain, cloudy. 
 NW., clear. 
 
 NE., cloudy, hvy. snow. 
 W.,fair. 
 Do. 
 
 NW., cloudy. 
 
MEMOIES OF THE NATIONAL ACADEMY OF SCIENCES. 
 
 225 
 
 Table O. — Daily observations with hourly, daily, monthly, and annual means, New Raven, Conn., 
 
 August 1, 1886, to July 31, 1887— Coutinued, 
 
 MARCH, 1887. 
 
 Day of month. 
 
 1 
 
 2 
 
 3 
 
 4 
 
 5 
 
 7 
 
 8 
 
 9 
 
 10 
 
 11 
 
 12 
 
 14 
 
 15 
 
 16 
 
 17 
 
 18 
 
 19 
 
 21 
 
 22 
 
 23 
 
 24 
 
 25 
 
 26 
 
 28 
 
 29 
 
 30 
 
 31 
 
 Sums. 
 Means 
 
 9 a. m. 11 a. m. 1 p. m. 
 
 14.0 
 12.4 
 
 6.9 
 38.0 
 52.5 
 47.3 
 22.3 
 30.8 
 81.4 
 13.3 
 13.9 
 20.6 
 
 6.1 
 12.4 
 18.1 
 14.7 
 17.1 
 .8 
 
 36. 
 —135. 
 17. 
 18. 
 34. 
 19. 
 
 104. 
 
 10.3 
 
 16.4 
 
 7.4 
 
 180.1 
 6.7 
 
 13. 
 10. 
 16. 
 28. 
 40. 
 47. 
 16. 
 20. 
 -136. 
 14. 
 16. 
 17. 
 11. 
 18. 
 24. 
 22. 
 17. 
 45. 
 22. 
 32. 
 23. 
 39. 
 26. 
 7. 
 25. 
 31. 
 32. 
 
 486.0 
 18.0 
 
 16.2 
 15. 8 
 14.2 
 33.6 
 37.8 
 30.3 
 12.3 
 20.2 
 11.0 
 14.1 
 21.7 
 18.2 
 19.8 
 21.2 
 24.5 
 23.5 
 21.9 
 26.6 
 
 3.8 
 26.5 
 19.4 
 25.4 
 26.6 
 15.4 
 13.8 
 28.8 
 
 6.0 
 
 548.6 
 20.3 
 
 3 p. m. Means. 
 
 1.3.8 
 18.8 
 10.9 
 16.8 
 36.2 
 51.0 
 11.9 
 14.2 
 9.0 
 17.8 
 19.8 
 17.4 
 15.7 
 23.1 
 
 20, 
 25, 
 15, 
 22, 
 94. 
 13. 
 20, 
 17.3 
 28.3 
 35.6 
 9.7 
 20.5 
 16.4 
 
 615. 
 22. 
 
 14.3 
 14.4 
 12.0 
 29.1 
 41.8 
 44.0 
 15.6 
 21.4 
 
 -49.4 
 15.0 
 18.0 
 18.5 
 13.2 
 18.8 
 21.9 
 21.5 
 17.9 
 32.8 
 
 -3.8 
 22.6 
 20.6 
 29.2 
 25.0 
 
 -11.3 
 14.7 
 24.2 
 15.6 
 
 457. 6 
 16.9 
 
 He marks. 
 
 N., cloudy, snow, fair. 
 
 SW., cloudy. 
 
 NE.,fair. 
 
 N., cloudy. 
 
 NE., clear, cloudy. 
 
 E., clear. 
 
 N., clear. 
 
 SE., clear. 
 
 N., hvy. and It. rain, cloudy. 
 
 N., fair. . 
 
 N., cloudy, clear. 
 
 N., clear, hazy, cloudy. 
 
 NW., clear. 
 
 NW.,fair. 
 
 NW., cloudy. 
 
 Do. 
 N., fair. 
 SE., fair. 
 
 NE., hvy. and It. rain, sleet. 
 W., cloudy. 
 SW., clear. 
 W., clear. 
 N., clear. 
 
 NE.,lt. rain, cloudy. 
 NW., cloudy. 
 W.,fair. 
 S., clear, cloudy. 
 
 N., cloudy. 
 
 APEIL, 1887. 
 
 1 
 
 65.6 
 166.0 
 27.5 
 10.3 
 10.4 
 26.6 
 28.1 
 18.4 
 
 7.0 
 19.0 
 
 4.4 
 14.1 
 17.4 
 
 5.7 
 —17.0 
 27.6 
 19.8 
 31.0 
 30.8 
 
 0.6 
 19.8 
 —74.8 
 63.4 
 — 2.6 
 29.4 
 30.8 
 
 49.8 
 
 88.5 
 
 13.1 
 
 10.6 
 
 1.4 
 
 4.2 
 
 21.8 
 
 19.5 
 
 •24.2 
 
 9.6 
 
 12.0 
 
 4.7 
 
 6.0 
 
 12.9 
 
 -42.9 
 
 13.1 
 
 17.6 
 
 15.7 
 
 28.2 
 
 26.8 
 
 17.2 
 
 11.4 
 
 19.4 
 
 26.6 
 
 5.8 
 
 12.2 
 
 8.4, 
 
 22.8 
 
 17,5 
 
 6.7 
 
 6.1 
 
 4,9 
 
 19,5 
 
 14,6 
 
 3,9 
 
 18,4 
 
 9.0 
 
 — 9.3 
 4.1 
 
 24.1 
 24.9 
 
 9.5 
 23.0 
 12.2 
 10.2 
 
 9.8 
 16.6 
 
 7.7 
 24.4 
 16.8 
 
 — 3,0 
 3.6 
 
 12.1 
 
 151.0 
 
 5.7 
 
 8.1 
 
 7.8 
 
 3.6 
 
 21.0 
 
 17.2 
 
 1.6 
 
 9.0 
 
 7.7 
 
 5.7 
 
 — 7.0 
 
 25.4 
 
 26.3 
 
 13.4 
 
 17.6 
 
 U.l 
 
 32.0 
 
 19.0 
 
 21.8 
 
 58.2 
 
 —13.8 
 
 1.0 
 
 94.0. 
 
 2.S 
 
 34.0 
 
 107.1 
 
 16.0 
 
 8.9 
 
 6.4 
 
 9.8 
 
 22.6 
 
 17.4 
 
 9.2 
 
 14.0 
 
 8.3 
 
 3.8 
 
 5.1 
 
 17.0 
 
 — 2.2 
 
 15.9 
 
 19.5 
 
 17.5 
 
 25.3 
 
 14.0 
 
 18.8 
 
 0.6 
 
 23.4 
 
 10.4 
 
 31.6 
 
 12.3 
 
 NE., It. snow. 
 
 Do. 
 SW.,fair. 
 W., cloudy. 
 NW., clear. 
 NW., fair 
 S., clear. 
 SW., cloudy. 
 W., fair. 
 S., cloudy. ^ 
 NE., cloudy. 
 Var., cloudy. 
 E., cloudy. 
 NW., cloudy. 
 NE., cloudy. It. snow 
 NW., cloudy, clear. 
 Var., fair. 
 SE.,fair. 
 S., fair. 
 E.,lt. rain, 
 SE., clear, cloudy. 
 W. It. rain, cloudy. 
 SW., cloudy. 
 E.,lt. rain, cloudy. 
 SW., cloudy. 
 NW., cloudy. 
 
 NW., cloudy. 
 
 sleet. 
 
 2 
 
 4 
 
 5 
 
 6 . . , 
 
 7 
 
 8 
 
 9 
 
 11 
 
 12 
 
 13 
 
 14 
 
 15 
 
 16 
 
 18 
 
 19 
 
 20 
 
 21 
 
 22 ...-. 
 
 23 
 
 25 
 
 26 
 
 27 
 
 28 
 
 29 
 
 30 
 
 
 579. 3 
 22.3 
 
 429.4 
 16.5 
 
 304.4 
 11.7 
 
 552.1 
 21.2 
 
 466.8 
 18.0 
 
 
 
 S. Mis. 94- 
 
 jfOTB. On and after April 19 obaervations were made at 7 a. m. instead of 9 a. m. 
 
 -15 
 
226 
 
 MBMOIES OF THE NATIONAL ACADEMY OF SCIENCES. 
 
 Table G.— Daily observations with hourly, daily, monthly, and annual means, New Haven, Conn., 
 
 August 1, 1886, to July, 31, 1887— Continued. 
 
 MAY, 1887. 
 
 Day of month. 
 
 7 a.m. 
 
 11a.m. 
 
 1p.m. 
 
 3 p.m. 
 
 Means. 
 
 Bemarkg. 
 
 2 
 
 18.2 
 
 19.8 
 
 21.2 
 
 8.8 
 
 8.5 
 
 5.6 
 
 28.1 
 
 28.3 
 
 13.7 
 
 — 2.1 
 '7.8 
 
 10.4 
 27.8 
 
 3.0 
 34.0. 
 18.4 
 
 4.5 
 19.5 
 25.3 
 
 2.3 
 11.3 
 95.5 
 23.8 
 
 — 4.4 
 14.9 
 13.7 
 
 10.8 
 
 6.1 
 
 28.2 
 
 11.7 
 
 7.3 
 
 — 8.0 
 28.3 
 31.2 
 
 — 5.4 
 
 — 2.0 
 13.7 
 
 6.9 
 
 16.0 
 
 7.4 
 
 8.2 
 
 1.6 
 
 10.5 
 
 13.5 
 
 18.3 
 
 10.2 
 
 17.7 
 
 29.0 
 
 25.4 
 
 2.6 
 
 23.7 
 
 7.6 
 
 10.2 
 5.6 
 
 19.0 
 5.5 
 
 19.7 
 0.3 
 
 26.5 
 
 34.0 
 
 0.6 
 
 -10.2 
 
 5.9 
 
 6.2 
 
 21.4 
 7.0 
 8.6 
 —12.8 
 0.8 
 1.8 
 
 10.2 
 
 - 8.3 
 
 , 58.0 
 
 64.3 
 
 14.6 
 4.1 
 
 14.7 
 1.6 
 
 15.6 
 
 6.5 
 
 —13.3 
 
 5.9 
 
 5.2 
 
 —13.7 
 
 16.8 
 
 30.3 
 
 — 0.9 
 
 — 0.1 
 16.4 
 25.8 
 11.4 
 
 5.2 
 13.0 
 
 2.7 
 
 5.2 
 10.5 
 
 8.4 
 
 — 8.7 
 11.0 
 35.9 
 
 7.7 
 
 5.3 
 
 14.2 
 
 3.8 
 
 13.7 
 9.5 
 
 13.8 
 8.0 
 
 10.2 
 
 — 4.0 
 24.9 
 31.0 
 
 2.0 
 
 — 3.6 
 11.0 
 12.3 
 19.2 
 
 5.6 
 16.0 
 
 2.5 
 
 5.2 
 11.3 
 15.6 
 -1.1 
 24.5 
 56.2 
 17.9 
 
 1.9 
 16. 9 
 
 6.7 
 
 SE., clear, cloudy. 
 E., cloudy. 
 S., cloudy. 
 
 Do. 
 E., cloudy. 
 
 Do. 
 S., cloudy. 
 S., fair. 
 Jf., clear. 
 N., cloudy, hazy. 
 N., clear. 
 NE., fair. 
 S., hazy. 
 
 Do. 
 SE., hazy. 
 N., clear. 
 SW.,hazy. 
 
 Do. 
 W., cloudy. 
 
 S., cloudy. It. rain, cloudy. 
 S., It. rain, cloudy. 
 S., cloudy. 
 S., clear, 3-10 clouds. 
 NE., cloudy. 
 SE., cloudy. 
 E., cloudy. 
 
 S., cloudy. 
 
 3 
 
 4 
 
 5 
 
 6 
 
 7 
 
 9 
 
 10 
 
 11 
 
 12 
 
 13 
 
 14 
 
 16.... 
 
 17 
 
 18 
 
 19 
 
 20 
 
 21 
 
 23 
 
 24 
 
 25 
 
 26 ; 
 
 27 
 
 28 
 
 30 
 
 31 
 
 
 457.9 
 17.6 
 
 320.5 
 12.3 
 
 308.4 
 11.9 
 
 220.8 
 8.5 
 
 327.2 
 12.1 
 
 MeauB .. ...*.. 
 
 
 JUNE, 1887. 
 
 1 
 
 2 
 
 3 
 
 4 
 
 6 
 
 r 
 
 8 
 
 9 
 
 10 
 
 11 
 
 13 
 
 14... 
 
 15 
 
 16 
 
 17 
 
 18 J. 
 
 20 
 
 21 , 
 
 22 
 
 23 
 
 24 
 
 25 
 
 27 
 
 28 
 
 29 
 
 30 
 
 Sums. 
 Means 
 
 —168.8 
 
 1.0 
 
 21.2 
 
 18.0 
 
 —32.1 
 
 14.8 
 
 59.4 
 
 16.6 
 
 28.2 
 
 29.7 
 
 19.0 
 
 31.3 
 
 22.0 
 
 14.8 
 
 21.8 
 
 11.6 
 
 13.2 
 
 10.8 
 
 17.0 
 
 13.2 
 
 16.4 
 
 21.3 
 
 35.6 
 
 36.0 
 
 - 27.3 
 
 16.5 
 
 16.9 
 
 35.6 
 
 55.1 
 
 31.0 
 
 18.5 
 
 34.1 
 
 7.1 
 
 10.0 
 
 17.4 
 
 10.8 
 
 0.9 
 
 2.5 
 
 9.4 
 
 5.9 
 
 17.5 
 
 15.9 
 
 16.4 
 
 13.0 
 
 15.7 
 
 16.0 
 
 15.4 
 
 11.5 
 
 41.5 
 
 21.1 
 
 41.0 
 
 10.9 
 
 6.8 
 
 14.7 
 
 18.3 
 
 18.0 
 
 8.7 
 
 4.0 
 
 6.7 
 
 9.3 
 
 25.0 
 
 20.1 
 
 36.5 
 
 18.5 
 
 25.0 
 
 18.4 
 
 6.7 
 
 4.4 
 
 14.0 
 
 10.9 
 
 6.7 
 
 1.3 
 
 
 16.7 
 
 8.3 
 
 35.3 
 
 13.1 
 
 26.3 
 
 22.0 
 
 24.2 
 
 6.7 
 
 38.9 
 
 8.7 
 
 7.3 
 
 15.4 
 
 26.9 
 
 17.1 
 
 12.6 
 
 8.7 
 
 16.3 
 
 28.7 
 
 29.1 
 
 6.0 
 
 15.1 
 
 19.7 
 
 10.8 
 
 14.8 
 
 — 2.0 
 
 —342. 
 
 —79.6 
 
 13.8 
 
 59.0 
 
 12.5 
 
 11.1 
 
 24.1 
 
 8.7 
 
 13.4 
 
 9.5 
 
 9.3 
 
 10.2 
 
 9.5 
 
 7.4 
 
 7.0 
 
 
 8.0 
 
 18.0 
 
 31.5 
 
 19.0 
 
 11.6 
 
 20.0 
 
 24.6 
 
 55.5 
 
 10.5 
 
 24.0 
 
 28.6 
 
 27.0 
 
 26.8 
 
 6.5 
 
 9.1 
 
 17.4 
 
 291.4 
 
 563.7 
 
 357.6 
 
 89.8 
 
 327.1 
 
 11.2 
 
 21.7 
 
 14.3 
 
 3.5 
 
 12,6 
 
 E.,hvy. rain, cloudy. 
 SE.,lt. rain, cloudy. 
 SW., cloudy. 
 Var., cloudy. 
 SE., cloudy. 
 S., It. rain, cloudy. 
 S., cloudy, It. rain, cloudy. 
 NW., fair, cloudy. 
 E., cloudy. 
 NE., clear. 
 NE., fair. 
 Do. 
 S., clear. 
 SW., cloudy, 
 S., cloudy. It. rain. 
 S.,oloudy, It. rain, cloudy. 
 S., cloudy. 
 
 E.,fog, hazy, cloudy. 
 S., cloudy, It. rain, cloudy. 
 S. , It. rain, h vy. rain. 
 SW., cloudy. 
 S., fair. 
 N., fair. 
 Var., fair. 
 S., clear. 
 W., clear. 
 
 8., cloudy. 
 
MBMOIES OF THE NATIONAL ACADEMY OF SCIENCES. 227 
 
 Table C— Daily observations with hourly, daily, monthly, and annual means. New Haven, Conn., 
 
 August 1, 1886, to July 31, 1887— Continued. 
 
 JULY, 1887. 
 
 Day of mouth. 
 
 1 
 
 2 
 
 4 
 
 5 
 
 6 
 
 7 
 
 8 
 
 9 
 
 11 
 
 12 
 
 13 
 
 14 
 
 Xh 
 
 16 
 
 18...: 
 
 19 
 
 20 
 
 21 
 
 22 
 
 23 
 
 25 
 
 26 
 
 27 
 
 28 
 
 29 
 
 30 
 
 Sums. 
 Means 
 
 7 a. m. 
 
 11 a. m. 
 
 1 p. ni. 
 
 3 p.m. 
 
 Means. 
 
 10.9 
 
 28.5 
 
 33.0 
 
 22.5 
 
 23.7 
 
 27.5 
 
 32.0 
 
 39.5 
 
 14.0 
 
 2^.2 
 
 13.0 
 
 4.1 
 
 6.8 
 
 7.5 
 
 7.9 
 
 13.0 
 
 4.5 
 
 11.5 
 
 5.3 
 
 8.6 
 
 88.5 
 
 4.7 
 
 1.7 
 
 2.2 
 
 24.3 
 
 5.9 
 
 1.5 
 
 1.2 
 
 3.8 
 
 3.1 
 
 16.0 
 
 23.7 
 
 39.7 
 
 6.4 
 
 21.4 
 
 28.2 
 
 20.3 
 
 24.3 
 
 12.5 
 
 21.3 
 
 61.5 
 
 9.4 
 
 4.5 
 
 11.7 
 
 21.8 
 
 12.0 
 
 4.5 
 
 1.0 
 
 7.0 
 
 6.1 
 
 —35.5 
 
 18.0 
 
 13.0 
 
 
 —1.5 
 
 19.8 
 
 — 2.0 
 
 — 15.0 
 
 2.5 
 
 1.3 
 
 14.5 
 
 5.5 
 
 5.0 
 
 9.0 
 
 8.5 
 
 36.5 
 
 14.2 
 
 33.0 
 
 38.0 
 
 30.2 
 
 50.5 
 
 27.6 
 
 —531. 
 
 11.5 
 
 —110.4 
 
 17.2 
 
 99.5 
 
 23.0 
 
 
 46.6 
 
 17.5 
 
 22.7 
 
 29.0 
 
 20.6 
 
 22.3 
 
 32.3 
 
 20.8 
 
 27.2 
 
 —209. 3 
 
 -32.2 
 
 — 6.0 
 
 6.0 
 
 5.1 
 
 4.0 
 
 2.3 
 
 10.7 
 
 2.7 
 
 3.0 
 
 
 5.5 
 
 4.5 
 
 3.0 
 
 5.3 
 
 17.0 
 
 7.4 
 
 21.5 
 
 12.3 
 
 9.0 
 
 10.5 
 
 13.3 
 
 17.5 
 
 S2.5 
 
 16.5 
 
 10.5 
 
 16.8 
 
 23.5 
 
 28.5 
 
 17.0 
 
 19.5 
 
 22.1 
 
 21.0 
 
 12.7 
 
 20.5 
 
 8.3 
 
 1.5.6 
 
 4.5 
 
 7.0 
 
 9.5 
 
 9.9 
 
 7.7 
 
 526.5 
 
 434.2 
 
 —167. 7 
 
 44.2 
 
 221.9 
 
 20.2 
 
 16.7 
 
 — 6.5 
 
 1.9 
 
 8.5 
 
 Kemarkn. 
 
 SW.,fair. 
 
 SW., clear. 
 
 SW., cloudy, clear. 
 
 S., cloudy. 
 
 8., It. rain, cloudy. 
 
 W., cloudy, fair. 
 
 SW.,fair. \ 
 
 S., cloudy. 
 
 NW. , cloudy. 
 
 NW.,falr. 
 
 W., cloudy. 
 
 N., clear, fair. 
 
 NW., cloudy. 
 
 S., cloudy, clear. 
 
 NE., cloudy, It. rain,'cloudy. 
 
 SE., cloudy. 
 
 S., cloudy, clear. 
 
 S., cloudy. It. rain. 
 
 S., hvy. rain, cloudy. 
 
 S., cloudy. It. rain. 
 
 S., It. rain, cloudy. 
 
 S., cloudy, fair. 
 
 Do. 
 S., cloudy, clear. 
 SW., cloudy. 
 S., cloudy. 
 
 S., cloudy. 
 
 SUMMARY MEAN POTENTIAL AT NEW HAVEN. 
 
 Months. 
 
 1 p. m. 
 
 3 p. m. 
 
 Means. 
 
 August, 1886 
 
 September, 1886 
 October, 1886... 
 November, 1886: 
 December, 1886 . 
 January, 1887 . . 
 February, 1887 . 
 March, 1887.... 
 
 April, 1887 
 
 May, 1887 
 
 June, 1887 
 
 July, 1887 
 
 Sums 
 
 Means 
 
 161.0 
 209.0 
 271.8 
 541.5 
 2, 112. 6 
 733.8 
 153.9 
 180.1 
 *5r9. 3 
 457.9 
 291.4 
 526.5 
 
 6,218.8 
 21.5 
 
 198.9 
 139.0 
 387. 9 
 512.4 
 1,544.6 
 460.6 
 680.7 
 486.0 
 429.4 
 320.5 
 563.7 
 434.2 
 
 132.4 
 140.7 
 412.7 
 504.9 
 954.8 
 442.2 
 561.7 
 548.6 
 304.4 
 308.4 
 357.6 
 —167.7 
 
 180.6 
 113.4 
 245.3 
 484.5 
 940.7 
 614.5 
 378.2 
 615.8 
 552.1 
 220.8 
 89.8 
 44.2 
 
 6, 157. 9 
 21.6 
 
 4,500.7 
 16.1 
 
 4, 479. 9 
 16.6 
 
 168.2 
 150.5 
 329,4 
 510.8 
 1, 388. 2 
 562.8 
 443.6 
 457.6 
 466.3 
 326.9 
 325.6 
 209.3 
 
 5, 339. 2 
 18.9 
 
 ' 7 a. m. 
 
228 
 
 MEMOIES OF THE lirATIO^AL ACADEMY OP SOIENOES. 
 
 Table C — Daily observations with hourly, daily, monthly, and annual means, New Ma/oen, Conn,, 
 ^ August 1, 1886, to July 31, 1887— Continued. 
 
 SUMMARY MEAN POTENTIAL AT NEW HAVEN— Continued. 
 [From actual readings. ] 
 
 Slontlis. 
 
 August, 1886 
 
 September, 1886 
 
 October, 1886 
 
 November, 1886 
 
 December, 1886 
 
 January, 1887 
 
 February, 1887 
 
 March, 1887 
 
 April, 1887 
 
 May, 1887 
 
 June, 1887 
 
 July, 1887 
 
 Sums 
 
 Means 
 
 9 a. m. 
 
 10.1 
 
 23.2 
 
 10.8 
 
 20.8 
 
 78.2 
 
 28.2 
 
 6.2 
 
 6.7 
 
 *22.3 
 
 17.6 
 
 11.2 
 
 20.2 
 
 255.5 
 21.3 
 
 13.3 
 14.3 
 .15.5 
 20.5 
 59.4 
 17.7 
 28.4 
 18.0 
 16.5 
 12.3 
 21.7 
 16. T 
 
 1 p.m. 
 
 254.3 
 21.2 
 
 8.8 
 17.6 
 17.2 
 19.4 
 36.7 
 17.0 
 22.5 
 20.3 
 11.7 
 11.9 
 14.3 
 -6.5 
 
 190.9 
 15.9 
 
 3 p.m. 
 
 [Relative values.] 
 
 August, 1886 ... 
 September, 1886 
 October, 1886... 
 November, 1886. 
 December, 1886 . 
 January, 1887 . . 
 Februarv, 1887 . 
 March, 1887 .... 
 April, 1887 1.... 
 
 May, 1887 
 
 June, 1887 
 
 July, 1887 
 
 Sums 
 
 Means 
 
 .92 
 1.34 
 
 .77 
 1.05 
 1.48 
 1.31 
 
 .34 
 
 .39 
 
 "1.25 
 
 1.40 
 
 .88 
 2.49 
 
 13.62 
 1.14 
 
 1.21 
 
 .83 
 
 1.11 
 
 1.04 
 
 1.12 
 
 .82 
 
 1.54 
 
 1.06 
 
 .92 
 
 .98 
 
 L71 
 
 2.06 
 
 14.40 
 1.20 
 
 .80 
 
 1.02 
 
 1.23 
 
 .98 
 
 .69 
 
 .79 
 
 1.22 
 
 L19 
 
 .65 
 
 .94 
 
 1.13 
 
 - .80 
 
 9.84 
 .82 
 
 12.0 
 
 14.2 
 
 12.3 
 
 18.6 
 
 37.6 
 
 23.6 
 
 16.4 
 
 22.8 
 
 2L2 
 
 8.5 
 
 3.5 
 
 1.9 
 
 192.6 
 16.0 
 
 1.09 
 .82 
 
 .94 
 
 .71 
 
 L09 
 
 .89 
 
 1.34 
 
 1.18 
 
 .28 
 .23 
 
 10.13 
 
 .84 
 
 11.0 
 17.3 
 14.0 
 19.8 
 53.0 
 2L6 
 18.4 
 17.0 
 17.9 
 12.6 
 12.7 
 8.1 
 
 223.4 
 18.6 
 
 1.00 
 1.00 
 1.00 
 1.00 
 1.00 
 1.00 
 1.00 
 1.00 
 1.00 
 1.00 
 LOO 
 1.00 
 
 12.00 
 LOO 
 
 * 7 a. m. 
 
MEMOIRS OF THE NATIONAL ACADEMY OP SCIENCES. 
 
 229 
 
 Table B.—Potential on clear and fair days, Terre Raute, Ind., April 1, 1887, to August 31, 1888. 
 
 Date. 
 
 April 5 . 
 April 7 ., 
 April 8 . , 
 April 9 .. 
 Aprilll . 
 Aprill2. 
 ApriU9. 
 April sJ5 . 
 April 30 . 
 May 4 . . . 
 
 Suras.. 
 Means. 
 
 May 7 , , 
 May9.. 
 May 10 . 
 May 12 . 
 May 13 . 
 May 16 . 
 May 18 . 
 May 19 . 
 June 3 . 
 June 8 . 
 
 Sums 
 
 Means... 
 
 June 11 . , 
 Juno 13 . . 
 June 15 . . 
 June 18.. 
 June 21 . , 
 June 24 
 Jane 27 . . 
 June 28 - . 
 June 29 . . 
 July 11 . . 
 
 Sums 
 
 Means 
 
 July 13.... 
 July 15.... 
 July 23.... 
 July 25.... 
 August 1 . . 
 jtngnst 6 .. 
 August 8 . . 
 August 12 . 
 August 13 . 
 August 16 . 
 
 Sums 
 
 Means 
 
 August 24 
 
 August 27 
 
 August 29 .*.... 
 August 31 . . . . . 
 September 15.. 
 September 21.. 
 September 24 . . 
 
 Sums. . 
 Means. 
 
 a.m 10a.m. Ua.m. 12m. Ip.m, 2p.in. 3p.m. ip.m. 6p.m. 6p.m. Means. 
 
 175 
 235 
 220 
 250 
 130 
 95 
 270 
 214 
 220 
 134 
 
 1,943 
 194 
 
 120 
 80 
 120 
 180 
 140 
 110 
 250 
 180 
 170 
 150 
 
 1,500 
 150 
 
 120 
 135 
 225 
 225 
 180 
 120 
 165 
 150 
 225 
 110 
 
 325 
 
 280 
 350 
 280 
 180 
 95 
 -235 
 173 
 266 
 167 
 
 3, 351 
 235 
 
 200 
 .'SO 
 80 
 167 
 140 
 110 
 230 
 190 
 110 
 120 
 
 400 
 160 
 310 
 210 
 310 
 330 
 205 
 188 
 253 
 167 
 
 2, ,523 
 252 
 
 1,387 
 139 
 
 135 
 200 
 135 
 150 
 190 
 120 
 150 
 140 
 205 
 110 
 
 1,655 
 166 
 
 100 
 
 60 
 
 50 
 
 80 
 
 80 
 
 160 
 
 50 
 
 110 
 
 130 
 
 170 
 
 990 
 99 
 
 130 
 
 120 
 70 
 
 110 
 30 
 50 
 
 130 
 
 1,535 
 154 
 
 110 
 
 85 
 
 50 
 
 90 
 
 70 
 
 130 
 
 70 
 
 150 
 
 110 
 
 100 
 
 180 
 90 
 80 
 153 
 140 
 100 
 180 
 180 
 140 
 120 
 
 1,363 
 136 
 
 150 
 225 
 120 
 150 
 195 
 120 
 120 
 130 
 180 
 120 
 
 200 
 150 
 200 
 130 
 140 
 75 
 135 
 204 
 200 
 156 
 
 1, ,590 
 159 
 
 150 
 100 
 80 
 140 
 160 
 150 
 180 
 170 
 170 
 100 
 
 1,400 
 140 
 
 1,510 
 151 
 
 965 
 96 
 
 640 
 91 
 
 150 
 110 
 50 
 80 
 60 
 50. 
 1.50 
 
 650 
 93 
 
 120 
 110 
 
 50 
 160 
 
 70 
 200 
 
 70 
 140 
 120 
 110 
 
 1,150 
 115 
 
 130 
 80 
 70 
 
 100 
 
 110 
 50 
 
 140 
 
 135 
 
 115 
 105 
 105 
 172 
 120 
 130 
 130 
 190 
 120 
 
 200 
 150 
 190 
 155 
 155 
 130 
 275 
 219 
 146 
 146 
 
 1,766 
 177 
 
 140 
 
 90 
 
 80 
 
 140 
 
 180 
 
 150 
 
 -140 
 
 180 
 
 200 
 
 100 
 
 1,400 
 140 
 
 1,302 
 130 
 
 100 
 90 
 40 
 
 . 70 
 50 
 
 130 
 80 
 
 120 
 90 
 
 130 
 
 890 
 
 89 
 
 130 
 90 
 120 
 130 
 110 
 55 
 135 
 
 680 
 97 
 
 130 
 100 
 105 
 150 
 150 
 30 
 120 
 130 
 180 
 120 
 
 220 
 150 
 225 
 200 
 150 
 150 
 270 
 263 
 137 
 156 
 
 1,921 
 li'3 
 
 180 
 80 
 80 
 170 
 140 
 130 
 130 
 130 
 150 
 120 
 
 1,310 
 131 
 
 1,205 
 120 
 
 100 
 80 
 30 
 60 
 40 
 
 100 
 90 
 
 110 
 90 
 
 110 
 
 810 
 81 
 
 100 
 80 
 
 110 
 80 
 
 110 
 60 
 
 100 
 
 750 
 107 
 
 640 
 91 
 
 135 
 110 
 105 
 130 
 150 
 W5 
 75 
 140 
 165 
 140 
 
 150 
 150 
 330 
 160 
 145 
 185 
 260 
 307 
 145 
 167 
 
 180 
 
 70 
 
 80 
 
 300 
 
 .100 
 
 100 
 
 120 
 
 80 
 
 100 
 
 1,50 
 
 1,180 
 118 
 
 1,355 
 136 
 
 90 
 
 140 
 
 30 
 
 60 
 
 40 
 
 110 
 
 120 
 
 120 
 
 100 
 
 90 
 
 900 
 90 
 
 100 
 80 
 110 
 105 
 150 
 90 
 130 
 
 150 
 120 
 105 
 120 
 150 
 180 
 75 
 150 
 1,50 
 150 
 
 145 
 155 
 250 
 150 
 200 
 130 
 200 
 250 
 167 
 153 
 
 1,800 
 180 
 
 120 
 50 
 80 
 170 
 120 
 140 
 130 
 105 
 130 
 150 
 
 1,195 
 120 
 
 205 
 150 
 140 
 135 
 240 
 320 
 235 
 200 
 73 
 140 
 
 1,838 
 184 
 
 100 
 
 60 
 
 50 
 
 140 
 
 140 
 
 90 
 
 125 
 
 130 
 
 170 
 
 150 
 
 1,155 
 116 
 
 1, 350 
 135 
 
 1,000 
 100 
 
 755 
 108 
 
 120 
 90 
 110 
 130 
 7Q 
 130 
 130 
 
 225 
 110 
 150 
 120 
 140 
 135 
 75 
 135 
 150 
 i30 
 
 1,370 
 137 
 
 80 
 
 150 
 
 50 
 
 50 
 
 40 
 
 130 
 
 70 
 
 130 
 
 100 
 
 80 
 
 880 
 
 130 
 90 
 180 
 100 
 50 
 160 
 105 
 
 780 
 111 
 
 815 
 116 
 
 150 
 100 
 195 
 120 
 130 
 90 
 75 
 120 
 150 
 100 
 
 120 
 145 
 140 
 
 300 
 400 
 235 
 146 
 115 
 130 
 
 1,731 
 192 
 
 70 
 60 
 
 140 
 
 90 
 120 
 
 130 
 
 214 
 172 
 236 
 186 
 195 
 190 
 232 
 216 
 172 
 152 
 
 1,965 
 197 
 
 610 
 
 102 
 
 1,230 
 133 
 
 90 
 
 100 
 
 40 
 
 30 
 
 30 
 
 200 
 
 30 
 
 80 
 
 100 
 
 80 
 
 780 
 
 78 
 
 100 
 80 
 
 100 
 80 
 30 
 
 100 
 
 110 
 
 105 
 
 90 
 
 100 
 
 'rio' 
 
 30 
 
 75 
 
 130 
 
 112 
 
 762 
 
 95 
 
 90 
 
 100 
 
 30 
 
 30 
 
 30 
 
 100 
 
 50 
 
 ,70 
 
 90 
 
 670 
 67 
 
 130 
 50 
 
 60 
 
 80 
 
 60 
 
 120 
 
 144 
 
 73 
 81 
 160 
 140 
 117 
 160 
 149 
 149 
 129 
 
 1,302 
 130 
 
 142 
 130 
 134 
 141 
 158 
 105 
 105 
 134 
 171 
 123 
 
 1,342 
 134 
 
 96 
 
 112 
 
 41 
 
 68 
 
 48 
 
 137 
 
 81 
 
 116 
 
 103 
 
 102 
 
 904 
 90 
 
 122 
 87 
 
 102 
 96 
 78 
 80 
 
 133 
 
 600 
 
 86 
 
 480 
 
 688 
 98 
 
 Kemarfca. 
 
 N.fr.,fair. 
 SE.lt., clear. 
 
 Do. 
 SW.lt., clear. 
 
 Do. 
 SW.lt., fair. 
 SW.lt., clear. 
 Var. It., fair. 
 SE. fr., fair. 
 E. fr., fair. 
 
 SE. It., fair. 
 S. It., clear. 
 E. It., fair. 
 S. It., fair. 
 SE.lt., clear. 
 SE.lt., fair. 
 
 Do. 
 E.lt., clear. 
 SW. It., fair. 
 SW.fr., clear. 
 
 SE. fr., clear. 
 SE. It., clear. 
 W. It., clear. 
 N. fr., clear. 
 W. fr., fair. 
 
 Do. 
 E. fr., clear. 
 E. fr., fair. 
 SE. fr., fair. 
 Var. It., clear. 
 
 Var.lt., clear. 
 W. fr., fair. 
 NE.fr., flear. 
 NE. lt„ clear. 
 N. fr., clear. 
 NE. It., clear. 
 E.lt., clear. 
 E:fr.,fair. 
 E. It., fair. 
 Do. 
 
 N. f r., fair. 
 E.lt., fair. 
 E.lt., clear. 
 
 Do. 
 NE.fr., clear. 
 SW.lt., fair. 
 E. It., fair. 
 
 STTMMAET. 
 
 (10) 
 
 (10) 
 
 (10) 
 
 (10) 
 
 (7) 
 
 Sums 
 
 Means 
 
 1,943 
 
 2, 351 
 
 2,523 
 
 1,590 
 
 1, 766 
 
 1,921 
 
 1,999 
 
 1,800 
 
 1,838 
 
 1,731 
 
 1,965 
 
 1,500 
 
 1,387 
 
 1,863 
 
 1,400 
 
 1,400 
 
 1,310 
 
 1,180 
 
 1,195 
 
 1,155 
 
 610 
 
 1,302 
 
 1,655 
 
 1,535 
 
 1,510 
 
 1,302 
 
 1,205 
 
 1,255 
 
 1,350 
 
 1,370 
 
 1,230 
 
 762 
 
 1,343 
 
 990 
 
 965 
 
 1,150 
 
 890 
 
 810 
 
 900 
 
 1,000 
 
 880 
 
 780 
 
 670 
 
 904 
 
 640 
 
 650 
 
 680 
 
 750 
 
 640 
 
 755 
 
 780 
 
 815 
 
 600 
 
 480 
 
 688 
 
 6,728 
 
 6,888 
 
 7,226 
 
 5,932 
 
 5, 821 
 
 6,141 
 
 6,309 
 
 6,060 
 
 5, 603 
 
 4,253 
 
 6,201 
 
 143 
 
 ■ 147 
 
 154 
 
 126 
 
 124 
 
 131 
 
 134 
 
 129 
 
 119 
 
 109 
 
 132 
 
230 
 
 MEMOIES OP THE NATIONAL ACADEMY OE SOIEFOES. 
 
 Table D. — Potential on clear and fair days, Terre Haute, Ind., April 1, 1887, to August 31, 1888 — 
 
 Continued. 
 
 Date. 
 
 1887. 
 
 October 4 
 
 October 12... 
 
 October 14 
 
 October 15 
 
 October 19... 
 October 25-.. 
 Octobers?... 
 November 11 
 November 15 
 November 88 
 
 Sums.. 
 Meaus . 
 
 November 29.. 
 December 5 . . . 
 December 6 . . . 
 December 13. 
 December 22.. 
 December 24 . . 
 1888. 
 January 10 ... 
 January 11 . . . 
 January 18 . . . 
 January 19... 
 
 Sums. . 
 Means. 
 
 January 26.. 
 January 27.. 
 February 6.. 
 February 16. 
 February 22. 
 
 March 8 
 
 March 15 
 
 March 29 
 
 March 30 
 
 April 3 
 
 Snma .. 
 Means 
 
 April 4.. 
 April 6.. 
 April 11 . 
 April 13 . 
 April 14. 
 April 25. 
 June 2 „ 
 June 4 .. 
 June 30 ., 
 July 2..., 
 
 Sums .. 
 Means, 
 
 July 3.. 
 July 5. . 
 July 11. 
 July 12. 
 July 13. 
 July 19. 
 July 20. 
 July 21. 
 July 24. 
 July 25. 
 
 Sums.. 
 Means . 
 
 200 
 480 
 180 
 220 
 280 
 200 
 320 
 200 
 250 
 200 
 
 180 
 ,400 
 200 
 20O 
 280 
 400 
 240 
 200 
 180 
 150 
 
 2,530 
 253 
 
 200 
 240 
 440 
 340 
 300 
 660 
 
 280 
 220 
 300 
 660 
 
 3,640 
 364 
 
 330 
 260 
 540 
 800 
 600 
 350 
 220 
 80 
 70 
 180 
 
 2,430 
 243 
 
 1 p.m. 
 
 210 
 450 
 160 
 200 
 300 
 400 
 220 
 210 
 150 
 300 
 
 2.600 
 260 
 
 350 
 240 
 360 
 260 
 400 
 360 
 
 260 
 440 
 220 
 760 
 
 3,650 
 365 
 
 560 
 400 
 580 
 1,400 
 700 
 320 
 240 
 130 
 50 
 135 
 
 3,430 
 343 
 
 144" 
 144 
 
 180 
 300 
 90 
 70 
 30 
 25 
 50 
 100 
 
 1.133 
 113 
 
 60 
 
 60 
 
 240 
 
 160 
 
 146 
 
 105 
 
 105 
 
 75 
 
 85 
 
 80 
 
 4,515 
 452 
 
 190 
 
 150 
 
 300 
 
 140 
 
 75 
 
 100 
 
 40 
 
 30 
 
 60 
 
 120 
 
 350 
 300 
 300 
 400 
 440 
 360 
 
 200 
 240 
 340 
 630 
 
 3 p.m. 
 
 150 
 500 
 180 
 220 
 50 
 200 
 180 
 220 
 150 
 200 
 
 150 
 350 
 100 
 220 
 150 
 350 
 100 
 180 
 200 
 300 
 
 M^eans. 
 
 2,050 
 
 205 
 
 3,560 
 356 
 
 380 
 380 
 300 
 760 
 520 
 160 
 180 
 150 
 50 
 200 
 
 ^ 
 
 1,205 
 120 
 
 1,116 
 117 
 
 100 
 
 80 
 
 256 
 
 170 
 
 160 
 
 125 
 
 100 
 
 80 
 
 120 
 
 80 
 
 1,271 
 127 
 
 3,080 
 308 
 
 135 
 
 135 
 
 225 
 
 120 
 
 138 
 
 60 
 
 30 
 
 25 
 
 35 
 
 80 
 
 250 
 
 400 
 300 
 700 
 400 
 300 
 
 160 
 320 
 300 
 
 700 
 
 3,830 
 383 
 
 ■360 
 360 
 560 
 760 
 240 
 150 
 150 
 130 
 70 
 135 
 
 2,100 
 210 
 
 200 
 360 
 280 
 500 
 .420 
 400 
 
 180 
 440 
 200 
 700 
 
 3.680 
 
 368 
 
 983 
 
 98 
 
 100 
 120 
 240 
 
 180 
 100 
 U5 
 
 85 
 75 
 80 
 75 
 
 1,170 
 117 
 
 2,815 
 282 
 
 114 
 
 150 
 
 210 
 
 225 
 
 90 
 
 45 
 
 40 
 
 40 
 
 50 
 
 100 
 
 1,064 
 106 
 
 40 
 
 80 
 
 120 
 
 980 
 
 84 
 
 80 
 
 95 
 
 100 
 
 105 
 
 75 
 
 1,059 
 106 
 
 400 
 270 
 360 
 750 
 240 
 280 
 180 
 70 
 110 
 162 
 
 178 
 436 
 164 
 212 
 212 
 310 
 212 
 202 
 186 
 230 
 
 2,342 
 234 
 
 270 
 308 
 336 
 440 
 392 
 416 
 
 216 
 332 
 272 
 690 
 
 Kemarks. 
 
 3,672 
 367 
 
 2,822 
 282 
 
 225 
 
 90 
 225 
 200 
 96 
 35 
 30 
 48 
 40 
 80 
 
 1,069 
 
 107 
 
 100 
 110 
 150 
 144 
 66 
 80 
 110 
 105 
 250 
 100 
 
 1,215 
 122 
 
 386 
 334 
 468 
 894 
 460 
 252 
 194 
 112 
 70 
 162 
 
 3,332 
 . 333 
 
 162 
 
 134 
 
 228 
 
 197 
 
 98 
 
 , 62 
 
 34 
 
 34 
 
 46 
 
 96 
 
 1,091 
 109 
 
 80 
 
 90 
 
 201 
 
 187 
 
 111 
 
 101 
 
 9a 
 
 87 
 
 128 
 
 82 
 
 1,166 
 117 
 
 NW. br., clear, gale. 
 SW. fr., clear. 
 N. It., clear. 
 SE. It., clear. 
 
 Do. 
 N. It. , clear. 
 E. It., clear, 
 N, It., clear. 
 W. fr.,fair. 
 Vkr. It., clear. 
 
 SE. fr., clear. 
 W. It. , clear. 
 S. fr,, Jfair. 
 S, fr., clear. 
 SW.fr., clear. 
 NW. fr., clear. 
 
 W. br.,fair. 
 NW.&., clear. 
 W.fr., clear. 
 S. br,, clear. 
 
 W.fr., clear. 
 N. br., clear. 
 S. f r. , clear. 
 
 Do. 
 E. It. , clear. 
 Var. It. , clear. 
 S. It., clear. 
 W. It., clear. 
 S. f r. , clear. 
 Clear. 
 
 E. It., fair. 
 N. It., clear. 
 W. It. , clear. 
 S.fr., clear, 
 N. It., clear. 
 S.fr.,fair. 
 N.br,, clear. 
 NE.fr., clear. 
 N. It. , clear. 
 E, It,, clear. 
 
 S.fr., fair. 
 N. fr., fair. 
 SW. fr. , clear. 
 
 Do. 
 E. br., clear. 
 NW.fr., fair. 
 E. It., fair. 
 
 Do. 
 NE. It., fair. 
 E. It., fair. 
 
MEMOIES OF THE NATIONAL ACADEMY OP SCIENCES. 
 
 231 
 
 TABiii; D — Potential on clear and fair days, Terre Saute, Ind., April 1, 1887, to August 31, 1888 
 
 Continued. 
 
 Date. 
 
 9 a.m. 
 
 IL a.m. 
 
 1 p.m. 
 
 3 p.m. 
 
 5 p.m. 
 
 Means. 
 
 Bemarks. 
 
 1888. 
 July 31 
 
 140 
 100 
 300 
 200 
 
 90 
 120 
 
 80 
 
 200 
 120 
 150, 
 160 
 90 
 50 
 100 
 
 40 
 90 
 110 
 200 
 120 
 40 
 100 
 
 180 
 95 
 80 
 
 120 
 
 145 
 60 
 
 100 
 
 125 
 
 110 
 110 
 250 
 280 
 60 
 ,, 120 
 
 137 
 103 
 150 
 186 
 145 
 66 
 100 
 
 S. fr., fair, hazy. 
 E.lt., fair. 
 E.fr.,fair. 
 N. It., fair. 
 NE. fr., fair. 
 E.lt., clear. 
 S. It., clear. 
 
 / 
 
 
 
 August 18 
 
 August 22 ...... . 
 
 
 Angast24 
 
 Sums .----- 
 
 1,030 
 147 
 
 870 
 124 
 
 700 
 100 
 
 780 
 111 
 
 1,055 
 151 
 
 887 
 89 
 
 Means ...... ...... 
 
 
 SUMMARY. 
 
 (10) 
 
 (10) 
 
 (10) 
 
 (10) 
 
 (10) 
 
 (7) 
 
 Sums. 
 Means 
 
 2,530 
 
 2,430 
 
 2,600 
 
 . 2,050 
 
 2,100 
 
 2,342 
 
 3,640 
 
 3,650 
 
 3, 560 , 
 
 3, 830 
 
 3,680 
 
 3,672 
 
 3,430 
 
 4,515 
 
 3,080 
 
 2,815 
 
 2,822 
 
 3,332 
 
 1,133 
 
 1,205 
 
 983 
 
 1,064 
 
 1,069 
 
 1,091 
 
 1,116 
 
 1,271 
 
 1,170 
 
 1,059 
 
 1,215 
 
 1,166 
 
 1,030 
 
 870 
 
 700 
 
 780 
 
 1,055 
 
 887 
 
 12, 879 
 
 13, 941 
 
 12, 093 
 
 11, 598 
 
 11,941 
 
 12, 490 
 
 226 
 
 245 
 
 212 
 
 203 
 
 209 
 
 221 
 
23232 MEMOIES OP THE NATIONAL ACADEMY OF SCIENCES. 
 
 Table Ji.— Potential on clear and fair days, Columbus, Ohio, July, 1886, to July, 1888. 
 
 Date. 
 
 9 a. m. 
 
 11 a.ni. 
 
 1p.m. 
 
 3 p.m. 
 
 Meana. 
 
 Bemarka. 
 
 1836. 
 July 19 
 
 69 
 20 
 60 
 18 
 24 
 15 
 10 
 21 
 31 
 62 
 
 80 
 19 
 62 
 18 
 13 
 32 
 3 
 17 
 41 
 59 
 
 81 
 45 
 67 
 33 
 12 
 16 
 10 
 18 
 36 
 67 
 
 82 
 12 
 70 
 26 
 6 
 16 
 17 
 21 
 37 
 71 
 
 78 
 24 
 65 
 24 
 14 
 20 
 10 
 19 
 36 
 65 
 
 S.br., fair, 
 W. br., clear. 
 NW.fr., fair. 
 NW. br., fair. 
 SE. br., fair. 
 E. br., clear. 
 SE. br., fair. 
 W. br., clear. 
 NW.br., clear. 
 E. br., fair. 
 
 JnlySS 
 
 Auffust 3 .----. 
 
 AusTust 5 .-.-.- 
 
 Aiiffiist 6 .... ...... 
 
 Aiiffiist 19 . .... 
 
 Ausust 20 
 
 Auffust 27 ......... 
 
 August 31 
 
 September 1 
 
 Sams 
 
 330 
 
 344 
 
 385 
 
 358 
 
 355 
 
 Means 
 
 33 
 
 34 
 
 38 
 
 36 
 
 36 
 
 
 September 2 
 
 70 
 
 76 
 
 67 
 
 70 
 
 71 
 
 E. br., fair. 
 
 September 3 
 
 59 
 
 49 
 
 50 
 
 49 
 
 52 
 
 SE. br., fair. 
 
 September 6 
 
 39 
 
 46 
 
 51 
 
 41 
 
 44 
 
 SE. br., clear. 
 
 September 7 
 
 34 
 
 -41 
 
 29 
 
 43 
 
 37 
 
 SE. br., fair. 
 
 September 8 
 
 37 
 
 42 
 
 43 
 
 39 
 
 40 
 
 W. It., fair. 
 
 September 9 
 
 29 
 
 32 
 
 27 
 
 29 
 
 29 
 
 W. br., fair. 
 
 September 20 
 
 42 
 
 48 
 
 55 
 
 50 
 
 49 
 
 N. fr., clear. 
 
 October 7 
 
 34 
 50 
 60 
 
 53 
 
 77 
 
 105 
 
 66 
 107 
 100 
 
 54 
 
 103 
 
 98 
 
 52 
 
 84 
 91 
 
 S. br., clear. 
 
 Do. 
 SW. br., clear. 
 
 SW.br., clear. 
 
 October 8 
 
 October 11 
 
 Sums. . .. 
 
 454 
 45 
 
 569 
 57 
 
 595 
 60 
 
 576 
 
 58 
 
 549 
 55 
 
 Means 
 
 October 12 
 
 62 
 
 67 
 
 63 
 
 73 
 
 66 
 
 October 13 
 
 63 
 
 73 
 
 63 
 
 60 
 
 65 
 
 Do. 
 
 October 18 
 
 7 
 
 15 
 
 16 
 
 14 
 
 13 
 
 S. br. , clear. 
 
 October 19 
 
 18 
 
 17 
 
 20 
 
 19 
 
 18 
 
 SW.br., clear. 
 
 OctoberaO 
 
 4 
 
 7 
 
 7 
 
 4 
 
 6 
 
 SW.fr., fair. 
 
 October21 
 
 8 
 
 8 
 
 9 
 
 8 
 
 8 
 
 NW.fr., clear. 
 
 October 22 
 
 3 
 
 4 
 
 14 
 
 16 
 
 9 
 
 Do. 
 
 November 1 
 
 98 
 
 120 
 
 130 
 
 118 
 
 116 
 
 SW.fr., clear. 
 
 November 4 
 
 126 
 
 183 
 
 50 
 
 103 
 
 , 103 
 
 W.fr.,fair. 
 
 November 5 
 
 Sums 
 
 42 
 
 51 
 
 46 
 
 38 
 
 44 
 
 S. fr. , clear. 
 
 431 
 
 495 
 
 418 
 
 453 
 
 448 
 
 Means 
 
 November 8 
 
 43 
 
 50 
 
 42 
 
 45 
 
 45 
 
 W.fr.,fair. 
 
 96 
 
 106 
 
 120 
 
 118 
 
 110 
 
 November 15 
 
 24 
 
 36 
 
 41 
 
 38 
 
 35 
 
 NW.fr., clear. 
 
 November 16 
 
 32 
 
 23 
 
 26 
 
 30 
 
 28 
 
 SE.fr., fair. 
 
 November 19 
 
 15 
 
 13 
 
 18 
 
 26 
 
 18 
 
 SW. fr., clear. 
 
 December 6 
 
 15 
 
 25 
 
 27 
 
 20 
 
 22 
 
 N. fr. , clear. 
 
 December 8 
 
 30 
 
 55 
 
 57 
 
 32 
 
 44 
 
 S. br. , clear. 
 
 December 10 
 
 49 
 
 30 
 
 18 
 
 S 
 
 26 
 
 Do. 
 
 December 16 
 
 27 
 
 56 
 
 73 
 
 38 
 
 48 
 
 W. fr, , clear. 
 
 December 20 
 
 53 
 
 38 
 
 32 
 
 24 
 
 37 
 
 SW.fr., clear. 
 
 December 27 
 
 Sums 
 
 , 21 
 
 :u 
 
 26 
 
 15 
 
 23 
 
 NW.fr., clear. 
 
 362 
 
 413 
 
 438 
 
 349 
 
 391 
 
 Means 
 
 36 
 
 41 
 
 44 
 
 35 
 
 39 
 
 
 SUMMAEY. 
 
 (10). 
 
 (10) 
 
 (10) 
 
 (10) 
 
 Suras . 
 Means 
 
 330 
 
 344 
 
 385 
 
 358 
 
 x^r, 
 
 454 
 
 569 
 
 595 
 
 576 
 
 M'? 
 
 431 
 
 495 
 
 418 
 
 453 
 
 448 
 
 362 
 
 413 
 
 438 
 
 349 
 
 391 
 
 1,577 
 
 1,821 
 
 1,836 
 
 1,736 
 
 1,743 
 
 39 
 
 46 
 
 46 
 
 43 
 
 44 
 
MEMOIRS OF THE I^TATIOJiTAL ACADEMY OF SCIENCES. 233 
 
 Table E. — Potential on clear and fair days, Columbus, Ohio, July, 1886, to July, 188S — Continued 
 
 Date. 
 
 1887. 
 January 3..., 
 January 12... 
 
 March 1 ,. 
 
 March 2 
 
 March 8 
 
 March 17 
 
 March 23 
 
 March 25 . 
 
 Aprils 
 
 May 13 , 
 
 Sums 
 
 Means... 
 
 May 19 
 
 May 20 
 
 June 13 
 
 June 16 
 
 June 17 
 
 June 27 
 
 June 28 .t... 
 
 June 29 , 
 
 July 1 
 
 July 12 
 
 Sums 
 
 Means... 
 
 July 13 
 
 July 15 
 
 July 26 
 
 .July 27 
 
 July 28 
 
 July 29 
 
 August 3 
 
 August 8 
 
 August 9 
 
 August 10 . . . 
 
 Sums. .. 
 Means -- 
 
 August 16 ... 
 August 19 ... 
 August 30 . - . 
 August 31 ... 
 September 1- 
 September 8. 
 September 14 
 September 15 
 September 20 
 October 1 
 
 Sums... 
 Means. - 
 
 October 7 
 
 October 12 ... 
 October 13 ... 
 October 14 .. 
 October 19 ... 
 October 25 ... 
 November 1 . 
 November 2 . 
 November 3 . 
 November 4 . 
 
 Sums... 
 Means.. 
 
 9 a. m. 
 
 11 a. m. 
 
 Ip. m. 
 
 3 p. m. 
 
 Means. 
 
 Ill 
 
 206 
 
 140 
 
 65 
 
 132 
 
 140 
 
 207 
 
 220 
 
 106 
 
 168 
 
 294 
 
 318 
 
 228 
 
 246 
 
 272 
 
 165 
 
 133 
 
 159 
 
 174 
 
 155 
 
 309 
 
 288 
 
 324 
 
 252 
 
 293 
 
 243 
 
 240 
 
 240 
 
 207 
 
 232 
 
 207 
 
 210 
 
 192 
 
 189 
 
 200 
 
 171 
 
 183 
 
 219 
 
 180 
 
 188 
 
 213 
 
 246 
 
 270 
 
 213 
 
 236 
 
 114 
 
 177 
 
 114 
 
 105 
 
 128 
 
 1,967 
 
 3,198 
 
 2,112 
 
 1,737 
 
 2,004 
 
 197 
 
 220 
 
 211 
 
 174 
 
 200 
 
 147 
 
 180 
 
 114 
 
 141 
 
 146 
 
 102 
 
 192 
 
 129 
 
 105 
 
 132 
 
 138 
 
 120 
 
 126 
 
 99 
 
 121 
 
 69 
 
 78 
 
 75 
 
 72 
 
 74 
 
 72 
 
 90 
 
 120 
 
 99 
 
 95 
 
 90 
 
 156 
 
 150 
 
 159 
 
 139 
 
 177 
 
 159 
 
 162 
 
 153 
 
 163 
 
 183 
 
 144 
 
 147, 
 
 222 
 
 174 
 
 90 
 
 108 
 
 135 
 
 147 
 
 120 
 
 120 
 
 102 
 
 105 
 
 132 
 
 115 
 
 1,188 
 
 1,329 
 
 1,263 
 
 1,329 
 
 1,279 
 
 119 
 
 133 
 
 126 
 
 133 
 
 128 
 
 120 
 
 135 
 
 186 
 
 180 
 
 155 
 
 105 
 
 135 
 
 156 
 
 126 
 
 130 
 
 75 
 
 106 
 
 135 
 
 120 
 
 109 
 
 90 
 
 138 
 
 126 
 
 84 
 
 110 
 
 150 
 
 165 
 
 186; 
 
 168 
 
 167 
 
 135 
 
 261 
 
 255 
 
 150 
 
 200 
 
 27 
 
 54 
 
 21 
 
 156 
 
 64 
 
 111 
 
 117 
 
 135 
 
 156 
 
 130 
 
 90 
 
 66 
 
 57 
 
 72 
 
 71 
 
 60 
 
 • 87 
 
 133 
 
 105 
 
 96 
 
 963 
 
 1,264 
 
 1,390 
 
 1,317 
 
 1,232 
 
 96 
 
 126 
 
 139 
 
 132 
 
 123 
 
 48 
 
 72 
 
 72 
 
 126 
 
 80 
 
 72 
 
 114 
 
 51 
 
 108 
 
 86 
 
 45 
 
 144 
 
 75 
 
 69 
 
 83 
 
 45 
 
 105 
 
 66 
 
 48 
 
 66 
 
 69. 
 
 90 
 
 30 
 
 63 
 
 63 
 
 319 
 
 153 
 
 141 
 
 123 
 
 159 
 
 99 
 
 69 
 
 84 
 
 147 
 
 100 
 
 132 
 
 81 
 
 81 
 
 69 
 
 91 
 
 189 
 
 102 
 
 165 
 
 45 
 
 125 
 
 135 
 
 134 
 
 90 
 
 75 
 
 108 
 
 1,053 
 
 1,064 
 
 855 
 
 873 
 
 961 
 
 105 
 
 106 
 
 86 
 
 87 
 
 96 
 
 270 
 
 136 
 
 120 
 
 135 
 
 165 
 
 180 
 
 165 
 
 150 
 
 42 
 
 134 
 
 159 
 
 165 
 
 159 
 
 120 
 
 151 
 
 134 
 
 150 
 
 138 
 
 120 
 
 136 
 
 228 
 
 243 
 
 144 
 
 120 
 
 184 
 
 285 
 
 180 
 
 330 
 
 225 
 
 255 
 
 162 
 
 225 
 
 129 
 
 120 
 
 159 
 
 69 
 
 168 
 
 150 
 
 270 
 
 164 
 
 72 
 
 165 
 
 231 
 
 180 
 
 162 
 
 192 
 
 105 
 
 15 
 
 30 
 
 86 
 
 1,751 
 
 1,702 
 
 1.566 
 
 1,362 
 
 1,596 
 
 175 
 
 170 
 
 , 157 
 
 136 
 
 160 
 
 
 
 
 
 
 Kemarks. 
 
 SW. br., clear. 
 SW.br., fair. 
 W. ft., fair. 
 W. br., clear. 
 E. fr., clear. 
 N. fr., fair. 
 NW. fr., clear. 
 
 Do. 
 S. br., clear. 
 NE.fr., clear. 
 
 S. br., clear. 
 SE. br., clear. 
 N. br., clear. 
 W. br., fair. 
 W. br., clear. 
 E. fr., clear. 
 
 Do. 
 SE.fr., fair. 
 SW.fr., fair. 
 SW.br., clear. 
 
 SW. br., fair. 
 SW. fr., fair. 
 NE.fr., fair. 
 
 Do. 
 NW. fr., fair. 
 N. br., clear. 
 N. fr., clear. ^ 
 E. fr., clear. 
 SE.br., fair. 
 SW, br., clear. 
 
 NE.br., fair. 
 NW. fr., fair. 
 SE.br., clear. 
 
 Do. 
 
 Do. 
 N.fr., clear. 
 S. br., clear. 
 N. br., fair. 
 SE.br., fair. 
 W. fr., fair. 
 
 SW. br., clear. 
 NW. fr., fair. 
 W. fr., clear. 
 W. fr., fair. 
 E. fr., fair. 
 N. fr., clear. 
 E. br., clear. 
 S. br., clear. 
 
 Do. 
 W. fr., fair. 
 
234 
 
 MEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES. 
 
 Table E. — Potential on clear and fair days, Columbus, Ohio, July, 1886, to July, 1888 — Continued. 
 
 Date. 
 
 1887. 
 November 17 . 
 November 18 . 
 November 28 . 
 November 30 . 
 December 1 . . . 
 Decembers... 
 December 6 . . . 
 December 8 . . . 
 December 19. . 
 December 22. . 
 
 Sums. . 
 Means . 
 
 1888. 
 January 2 . . . 
 Jafauary 10 . . 
 January 11 .. 
 January 19 . . 
 January 24 . . 
 January 26 . . 
 February 6 . . 
 February 13 . 
 February 15 . 
 February 16 . 
 
 Sums.. 
 Means. 
 
 February 21 . 
 February 22 . 
 February 23 . 
 February 27 . 
 
 March 7 
 
 March 8 
 
 March 9 
 
 March 13 
 
 March 15 ...i 
 March 19 
 
 Sums.. 
 Mean 8- 
 
 March 30 . 
 April 2... 
 Apwlll.. 
 April 12.. 
 April 13.. 
 April 17.. 
 April 24.. 
 April 25.. 
 April 26.. 
 April 27.. 
 
 Sums.. 
 Means. 
 
 May 2 . . 
 May 3 . . 
 May 11 . 
 May 16 . 
 May 17 . 
 May 21 . 
 May 22 . 
 May 23 . 
 Jane 4.. 
 June 5.. 
 
 Sums. . 
 Means . 
 
 195 
 225 
 189 
 180 
 466 
 96 
 132 
 162 
 531 
 234 
 
 2,410 
 241 
 
 195 
 177 
 183 
 150 
 111 
 
 75 
 630 
 396 
 
 54 
 612 
 
 2,259 
 226 
 
 390 
 449 
 291 
 270 
 120 
 66 
 708 
 240 
 279 
 375 
 
 3,188 
 319 
 
 342 
 223 
 156 
 150 
 192 
 294 
 210 
 375 
 144 
 90 
 
 2,175 
 218 
 
 156 
 240 
 219 
 120 
 90 
 144 
 180 
 285 
 iOi< 
 J80 
 
 1,722 
 172 
 
 213 
 210 
 315 
 180 
 555 
 153 
 150 
 150 
 369 
 174 
 
 2,469 
 247 
 
 192 
 . 84 
 150 
 300 
 309 
 180 
 339 
 645 
 156 
 615 
 
 2,970 
 
 297 
 
 294 
 330 
 429 
 435 
 210 
 261 
 480 
 297 
 351 
 144 
 
 1 p.m. 
 
 174 
 159 
 288 
 194 
 501 
 69 
 300 
 225 
 390 
 186 
 
 2,486 
 249 
 
 186 
 210 
 90 
 300 
 321 
 297 
 363 
 609 
 120 
 390 
 
 3 p.m. 
 
 186 
 198 
 255 
 168 
 435 
 180 
 126 
 21 
 480 
 210 
 
 2,259 
 226 
 
 2,886 
 289 
 
 3,231 
 323 
 
 300 
 183 
 210 
 180 
 282 
 369 
 270 
 390 
 135 
 135 
 
 2,454 
 245 
 
 255 
 75 
 300 
 150 
 150 
 156 
 300 
 315 
 180 
 165 
 
 2,046 
 205 
 
 309 
 315 
 270 
 225 
 300 
 318 
 360 
 315 
 186 
 189 
 
 2,787 
 279 
 
 252 
 120 
 180 
 165 
 183 
 360 
 135 
 369 
 198 
 138 
 
 246 
 150 
 90 
 156 
 330 
 282 
 354 
 339 
 360 
 384 
 
 2,691 
 269 
 
 306 
 252 
 210 
 96 
 288 
 192 
 471 
 120 
 261 
 246 
 
 2,442 
 244 
 
 2,100 
 210 
 
 201 
 189 
 240 
 54 
 105 
 210 
 270 
 240 
 135 
 120 
 
 1,764 
 176 
 
 228 
 60 
 180 
 162 
 219 
 165 
 105 
 186 
 195 
 120 
 
 MeaDB. 
 
 192 
 198 
 262 
 180 
 489 
 123 
 177 
 140 
 442 
 201 
 
 2,404 
 240 
 
 205 
 155 
 128 
 226 
 268 
 208 
 340 
 497 
 172 
 500 
 
 2,699 
 270 
 
 325 
 336 
 300 
 256 
 230 
 209 
 505 
 243 
 269 
 238 
 
 2,911 
 291 
 
 1, 620 
 162 
 
 240 
 135 
 120 
 135 
 60 
 165 
 240 
 195 
 165 
 150 
 
 ,605 
 160 
 
 280 
 146 
 182 
 164 
 219 
 297 
 180 
 330 
 168 
 121 
 
 2, 087 
 209 
 
 213 
 160 
 220 
 115 
 101 
 169 
 248 
 259 
 147 
 164 
 
 1,786 
 179 
 
 Kemarkg. 
 
 NW. ic., clear. 
 SW., clear. 
 NW., clear. 
 NE.,fair. 
 E., clear. 
 NW., fair. 
 S., clear. 
 E., clear. 
 SE.,fair. 
 W.,faiir. 
 
 W.,fair. 
 
 Do. 
 NW.,fair. 
 W., clear. 
 N., clear. 
 NW.,fair.' 
 S., clear. 
 
 Do. 
 N., clear. 
 S., clear. 
 
 SW.,fair. 
 E., clear. 
 SW.br., clear. 
 NW., fair. 
 NW., clear. 
 
 Do. 
 SE.,fair. 
 NW.,,clear. 
 SW., clear. 
 
 Do, 
 
 S W. , clear. 
 NW.,fair. 
 NW., clear. 
 NW.,fair. 
 SW.,fair. 
 NE.,fair. 
 N.,fair. 
 iSE., clear. 
 W., clear. 
 SW.br., clear. 
 
 E.,fair. 
 SE., fair. 
 SE., clear. 
 NE.,fair. 
 
 Do. 
 E.,fair. 
 
 Do. 
 
 Do. 
 NE., clear. 
 SW.,fair. 
 
MEMOIES OP THE NATIONAL ACADEMY OF SCIENCES. 235 
 
 Table E — Potential on clear and fair days, Columbus, Ohio, July, 1886, to July, 1888 — Continued. 
 
 Date. 
 
 9 a.m. 
 
 11 a. m. 
 
 1p.m. 
 
 3 p. m. 
 
 Means. 
 
 Kemarks. 
 
 1888. 
 June 7 , 
 
 120 
 210 
 150 
 180 
 120 
 135 
 120 
 
 75 
 192 
 
 75 
 
 150 
 240 
 150 
 150 
 114 
 105 
 111 
 105 
 180 
 165 
 
 162 
 210 
 150 
 75 
 75 
 123 
 135 
 150 
 129 
 129 
 
 141 
 180 
 156 
 120 
 60 
 112 
 114 
 120 
 150 
 120 
 
 143 
 210 
 152 
 131 
 92 
 119 
 120 
 112 
 163 
 122 
 
 N., fair. 
 NE., fair. 
 NE., clear. 
 SW., fair. 
 
 Do. 
 NW.,fair. 
 NE., clear. 
 NE.,fair. 
 
 Do. 
 SE., clear. 
 
 SW., fair. 
 N., clear. 
 W.i clear. 
 
 Do. 
 SE.,fair. 
 SW., fair. 
 SE., fair. 
 NW., clear. 
 SW., clear. 
 SW., fair. 
 
 JnneS 
 
 June 12 
 
 
 June 15 
 
 June 18 
 
 June 19 
 
 June 26 
 
 July2 
 
 Julys 
 
 Siima 
 
 1,377 
 138 
 
 1,470 
 147 
 
 1, 338 
 134 
 
 1,273 
 127 
 
 1,364 
 136 
 
 Means 
 
 July 4 
 
 102 
 90 
 105 
 120 
 120 
 120 
 162 
 150 
 195 
 66 
 
 150 
 120 
 117 
 135 
 135 
 135 
 159 
 150 
 150 
 108 
 
 150 
 120 
 135 
 150 
 144 
 150 
 66 
 150 
 105 
 102 
 
 135 
 
 90 
 
 120 
 
 135 
 
 129 
 
 135 
 
 78 
 
 195 
 
 90 
 
 111 
 
 134 
 105 
 119 
 135 
 132 
 135 
 116 
 161 
 135 
 97 
 
 July 10 
 
 Julyll 
 
 July 12 
 
 July 16 
 
 July 17 
 
 July 19 
 
 July 24 
 
 July 25 
 
 Julv26 
 
 
 1,210 
 121 
 
 1,359 
 136 
 
 1,272 
 
 1,218 
 122 
 
 ■ 
 
 1, 269 
 127 
 
 Means 
 
 SUMMARY OF CLEAR AND FAIR DAYS, JANUARY, 1887, TO JULY, 1888. 
 
 Number of days. 
 
 (10) 
 
 (10) 
 
 (10) 
 
 (10) 
 
 (10) 
 
 (10) 
 
 (10) 
 
 (10) -. 
 
 (10) 
 
 (10) 
 
 (10) 
 
 (10) 
 
 Sums (120) 
 MeanB(l). . 
 
 9 a.m. 
 
 11 a.m. 
 
 1 p.m. 
 
 3 p.m. 
 
 Meana. 
 
 1,967 
 
 2,198 
 
 2,112 
 
 1,737 
 
 2,004 
 
 1,188 
 
 1,329 
 
 1,263 
 
 1,329 
 
 . 1,279 
 
 963 
 
 1,264 
 
 1,390 
 
 1,317 
 
 1,232 
 
 1,053 
 
 1,064 
 
 855 
 
 873 
 
 961 
 
 1,751 
 
 1,702 
 
 1,566 
 
 1,362 
 
 1,596 
 
 2,410 
 
 2,469 
 
 2, 486 
 
 2,259 
 
 2,404 
 
 2,259 
 
 2,970 
 
 2,886 
 
 2,691 
 
 2,699 
 
 3, 188 
 
 3,231 
 
 2,787 
 
 2,442 
 
 2,911 
 
 2,175 
 
 2,454 
 
 2, 100 
 
 1,620 
 
 2,087 
 
 1,722 
 
 2,046 
 
 1,764 
 
 1,605 
 
 1,786 
 
 1,377 
 
 1,470 
 
 1,338, 
 
 r,273 
 
 1,364 
 
 1,210 
 
 1, 3.59 
 
 1,272 
 
 1,218 
 
 1,269 
 
 21,263 
 
 23, 556 
 
 21,819 
 
 19, 726 
 
 21,592 
 
 177 
 
 196 
 
 182 
 
 164 
 
 180 
 
 Kemarks. 
 
236 
 
 MEMOIRS OP THE NATIONAL ACADEMY OF SCIENCES. 
 
 Table P. — Potential on clear and fair days, Ithaca, N". T. 
 JUNE, 1886, TO SEPTEMBER, 1887, INCLUSIVE. 
 
 Bate. 
 
 1 p.m. 
 
 Means. 
 
 Kemarbs. 
 
 1886. 
 
 June 27 
 
 June 28 
 
 June 30 .... 
 
 Jnlyl 
 
 Julys 
 
 July 4 
 
 July 5 
 
 July 6 .. 
 
 Julys 
 
 July 11 
 
 Sums .. 
 Means . 
 
 July 12.... 
 
 July22 
 
 July23.... 
 July 24.... 
 ^ugust 2.. 
 August 4.. 
 August 6.. 
 August 8.. 
 August 9.. 
 August 10- 
 
 Snms .. 
 Means . 
 
 August 12. 
 August 15. 
 August 18. 
 August 19. 
 August 21. 
 August 22. 
 August 26. 
 August 27. 
 August 28. 
 August 29. 
 
 Sums. - 
 Means . 
 
 September 1.. 
 September 6. . 
 September 7. . 
 September 8. . 
 September 9- . 
 September 10. 
 Septeniber 11 . 
 September 13. 
 September 17. 
 September 18 , 
 
 Suras. - 
 Means. 
 
 September 30 . 
 
 October 3 
 
 October 6 
 
 October 8 
 
 October 9 
 
 October 10 ... 
 October 11 ... 
 October 21 ... 
 October 22 . . . 
 October 23 ... 
 
 Slims.. 
 Means. 
 
 80 
 50 
 45 
 117 
 43 
 80 
 86 
 89 
 64 
 63 
 
 717 
 72 
 
 136 
 90 
 88 
 23 
 '90 
 80 
 80 
 70 
 45 
 65 
 
 767 
 77 
 
 158 
 
 -68 
 
 101 
 
 158 
 
 49 
 
 96 
 
 78 
 
 92 
 
 94 
 
 115 
 
 1,009 
 101 
 
 68 
 
 108 
 
 85 
 
 98 
 
 57 
 
 108 
 
 84 
 
 258 
 
 56 
 
 40 
 
 962 
 96 
 
 118 
 
 101 
 
 92 
 
 80 
 
 142 
 
 198 
 
 84 
 
 46 
 
 150 
 
 180 
 
 1, 191 
 119 
 
 81 
 58 
 77 
 72 
 67 
 113 
 46 
 73 
 80 
 79 
 
 70 
 77 
 52 
 78 
 78 
 101 
 31 
 73 
 55 
 76 
 
 746 
 75 
 
 691 
 69 
 
 44 
 
 120 
 
 95 
 
 105 
 
 110 
 
 75 
 
 98 
 
 46 
 
 109 
 
 87 
 
 65 
 150 
 
 61 
 131 
 
 83 
 
 50 
 127 
 
 44 
 103 
 119 
 
 889 
 89 
 
 933 
 93 
 
 158 
 71 
 
 108 
 80 
 94 
 
 105 
 77 
 87 
 99 
 78 
 
 957 
 96 
 
 77 
 123 
 115 
 121 
 
 62 
 119 
 
 74 
 112 
 
 41 
 
 31 
 
 875 
 88 
 
 111 
 96 
 96 
 
 165 
 92 
 
 109 
 76 
 95 
 
 168 
 
 382 
 
 1,450 
 145 
 
 176 
 101 
 105 
 
 80 
 104 
 110 
 
 87 
 103 
 
 94 
 
 72 
 
 1,032 
 103 
 
 104 
 110 
 109 
 130 
 
 76 
 78 
 58 
 88 
 36 
 44 
 
 833 
 83 
 
 135 
 
 69 
 
 131 
 
 159 
 
 109 
 
 143 
 
 60 
 
 60 
 
 170 
 
 372 
 
 1,498 
 
 84 
 115 
 70 
 108 
 90 
 44 
 86 
 78 
 68 
 
 825 
 82 
 
 63 
 183 
 103 
 125 
 
 96 
 
 76 
 119 
 
 85 
 118 
 116 
 
 1,084 
 108 
 
 136 
 143 
 126 
 
 87 
 136 
 118 
 125 
 146 
 
 91 
 103 
 
 1,211 
 121 
 
 107 
 118 
 86 
 117 
 60 
 99 
 70 
 77 
 73 
 79 
 
 886 
 89 
 
 140 
 100 
 155 
 134 
 158 
 126 
 65 
 103 
 177 
 255 
 
 1,413 
 
 -141 
 
 78 
 67 
 72 
 84 
 74 
 96 
 52 
 80 
 69 
 72 
 
 744 
 74 
 
 77 
 136 
 87 
 96 
 95 
 70 
 106 
 61 
 94 
 97 
 
 919 
 92 
 
 157 
 96 
 
 110 
 
 101 
 96 
 
 107 
 92 
 
 107 
 94 
 92 
 
 ,052 
 105 
 
 115 
 99 
 
 116 
 64 
 
 101 
 72 
 
 134 
 52 
 48 
 
 890 
 
 126 
 
 96 
 
 118 
 
 134 
 
 125 
 
 159 
 
 71 
 
 76 
 
 166 
 
 297 
 
 1,368 
 137 
 
 NW., clear. 
 N. It., fair. 
 NW. It., clear. 
 N. It. , clear. 
 Fair. 
 NW.lt., clear. 
 
 Do. 
 NW.lt., fair. 
 NW.br., clear. 
 NW. br., fair. 
 
 NW.lt., clear. 
 Clear. 
 Do. 
 Var.lt., clear. 
 NW.br., fair. 
 W. It., fair. 
 NW.lt., fair. 
 Clear. 
 
 SW.fr., clear. 
 B. fr., clear. 
 
 NW. fr., fair. 
 NW. It., clear. 
 Clear. 
 
 W. It., clear. 
 SW. br., fair. 
 SW.fr., clear. 
 N.lt., clear. 
 Clear. 
 
 Do. 
 SW, fr., fair. 
 
 NW.br., fair. 
 W. It., clear. 
 W. fr., clear. 
 SW. fr., clear. 
 SW. &., fair. 
 
 Do. 
 NW. fr., clear. 
 NW. br., fair. 
 W. br., fair. 
 Fair. 
 
 W. br., clear. 
 N. It., clear. 
 W. It., fair. 
 W. It., clear. 
 W. fr., clear. 
 W.lt., fair. 
 SW. fr., clear. 
 NW.br., fair. 
 W, fr., clear. 
 Do. 
 
MEMOIRS OP THE NATIONAL ACADEMY OF SCIENCES. 
 
 237 
 
 Table F. — Potential on clear and fair days, Ithaca, N. Y. — Continued. 
 JUNE, 1886, TO SEPTEMBER 1887, INCLUSIVE— Continued. 
 
 Date. 
 
 9 a.m. 
 
 11 a. m. 
 
 1 p.m. 
 
 3 p.m. 
 
 Means. 
 
 265 
 
 249 
 
 208 
 
 161 
 
 221 
 
 187 
 
 104 
 
 154 
 
 118 
 
 141 
 
 145 
 
 206 
 
 180 
 
 167 
 
 174 
 
 182 
 
 297 
 
 22 
 
 417 
 
 230 
 
 205 
 
 315 
 
 265 
 
 250 
 
 259 
 
 55 
 
 55 
 
 45 
 
 20 
 
 ,44 
 
 290 
 
 270 
 
 285 
 
 200 
 
 ^61 
 
 127 
 
 177 
 
 43 
 
 V67 
 
 104 
 
 170 
 
 92 
 
 123 
 
 112 
 
 124 
 
 217 
 
 250 
 
 200 
 
 140 
 
 202 
 
 1,843 
 
 2,015 
 
 1,525 
 
 1,652 
 
 1,760 
 
 184 
 
 202 
 
 152 
 
 165 
 
 176 
 
 157 
 
 217 
 
 180 
 
 95 
 
 162 
 
 99 
 
 143 
 
 115 
 
 110 
 
 117 
 
 99 
 
 82 
 
 101 
 
 88 
 
 92 
 
 143 
 
 44 
 
 47 
 
 47 
 
 70 
 
 115 
 
 148 
 
 148 
 
 11 
 
 106 
 
 44 
 
 115 
 
 126 
 
 93 
 
 94 
 
 146 
 
 132 
 
 93 
 
 77 
 
 112 
 
 115 
 
 137 
 
 123 
 
 93 
 
 117 
 
 27 
 
 66 
 
 11 
 
 88 
 
 48 
 
 22 
 
 88 
 
 82 
 
 88 
 
 70 
 
 967 
 
 1,172 
 
 1,026 
 
 790 
 
 988 
 
 97 
 
 117 
 
 103 
 
 79 
 
 99 
 
 183 
 
 88 
 
 91 
 
 121 
 
 121 
 
 160 
 
 82 
 
 82 
 
 99 
 
 106 
 
 1«) 
 
 104 
 
 99 
 
 104 
 
 104 
 
 104 
 
 104 
 
 132 
 
 143 
 
 121 
 
 66 
 
 82 
 
 77 
 
 99 
 
 81 
 
 71 
 
 77 
 
 60 
 
 ■ 82 
 
 72 
 
 45 
 
 60 
 
 60 
 
 65 
 
 58 
 
 125 
 
 125 
 
 112 
 
 112 
 
 118 
 
 95 
 
 80 
 
 75 
 
 110 
 
 90 
 
 75 
 
 70 
 
 85 
 
 80 
 
 78 
 
 1,034 
 
 872 
 
 873 
 
 1,015 
 
 949 
 
 103 
 
 87 
 
 87 
 
 102 
 
 95 
 
 125 
 
 90 
 
 80 
 
 100 
 
 99 
 
 • 100 
 
 80 
 
 100 
 
 155 
 
 109 
 
 85 
 
 70 
 
 85 
 
 90 
 
 82 
 
 70 
 
 70 
 
 65 
 
 60 
 
 66 
 
 125 
 
 75 
 
 115 
 
 110 
 
 106 
 
 55 
 
 115 
 
 75 
 
 110 
 
 89 
 
 65 
 
 105 
 
 110 
 
 105 
 
 96 
 
 125 
 
 85 
 
 85 
 
 55 
 
 88 
 
 135 
 
 100 
 
 150 
 
 125 
 
 128 
 
 885 
 
 790 
 
 865 
 
 910 
 
 863 
 
 98 
 
 88 
 
 96 
 
 101 
 
 96 
 
 Remarks. 
 
 1886. 
 November 1 . 
 November 4 . 
 November 22 
 
 1887. 
 Januarys ... 
 January 11 . . 
 March 12 .... 
 
 March 31 
 
 Aprils 
 
 Aprils 
 
 Aprils 
 
 Sums... 
 Means.. 
 
 April 20 
 
 May 13 
 
 June 11 
 
 June 12 
 
 June 14 
 
 June 15 
 
 June 20 
 
 June 23 
 
 June 25 
 
 June 26 
 
 Sums... 
 Means.. 
 
 June 28 
 
 June 29 
 
 July 1 
 
 July 2 
 
 Julys 
 
 July 4 
 
 July 7 
 
 July 13 
 
 July 19 
 
 July 27 
 
 Sums... 
 Means.. 
 
 July 28 
 
 July SO 
 
 July 31 
 
 August 7 
 
 August 8 
 
 August 12 . .. 
 August 13 . . . 
 August 14 ... 
 August 25 ... 
 
 Sums .. 
 Means.. 
 
 Clear. 
 
 NW. br.^ clear. 
 
 S. It., clear. 
 
 NW. It., clear. 
 SE.fr., clear. 
 NW.fr., clear. 
 E. It., clear. 
 N. It., clear. 
 Fair. 
 Clear. 
 
 SW.lt., clear. 
 Var.lt., clear. 
 SE.lt., fair. 
 NW.lt., clear. 
 
 Do. 
 SW. fr., clear. 
 NW.lt., fair. 
 S. fr., fair. 
 Fair. 
 NW.fr., fair. 
 
 NW.fr., clear. 
 NW. It., clear. 
 SW.lt., fair. 
 
 Do. 
 SE.lt., clear. 
 SW. br., fair. 
 W. fr., clear. 
 Var. It., fair. 
 Fair. 
 NW. It., clear. 
 
 Var. It., clear. 
 SW.fr., clear. 
 W. It., clear. 
 NW. fl:., clear. 
 Clear. 
 
 NW. fr., clear. 
 NW. It., clear. 
 Clear. 
 NW.high, fair. 
 
 SUMMARY. 
 
 (10) 
 
 (10) 
 
 (10) 
 
 (10) 
 
 (10) 
 
 (10) 
 
 (10) 
 
 (10) 
 
 (9) 
 
 Sums (89).... 
 Means 
 
 717 
 
 746 
 
 691 
 
 825 
 
 744 
 
 767 
 
 889 
 
 933 
 
 1,084 
 
 919 
 
 1,009 
 
 957 
 
 1,032 
 
 1,211 
 
 1,052 
 
 962 
 
 875 
 
 . 833 
 
 886 
 
 890 
 
 1,191 
 
 1,450 
 
 1,428 
 
 1,413 
 
 1,368 
 
 1,843. 
 
 2,015 
 
 1,525 
 
 1,652 
 
 1,760 
 
 967 
 
 1,172 
 
 1,026 
 
 790 
 
 988 
 
 1,034 
 
 872 
 
 873 
 
 1,015 
 
 949 
 
 885 
 
 790 
 
 865 
 
 910 
 
 863 
 
 9,374 
 
 9,766 
 
 9,206 
 
 9,786 
 
 9,533 
 
 105 
 
 110 
 
 103 
 
 110 
 
 107 
 
238 
 
 MEMOIRS OF THE NATIONAL ACADEMY OP SOIENOBS. 
 
 Table F. — Potential on clear and fair days, Ithaca, N'. Y. — Continued. 
 OCTOBER, 1887, TO AUGUST, 1888, INCLUSIVE. 
 
 Date. 
 
 1887. 
 
 October 8 
 
 October 15 . . . 
 October 16 ... 
 October 26 ... 
 October 28 ... 
 October 31 ... 
 November 1 . . 
 November 2 . . 
 November 6 .. 
 November 9 . . 
 
 Sums . . 
 Means . 
 
 December 1 . . 
 December 6 .. 
 December 13 . 
 December 14 . 
 
 188H. 
 February 12.. 
 February 13. . 
 February 16. . 
 February 23. . 
 February 24. . 
 March 9 
 
 Sums .. 
 Means . 
 
 March 18. 
 March 19. 
 March 25 . 
 April 9... 
 April 29.. 
 
 May 3 
 
 May 22... 
 May 23... 
 June 3 . . . 
 June 5 ... 
 
 Sums . . 
 
 Means 
 
 June 8 . . 
 June 9 . . 
 June 17 . 
 June 18 . 
 June 19 - 
 June 20 . 
 June 21 . 
 June 22 . 
 Julyl.^. 
 July2.-. 
 
 Sums .. 
 Means . 
 
 Julys.. 
 July 4.. 
 July 6.. 
 July 7.. 
 July 12. 
 July 14. 
 July 16. 
 July 21. 
 July 22. 
 July 28. 
 
 Sums.. 
 Means . 
 
 375 
 546 
 382 
 ,198 
 368 
 455 
 264 
 434 
 331 
 391 
 
 4,744 
 474 
 
 1,053 
 590 
 300 
 760 
 
 915 
 950 
 330 
 640 
 320 
 610 
 
 6,468 
 647 
 
 909 
 877 
 316 
 312 
 111 
 260 
 250 
 406 
 164 
 250 
 
 3,855 
 386 
 
 280 
 275 
 95 
 130 
 230 
 ^10 
 140 
 210 
 100 
 178 
 
 1,848 
 185 
 
 205 
 215 
 330 
 240 
 578 
 491 
 110 
 242 
 160 
 127 
 
 2,698 
 270 
 
 342 
 400 
 236 
 950 
 385 
 368 
 430 
 435 
 450 
 443 
 
 4, 439. 
 444 
 
 1,131 
 380 
 560 
 
 880 
 
 ,210 
 915 
 380 
 500 
 400 
 600 
 
 6,956 
 696 
 
 870 
 ,250 
 537 
 164 
 200 
 445 
 389 
 360 
 190 
 300 
 
 4, 705 
 470 
 
 149 
 230 
 126 
 350 
 295 
 180 
 186 
 240 
 103 
 148 
 
 2,007 
 201 
 
 205 
 220 
 350 
 249 
 560 
 358 
 200 
 110 
 180 
 120 
 
 2,552 
 255 
 
 1 p.m. 
 
 243 
 362 
 150 
 725 
 204 
 330 
 312 
 300 
 205 
 335 
 
 3,166 
 317 
 
 ,195 
 149 
 800 
 970 
 
 890 
 815 
 520 
 550 
 360 
 850 
 
 7,099 
 710 
 
 830 
 880 
 239 
 148 
 145 
 280 
 355 
 331 
 140 
 350 
 
 3,698 
 370 
 
 210 
 280 
 
 95 
 145 
 220 
 150 
 124 
 180 
 
 60 
 128 
 
 1,592 
 159 
 
 197 
 160 
 230 
 264 
 562 
 222 
 150 
 107 
 215 
 90 
 
 2,197 
 220 
 
 3 p.m. 
 
 235 
 308 
 164 
 766 
 214 
 317 
 249 
 315 
 260 
 340 
 
 3,168 
 317 
 
 535 
 256 
 
 680 
 780 
 
 895 
 650 
 620 
 408 
 600 
 750 
 
 6,174 
 617 
 
 740 
 810 
 478 
 219 
 125 
 235 
 325 
 141 
 190 
 280 
 
 3,543 
 354 
 
 270 
 250 
 90 
 220 
 260 
 280 
 160 
 210 
 140 
 210 
 
 2,090 
 209 
 
 200 
 168 
 210 
 218 
 380 
 232 
 150 
 120 
 145 
 40 
 
 1, 863 
 
 186 
 
 5 p.m. 
 
 270 
 398 
 173 
 680 
 214 
 367 
 304 
 343 
 410 
 330 
 
 3,489 
 349 
 
 n874 
 440 
 791 
 640 
 
 970 
 500 
 260 
 370 
 430 
 760 
 
 6,035 
 604 
 
 601 
 ,030 
 491 
 255 
 208 
 203 
 514 
 156 
 265 
 180 
 
 3,903 
 390 
 
 110 
 230 
 120 
 282 
 310 
 280 
 241 
 261 
 162 
 115 
 
 2,111 
 211 
 
 227 
 
 ^160 
 
 295 
 
 214 
 
 262 
 
 195 
 
 170 
 
 185 
 
 90 
 
 80 
 
 1,878 
 188 
 
 Means. 
 
 293 
 403 
 221 
 864 
 277 
 367 
 312 
 365 
 331 
 368 
 
 3,801 
 380 
 
 958 
 363 
 626 
 806 
 
 975 
 766 
 422 
 494 
 422 
 714 
 
 6,546 
 655 
 
 790 
 969 
 412 
 220 
 158 
 285 
 367 
 279 
 190 
 272 
 
 3,942 
 394 
 
 204 
 253 
 105 
 225 
 263 
 220 
 170 
 220 
 113 
 156 
 
 1,929 
 193 
 
 207 
 185 
 283 
 237 
 468 
 300 
 156 
 153 
 158 
 91 
 
 2,238 
 224 
 
 Bemarks. 
 
 W. It., fair. 
 W. It., clear. 
 SW. fr., fair. 
 Var, It., fair, 
 NW.lt., fair, hazy. 
 SW.lt., fair. 
 NW. br., clear. 
 N. It., clear. 
 S. It., clear. 
 SE. It., fair. 
 
 E. It., clear. 
 Var. it., clear. 
 Var. It., fair. 
 SE.lt., clear. 
 
 SE.lt., fair. 
 S. It., fair. 
 W. It., fair. 
 S. fr. , fair. 
 SE.fr., fair. 
 N. fr. , fair. 
 
 N. It. , cloar. 
 SE.br., fair. 
 SE.lt., fair, 
 SE.lt., clear. 
 NW.fr., fair. 
 S. fr.,fair. 
 
 Do, 
 SE.fr.. fair. 
 NW. fr., clear. 
 SW. fr., clear, hazy. 
 
 NW.lt., clear. 
 S. fr. , ciear. 
 NW.fr., clear. 
 NW. fr., fair. 
 NW.lt., clear. 
 NW.lt., fair. 
 SE.lt., fair. 
 W. It., fair. 
 NW.fr., fair. 
 N. It., fair. 
 
 S. fr. , fair. 
 SW. fr., fair. 
 NW. It., clear. 
 NW. fr., fair, haze. 
 W. fr., fair, haze. 
 NW.fr., fair. 
 NW.fr., clear. 
 
 Do. 
 NW.It., clear. 
 NW. fr., fair. 
 
MEMOIRS OP THE NATIONAL ACADEMY OP SCIENCES. 
 
 239 
 
 Table F. — Potential on clear and fair days, Ithaca, N. Y. — Continued. 
 OCTOBER, 1887, TO AUGUST, 1888, INCLUSIVE— Continued. 
 
 Dat<^ 
 
 1888, 
 
 July 29 
 
 July 30 
 
 August 1 
 
 August S 
 
 August 6 
 
 August 7 
 
 August 8 
 
 August 9 
 
 August 10 . . . 
 August 19 . . . 
 
 Sums.. 
 Means 
 
 August 28 . . . 
 August 29 . . . 
 August ao ... 
 
 Sums . 
 Means. 
 
 110 
 100 
 350 
 160 
 110 
 160 
 190 
 150 
 210 
 215 
 
 1,755 
 176 
 
 280 
 290 
 390 
 
 960 
 96 
 
 11 a. in. 
 
 130 
 145 
 
 100 
 140 
 120 
 190 
 140 
 155 
 200 
 220 
 
 1,540 
 154 
 
 270 
 310 
 395 
 
 975 
 98 
 
 1 p. m. 
 
 lOO 
 125 
 100 
 120 
 170 
 190 
 140 
 200 
 225 
 200 
 
 1,570 
 157 
 
 220 
 230 
 240 
 
 690 
 69 
 
 3 p. m. 
 
 110 
 150 
 190 
 200 
 200 
 140 
 160 
 255 
 230 
 230 
 
 1,865 
 186 
 
 230 
 280 
 360 
 
 870 
 
 87 
 
 5 p. m. 
 
 170 
 270 
 210 
 110 
 210 
 150 
 150 
 220 
 165 
 270 
 
 1,925 
 192 
 
 370 
 395 
 340 
 
 1,105 
 110 
 
 MeauB. 
 
 124 
 
 158 
 190 
 146 
 162 
 166 
 156 
 196 
 206 
 227 
 
 1,731 
 173 
 
 274 
 301 
 345 
 
 920 
 92 
 
 Kemarlca. 
 
 NW.fr., fair. 
 SE.lt., fair, haze. 
 NW. fr.j,clear, haze. 
 SW.fr., fair. 
 W. It., fair. 
 NW. fr., fair. 
 SW.fr., fair. 
 NW.fr., fair, 
 NW. fr., clear. 
 S. fr., clear. 
 
 N. fr., fair. 
 NW.fr., fair. 
 SW.fr., fair., 
 
 SUMMABT. 
 
 Number of days. 
 
 (10) 
 
 (10) 
 
 (10)—.- 
 
 (10) 
 
 (10) - 
 
 (10) 
 
 (3) 
 
 Sums *. 
 
 Means 
 
 4,744 
 6,468 
 3,855 
 1,848 
 2,698 
 1,755 
 960 
 
 22, 328 
 355 
 
 4, 439 
 6,956 
 4,705 
 2,007 
 2,552 
 1,540 
 975 
 
 23, 174 
 368 
 
 1 p. m. 
 
 3,166 
 7,099 
 3,698 
 1,592 
 2,197 
 1,570 
 690 
 
 20,012 
 318 
 
 3 p.m. 
 
 3,168 
 6,174 
 3,543 
 2,090 
 1,863 
 1,865 
 870 
 
 19,573 
 311 
 
 5 p. m. 
 
 3,489 
 6,035 
 3,903 
 2,111 
 1,878 
 1,925 
 1,105 
 
 20, 446 
 325 
 
 Means. 
 
 3,801 
 6,546 
 3,942 
 1,929 
 2,238 
 1,731 
 920 
 
 21, 107 
 335 
 
^240 
 
 MEMOIE8 OF THE NiCTIOKAL ACADEMY OF SCIENCES. 
 
 Table Q.— Potential on Clear and Fair Days, 
 [Hourly observations from 
 
 Date. 
 
 1 a.m. 
 
 2 a. m: 
 
 3 a. m. 
 
 4 a. no. 
 
 5 a.m. 
 
 6 a.m. 
 
 7 a.m. 
 
 8 a.m. 
 
 9 a.m. ^ 
 
 10 a. m. 
 
 11 a.m. 
 
 12 m. 
 
 1885. 
 
 100 
 
 75 
 
 40 
 
 140 
 
 75 
 
 150 
 
 60 
 
 150 
 
 30 
 
 40 
 
 125 
 
 100 
 
 100 
 
 100 
 
 100 
 
 30 
 
 110 
 
 40 
 
 35 
 
 50 
 
 135 
 
 120 
 
 75 
 
 60 
 
 65 
 
 95 
 
 50 
 
 50 
 
 140 
 
 ■ 50 
 
 125 
 
 75 
 
 40 
 
 150 
 
 150 
 
 175 
 
 50 
 
 120 
 
 25 
 
 20 
 
 175 
 
 100 
 
 100 
 
 100 
 
 120 
 
 60 
 
 75 
 
 50 
 
 35 
 
 60 
 
 140 
 
 80 
 
 70 
 
 60 
 
 60 
 
 95 
 
 60 
 
 60 
 
 140 
 
 25 
 
 100 
 
 75 
 
 40 
 
 150 
 
 200 
 
 140 
 
 50 
 
 100 
 
 25 
 
 40 
 
 150 
 
 110 
 
 100 
 
 125 
 
 130 
 
 125 
 
 75 
 
 60 
 
 55 
 
 60 
 
 115 
 
 90 
 
 70 
 
 60 
 
 60 
 
 100 
 
 55 
 
 60 
 
 135 
 
 ' 40 
 
 100 
 
 75 
 
 40 
 
 140 
 
 175 
 
 140 
 
 50 
 
 90 
 
 25 
 
 40 
 
 150 
 
 100 
 
 100 
 
 125 
 
 160 
 
 90 
 
 75 
 
 50 
 
 50 
 
 65 
 
 100 
 
 100 
 
 70 
 
 45 
 
 50 
 
 100 
 
 55 
 
 65 
 
 130 
 
 40 
 
 100 
 
 75 
 
 40 
 
 125 
 
 150 
 
 175 
 
 60 
 
 100 
 
 40 
 
 40 
 
 125 
 
 100 
 
 110 
 
 125 
 
 150 
 
 100 
 
 60 
 
 50 
 
 40 
 
 60 
 
 50 
 
 105 
 
 70 
 
 50 
 
 60 
 
 100 
 
 90 
 
 90 
 
 135 
 
 30 
 
 ^ 100 
 
 150 
 
 
 
 125 
 
 150 
 
 250 
 
 75 
 
 100 
 
 50 
 
 §0 
 
 160 
 
 100 
 
 110 
 
 200 
 
 160 
 
 125 
 
 75 
 
 50 
 
 50 
 
 70 
 
 60 
 
 110 
 
 65 
 
 50 
 
 50 
 
 85 
 
 100 
 
 70 
 
 150 
 
 40 
 
 50 
 150 
 
 10 
 150 
 150 
 200 
 
 30 
 120 
 100 
 
 75 
 250 
 100 
 
 90 
 175 
 175 
 150 
 —5 
 
 50 
 
 15 
 
 60 
 190 
 100 
 
 65 
 
 50 
 
 
 
 100 
 
 100 
 
 5 
 
 130 
 
 45 
 
 25 
 
 50 
 
 50 
 
 200 
 
 100 
 
 175 
 
 40 
 
 125 
 
 50 
 
 150 
 
 75 
 
 . 150 
 
 75 
 
 100 
 
 200 
 
 110 
 
 125 
 
 50 
 
 50 
 
 60 
 
 140 
 
 110 
 
 70 
 
 35 
 
 100 
 
 100 
 
 110 
 
 30 
 
 110 
 
 60 
 
 25 
 25 
 75 
 
 160 
 
 150 
 
 150 
 75 
 
 150 
 50 
 
 125 
 60 
 
 175 
 60 
 75 
 
 190 
 40 
 
 175 
 
 100 
 85 
 60 
 
 150 
 95 
 55 
 50 
 
 100 
 
 100 
 95 
 45 
 
 110 
 50 
 
 25 
 
 100 
 
 75 
 
 60 
 
 200 
 
 150 
 
 100 
 
 100 
 
 10 
 
 100 
 
 50 
 
 150 
 
 40 
 
 40 
 
 150 
 
 30 
 
 125 
 
 85 
 
 70 
 
 75 
 
 100 
 
 110 
 
 55 
 
 50 
 
 110 
 
 85 
 
 50 
 
 50 
 
 105 
 
 55 
 
 40 
 
 100 
 
 75 
 
 50 
 
 150 
 
 150 
 
 50 
 
 100 
 
 30 
 
 75 
 
 40 
 
 160 
 
 30 
 
 25 
 
 150 
 
 10 
 
 150 
 
 100 
 
 50 
 
 90 
 
 200 
 
 115 
 
 60 
 
 50 
 
 130 
 
 100 
 
 60 
 
 50 
 
 110 
 
 50 
 
 30 
 
 125 
 
 75 
 
 30 
 
 150 
 
 150 
 
 20 
 
 75 
 
 75 
 
 75 
 
 40 
 
 150 
 
 30 
 
 25 
 
 130 
 
 
 
 100 
 
 75 
 
 50 
 
 90 
 
 120 
 
 110 
 
 60 
 
 100 
 
 100 
 
 '""56" 
 
 50 
 
 110 
 
 50 
 
 
 Janiiarv 7 
 
 .Tanuarv 8 
 
 
 January 13 
 
 .Tamiarv 14 . 
 
 J anuarv '20 
 
 
 January ^7 _ 
 
 J-anuarv 30 
 
 January 31 -- 
 
 
 Ti^fthruarv 24 * 
 
 
 Marcli 5 
 
 March 30 
 
 April 9 
 
 AprillS- 
 
 April 19 
 
 April 20 
 
 May 10 
 
 June 12 
 
 June 20 
 
 June 29 
 
 July 1 
 
 July4 *., 
 
 July 11 
 
 July 12 
 
 
 2,490 
 83 
 
 2, 595 
 86 
 
 2,695 
 90 
 
 2,595 
 
 86 
 
 2,605 
 
 87 
 
 2,930 
 
 98 
 
 2,880 
 96 
 
 2,825 
 94 
 
 2,845 
 95 
 
 2,505 
 
 84 
 
 2,550 
 85 
 
 2,245 
 
 77 
 
 Means 
 
 July 15 
 
 25 
 55 
 50 
 60 
 "80 
 50 
 50 
 85 
 45 
 80 
 60 
 25 
 60 
 
 -60 
 30 
 40 
 50 
 50 
 50 
 55 
 55 
 40 
 25 
 90 
 65 
 
 100 
 30 
 65 
 75 
 30 
 
 45 
 60 
 60 
 40 
 25 
 45 
 50 
 85 
 40 
 70 
 65 
 30 
 70 
 
 100 
 40 
 40 
 55 
 50 
 50 
 70 
 70 
 50 
 40 
 
 100 
 50 
 
 110 
 30 
 50 
 60 
 75 
 
 25 
 65 
 60 
 20 
 30 
 40 
 60 
 70 
 50 
 45 
 50 
 30 
 60 
 90 
 45 
 50 
 50 
 40 
 45 
 75 
 60 
 50 
 60 
 100 
 50 
 95 
 50 
 50 
 100 
 95 
 
 40 
 65 
 60 
 60 
 20 
 50 
 70 
 40 
 40 
 40 
 60 
 30 
 
 100 
 70 
 50 
 50 
 55 
 35 
 70 
 40 
 60 
 50 
 55 
 
 110 
 55 
 95 
 40 
 75 
 50 
 60 
 
 70 
 90 
 65 
 50 
 50 
 70 
 80 
 60 
 30 
 55 
 50 
 40 
 60 
 70 
 50 
 70 
 55 
 35 
 50 
 50 
 60 
 50 
 60 
 105 
 55 
 90 
 50 
 75 
 60 
 65 
 
 100 
 
 90 
 
 80 
 
 
 
 100 
 
 100 
 
 100 
 80 
 30 
 60 
 50 
 50 
 70 
 80 
 60 
 
 110 
 
 100 
 40 
 75 
 60 
 50 
 20 
 60 
 
 125 
 75 
 
 100 
 75 
 
 105 
 60 
 
 125 
 
 
 100 
 
 fo 
 
 50 
 
 20 
 
 110 
 
 100 
 
 50 
 
 80 
 
 60 
 
 55 
 
 
 
 90 
 
 70 
 
 90 
 
 50 
 
 30 
 
 85 
 
 20 
 
 50 
 
 25 
 
 60 
 
 150 
 
 100 
 
 100 
 
 75 
 
 100 
 
 65 
 
 125 
 
 50 
 70 
 110 
 60 
 50 
 20 
 90 
 70 
 60 
 50 
 70 
 65 
 70 
 50 
 70 
 60 
 60 
 35 
 50 
 35 
 60 
 20 
 80 
 50 
 110 
 140 
 90 
 100 
 30 
 130 
 
 50 
 60 
 50 
 
 100 
 35 
 50 
 90 
 80 
 50 
 75 
 60 
 50 
 60 
 90 
 80 
 70 
 80 
 25 
 40 
 
 —20 
 
 45 
 
 30 
 
 50 
 
 115 
 
 90 
 
 150 
 
 110 
 
 175 
 
 60 
 
 95 
 
 25 
 40 
 60 
 130 
 30 
 70 
 85 
 80 
 50 
 90 
 55 
 50 
 30 
 100 
 85 
 70 
 30 
 25 
 35 
 70 
 30 
 50 
 60 
 130 
 75 
 150 
 90 
 160 
 60 
 80 
 
 40 
 40 
 60 
 
 100 
 30 
 60 
 85 
 
 100 
 50 
 
 100 
 50 
 50 
 15 
 
 110 
 75 
 60 
 75 
 25 
 20 
 80 
 40 
 80 
 
 100 
 
 125 
 80 
 25 
 75 
 
 175 
 
 100 
 
 60 
 
 50 . 
 30 
 50 
 
 70 • 
 30 
 70 
 100 
 70 
 50 
 100 
 50 
 25 
 
 
 
 120 
 
 95 
 
 60 
 
 60 
 
 25 
 
 15 
 
 100 
 
 50 
 
 80 
 
 100 
 
 125 
 
 75 
 
 150 
 
 75 
 
 150 
 
 150 
 
 60 
 
 July 16 
 
 July 17 
 
 July '23 
 
 August 5 . 
 
 
 
 Anffust 11 ....... .. 
 
 
 August 28 
 
 Sftntenaber 1 - . 
 
 September J2. 
 
 September 3 .-.-.-._.- 
 
 
 
 fiftntember 16 
 
 Sflntember 17.---- . 
 
 Sentember SO' . . 
 
 
 September UG 
 
 
 SfiTttem ber S8 
 
 September 29 * - 
 
 Ofitober 5 .......... 
 
 October 7 
 
 October 11 . ---- - 
 
 
 October 16 
 
 
 October 18 .1 
 
 
 1,585 
 53 
 
 1,725 
 58 
 
 1,710 
 57 
 
 1,695 
 56 
 
 1,820 
 61 
 
 3,230 
 74 
 
 1,965 
 66 
 
 2,005 
 67 
 
 •2,095 
 70 
 
 2,095 
 70 
 
 2,085 
 70 
 
 2,185 
 ' 73 
 
 
 
MEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES. 
 
 241 
 
 Baltimore, Md., 1885, 1886, and 1887. 
 the photographic sheets.] 
 
 Ip. m. 
 
 2 p.m. 
 
 8 p.m. 
 
 4 p.m. 
 
 5 p.m. 
 
 6 p.m. 
 
 7 p.m. 
 
 8 p.m. 
 
 9 p.m. 
 
 10 p.m. 
 
 11 p. m. 
 
 12 riiid. 
 
 Eemarka- 
 
 30 
 
 50 
 
 60 
 
 75 
 
 75 
 
 80 
 
 100 
 
 100 
 
 125 
 
 125 
 
 100 
 
 80 
 
 NW.br., clear. 
 
 100 
 
 150 
 
 150 
 
 125 
 
 100 
 
 100 
 
 125 
 
 125 
 
 125 
 
 100 
 
 100 
 
 90 
 
 SE.fr., fair. 
 
 75 
 
 75 
 
 75 
 
 75 
 
 90 
 
 100 
 
 100 
 
 90 
 
 75 
 
 100 
 
 125 
 
 125 
 
 W. br., <air. 
 
 75 
 
 100 
 
 100 
 
 100 
 
 90 
 
 150 
 
 150 
 
 100 
 
 125 
 
 75 
 
 50 
 
 50 
 
 SW. fr., fair. 
 
 150 
 
 100 
 
 100 
 
 100 
 
 100 
 
 50 
 
 50 
 
 ■ 50 
 
 40 
 
 
 
 —10 
 
 
 
 SW.fr., clear, fog. 
 
 '65 
 
 80 
 
 65 
 
 65 
 
 65 
 
 75 
 
 80 
 
 75 
 
 100 
 
 , 65 
 
 75 
 
 50 
 
 NW.fr., fair. 
 
 125 
 
 160 
 
 100 
 
 125 
 
 100 
 
 75 
 
 75 
 
 60 
 
 50 
 
 50 
 
 80 
 
 60 
 
 E.fr., clear. 
 
 50 
 
 60 
 
 50 
 
 50 
 
 60 
 
 60 
 
 80 
 
 80 
 
 100 
 
 100 
 
 100 
 
 75 
 
 NW.fr., fair. 
 
 75 
 
 50 
 
 50 
 
 80 
 
 75 
 
 50 
 
 60 
 
 50 
 
 75 
 
 60 
 
 50 
 
 30 
 
 NW.br., clear. 
 
 100 
 
 130 
 
 loa 
 
 100 
 
 100 
 
 50 
 
 75 
 
 100 
 
 90 
 
 90 
 
 100 
 
 150 
 
 NW.br., fair. 
 
 200 
 
 175 
 
 165 
 
 165, 
 
 125 
 
 150 
 
 .50 
 
 50 
 
 100 
 
 75 
 
 50 
 
 120 
 
 W.fr.,fair. 
 
 140 
 
 130 
 
 150 
 
 150 
 
 100 
 
 50 
 
 50 
 
 75 
 
 75 
 
 75 
 
 60 
 
 
 
 NE.lt., fair. 
 
 150 
 
 125 
 
 100 
 
 75 
 
 75 
 
 50 
 
 60 
 
 50 
 
 .50 
 
 60 
 
 75 
 
 75 
 
 NW.fr., clear 
 
 100 
 
 100 
 
 110 
 
 110 
 
 125 
 
 90 
 
 75 
 
 80 
 
 90 
 
 75 
 
 100 
 
 100 
 
 Do. 
 
 30 
 
 60 
 
 60 
 
 60 
 
 60 
 
 60 
 
 50 
 
 50 
 
 40 
 
 50 
 
 75 
 
 100 
 
 S.fr.,fair. 
 
 30 
 
 25 
 
 10 
 
 25 
 
 
 
 25 
 
 -10 
 
 10 
 
 10 
 
 30 
 
 50 
 
 25 
 
 N.fr.,fair. 
 
 50 
 
 100 
 
 75 
 
 100 
 
 100 
 
 50 
 
 125 
 
 75 
 
 75 
 
 30 
 
 20 
 
 30 
 
 W. It., fair. 
 
 80 
 
 75 
 
 50 
 
 .50 
 
 40 
 
 50 
 
 50 
 
 50 
 
 50 
 
 60 
 
 50 
 
 50 
 
 NW.fr., clear. 
 
 50 
 
 85 
 
 95 
 
 75 
 
 50 
 
 35 
 
 35 
 
 45 
 
 60 
 
 60 
 
 50 
 
 50 
 
 Var.lt., fair. 
 
 100 
 
 150 
 
 200 
 
 150 
 
 160 
 
 140 
 
 160 
 
 150 
 
 140 
 
 100 
 
 150 
 
 120 
 
 E.fr., clear. 
 
 200 
 
 170 
 
 150 
 
 160 
 
 200 
 
 50 
 
 25 
 
 50 
 
 J5 
 
 40 
 
 50 
 
 50 
 
 SE.fr., clear. 
 
 15 
 
 100 
 
 100 
 
 100 
 
 100 
 
 85 
 
 70 
 
 50 
 
 50 
 
 40 
 
 40 
 
 40 
 
 NW.fr., fair. 
 
 50 
 
 75; 
 
 ■ 50 
 
 50 
 
 100 
 
 80. 
 
 100 
 
 90 
 
 100 
 
 100 
 
 95 
 
 ,75 
 
 SE.fr., clear. 
 
 100 
 
 150 
 
 130 
 
 110 
 
 100 
 
 100 
 
 50 
 
 no 
 
 95 
 
 70 
 
 70 
 
 70 
 
 S. fr., clear. 
 
 60 
 
 100 
 
 75 
 
 60 
 
 60 
 
 25 
 
 50 
 
 30 
 
 60 
 
 55 
 
 50 
 
 50 
 
 W. It., fair. 
 
 
 50 
 
 70 
 
 75 
 
 60 
 
 75 
 
 75 
 
 85 
 
 80 
 
 70 
 
 60 
 
 70 
 
 W.fr.,fair. 
 
 """46' 
 
 35 
 
 40 
 
 40 
 
 25 
 
 35 
 
 20 
 
 25 
 
 30 
 
 40 
 
 40 
 
 40 
 
 NW.fr., fair. 
 
 40 
 
 50 
 
 65 
 
 80 
 
 80 
 
 90 
 
 110 
 
 95 
 
 90 
 
 65 
 
 45 
 
 25 
 
 SW.fr., clear. 
 
 100 
 
 40 
 
 25 
 
 40 
 
 60 
 
 
 
 
 
 50 
 
 15 
 
 40 
 
 40 
 
 40 
 
 Var.fr., fair. 
 
 50 
 
 50 
 
 50 
 
 60 
 
 60 
 
 50 
 
 50 
 
 60 
 
 70 
 
 50 
 
 50 
 
 55 
 
 NE.fr., clear. 
 
 2,430 
 
 2,800 
 
 2, 620 
 
 2,630 
 
 2,535 
 
 2,080 
 
 2,110 
 
 2,130 
 
 2,000 
 
 1,950 
 
 1,990 
 
 1,895 
 
 84 
 
 93 
 
 87 
 
 88 
 
 84 
 
 69 
 
 70 
 
 71 
 
 67 
 
 65 
 
 66 
 
 63 
 
 • 
 
 Var.fr., clear. 
 
 50 
 
 75 
 
 100 
 
 140 
 
 90 
 
 50 
 
 50 
 
 50 
 
 70 
 
 70 
 
 50 
 
 100 
 
 ,50 
 
 65 
 
 65 
 
 60 
 
 50 
 
 55 
 
 40 
 
 50 
 
 50 
 
 
 
 50 
 
 25 
 
 S. It., clear. 
 
 45 
 
 25 
 
 50 
 
 80 
 
 80 
 
 50 
 
 30 
 
 70 
 
 30 
 
 50 
 
 100 
 
 25 
 
 S. It., fair. 
 
 50 
 
 75 
 
 100 
 
 115 
 
 100 
 
 60 
 
 100 
 
 60 
 
 65 
 
 80 
 
 60 
 
 85 
 
 SE.lt., fair. 
 
 50 
 
 45 
 
 45 
 
 45 
 
 55 
 
 60 
 
 50 
 
 45 
 
 55 
 
 20 
 
 50 
 
 25 
 
 NW.fr., clear. 
 
 65 
 
 50 
 
 55 
 
 55 
 
 20 
 
 15 
 
 10 
 
 15 
 
 70 
 
 100 
 
 65 
 
 100 
 
 N. fr. , clear. 
 
 100 
 
 100 
 
 110 
 
 135 
 
 160 
 
 125 
 
 150 
 
 130 
 
 130 
 
 170 
 
 60 
 
 35 
 
 NW.fr., fair. 
 
 60 
 
 100 
 
 125 
 
 125 
 
 135 
 
 155 
 
 120 
 
 100 
 
 70 
 
 70 
 
 60 
 
 85 
 
 SE.fr., fair. 
 
 50 
 
 50 
 
 45 
 
 50 
 
 55 
 
 100 
 
 80 
 
 95 
 
 90 
 
 100 
 
 100 
 
 100 
 
 N.fr.. clear. 
 
 60 
 
 70 
 
 60 
 
 00 
 
 65 
 
 70 
 
 80 
 
 - 50 
 
 80 
 
 50 
 
 50 
 
 50 
 
 NW.fr., fair. 
 
 40 
 
 50 
 
 45 
 
 50 
 
 45 
 
 50 
 
 50 
 
 40 
 
 45 
 
 40 
 
 30 
 
 ■20 
 
 NW;fr., clear. 
 
 50 
 
 25 
 
 40 
 
 25 
 
 15 
 
 50 
 
 30 
 
 60 
 
 25 
 
 50 
 
 40 
 
 70 
 
 NW.lt., clear. 
 
 45 
 
 160 
 
 80 
 
 50 
 
 60 
 
 60 
 
 50 
 
 70 
 
 40 
 
 60 
 
 70 
 
 60 
 
 S. It., clear. 
 
 100 
 
 110 
 
 50 
 
 5 
 
 100 
 
 100 
 
 20 
 
 40 
 
 10 
 
 10 
 
 10 
 
 20 
 
 S.fr.,fair. 
 
 70 
 
 75 
 
 70 
 
 55 
 
 60 
 
 70 
 
 90 
 
 70 
 
 50 
 
 40 
 
 40 
 
 30 
 
 W. It., clear. 
 
 50 
 
 55 
 
 60 
 
 5 
 
 70 
 
 20 
 
 40 
 
 50 
 
 50 
 
 70 
 
 60 
 
 55 
 
 NW. fr., clear. 
 
 100 
 
 120 
 
 50 
 
 100 
 
 130 
 
 135 
 
 100 
 
 70 
 
 60 
 
 60 
 
 80 
 
 50 
 
 NW.lt., clear. 
 
 35 
 
 50 
 
 50 
 
 50 
 
 70 
 
 75 
 
 60 
 
 40 
 
 30 
 
 50 
 
 20 
 
 30 
 
 NE.lt., fair. 
 
 5 
 
 5 
 
 15 
 
 25 
 
 50 
 
 50 
 
 50 
 
 60 
 
 40 
 
 25 
 
 . 25 
 
 50 
 
 SW.fr., clear. 
 
 110 
 
 110 
 
 120 
 
 100 
 
 110 
 
 90 
 
 50 
 
 70 
 
 20 
 
 25 
 
 40 
 
 40 
 
 Var. It., clear. 
 
 100 
 
 90 
 
 130 
 
 90 
 
 100 
 
 100 
 
 10 
 
 50 
 
 50 
 
 50 
 
 70 
 
 50 
 
 Var. It., faft-. 
 
 70 
 
 70 
 
 100 
 
 100 
 
 70 
 
 40 
 
 10 
 
 40 
 
 40 
 
 50 
 
 45 
 
 40 
 
 Do. 
 
 70 
 
 50 
 
 50 
 
 50 
 
 100 
 
 130 
 
 100 
 
 70 
 
 70 
 
 25 
 
 30 
 
 40 
 
 Var. It., clear. 
 
 65 
 
 60 
 
 75 
 
 70 
 
 60 
 
 75 
 
 100 
 
 110 
 
 75 
 
 85 
 
 90 
 
 60 
 
 SW.lt., fair. 
 
 70 
 
 75 
 
 75 
 
 80 
 
 80 
 
 75 
 
 75 
 
 60 
 
 40 
 
 60 
 
 60 
 
 50 
 
 Var. It., fair. 
 
 125 
 
 125 
 
 140 
 
 65 
 
 95 
 
 125 
 
 100 
 
 90 
 
 85 
 
 65 
 
 100 
 
 75 
 
 Var. It., fair. 
 
 50 
 
 60 
 
 75 
 
 ' 60 
 
 75 
 
 60 
 
 60 
 
 75 
 
 60 
 
 60 
 
 60 
 
 80 
 
 NW.fr., cloudy. 
 
 150 
 
 150 
 
 160 
 
 200 
 
 200 
 
 120 
 
 100 
 
 75 
 
 50 
 
 
 
 50 
 
 25 
 
 SE.fr., fair. 
 
 150 
 
 l.SO 
 
 150 
 
 150 
 
 150 
 
 50 
 
 —25 
 
 30 
 
 110 
 
 30 
 
 60 
 
 50 
 
 Var. It., fair. 
 
 
 100 
 
 90 
 
 80 
 
 75 
 
 75 
 
 60 
 
 60 
 
 65 
 
 60 
 
 60 
 
 60 
 
 Do. 
 
 2, 035 
 
 2,285 
 
 2,380 
 
 2,275 
 
 2,525 
 
 2,280 
 
 1,840 
 
 1,895 
 
 1,725 
 
 1,625 
 
 1,685 
 
 1,585 
 
 70 
 
 76 
 
 79 
 
 76 
 
 84 
 
 76 
 
 61 
 
 63 
 
 58 
 
 54 
 
 56 
 
 53 
 
 
 S. Mis. 94- 16 
 
242 
 
 MEMOIRS OF THE NATIONAL ACADEMY OP SCIENCES. 
 
 Table G. — Potential on Olear and Fair DatfS, 
 [Hourly observations from 
 
 Date. 
 
 1885. 
 October 20 ... 
 October 2i ... 
 October 24 ... 
 October 25 ... 
 October 26 ... 
 November 3 . . 
 November 4 .. 
 November 11 . 
 November 12 . 
 November 14 . 
 November 17 . 
 November 20 . 
 December 2. .. 
 December 10 . . 
 December 11.. 
 December 12 . . 
 December 15 . . 
 December 16 . . 
 December 17.. 
 December 22.. 
 December 24 . . 
 December 25.. 
 
 1886. 
 
 January 1 
 
 January 2 
 
 January 7 
 
 February 16 . . 
 February 18 . . 
 February 21 . . 
 February 22 . . 
 February 24 . . 
 
 Sums. . 
 Means. 
 
 March 5 . . 
 March 6 . . 
 March 7 . . 
 March 11 . 
 March 14 . 
 March 15 . 
 March 16 . 
 March 17 . 
 March 24 . 
 April 10 . . 
 April 14 -. 
 
 July 3 
 
 July 4 
 
 July 5 
 
 July 6 
 
 July 7 
 
 July 11... 
 July 12... 
 July 17.... 
 July 22.... 
 July 24.... 
 July 29.... 
 August 3 .". 
 August 4 .'. 
 August 8 .'. 
 August 12 . 
 August 13 - 
 ' August 15 . 
 August 19 . 
 August 21 - 
 
 1 a. m. 2 a. m. 3 a. m. i a. va. 5 a. m. 
 
 60 
 
 50 
 
 60 
 
 60 
 
 75 
 
 50 
 
 75 
 
 85 
 
 130 
 
 100 
 
 90 
 
 40 
 
 60 
 
 130 
 
 40 
 
 100 
 
 70 
 
 150 
 
 150 
 
 40 
 
 40 
 
 40 
 
 50 
 100 
 50 
 45 
 90 
 45 
 
 50 
 
 2,125 
 71 
 
 Sums- . 
 Means. 
 
 50 
 60 
 50 
 70 
 25 
 50 
 00 
 80 
 50 
 
 100 
 50 
 80 
 30 
 50 
 
 150 
 60 
 30 
 20 
 50 
 50 
 30 
 60 
 
 125 
 60 
 55 
 .lO 
 50 
 25 
 
 120 
 70 
 
 50 
 
 50 
 
 60 
 
 75 
 
 70 
 
 60 
 
 125 
 
 105 
 
 125 
 
 150 
 
 90 
 
 50 
 
 70 
 
 100 
 
 40 
 
 100 
 
 100 
 
 180 
 
 13& 
 
 50 
 
 50 
 
 60 
 
 65 
 40 
 65 
 60 
 60 
 50 
 100 
 80 
 
 2,415 
 80 
 
 ,810 
 60 
 
 50 
 50 
 40 
 80 
 30 
 80 
 70 
 80 
 50 
 
 130 
 
 100 
 90 
 25 
 50 
 
 100 
 60 
 30 
 30 
 50 
 40 
 30 
 75 
 
 100 
 65 
 60 
 55 
 5 
 30 
 
 140 
 70 
 
 60 
 
 50 
 
 50 
 
 75 
 
 60 
 
 60 
 
 150 
 
 110 
 
 150 
 
 100 
 
 90 
 
 50 
 
 70 
 
 10 
 
 40 
 
 100 
 
 60 
 
 160 
 
 135 
 
 55 
 
 50 
 
 55 
 
 60 
 
 60 
 60 
 60 
 60 
 50 
 100 
 70 
 
 2,260 
 75 
 
 1,865 
 
 50 
 30 
 40 
 75 
 30 
 60 
 80 
 80 
 50 
 100 
 100 
 90 
 35 
 65 
 110 
 75 
 30 
 10 
 55 
 50 
 50 
 60 
 90 
 65 
 60 
 20 
 50 
 30 
 125 
 
 60 
 
 40 
 
 50 
 
 50 
 
 60 
 
 75 
 
 ■150 
 
 100 
 
 110 
 
 150 
 
 90 
 
 75 
 
 50 
 
 10 
 
 40 
 
 100 
 
 90 
 
 210 
 
 ,150 
 
 50 
 
 55 
 
 50 
 
 70 
 70 
 60 
 50 
 70 
 50 
 50 
 65 
 
 2,300 
 
 77 
 
 50 
 50 
 40 
 70 
 30 
 70 
 90 
 90 
 50 
 90 
 
 100 
 90 
 40 
 80 
 
 110 
 65 
 30 
 20 
 50 
 60 
 40 
 50 
 90 
 60 
 60 
 45 
 65 
 30 
 
 120 
 60 
 
 1,820 
 61 
 
 1,895 
 63 
 
 60 
 
 60 
 
 55 
 
 30. 
 
 60 
 
 75 
 
 175 
 
 100 
 
 125 
 
 125 
 
 60 
 
 75 
 
 20 
 
 5 
 
 35 
 
 95 
 
 90 
 
 230 
 
 150 
 
 100 
 
 40 
 
 45 
 
 60 
 70 
 70 
 65 
 
 100 
 50 
 60 
 
 100 
 
 m. 7 a. m. 8 a. m. 9 a.m. 10 a.m. 11a.m. -12 m. 
 
 2,385 
 80 
 
 50 
 50 
 40 
 70 
 30 
 30 
 60 
 95 
 45 
 75 
 60 
 90 
 20 
 80 
 
 100 
 75 
 30 
 50 
 60 
 75 
 50 
 60 
 90 
 80 
 60 
 50 
 30 
 30 
 
 135 
 65 
 
 75 
 
 95 
 
 65 
 
 40 
 
 50 
 
 110 
 
 175 
 
 175 
 
 110 
 
 150 
 
 •60 
 
 100 
 
 35 
 
 
 
 40 
 
 100 
 
 100 
 
 230 
 
 150 
 
 70 
 
 30 
 
 55 
 
 80 
 100 
 
 85 
 100 
 100 
 
 50 
 
 60 
 200 
 
 2,790 
 93 
 
 80 
 
 130 
 
 75 
 
 60 
 
 10 
 
 90 
 
 225 
 
 200 
 
 150 
 
 100 
 
 150 
 
 90 
 
 15 
 
 
 
 45 
 
 110 
 
 110 
 
 300 
 
 175 
 
 100 
 
 55 
 
 60 
 
 200 
 50 
 80 
 
 120 
 
 120 
 90 
 75 
 
 120 
 
 ,835 
 61 
 
 50 
 50 
 45 
 80 
 40 
 60 
 65 
 
 100 
 
 .70 
 80 
 60 
 90 
 
 50 
 
 100 
 
 100 
 50 
 30 
 80 
 
 100 
 25 
 90 
 75 
 
 110 
 65 
 55 
 45 
 50 
 
 140 
 45 
 
 2, 000 
 
 67 
 
 3,185 
 106 
 
 50 
 
 50 
 80 
 85 
 • 50 
 60 
 
 eo 
 
 100 
 80 
 
 100 
 60 
 90 
 20 
 65 
 75 
 
 100 
 50 
 40 
 90 
 80 
 10 
 90 
 90 
 60 
 70 
 50 
 — 5 
 50 
 
 140 
 45 
 
 1,985 
 66 
 
 100 
 
 90 
 
 75 
 
 100 
 
 50 
 
 90 
 
 200 
 
 180 
 
 100 
 
 100 
 
 50 
 
 110 
 
 50 
 
 20 
 
 50 
 
 80 
 
 130 
 
 300 
 
 140 
 
 150 
 
 60 
 
 70 
 
 180 
 
 50 
 
 110 
 
 150 
 
 150 
 
 75 
 
 80 
 
 105 
 
 3,195 
 106 
 
 40 
 60 
 70 
 80 
 60 
 — 5 
 30 
 100 
 95 
 70 
 60 
 90 
 50 
 25 
 75 
 25 
 10 
 50 
 50 
 50 
 10 
 75 
 65 
 65 
 75 
 50 
 20 
 55 
 130 
 50 
 
 1,680 
 56 
 
 90 
 
 SO 
 
 70 
 
 110 
 
 - 50 
 
 80 
 
 100 
 
 125 
 
 125 
 
 150 
 
 100 
 
 100 
 
 65 
 
 10 
 
 45 
 
 90 
 
 130 
 
 300 
 
 150 
 
 110 
 
 60 
 
 80 
 
 140 
 
 140 
 
 70 
 
 100 
 
 180 
 
 90 
 
 70 
 
 110 
 
 2,960 
 9i 
 
 20 
 40 
 50 
 80 
 65 
 10 
 50 
 95 
 70 
 60 
 60 
 75 
 50 
 40 
 90 
 25 
 
 60 
 40 
 60 
 100 
 100 
 50 
 50 
 50 
 35 
 70 
 70 
 120 
 55 
 
 1,740 
 58 
 
 85 
 
 75 
 
 65 
 
 100 
 
 150 
 
 60 
 
 90 
 
 225 
 
 125 
 
 100 
 
 100 
 
 100 
 
 105 
 
 10 
 
 50 
 
 80 
 
 100 
 
 200 
 
 200 
 
 150 
 
 55 
 
 70 
 
 150 
 120 
 70 
 70 
 80 
 60 
 70 
 150 
 
 3060 
 102 
 
 50 
 50 
 50 
 80 
 65 
 50 
 60 
 
 110 
 50 
 70 
 90 
 60 
 40 
 60 
 65 
 30 
 25 
 50 
 40 
 50 
 
 100 
 75 
 75 
 50 
 50 
 30 
 60 
 70 
 
 110 
 45 
 
 1,810 
 60 
 
 80 
 
 50 
 
 65 
 
 95 
 
 140 
 
 60 
 
 110 
 
 250 
 
 125 
 
 160 
 
 60 
 
 100 
 
 100 
 
 40 
 
 45 
 
 25 
 
 120 
 
 180 
 
 175 
 
 100 
 
 50 
 
 70 
 
 120 
 
 100 
 70 
 70 
 50 
 
 110 
 70 
 
 200 
 
 2,990 
 100 
 
 40 
 30 
 50 
 80 
 60 
 50 
 30 
 
 100 
 30 
 25 
 
 110 
 50 
 20 
 75 
 75 
 30 
 30 
 75 
 40 
 30 
 90 
 80 
 95 
 60 
 50 
 30 
 55 
 75 
 90 
 40 
 
 1,695 
 57 
 
 75 
 
 40 
 
 60 
 
 95 
 
 100 
 
 60 
 
 100 
 
 150 
 
 125 
 
 100 
 
 60 
 
 100 
 
 100 
 
 55 
 
 25 
 
 20 
 
 80 
 
 150 
 
 175 
 
 100 
 
 50 
 
 80 
 
 100 
 110 
 
 70 
 
 50 
 100 
 
 70 
 200 
 
 2,600 
 90 
 
 40 
 30 
 50 
 20 
 50 
 60 
 25 
 
 100 
 25 
 25 
 
 120 
 60 
 75 
 90 
 75 
 50 
 40 
 75 
 50 
 40 
 
 100 
 80 
 
 100 
 50 
 50 
 30 
 60 
 
 55 
 
 1,615 
 
 58 
 
MEMOIRS OF THE NATIONAL ACADEMY OP SCIENCES. 
 Baltimore, Md., 1885, 1886, and 1887— Coutinued. 
 the photographic sheets. ] * 
 
 243 
 
 Ip. m. 
 
 2 p. ui. 
 
 3 p. m. 
 
 4 p. m. 
 
 Sp. m. 
 
 6 p. m. 
 
 7 p. m. 
 
 8 p. m. 
 
 9 p. m. 
 
 10 p.m. 
 
 11 p. m. 
 
 12 mid. 
 
 Kemarks. 
 
 75 
 
 75 
 
 60 
 
 65 
 
 60 
 
 60 
 
 50 
 
 50 
 
 50 
 
 40 
 
 40 
 
 50 
 
 SE.fr., fair. 
 
 50 
 
 60 
 
 60 
 
 60 
 
 75 
 
 80 
 
 100 
 
 110 
 
 100- 
 
 75 
 
 50 
 
 50 
 
 NW.fr., clear. 
 
 50 
 
 50 
 
 60 
 
 60 
 
 60 
 
 50 
 
 50 
 
 90 
 
 65 
 
 60 
 
 75 
 
 60 
 
 N. It., fair. 
 
 90 
 
 75 
 
 50 
 
 90 
 
 95 
 
 80 
 
 75 
 
 30 
 
 
 
 50 
 
 65 
 
 50 
 
 Var.it., clear. 
 
 HO 
 
 150 
 
 150 
 
 125 
 
 100 
 
 75 
 
 65 
 
 55 
 
 65 
 
 60 
 
 60 
 
 50 
 
 N. It., clear. 
 
 50 
 
 50 
 
 60 
 
 65 
 
 60 
 
 75 
 
 90 
 
 80 
 
 75 
 
 75 
 
 80 
 
 80 
 
 W.br.,fair. 
 
 100 
 
 125 
 
 100 
 
 125 
 
 125 
 
 110 
 
 150 
 
 125 
 
 125 
 
 100 
 
 105 
 
 110 
 
 W.fr.,fair 
 
 250 
 
 125 
 
 125. 
 
 100 
 
 125 
 
 125 
 
 150 
 
 125 
 
 175 
 
 250 
 
 200 
 
 150 
 
 Do. 
 
 125 
 
 130 
 
 125 
 
 110 
 
 120 
 
 100 
 
 90 
 
 80 
 
 105 
 
 75 
 
 75 
 
 75 
 
 8W.lt., fair. 
 
 100 
 
 150 
 
 90 
 
 160 
 
 150 
 
 75 
 
 125 
 
 100 
 
 110 
 
 65 
 
 60 
 
 55 
 
 Var. It., fair. 
 
 60 
 
 30 
 
 50 
 
 50 
 
 75 
 
 100 
 
 100 
 
 95 
 
 100 
 
 100 
 
 95 
 
 90 
 
 N. It., fair. 
 
 100 
 
 100 
 
 100 
 
 100 
 
 125 
 
 100 
 
 100 
 
 75 
 
 50 
 
 —25 
 
 —20 
 
 20 
 
 N. It., clear. 
 
 100 
 
 100 
 
 85 
 
 70 
 
 80 
 
 95 
 
 100 
 
 120 
 
 100 
 
 85 
 
 75 
 
 60 
 
 Do. 
 
 50 
 
 60 
 
 60 
 
 70 
 
 75 
 
 75 
 
 90 
 
 60 
 
 50 
 
 55 
 
 50 
 
 40 
 
 Var. It., fair. 
 
 50 
 
 65 
 
 70 
 
 50 
 
 55 
 
 60 
 
 50 
 
 50 
 
 50 
 
 50 
 
 75 
 
 90 
 
 NW.lt., fair. 
 
 25 
 
 90 
 
 150 
 
 120 
 
 180 
 
 90 
 
 100 
 
 130 
 
 130 
 
 100 
 
 120 
 
 100 
 
 NE.lt., clear. 
 
 200 
 
 180 
 
 200 
 
 175 
 
 200 
 
 300 
 
 70 
 
 90 
 
 75 
 
 150 
 
 150 
 
 150 
 
 Var. It., fair. 
 
 150 
 
 200 
 
 800 
 
 150 
 
 250 
 
 170 
 
 150 
 
 125 
 
 80 
 
 30 
 
 30 
 
 30 
 
 E. It., fair. 
 
 130 
 
 110 
 
 160 
 
 170 
 
 100 
 
 150 
 
 150 
 
 145 
 
 160 
 
 150 
 
 150 
 
 145 
 
 NW.br., fair. 
 
 100 
 
 50 
 
 75 
 
 80 
 
 75 
 
 150 
 
 200 
 
 160 
 
 150 
 
 20 
 
 20 
 
 100 
 
 W.fr.,fair. 
 
 50 
 
 50 
 
 75 
 
 70 
 
 50 
 
 50 
 
 50 
 
 30 
 
 50 
 
 70 
 
 40 
 
 50 
 
 NW.fr., fai?. 
 
 70 
 
 80 
 
 95 
 
 50 
 
 50 
 
 100 
 
 80 
 
 50 
 
 30 
 
 ■ 40 
 
 25 
 
 10 
 
 NE. fr., fair. 
 
 90 
 
 90 
 
 100 
 
 100 
 
 120 
 
 100 
 
 160 
 
 140 
 
 100 
 
 40 
 
 \ 
 100 
 
 100 
 
 W. It., clear. 
 
 80 
 
 120 
 
 200 
 
 190 
 
 70 
 
 60 
 
 70 
 
 80 
 
 80 
 
 90 
 
 90 
 
 90 
 
 E. It., clear. 
 
 70 
 
 80 
 
 80 
 
 80 
 
 85 
 
 70 
 
 80 
 
 80 
 
 80 
 
 85 
 
 80 
 
 75. 
 
 NW.fr., clear. 
 
 
 80 
 
 80 
 
 85 
 
 85 
 
 60 
 
 50 
 
 80 
 
 60 
 
 65 
 
 65 
 
 90 
 
 NW.br., fair. 
 
 '""45 
 
 40 
 
 40 
 
 35 
 
 20 
 
 100 
 
 80 
 
 70 
 
 80 
 
 60' 
 
 35 
 
 40 
 
 SW.fr., clear. 
 
 
 100 
 
 110 
 
 70 
 
 85 
 
 120 
 
 100 
 
 100 
 
 150 
 
 200 
 
 130 
 
 130 
 
 SW, fr., fair. 
 
 '"'76' 
 
 70 
 
 80 
 
 70 
 
 60 
 
 85 
 
 160 
 
 120 
 
 150 
 
 100 
 
 60 
 
 85 
 
 NW. br., clear. 
 
 200 
 
 200 
 
 200 
 
 200 
 
 200 
 
 220 
 
 200 
 
 140 
 
 110 
 
 60 
 
 60 
 
 60 
 
 SE.lt., fair. 
 
 2,640 
 
 2,885 
 
 3,090 
 
 2,945 
 
 3,010 
 
 3,085 
 
 3,080 
 
 2,785 
 
 2,705 
 
 2,375 
 
 2, 240 
 
 2,285 
 
 94 
 
 96 
 
 103 
 
 98 
 
 100 
 
 103 
 
 103 
 
 93 
 
 90 
 
 79 
 
 75 
 
 76 
 
 \ 
 NW. fr., fair. 
 
 40 
 
 45 
 
 50 
 
 50 
 
 50 
 
 50 
 
 50 
 
 75 
 
 60 
 
 100 
 
 110 
 
 90 
 
 40 
 
 40 
 
 40 
 
 45 
 
 40 
 
 40 
 
 80 
 
 100 
 
 10 
 
 80 
 
 80 
 
 60 
 
 NW.fr., clear. 
 
 
 60 
 
 60 
 
 100 
 
 110 
 
 150 
 
 110 
 
 150 
 
 100 
 
 100 
 
 70 
 
 70 
 
 N. It., fair. 
 
 '"""76' 
 
 75 
 
 60 
 
 70 
 
 80 
 
 90 
 
 100 
 
 150 
 
 100 
 
 70 
 
 20 
 
 10 
 
 NW.fr., clear 
 
 
 40 
 
 60 
 
 50 
 
 100 
 
 70 
 
 80 
 
 80 
 
 60 
 
 70 
 
 70 
 
 60 
 
 SW. It., clear. 
 
 ■"""45" 
 
 50 
 
 50 
 
 50 
 
 150 
 
 10 
 
 60 
 
 60 
 
 100 
 
 90 
 
 60 
 
 60 
 
 Do. 
 
 
 
 —50 
 
 
 
 20 
 
 60 
 
 50 
 
 60 
 
 60 
 
 £0 
 
 55 
 
 60 
 
 70 
 
 SW.fr., clear. 
 
 100 
 
 100 
 
 100 
 
 110 
 
 120 
 
 80 
 
 100 
 
 75 
 
 75 
 
 60 
 
 
 
 —10 
 
 NW. fr., clear. 
 
 50 
 
 50 
 
 55 
 
 65 
 
 65 
 
 60 
 
 60 
 
 80 
 
 95 
 
 150 
 
 150 
 
 100 
 
 NW.br., fair. 
 
 
 140 
 
 120 
 
 130 
 
 105 
 
 70 
 
 50 
 
 50 
 
 50 
 
 50 
 
 5 
 
 10 
 
 S. It., fair. 
 
 ""126' 
 
 150 
 
 200 
 
 200 
 
 150 
 
 200 
 
 200 
 
 80 
 
 100 
 
 75 
 
 60 
 
 80 
 
 E. It. , clear. 
 
 30 
 
 25 
 
 10 
 
 
 
 25 
 
 30 
 
 50 
 
 70 
 
 60 
 
 10 
 
 125 
 
 60 
 
 N. It., £»r. 
 
 40 
 
 40 
 
 50 
 
 50 
 
 40 
 
 65 
 
 35 
 
 50 
 
 60 
 
 50 
 
 50 
 
 75 
 
 Var. it., fair. 
 
 75 
 
 60 
 
 40 
 
 60 
 
 75 
 
 75 
 
 65 
 
 60 
 
 75 
 
 25 
 
 20 
 
 75 
 
 SW.lt., clear. 
 
 65 
 
 50 
 
 65 
 
 110 
 
 150 
 
 130 
 
 65 
 
 75 
 
 100 
 
 65 
 
 65 
 
 60 
 
 E. It., clear. 
 
 50 
 
 50 
 
 50 
 
 50 
 
 30 
 
 20 
 
 50 
 
 100 
 
 65 
 
 40 
 
 40 
 
 25 
 
 SW.fi-., clear. 
 
 
 
 40 
 
 50 
 
 20 
 
 30 
 
 35 
 
 30 
 
 50 
 
 75 
 
 30 
 
 30 
 
 20 
 
 N. It. , clear. 
 
 50 
 
 60 
 
 40 
 
 75 
 
 50 
 
 60 
 
 30 
 
 50 
 
 110 
 
 40 
 
 50 
 
 50 
 
 E, It. , clear. 
 
 50 
 
 75 
 
 110 
 
 100 
 
 200 
 
 150 
 
 110 
 
 90 
 
 110 
 
 90 
 
 80 
 
 60 
 
 Var. It. , clear. 
 
 30 
 
 30 
 
 40 
 
 25 
 
 30 
 
 30 
 
 40 
 
 30 
 
 30 
 
 30 
 
 30 
 
 30 
 
 W. It. clear. 
 
 75 
 
 100 
 
 125 
 
 100 
 
 90 
 
 60 
 
 60 
 
 60 
 
 60 
 
 50 
 
 50 
 
 50 
 
 E. It., clear. 
 
 100 
 
 60 
 
 100 
 
 90 
 
 100 
 
 100 
 
 100 
 
 . 75 
 
 80 
 
 60 
 
 60 
 
 60 
 
 Do. 
 
 60 
 
 75 
 
 65 
 
 75 
 
 75 
 
 75 
 
 75 
 
 65 
 
 60 
 
 60 
 
 65 
 
 60 
 
 NW.fr., clear. 
 
 50 
 
 60 
 
 65 
 
 75 
 
 60 
 
 60 
 
 80 
 
 75 
 
 60 
 
 50 
 
 10 
 
 
 
 Do. 
 
 
 50 
 
 75 
 
 85 
 
 70 
 
 70 
 
 60 
 
 115 
 
 65 
 
 65 
 
 50 
 
 55 
 
 NW. It., clear. 
 
 "'""36" 
 
 60 
 
 50 
 
 45 
 
 85 
 
 85 
 
 45 
 
 100 
 
 65 
 
 60 
 
 65 
 
 50 
 
 W.fr.,fair. 
 
 , 60 
 
 60 
 
 85 
 
 140 
 
 100 
 
 70 
 
 70 
 
 60 
 
 40 
 
 40 
 
 50 
 
 55 
 
 S. It , fair. 
 
 
 40 
 
 55 
 
 75 
 
 55 
 
 55 
 
 60 
 
 90 
 
 70 
 
 80 
 
 70 
 
 20 
 
 Var. It., clear. 
 
 '""56' 
 
 55 
 
 75 
 
 80 
 
 45 
 
 35 
 
 25 
 
 40 
 
 20 
 
 20 
 
 50 
 
 50 
 
 E.fr., clear. 
 
 45 
 
 65 
 
 60 
 
 60 
 
 25 
 
 40 
 
 65 
 
 70 
 
 70 
 
 70 
 
 45 
 
 40 
 
 E.fr.,fair. 
 
 1,325 
 
 1,755 
 
 2,005 
 
 2,205 
 
 2, 365 
 
 2,115 
 
 2,065 
 
 2,285 
 
 2,075 
 
 1,855 
 
 1,740 
 
 1,495 
 
 53 
 
 58 
 
 67 
 
 74 
 
 79 
 
 70 
 
 69 
 
 76 
 
 69 
 
 62 
 
 58 
 
 50 
 
 
5244 
 
 MEMOIRS OF THE NATIONAL ACADEMY OP SCIENCES. 
 
 Table G. — Potential on Clear and Fair Days, 
 
 [ Hourly observations from 
 
 1886. 
 September 21 . 
 September 24. 
 September 25. 
 Septembers?. 
 
 Octobers 
 
 October 10 ... 
 October 11 ... 
 October 12 ... 
 October 17 . . . 
 October 18 ... 
 October 20 . . . 
 October 22 ... 
 October 23 ... 
 October 24 ... 
 October 25 ... 
 November 1 . . 
 November 2 . . 
 November 3 . . 
 November 4 . . 
 November 5 - . 
 November 8 . . 
 November 9 . . 
 November 14 . 
 November 15 . 
 November 16 . 
 November 19 . 
 November 20 . 
 November 21 . 
 November 26 . 
 November 27 . 
 
 Sums 
 
 Means . . . 
 
 November 28 . 
 November 29 . 
 December 9 . . 
 December 10 . 
 December 11 . 
 December 21 . 
 December 27 . 
 
 1887. 
 January 12 . . . 
 January 22 ... 
 January 31 . . . 
 February 9 . . . 
 February 17 . . 
 February 22 . . 
 February 25 . . 
 February 27 . . 
 
 March 8 - 
 
 March 11 
 
 March 20 
 
 March 23 
 
 March 26 
 
 March 30 
 
 Aprils 
 
 Aprils 
 
 April6 
 
 April9 
 
 AprillO....:. 
 
 April 11 
 
 April 12 
 
 April 13 
 
 April 14 
 
 Sums 
 
 Means... 
 
 1a.m. 2 a.m. 3 a.m. 4 a.m. 5 a.m. 6 a.m. 7 a.m. Sa. m. 
 
 110 
 
 20 
 
 30 
 
 6.5 
 
 25 
 
 40 
 
 60 
 
 50 
 
 50 
 
 120 
 
 10 
 
 70 
 
 100 
 
 40 
 
 50 
 
 60 
 
 100 
 
 140 
 
 60 
 
 95 
 
 60 
 
 75 
 
 25 
 
 50 
 
 30 
 
 100 
 
 110 
 
 120 
 
 50 
 
 100 
 
 2,015 
 67 
 
 100 
 20 
 40 
 60 
 25 
 40 
 60 
 50 
 40 
 
 150 
 10 
 
 100 
 
 110 
 50 
 70 
 65 
 
 110 
 
 140 
 60 
 90 
 75 
 
 100 
 30 
 40 
 50 
 90 
 
 100 
 
 130 
 50 
 
 100 
 
 2, 155 
 
 72 
 
 140 
 90 
 
 100 
 
 50 
 
 30 
 
 
 
 150 
 
 110 
 20 
 
 100 
 60 
 30 
 80 
 70 
 70 
 
 150 
 65 
 40 
 50 
 70 
 50 
 
 100 
 60 
 50 
 30 
 50 
 40 
 10 
 
 20 
 
 1,885 
 63 
 
 100 
 120 
 100 
 45 
 45 
 120 
 120 
 
 100 
 110 
 120 
 45 
 40 
 80 
 75 
 70 
 100 
 50 
 45 
 60 
 50 
 50 
 100 
 60 
 50 
 40 
 30 
 50 
 20 
 10 
 10 
 
 2,115 
 70 
 
 70 
 20 
 50 
 60 
 25 
 40 
 75 
 55 
 40 
 
 140 
 10 
 
 100 
 90 
 60 
 75 
 70 
 90 
 
 140 
 70 
 85 
 70 
 
 180 
 30 
 40 
 50 
 95 
 90 
 
 125 
 50 
 90 
 
 2,125 
 
 71 
 
 120 
 120 
 150 
 50 
 60 
 120 
 200 
 
 95 
 25 
 
 130 
 60 
 50 
 80 
 80 
 70 
 
 140 
 50 
 40 
 50 
 60 
 50 
 
 100 
 60 
 60 
 50 
 
 50 
 20 
 
 10 
 
 2,150 
 72 
 
 60 
 
 50 
 50 
 25 
 40 
 65 
 60 
 50 
 
 120 
 10 
 60 
 
 110 
 40 
 70 
 70 
 95 
 
 140 
 70 
 80 
 
 100 
 
 100 
 30 
 50 
 20 
 60 
 
 100 
 
 100 
 40 
 
 100 
 
 1,965 
 
 m 
 
 120 
 120 
 100 
 40 
 75 
 100 
 130 
 
 120 
 
 
 110 
 50 
 70 
 80 
 60 
 65 
 
 150 
 50 
 45 
 40 
 40 
 50 
 
 100 
 40 
 55 
 50 
 30 
 50 
 20 
 10 
 20 
 
 1, 990 
 66 
 
 100 
 
 50 
 50 
 30 
 15 
 60 
 85 
 50 
 
 105 
 10 
 80 
 
 150 
 50 
 
 100 
 
 .80 
 
 100 
 
 150 
 70 
 80 
 
 190 
 90 
 40 
 .50 
 40 
 70 
 
 115 
 60 
 70 
 
 110 
 
 2,250 
 
 75 
 
 100 
 105 
 100 
 50 
 70 
 130 
 120 
 
 60 
 30 
 
 no 
 
 50 
 70 
 
 100 
 70 
 70 
 
 130 
 60 
 50 
 40 
 40 
 70 
 
 100 
 40 
 60 
 50 
 40 
 
 100 
 10 
 
 15 
 
 2, 045 
 
 68 
 
 100 
 
 10 
 
 55 
 
 65 
 
 40 
 
 35 
 
 75 
 
 60 
 
 55 
 
 110 
 
 
 
 100 
 
 100 
 
 40 
 
 100 
 
 90 
 
 90 
 
 140 
 
 100 
 
 100 
 
 160 
 
 ISO 
 
 40 
 
 50 
 
 50 
 
 60 
 
 140 
 
 80 
 
 70 
 
 130 
 
 2, 365 
 79 
 
 80 
 110 
 100 
 70 
 25 
 150 
 160 
 
 90 
 20 
 
 130 
 50 
 
 100 
 
 100 
 80 
 80 
 
 150 
 80 
 55 
 55 
 50 
 70 
 
 100 
 50 
 60 
 50 
 40 
 70 
 5 
 10 
 10 
 
 2,200 
 73 
 
 100 
 
 10 
 
 80 
 
 90 
 
 40 
 
 35 
 
 80 
 
 30 
 
 60 
 
 100 
 
 
 
 140 
 
 120 
 
 35 
 
 70 
 
 95 
 
 120 
 
 125 
 
 100 
 
 100 
 
 90 
 
 100 
 
 50 
 
 70 
 
 50 
 
 160 
 
 100 
 
 85 
 
 80 
 
 160 
 
 2,475 
 
 82 
 
 75 
 115 
 
 70 
 100 
 
 50 
 160 
 145 
 
 110 
 30 
 
 100 
 50 
 
 100 
 
 110 
 60 
 80 
 
 150 
 60 
 60 
 50 
 50 
 70 
 
 110 
 60 
 CO 
 50 
 25 
 50 
 10 
 
 100 
 
 
 ,300 
 
 77 
 
 95 
 
 15 
 
 90 
 
 100 
 
 50 
 
 30 
 
 95 
 
 70 
 
 90 
 
 100 
 
 15 
 
 130 
 
 110 
 
 40 
 
 120 
 
 105 
 
 120 
 
 190 
 
 100 
 
 120 
 
 100 
 
 100 
 
 60 
 
 90 
 
 100 
 
 130 
 
 30 
 
 105 
 
 90 
 
 170 
 
 2,760 
 
 92 
 
 150 
 
 80 
 
 70 
 
 75 
 
 160 
 
 200 
 
 110 
 
 50 
 
 100 
 
 55 
 
 80 
 
 100 
 
 100 
 
 100 
 
 125 
 
 50 
 
 65 
 
 50 
 
 50 
 
 60 
 
 110 
 
 60 
 
 60 
 
 40 
 
 30 
 
 70 
 
 20 
 
 100 
 
 
 
 2, 400 
 80 
 
 a.m. 10 a.m. 11a.m. 12 m. 
 
 90 
 
 20 
 
 90 
 
 120 
 
 20 
 
 40 
 
 70 
 
 120 
 
 60 
 
 110 
 
 30 
 
 100 
 
 90 
 
 50 
 
 100 
 
 105 
 
 120 
 
 240 
 
 100 
 
 200 
 
 70 
 
 150 
 
 60 
 
 85 
 
 65 
 
 60 
 
 180 
 
 130 
 
 60 
 
 190 
 
 2, 925 
 
 98 
 
 140 
 150 
 120 
 75 
 110 
 150 
 150 
 
 120 
 50 
 
 110 
 55 
 80 
 90 
 90 
 80 
 
 120 
 60 
 50 
 60 
 50 
 70 
 70 
 50 
 60 
 50 
 30 
 60 
 5 
 
 100' 
 20 
 
 90 
 
 100 
 
 105 
 
 80 
 
 20 
 
 25 
 
 25 
 
 200 
 
 65 
 
 110 
 
 60 
 
 60 
 
 60 
 
 50 
 
 100 
 
 100 
 
 150 
 
 250 
 
 100 
 
 200 
 
 60 
 
 140 
 
 60 
 
 60 
 
 70 
 
 60 
 
 150 
 
 100 
 
 90 
 
 150 
 
 2,890 
 96 
 
 2,425 
 
 81 
 
 130 
 150 
 110 
 120 
 60 
 150 
 200 
 
 120 
 60 
 
 110 
 35 
 60 
 
 110 
 50 
 90 
 
 100 
 50 
 50 
 60 
 40 
 60 
 80 
 50 
 60 
 75 
 15 
 15 
 80' 
 80 
 30 
 
 2,410 
 80 
 
 75 
 
 70 
 
 100 
 
 70 
 
 30 
 
 50 
 
 25 
 
 200 
 
 60 
 
 70 
 
 65 
 
 60 
 
 50 
 
 60 
 
 110 
 
 130 
 
 110 
 
 240 
 
 100 
 
 140 
 
 50 
 
 150 
 
 60 
 
 50 
 
 100 
 
 60 
 
 130 
 
 100 
 
 85 
 
 100 
 
 2,700 
 90 
 
 125 
 160 
 150 
 120 
 100 
 150 
 200 
 
 120 
 80 
 
 120 
 30 
 60 
 
 100 
 50 
 80 
 
 100 
 45 
 50 
 60 
 50 
 60 
 60 
 60 
 60 
 
 100 
 30 
 25 
 80 
 
 105 
 50 
 
 2, .580 
 86 
 
 60 
 70 
 
 100 
 40 
 40 
 60 
 
 110 
 60 
 
 70 
 65 
 70 
 60 
 
 100 
 
 140 
 
 100 
 
 200 
 
 100 
 
 100 
 
 50 
 
 100 
 
 60 
 
 80 
 
 90 
 
 60 
 
 100 
 
 90 
 
 85 
 
 100 
 
 2,360 
 
 84 
 
 130 
 140 
 
 100 
 150 
 150 
 
 50 
 
 140 
 
 60 
 
 50 
 
 60 
 70 
 
 100 
 50 
 r>0 
 60 
 50 
 60 
 70 
 60 
 60 
 
 100 
 30 
 30 
 85 
 SO 
 30 
 
 2,015 
 
 78 
 
MEMOIRS OF THE NATIONAL ACADEMY OE SUIENOES. 
 
 245 
 
 Baltimore, Md., 1885, 1886, and 1887— Continued, 
 the photographic sheets.] 
 
 1 p. m. 
 
 2 p.m. 
 
 3 p. m. 
 
 4 p.m. 
 
 5 p.m. 
 
 6 p.m. 
 
 7 p.m. 
 
 8 p.m. 
 
 9 p. in. 
 
 10 p.m. 
 
 11 p.m. 
 
 12 mid. 
 
 Kemarks. 
 
 60 
 
 65 
 
 65 
 
 70 
 
 75 
 
 100 
 
 80 
 
 70 
 
 70 
 
 80 
 
 75 
 
 110 
 
 W. fr., clear. 
 
 100 
 
 100 
 
 150 
 
 100 
 
 100 
 
 80 
 
 100 
 
 50 
 
 50 
 
 20 
 
 10 
 
 40 
 
 SK. It. . clear. 
 
 120 
 
 170 
 
 180 
 
 85 
 
 50 
 
 30 
 
 30 
 
 40 
 
 60 
 
 70 
 
 60 
 
 60 
 
 S. It., clear. 
 
 35 
 
 30 
 
 85 
 
 105 
 
 70 
 
 10 
 
 70 
 
 75 
 
 55 
 
 60 
 
 60 
 
 ■ 40 
 
 SW. It., fair. 
 
 60 
 
 90 
 
 110 
 
 160 
 
 100 
 
 50 
 
 65 
 
 10 
 
 —30 
 
 
 
 10 
 
 20 
 
 Var. It., clear. 
 
 
 110 
 
 160 
 
 160 
 
 150 
 
 90 
 
 90 
 
 90 
 
 60 
 
 80 
 
 100 
 
 90 
 
 Do. 
 
 ioo 
 
 150 
 
 155 
 
 200 
 
 140 
 
 150 
 
 90 
 
 70 
 
 70 
 
 60 
 
 40 
 
 40 
 
 Do. 
 
 40 
 
 60 
 
 55 
 
 50 
 
 80 
 
 75 
 
 90 
 
 70 
 
 60 
 
 55 
 
 50 
 
 50 
 
 Do. 
 
 
 120 
 
 130 
 
 140 
 
 120 
 
 95 
 
 130 
 
 240 
 
 100 
 
 90 
 
 140 
 
 120 
 
 NE. fr., fair. 
 
 65 
 
 90 
 
 105 
 
 250 
 
 200 
 
 160 
 
 80 
 
 80 
 
 65 
 
 70 
 
 70 
 
 70 
 
 Var. It., clear. 
 
 100 
 
 120 
 
 120 
 
 90 
 
 80 
 
 50 
 
 50 
 
 50 
 
 40 
 
 30 
 
 40 
 
 40 
 
 Var. It., fair. 
 
 65 
 
 60 
 
 .55 
 
 55 
 
 70 
 
 110 
 
 130 
 
 60 
 
 25 
 
 50 
 
 60 
 
 50 
 
 W. fr., clear. 
 
 100" 
 
 200 
 
 180 
 
 200 
 
 200 
 
 100 
 
 50 
 
 35 
 
 50 
 
 40 
 
 60 
 
 50 
 
 Var. It., clear. 
 
 
 70 
 
 90 
 
 100 
 
 90 
 
 90 
 
 70 
 
 60 
 
 60 
 
 60 
 
 70 
 
 100 
 
 E. fr., clear. 
 
 "146 
 
 150 
 
 250 
 
 300 
 
 100 
 
 50 
 
 50 
 
 40 
 
 30 
 
 10 
 
 
 
 
 
 Var. It., fair. 
 
 140 
 
 150 
 
 130 
 
 130 
 
 140 
 
 150 
 
 110 
 
 110 
 
 110 
 
 100 
 
 95 
 
 lOO 
 
 NW. fr., clear. 
 
 100 
 
 300 
 
 260 
 
 270 
 
 240 
 
 240 
 
 220 
 
 150 
 
 175 
 
 140 
 
 110 
 
 130 
 
 Var. It., clear. 
 
 140 
 
 200 
 
 250 
 
 175 
 
 140 
 
 120 
 
 100 
 
 100 
 
 80 
 
 80 
 
 80 
 
 60 
 
 S. It., fair. 
 
 100 
 
 120 
 
 125 
 
 120 
 
 170 
 
 120 
 
 150 
 
 120 
 
 80 
 
 100 
 
 100 
 
 100 
 
 NW. fr., fair. 
 
 120 
 
 150 
 
 200 
 
 150 
 
 80 
 
 60 
 
 65 
 
 60 
 
 65 
 
 90 
 
 80 
 
 40 
 
 Var. It., fair. 
 
 50 
 
 65 
 
 40 
 
 55 
 
 50 
 
 50 
 
 60 
 
 70 
 
 100 
 
 90 
 
 100 
 
 (iO 
 
 NW. gale, clear. 
 NW. fr., clear. 
 
 100 
 
 95 
 
 150 
 
 180 
 
 120 
 
 230 
 
 160 
 
 180 
 
 190 
 
 95 
 
 75 
 
 75 
 
 
 
 75 
 
 60 
 
 60 
 
 65 
 
 65 
 
 50 
 
 50 
 25 
 
 40 
 30 
 
 30 
 50 
 
 50 
 40 
 
 NW. hr., clear. 
 NW. fr., clear. 
 
 '""eo' 
 
 45 
 
 50 
 
 90 
 
 60 
 
 50 
 
 45 
 
 30 
 
 105 
 
 120 
 
 210 
 
 160 
 
 190 
 
 2-20 
 
 160 
 
 100 
 
 60 
 
 "60 
 
 70 
 
 45 
 
 N. fr., fair. 
 
 45 
 
 60 
 
 60 
 
 50 
 
 55 
 
 50 
 
 75 
 
 60 
 
 70 
 
 90 
 
 100 
 
 105 
 
 W. hr., clear. 
 
 ' 100 
 
 75 
 
 60 
 
 50 
 
 65 
 
 80 
 
 80 
 
 , 80 
 
 90 
 
 110 
 
 110 
 
 100 
 
 SW. fr., fair. 
 
 
 
 140 
 
 150 
 
 105 
 
 150 
 
 100 
 
 100 
 
 100 
 110 
 
 95 
 120 
 
 90 
 160 
 
 100 
 165 
 
 Var. It., fair. 
 NW. hr., clear. 
 
 "ioo" 
 
 "'ioo' 
 
 120 
 
 120 
 
 120 
 
 100 
 
 110 
 
 100 
 
 " 100 
 
 75 
 
 65 
 
 75 
 
 75 
 
 100 
 
 110 
 
 80 
 
 140 
 
 80 
 
 100 
 
 110 
 
 NW. fr., clear. 
 
 2,245 
 
 3,140 
 
 3,825 
 
 3,900 
 
 3,295 
 
 3, 020 
 
 2, 785 
 
 2, 430 
 
 2,210 
 
 2,095 
 
 2,195 
 
 2,160 
 
 90 
 
 112 
 
 128 
 
 140 
 150 
 
 130 
 
 160 
 110 
 
 110 
 
 107 
 
 93 
 
 81 
 
 74 
 
 70 
 
 73 
 
 72 
 
 S. It., clear. 
 SW.lt., fair. 
 
 100 
 110 
 
 100 
 190 
 
 120 
 175 
 
 120 
 190 
 
 140 
 85 
 
 SOO 
 50 
 
 190 
 50 
 
 120 
 100 
 
 '"ioo" 
 
 "■ 'iso" 
 
 
 200 
 
 200 
 
 210 
 
 200 
 
 100 
 
 75 
 
 80 
 
 80 
 
 100 
 
 60 
 
 60 
 
 Var. U., clear. 
 
 r'iso' 
 
 160 
 
 165 
 
 165 
 
 165 
 
 60 
 
 50 
 
 50 
 
 —50 
 
 
 
 
 
 40 
 
 Do. 
 
 160 
 
 240, 
 
 200 
 
 160 
 
 130 
 
 110 
 
 140 
 
 100 
 
 100 
 
 100 
 
 90 
 
 100 
 
 Var It., fair. 
 
 130 
 
 160 
 
 200 
 
 200 
 
 120 
 
 120 
 
 100 
 
 100 
 
 100 
 
 CO 
 
 60 
 
 40 
 
 Var. It., clear. 
 
 120 
 
 100 
 
 130 
 
 100 
 
 85 
 
 85 
 
 80 
 
 65 
 
 100 
 
 110 
 
 110 
 
 100 
 
 NW.fr., fair. 
 
 
 160 
 
 200 
 
 130 
 
 175 
 
 200 
 
 250 
 
 300 
 
 300 
 
 150 
 
 210 
 
 240 
 
 SW.fr., fair. 
 
 "ioo' 
 
 130 
 
 150 
 
 105 
 
 110 
 
 80 
 
 20 
 
 50 
 
 . 60 
 
 70 
 
 95 
 
 60 
 
 Do. 
 
 150 
 
 140 
 
 115 
 
 105 
 
 110 
 
 80 
 
 80 
 
 70 
 
 80 
 
 150 
 
 140 
 
 100 
 
 E. fr, clear. 
 
 60 
 
 75 
 
 50 
 
 55 
 
 45 
 
 70 
 
 80 
 
 65 
 
 90 
 
 80 
 
 110 
 
 110 
 
 NW.fr., fair. 
 
 50 
 
 .50 
 
 60 
 
 50 
 
 120 
 
 100 
 
 100 
 
 75 
 
 25 
 
 60 
 
 50 
 
 60 
 
 NW.lt., clear. 
 
 75 
 
 90 
 
 60 
 
 80 
 
 65 
 
 100 
 
 100 
 
 140 
 
 75 
 
 140 
 
 120 
 
 100 
 
 NW.fr,, fair. 
 
 55 
 
 70 
 
 60 
 
 60 
 
 60 
 
 70 
 
 60 
 
 50 
 
 65 
 
 60 
 
 70 
 
 70 
 
 Var. It., fair. 
 
 75 
 
 60 
 
 55 
 
 60 
 
 40 
 
 50 
 
 60 
 
 100 
 
 80 
 
 50 
 
 50 
 
 60 
 
 NW. gale, clear. 
 
 100 
 
 100 
 
 100 
 
 90 
 
 100 
 
 100 
 
 90 
 
 75 
 
 120 
 
 80 
 
 70 
 
 10 
 
 Var. It. , clear. 
 
 45 
 
 50 
 
 45 
 
 45 
 
 50 
 
 50 
 
 50 
 
 50 
 
 55 
 
 45 
 
 40 
 
 45 
 
 NW. hr., clear. 
 
 
 100 
 
 100 
 
 100 
 
 100 
 
 loo 
 
 110 
 
 115 
 
 120 
 
 100 
 
 100 
 
 120 
 
 NW. fr., fair. 
 
 45' 
 
 65 
 
 60 
 
 50 
 
 50 
 
 50 
 
 70 
 
 60 
 
 65 
 
 60 
 
 50 
 
 50 
 
 NW.hr., fair. 
 
 50 
 
 50 
 
 50 
 
 65 
 
 50 
 
 25 
 
 50 
 
 50 
 
 40 
 
 20 
 
 30 
 
 40 
 
 N.fr.,fair. 
 
 50 
 
 50 
 
 45 
 
 40 
 
 40 
 
 40 
 
 60 
 
 60 
 
 70 
 
 60 
 
 75 
 
 100 
 
 NW.fr., (air. 
 
 70 
 
 70 
 
 60 
 
 60 
 
 40 
 
 50 
 
 50 
 
 70 
 
 40 
 
 20 
 
 50 
 
 . 60 
 
 Do. 
 
 
 60 
 
 60 
 
 65 
 
 80 
 
 80 
 
 80 
 
 50 
 
 50 
 
 50 
 
 50 
 
 25 
 
 SW.fr., clear. 
 
 """eo" 
 
 60 
 
 50 
 
 45 
 
 40 
 
 30 
 
 40 
 
 100 
 
 100 
 
 50 
 
 50 
 
 —5 
 
 NW.hr., fair. 
 
 100 
 
 120 
 
 150 
 
 140 
 
 90 
 
 50 
 
 50 
 
 30 
 
 30 
 
 60 
 
 40 
 
 50 
 
 Var. It., clear. 
 
 
 60 
 
 60 
 
 50 
 
 60 
 
 50 
 
 50 
 
 50 
 
 60 
 
 40 
 
 40 
 
 40 
 
 Do. 
 
 ""eo' 
 
 65 
 
 50 
 
 50 
 
 30 
 
 30 
 
 30 
 
 20 
 
 20 
 
 25 
 
 15- 
 
 10 
 
 W. fr., clear. 
 
 65 
 
 110 
 
 120 
 
 100 
 
 90 
 
 75 
 
 80 
 
 50 
 
 50 
 
 25 
 
 25 
 
 25 
 
 E. It., fair. 
 
 90 
 
 120 
 
 105 
 
 55 
 
 105 
 
 105 
 
 60 
 
 40 
 
 10 
 
 10 
 
 20 
 
 10 
 
 SE.lt., fair. 
 
 40 
 
 30 
 
 40 
 
 60 
 
 30 
 
 20 
 
 20 
 
 10 
 
 20 
 
 20 
 
 5 
 
 10 
 
 E. It,, fair. 
 
 2,000 
 
 2,885 
 
 3,030 
 
 2,760 
 
 2,590 
 
 2,370 
 
 2,380 
 
 2,385 
 
 2,190 
 
 2,035 
 
 2,075 
 
 1,950 
 
 80 
 
 99 
 
 101 
 
 92 
 
 86 
 
 79 
 
 79 
 
 80 
 
 73 
 
 s 
 
 68 
 
 69 
 
 65 
 
 
24t3 
 
 MEMOIES OF THE ITATIONAL ACADEMY OP SCIENCES. 
 
 Table G. — Potential on Clear and Fair Bays, 
 
 [Hourly observations from 
 
 Date. 
 
 1 a. Di, 
 
 2 a. m. 
 
 3 a. m. 
 
 4 a. m. 
 
 5 a. m. 
 
 6 a. m. 
 
 7 a. m. 
 
 8 a. III. 
 
 9 a. m. 
 
 10 a. m. 
 
 11 a. m. 
 
 )2m. 
 
 1887. 
 April 20 
 
 70 
 50 
 40 
 50 
 20 
 90 
 50 
 50 
 90 
 
 100 
 30 
 60 
 75 
 50 
 
 100 
 90 
 80 
 
 100 
 50 
 40 
 50 
 40 
 
 90 
 50 
 40 
 60 
 20 
 90 
 50 
 50 
 90 
 70- 
 40 
 70 
 75 
 50 
 110 
 90 
 80 
 90 
 50 
 40 ; 
 50 
 40 
 
 80 
 50 
 40 
 30 
 40 
 90 
 50 
 50 
 60 
 70 
 40 
 65 
 70 
 40 
 90 
 80 
 80 
 j 90 
 ' 50 
 50 
 50 
 50 
 
 60 
 40 
 50 
 50 
 40 
 90 
 50 
 10 
 60 
 80 
 40 
 75 
 50 
 40 
 90 
 80 
 60 
 100 
 50 
 60 
 50 
 50 
 
 80 
 50 
 , 50 
 50 
 30 
 90 
 60 
 60 
 60 
 70 
 50 
 60 
 65 
 60 
 100 
 100 
 70 
 100 
 60 
 70 
 40 
 55 
 
 70 
 50 
 50 
 50 
 50 
 90 
 70 
 60 
 60 
 
 110 
 60 
 70 
 80 
 50 
 80 
 
 100 
 65 
 
 100 
 70 
 90 
 50 
 60 
 
 90 
 50 
 60 
 60 
 50 
 60 
 70 
 50 
 70 
 
 105 
 60 
 80 
 80 
 70 
 
 100 
 
 110 
 70 
 
 120 
 60 
 60 
 30 
 50 
 
 90 
 50 
 60 
 65 
 60 
 50 
 50 
 60 
 60 
 90 
 50 
 90 
 60 
 50 
 140 
 100 
 80 
 130 
 40 
 40 
 40 
 50 
 
 90 
 
 100 
 
 60 
 
 90 
 
 , 60 
 
 70 
 
 40 
 
 40 
 
 50 
 
 105 
 
 65 
 
 75 
 
 60 
 
 50 
 
 130 
 
 130 
 
 60 
 
 70 
 
 40 
 
 60 
 
 50 
 
 50 
 
 70 
 
 105 
 
 60 
 
 ""ho 
 
 70 
 40 
 —60 
 60 
 80 
 50 
 60 
 60 
 80 
 125 
 160 
 60 
 90 
 20 
 50 
 50 
 50 
 
 70 ' 
 
 110 
 
 60 
 
 100 
 
 60 
 
 70 
 
 40 
 
 —60 
 
 60 
 
 70 
 
 60 
 
 60 
 
 40 
 
 80 
 
 160 
 
 160 
 
 50 
 
 90 
 
 "'"56" 
 50 
 60 
 
 70 
 150 
 
 "ioo" 
 
 60 
 70 
 40 
 —10 
 60 
 50 
 - 75 
 
 ""ho 
 
 80 
 
 "160' 
 50 
 90 
 30 
 50 
 50 
 60 
 
 April 21 .^. 
 
 April ;24 
 
 May 2 
 
 May 22 
 
 May 23 
 
 June 4 
 
 June 11 
 
 June 16 - - . : 
 
 June 24 
 
 June 25 . , - . 
 
 June 26 
 
 June 28 
 
 June 30 
 
 Julyl 
 
 July2 
 
 Julys 
 
 July 4 
 
 July 11 
 
 Julyl2 
 
 July 13 
 
 July 14 
 
 Sums ,.. 
 
 1,375 
 62 
 
 1,395 
 63 
 
 1,315 
 
 .60 
 
 1,275 
 
 58 
 
 1,430 
 65 
 
 1,535 
 70 
 
 1,555 
 71 
 
 1,505 
 
 68 
 
 1,545 
 70 
 
 1,340 
 64 
 
 1,440 
 69 
 
 1,235 
 65 
 
 
 
 SUMMARY 
 
 
 ] a. m. 
 
 2 a. m. 
 
 3 a. m. 
 
 la. m. 
 
 5 .a. m. 
 
 6 a.m. 
 
 7 a. m. 
 
 8 a. m. 
 
 9 a. m. 
 
 10 a.m. 
 
 Ha.m. 
 
 12 m. 
 
 1 
 
 83 
 58 
 71 
 60 
 67 
 63 
 62 
 
 86 
 58 
 80 
 '62 
 72 
 70 
 63 
 
 90 
 57 
 75 
 61 
 71 
 72 
 60 
 
 86 
 56 
 77 
 63 
 66 
 66 
 58 
 
 87 
 61 
 80 
 61 
 75 
 68 
 65 
 
 98 
 74 
 93 
 67 
 79 
 73 
 . 70 
 
 96 
 
 66 
 
 106 
 
 66 
 
 82 
 77 
 71 
 
 94 
 67 
 106 
 56' 
 92 
 80 
 68 
 
 95 
 70 
 99 
 
 58 
 98 
 81 
 70 
 
 84 
 70 
 102 
 60 
 96 
 80 
 64 
 
 85 
 70 
 100 
 57 
 90 
 86 
 69 
 
 77 
 73 
 90 
 58 
 84 
 78 
 65 
 
 2 
 
 3 ^ 
 
 4 
 
 5 
 
 6 
 
 7 
 
 
 Sums ...__■ .. 
 
 459 
 66 
 
 491 
 70 
 
 486 
 69 
 
 472 
 67 
 
 497 
 71 
 
 554 
 79 
 
 564 
 
 81 
 
 563 
 
 80 
 
 571 
 
 82 
 
 556 
 79 
 
 557 
 
 80 
 
 525 
 75 
 
 Means 
 
 
MBMOTKS OP THE NATIONAL ACADEMY OF SCIENCES. 
 Baltimore, Md., 1885, 1886, and 1887— Continued, 
 the photographic sheets.] 
 
 247 
 
 1 p.m. 
 
 2 p.m. 
 
 3 p.m. 
 
 4 p. m. 
 
 5 p. m. 
 
 6 p.m. 
 
 7 p. m. 
 
 8 p.m. 
 
 9 p. m. 
 
 lOp.m. 
 
 11 p. m. 
 
 12 mid. 
 
 Kemarks. 
 
 60 
 
 120 
 
 100 
 
 - 140 
 
 120 
 
 80 
 
 70 
 
 90 
 
 130 
 
 100 
 
 100 
 
 50 
 
 N. It., fair. 
 
 100 
 
 150 
 
 120 
 
 150 
 
 150 
 
 100 
 
 80 
 
 60 
 
 70 
 
 ■ 50 
 
 50 
 
 90 
 
 S. It., clear. 
 
 
 100 
 
 100 
 
 90 
 
 80 
 
 100 
 
 100 
 
 105 
 
 100 
 
 100 
 
 60 
 
 60 
 
 NW.fr., clear. 
 
 ioo 
 
 100 
 
 100 
 
 100 
 
 110 
 
 70 
 
 40 
 
 35 
 
 35 
 
 20 
 
 20 
 
 20 
 
 SE.fr., fair. 
 
 ■' 35 
 
 60 
 
 65 
 
 70 
 
 60 
 
 60 
 
 70 
 
 80 
 
 90 
 
 80 
 
 90 
 
 80 
 
 Var. It., clear. 
 
 100 
 
 130 
 
 110 
 
 75 
 
 90 
 
 50 
 
 50 
 
 50 
 
 50 
 
 50 
 
 50 
 
 50 
 
 S. It. , fair. 
 
 30 
 
 70 
 
 50 
 
 50 
 
 20 
 
 40 
 
 100 
 
 100 
 
 100 
 
 100 
 
 70 
 
 70 
 
 NW.fr., fair. 
 
 —20 
 
 —50 
 
 20 
 
 50 
 
 50 
 
 50 
 
 60 
 
 40 
 
 60 
 
 40 
 
 30 
 
 50 
 
 E.br., clear. 
 
 50 
 
 70 
 
 80 
 
 60 
 
 50 
 
 45 
 
 60 
 
 50 
 
 —10 
 
 10 
 
 20 
 
 50 
 
 SW.lt., clear. 
 
 70 
 
 80 
 
 90 
 
 70 
 
 60 
 
 50 
 
 60 
 
 50 
 
 50 
 
 30 
 
 25 
 
 20 
 
 W. fr., fair. 
 
 70 
 
 100 
 
 105 
 
 110 
 
 80 
 
 60 
 
 75 
 
 100 
 
 30 
 
 60 
 
 60 
 
 60 
 
 N.lr.,fair. 
 
 
 70 
 
 50 
 
 60 
 
 70 
 
 70 
 
 25 
 
 ICO 
 
 30 
 
 30 
 
 20 
 
 10 
 
 Var. It., fair. 
 
 40 
 
 150 
 
 80 
 
 150 
 
 160 
 
 140 
 
 80 
 
 120 
 
 90 
 
 80 
 
 80 
 
 60 
 
 Do. 
 
 70 
 
 90 
 
 90 
 
 95 
 
 80 
 
 BO 
 
 80 
 
 80 
 
 120 
 
 100 
 
 100 
 
 90 
 
 S. It., clear. 
 
 200, 
 
 140 
 
 100 
 
 150 
 
 170 
 
 120 
 
 120 
 
 80 
 
 110 
 
 105 
 
 100 
 
 100 
 
 S. fr. , clears 
 
 100 
 
 200 
 
 180 
 
 150 
 
 90 
 
 90 
 
 80 
 
 75 
 
 90 
 
 80 
 
 70 
 
 80 
 
 Do. 
 
 
 
 
 140 
 
 110 
 
 70 
 
 80 
 90 
 
 80 
 70 
 
 90 
 60 
 
 80 
 70 
 
 80 
 60 
 
 110 
 60 
 
 S. fr., fair. 
 SE.br., fair. 
 
 100 
 
 105 
 
 60 
 
 80 
 
 90 
 
 90 
 
 30 
 
 30 
 
 60 
 
 60 
 
 60 
 
 60 
 
 70 
 
 80 
 
 80 
 
 60 
 
 50 
 
 40 
 
 W.br., clear. 
 
 50 
 
 60 
 
 60 
 
 60 
 
 CO 
 
 60 
 
 70 
 
 70 
 
 120 
 
 60 
 
 60 
 
 50 
 
 bo. 
 
 50 
 
 60 
 
 65 
 
 70 
 
 70 
 
 75 
 
 80 
 
 90 
 
 60 
 
 65 
 
 50 
 
 50 
 
 W.fr.,fair. 
 
 50 
 
 55 
 
 45 
 
 10 
 
 10 
 
 10 
 
 30 
 
 30 
 
 30 
 
 40 
 
 40 
 
 30 
 
 Var. fr. , clear. 
 
 1,285 
 
 1,890 
 
 1,730 
 
 1,990 
 
 1,840 
 
 1,570 
 
 1,570 
 
 1,595 
 
 1,585 
 
 1,410 
 
 1,285 
 
 1,280 
 
 68 
 
 90 
 
 82 
 
 90 
 
 84 
 
 71 
 
 71 
 
 72 
 
 72 
 
 64 
 
 58 
 
 58 
 
 
 OF MEANS. 
 
 Ip. m. 
 
 2 p. m. 
 
 3. p m. 
 
 4 p. m. 
 
 5 p. m. 
 
 6 p. m. 
 
 7 p. m. 
 
 8 p. m. 
 
 9 p. m. 
 
 10 p. m. 
 
 1 
 11 p.m. 
 
 12 mid. 
 
 Heans. 
 
 84 
 
 93 
 
 87 
 
 38 
 
 84 
 
 69 
 
 70 
 
 71 
 
 67 
 
 65 
 
 66 
 
 63 
 
 82 
 
 70 
 
 76 
 
 79 
 
 76 
 
 84, 
 
 76 
 
 61 
 
 63 
 
 58 
 
 54 
 
 56 
 
 5a 
 
 66 
 
 94 
 
 96 
 
 103 
 
 98 
 
 100 
 
 103 
 
 103 
 
 93 
 
 90 
 
 79 
 
 75 
 
 76 
 
 91 
 
 53 
 
 58 
 
 67 
 
 74 
 
 79. 
 
 70 
 
 69 
 
 76 
 
 69 
 
 62 
 
 58 
 
 50 
 
 63 
 
 90 
 
 112 
 
 128 
 
 130 
 
 110 
 
 107 
 
 93 
 
 81 
 
 74 
 
 70 
 
 73 
 
 72 
 
 88 
 
 80 
 
 99 
 
 101 
 
 92 
 
 86 
 
 79 
 
 79 
 
 80 
 
 73 
 
 68 
 
 69 
 
 65 
 
 7a- 
 
 68 
 
 90 
 
 82 
 
 90 
 
 84 
 
 71 
 
 71 
 
 72 
 
 72 
 
 64 
 
 58 
 
 58 
 
 69 
 
 539 
 
 624 
 
 647 
 
 648 
 
 627 
 
 575 
 
 546 
 
 536 
 
 503 
 
 462 
 
 455 
 
 437 
 
 537 
 
 77 
 
 89 
 
 92 
 
 93 
 
 90 
 
 82 
 
 78 
 
 77 
 
 72 
 
 66 
 
 65 
 
 62 
 
 77 
 
248 
 
 MEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES. 
 
 Table H. — Potential on clear and fair days, Washington, D. G., October, 1887, to August, 1888, 
 
 inclusive. 
 
 Date. 
 
 II a. m. 
 
 1p.m. 
 
 3 p.m. 
 
 5 p.m. 
 
 Kemarks. 
 
 1887. 
 
 October? 
 
 October 12.... 
 
 October 13 
 
 October 15 
 
 October 17- .. 
 
 October 21 
 
 October 22 
 
 November 1 . . 
 November 2 . . 
 November 3 . . 
 
 Sums. . 
 Means . 
 
 November 5 . . 
 November 12 . 
 November 29 . 
 November 30 . 
 December 1 . , 
 December 5 . . 
 December 6 . 
 December 13 . 
 December 16 . 
 December 19 , 
 
 Sums. . 
 Means. 
 
 December 22 . 
 December 23 . 
 
 1888. 
 
 January 3 
 
 January 11... 
 January 19... 
 January 21... 
 January 24 . . , 
 January 28... 
 February 2 ... 
 February 13 . . 
 
 Sums. .. 
 Means . . 
 
 February 15 . 
 February 16 . 
 February 28 . 
 
 March 3 
 
 March 6 
 
 March 7 
 
 March 8 
 
 March 9 
 
 March 15 
 
 March 23 ... . 
 
 Sums.. 
 
 Means . 
 
 March 30. 
 April 3 ... 
 April i ... 
 April 11 . . 
 April 13 .. 
 April 17 . . 
 April 24 . . 
 April 25 , . 
 April 26.. 
 May 3 
 
 Sums.. 
 Means. 
 
 2no 
 
 128 
 108 
 118 
 157 
 120 
 200 
 142 
 172 
 269 
 
 220 
 62 
 134 
 112 
 248 
 196 
 161 
 157 
 168 
 322 
 
 180 
 115 
 215 
 89 
 138 
 126 
 190 
 1S6 
 217 
 258 
 
 ,614 
 161 
 
 1,780 
 178 
 
 1,684 
 16» 
 
 112 
 96 
 172 
 226 
 282 
 137 
 219 
 370 
 157 
 202 
 
 160 
 72 
 168 
 181 
 226 
 152 
 195 
 293 
 168 
 206 
 
 145 
 96 
 162 
 147 
 211 
 168 
 234 
 315 
 178 
 168 
 
 1,973 
 197 
 
 1,821 
 
 182. 
 
 1, 824 
 182 
 
 126 
 368 
 
 176 
 111 
 266 
 
 208 
 198 
 168 
 272 
 563 
 
 161 
 276 
 
 195 
 91 
 291 
 185 
 252 
 150 
 176 
 316 
 
 138 
 202 
 
 174 
 96 
 222 
 182 
 195 
 148 
 198 
 306 
 
 2, 456 
 246 
 
 2; 093 
 209 
 
 1,861 
 186 
 
 189 
 317 
 102 
 200 
 282 
 357 
 202 
 262 
 219 
 53 
 
 178 
 408 
 194 
 176 
 102 
 171 
 147 
 242 
 229 
 112 
 
 205 
 398 
 258 
 160 
 187 
 208 
 202 
 261 
 242 
 48 
 
 2,183 
 218 
 
 1,959 
 196 
 
 2, 169 
 
 217 
 
 408 
 128 
 '88 
 106 
 IW 
 122 
 126 
 132 
 138 
 120 
 
 277 
 
 130 
 
 56 
 
 95 
 
 117 
 
 84 
 
 82 
 
 110 
 
 149 
 
 98 
 
 146 
 
 120 
 
 126 
 
 70 
 
 90 
 
 124 
 
 74 
 
 115 
 
 131 
 
 101 
 
 1,478 
 148 
 
 1,198 
 120 
 
 1,097 
 110 
 
 121 
 170 
 84 
 244 
 126 
 200 
 141 
 189 
 158 
 
 150 
 150 
 128 
 70 
 224 
 106 
 224 
 114 
 269 
 163 
 
 1,513 
 151 
 
 1,598 
 160 
 
 124 
 72 
 176 
 150 
 222 
 144 
 278 
 157 
 168 
 183 
 
 83 
 79 
 182 
 133 
 201 
 117 
 325 
 266 
 202 
 277 
 
 ,674 
 167 
 
 1,865 
 186 
 
 165 
 207 
 
 121 
 71 
 182 
 158 
 238 
 166 
 194 
 340 
 
 134 
 274 
 
 155 
 72 
 182 
 130 
 219 
 141 
 158 
 337 
 
 1,842 
 184 
 
 1,802 
 180 
 
 187 
 320 
 258 
 163 
 291 
 180 
 149 
 222 
 221 
 99 
 
 192 
 235 
 245 
 lit 
 245 
 197 
 136 
 281 
 2i9 
 75 
 
 2,090 
 209 
 
 1,952 
 
 195 
 
 138 
 
 77 
 
 37 
 
 82 
 
 94 
 
 54 
 
 63 
 
 114 
 
 125 
 
 • 50 
 
 165 
 
 83 
 
 133 
 
 74 
 
 107 
 
 108 
 
 63 
 
 130 
 
 152 
 
 122 
 
 834 
 
 83 
 
 1, 137 
 114 
 
 166 
 115 
 151 
 95 
 202 
 135 
 195 
 142 
 203 
 234 
 
 1,638 
 164 
 
 125 
 83 
 172 
 167 
 228 
 144 
 250 
 280 
 175 
 207 
 
 ,831 
 183 
 
 145 
 265 
 
 164 
 88 
 229 
 173 
 220 
 155 
 200 
 372 
 
 2,011 
 201 
 
 190 
 336 
 211 
 163 
 221 
 223 
 167 
 254 
 228 
 77 
 
 2, 070 
 
 207 
 
 227 
 
 108 
 88 
 85 
 
 106 
 98 
 82 
 
 118 
 
 139 
 98 
 
 1,151 
 115 
 
 SE. It., clear. 
 NW.fr., fair. 
 SW.lt., clear. 
 N. It., clear. 
 S. It., fair. 
 NW. br.,fair. 
 NW.lt., clear. 
 N. fr.,fair. 
 NW.lt., clear. 
 Var. It., clear. 
 
 NW.fr., clear. 
 NW.fr., fair. 
 N. It., clear. 
 
 Do. ' 
 NE. It., clear. 
 NW.fr., clear. 
 NW.lt., clear. 
 S. It., clear. It. haze. 
 NW.fr., clear. 
 NW. It"., fair. 
 
 NW.fr., clear. 
 SW.lt., clear. 
 
 W. It., fair. 
 NW.fr., clear. 
 
 Do. 
 N.fr., clear. 
 
 Do. 
 NW. br. , clear. 
 NW.lt., clear. 
 N. It. , clear. 
 
 NW. br., clear. 
 S. It., clear. 
 NW. br., clear. 
 
 Do. 
 NW.lt., clear. 
 NW.fr., clear. 
 NW.br., clear. 
 NW. fr., clear. 
 NW. It., clear. 
 NW, fr,, clear. 
 
 S. It., clear. 
 N. It., clear. 
 S. It., fair. 
 NW. br. , clear. 
 NW.lt., fair. 
 S. It., clear. 
 NW.br., fair. 
 NE.lt., clear. 
 S. It., clear. 
 Do, 
 
MEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES. 
 
 249 
 
 Table H. — Potential on clear and fair days, Washington, D. 0., October 1887, to August, 1888, 
 
 inclusive — Continued. 
 
 Date. 
 
 1 p. m. 
 
 3 p. m. 
 
 5 p.m. 
 
 Means. 
 
 Kemarkfl. 
 
 1888. 
 
 Jnnel.-l 
 
 Jnne4 , 
 
 Jnne5 
 
 JnneG 
 
 June 7 
 
 June 9 , 
 
 June 13 
 
 Junei5 
 
 June 19 
 
 June20 
 
 Sums.. 
 Means.. 
 
 June 21 ..... 
 
 June 22 
 
 June 25 
 
 JnlyS 
 
 July 6 
 
 July 11 
 
 July 13 
 
 July 14 
 
 .Tnly23 , 
 
 July 25 , 
 
 Sums . . 
 Means 
 
 July 26 , 
 
 August 2 
 
 August 7 — 
 August 10 . . . 
 August 13 . . . 
 August 14 .- 
 August 15 ... 
 August 16 .. 
 August 23 .. 
 August 24 . . 
 
 Sums . . 
 Means. 
 
 August 25 . . 
 August 28... 
 August 29.. 
 
 Sums . . 
 Means . 
 
 157 
 70 
 66 
 72 
 48 
 56 
 
 110 
 90 
 46 
 82 
 
 797 
 80 
 
 34 
 
 101 
 48 
 
 125 
 
 127 
 64 
 
 195 
 45 
 99 
 
 157 
 
 995 
 100 
 
 98 
 52 
 105 
 119 
 175 
 151 
 162 
 15 
 141 
 335 
 
 ,353 
 135 
 
 200 
 216 
 105 
 
 521 
 
 174 
 
 38 
 62 
 58 
 30 
 42 
 48 
 50 
 32 
 50 
 
 498 
 50 
 
 38 
 80 
 46 
 141 
 118 
 147 
 179 
 119 
 108 
 169 
 
 1,145 
 114 
 
 94 
 
 94 
 
 115 
 
 106 
 
 127 
 
 139 
 
 73 
 
 46 
 
 137 
 
 171 
 
 ,102 
 110 
 
 172 
 
 202 
 108 
 
 482 
 161 
 
 48 
 93 
 66 
 53 
 47 
 66 
 66 
 78 
 52 
 
 81 
 42 
 67 
 62 
 53 
 61 
 43 
 50 
 58 
 72 
 
 66 
 
 61 
 
 102 
 
 84 
 58 
 90 
 61 
 
 78 
 70 
 78 
 
 655 
 66 
 
 59 
 
 748 
 75 
 
 38 
 
 66 
 
 61 
 
 104 
 
 116 
 
 136 
 
 146 
 
 98 
 
 102 
 
 105 
 
 972 
 97 
 
 74 
 
 76 
 
 70 
 
 45 
 
 90 
 
 108 
 
 134 
 
 39 
 
 143 
 
 182 
 
 961 
 96 
 
 161 
 127 
 158 
 
 446 
 149 
 
 47 
 
 91 
 
 67 
 
 102 
 
 127 
 
 123 
 
 104 
 
 140 
 
 104 
 
 94 
 
 31 
 
 84 
 
 48 
 
 147 
 
 195 
 
 111 
 
 98 
 
 88 
 
 77 
 
 137 
 
 999 
 100 
 
 1,016 
 102 
 
 119 
 
 .78 
 
 73 
 
 74 
 
 77 
 
 78 
 
 73 
 
 66 
 
 162 
 
 143 
 
 153 
 80 
 69 
 67 
 67 
 
 113 
 90 
 67 
 
 179 
 
 157 
 
 943 
 94 
 
 1,042 
 104 
 
 160 
 167 
 209 
 
 147 
 115 
 
 84 
 
 536 
 
 179 
 
 346 
 115 
 
 96 
 52 
 
 78 
 68 
 48 
 59 
 66 
 67 
 57 
 67 
 
 658 
 66 
 
 38 
 
 84 
 
 54 
 
 124 
 
 137 
 
 116 
 
 144 
 
 98 
 
 98 
 
 132 
 
 1,025 
 102 
 
 108 
 
 76 
 
 86 
 
 82 
 
 107 
 
 118 
 
 106 
 
 47 
 
 152 
 
 198 
 
 1,080 
 108 
 
 168 
 165 
 133 
 
 466 
 155 
 
 NW.fr., clear. 
 NW.lt., clear. 
 S. It., clear. 
 
 Do. 
 NW.fr., fair. 
 S.fr., clear. 
 SE.fr., fair. 
 S. It., fair. 
 E. It., fair. 
 SE.lt., fair. 
 
 SE. It, fair. 
 NW.lt., fair. 
 NW. ft. , clear. 
 SE.fr., fair. 
 NW.lt., clear. 
 W. fr., clear. It. haze. 
 NW. fr. , clear. 
 NW. fr., fair, It. baze. 
 W. it., clear. 
 S. It., clear. 
 
 SE.fr., clear. * 
 
 NE. It., clear. It. haze. 
 NW. fr. , clear. 
 N. It., clear. 
 NW.fr., fair. 
 W. It., fair. 
 
 Do. 
 S. It., clear. 
 NW.fr., clear. 
 SW.lt , clear. 
 
 W. It., clear. 
 N. It., clear. 
 S.fr., clear. 
 
 SUMMAET. 
 
 Number of days. 
 
 9 a.m. 
 
 11a.m. 
 
 Ip. m. 
 
 3 p. m. 
 
 5 p. m. 
 
 Means. 
 
 CIO") ,.' 
 
 1,614 
 
 1,973 
 
 2,456 
 
 2,183 
 
 1,478 
 
 797 
 
 995 
 
 1,353 
 
 521 
 
 1,780 
 1,821 
 2,093 
 1,959 
 1,198 
 
 498 
 1,145 
 1, 102 
 
 482 
 
 1,684 
 
 1,854 
 
 1,861 
 
 2, 169 
 
 1,097 
 
 655 
 
 972 
 
 961 
 
 446 
 
 1,513 
 
 1,674 
 
 1,842 
 
 2,090 
 
 834 
 
 589 
 
 999 
 
 943 
 
 536 
 
 * 1,598 
 1,865 
 1,802 
 1, 952 
 1,J37 
 
 748 
 1,016 
 1,042 
 
 346 
 
 1,638 
 1,831 
 2,011 
 2,070 
 1,151 
 
 658 
 1,025 
 1,080 
 
 466 
 
 MO^ 
 
 no^ 
 
 cio^ 
 
 no^ 
 
 no^ ... 
 
 no") 
 
 rioS 
 
 (3") 
 
 Sums - 
 
 13,370 
 161 
 
 12,078 
 146 
 
 11, 669 
 141 
 
 11,020 
 133 
 
 11,. 506 
 139 
 
 11,930 
 144 
 
 
 
250 MEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES. 
 
 Table I. — Potential on clear and fair days, Boston, Mass., July, 1886, to August, 1888. 
 
 Date. 
 
 1 p.m. 
 
 3 p.m. 
 
 Means. 
 
 Kemarks. 
 
 1886. 
 
 July 5 
 
 July 6 
 
 July 11 
 
 July 17 
 
 July 20 
 
 August 2 . . . 
 August 8 - . - 
 August 10 . . 
 August 13 . . 
 August 15 - . 
 
 Sums .. 
 Means . 
 
 August 18 . . 
 August 19 . . 
 August 20 . . 
 August 21 „ 
 August 22 . . 
 August 23 .. 
 August 24 . . 
 August 26 . - 
 August 27 . . 
 August 28 . . 
 
 Sums ., 
 
 Means. 
 
 August 29 
 
 September 1.. 
 September 2. . 
 September 3. . 
 September 7.. 
 September 8. . 
 September 13 . 
 September 14. 
 Septeniber 15 . 
 September 19 . 
 
 Sums .. 
 Means . 
 
 September 20 
 
 September 21 
 
 September 22 . A . . . 
 
 September 29 
 
 Octobers 
 
 October 6 
 
 October7i 
 
 Octobers 
 
 October 9 
 
 OctoberlO 
 
 Sums .. 
 Means . 
 
 October 11 . 
 October 12 . 
 October 14 . 
 October 16 - 
 October 18 . 
 October 19 . 
 October 20 . 
 October 22 . 
 October 23 . 
 0^ober24 . 
 
 Sums .., 
 Means . 
 
 November 2 . 
 November 5 . 
 November 8 . 
 November 9 . 
 
 10 
 10 
 16 
 79 
 20 
 55 
 18 
 110 
 10 
 
 336 
 34 
 
 la 
 
 5 
 12 
 
 4 
 95 
 29 
 45 
 10 
 
 8 
 28 
 
 246 
 25 
 
 2 
 
 160 
 
 550 
 
 420 
 
 40 
 
 15 
 
 10 
 
 80 
 
 170 
 
 150 
 
 1,597 
 160 
 
 20 
 10 
 17 
 19 
 15 
 7 
 7 
 31 
 31 
 20 
 
 177 
 18 
 
 18 
 64 
 
 321 
 
 30 
 
 9 
 
 4 
 
 21 
 
 112 
 14 
 92 
 
 685 
 68 
 
 14 
 
 4 
 19 
 16- 
 29 
 38 
 58 
 87 
 126 
 15 
 
 2 
 15 
 16 
 
 351 
 41 
 
 160 
 30 
 96 
 
 "12 
 
 6 
 
 3 
 
 14 
 
 17 
 82 
 25 
 141 
 37 
 6 
 18 
 
 406 
 41 
 
 731 
 73 
 
 349 
 35 
 
 12 
 
 20 
 
 45 
 
 5 
 
 110 
 
 52 
 
 60 
 
 3 
 
 10 
 
 28 
 
 10 
 
 5 
 
 20 
 
 40 
 
 105 
 
 55 
 
 45 
 
 7 
 
 25 
 
 50 
 
 345 
 34 
 
 362 
 36 
 
 10 
 162 
 340 
 410 
 
 56 
 150 
 6 
 124 
 260 
 192 
 
 1,710 
 171 
 
 41 
 31 
 33 
 -24 
 31 
 37 
 10 
 34 
 30 
 15 
 
 286 
 29 
 
 31 
 10 
 
 193 
 40 
 12 
 35 
 21 
 40 
 20 
 
 119 
 
 50 
 
 50 
 
 30 
 
 144 
 
 521 
 52 
 
 57r 
 
 80 
 
 46 
 
 130 
 
 10 
 196 
 560 
 240 
 
 50 
 140 
 
 20 
 130 
 290 
 181 
 
 1,817 
 182 
 
 10 
 25 
 20 
 22 
 37 
 51 
 15 
 37 
 29 
 23 
 
 269 
 27 
 
 31 
 33 
 
 311 
 46 
 12 
 40 
 29 
 70 
 31 
 
 190 
 
 793 
 
 79 
 
 192 
 110 
 
 71 
 120 
 
 30 
 5 
 105 
 10 
 76 
 55 
 45 
 10 
 20 
 40 
 
 396 
 40 
 
 15 
 
 S25 
 
 640 
 
 540 
 
 55 
 
 218 
 
 22 
 
 40 
 
 350 
 
 191 
 
 2,296 
 230 
 
 25 
 34 
 22 
 27 
 30 
 50 
 14 
 36 
 32 
 14 
 
 284 
 28 
 
 30 
 22 
 
 390 
 48 
 13 
 37 
 39 
 61 
 26 
 
 182 
 
 848 
 85 
 
 16 
 
 66 
 
 83 
 
 135 
 
 9 
 
 5 
 
 14 
 
 16 
 
 135 
 31 
 
 105 
 43 
 84 
 14 
 
 456 
 46 
 
 16 
 9 
 46 
 15 
 96 
 48 
 49 
 8 
 16 
 36 
 
 339 
 34 
 
 9 
 
 186 
 
 522 
 
 402 
 
 50 
 
 131 
 
 14 
 
 94 
 
 268 
 
 178 
 
 1,854 
 185 
 
 24 
 22 
 23 
 23 
 28 
 36 
 12 
 34 
 30 
 18 
 
 250 
 25 
 
 28 
 32 
 
 304 
 41 
 12 
 29 
 28 
 71 
 23 
 
 146 
 
 714 
 71 
 
 207 
 76 
 
 r^s 
 
 132 
 
 Clear. 
 
 Do. 
 
 Do. 
 
 Do. 
 
 Do. 
 N. fr.,fair. 
 
 Do. 
 W.br., clear. 
 E. fr., clear. 
 NW. fr,, clear 
 
 E,fr., clear. 
 SE.fr., clear. 
 
 Do. 
 S.fr., clear. 
 E. br., clear. 
 SW.fr., clear. 
 
 Do. 
 NW.fr., clear. 
 W. fr., clear. 
 SE. gen., clear. 
 
 E.fl-., clear. 
 NW. br. , clear. 
 NE.fr., clear. 
 E.fr., clear. 
 W. fr., fair. 
 SW.fr., clear. 
 W. br., clear. 
 S. br., clear. 
 E.fr., fair. 
 SE.fr., fair. 
 
 NW.br., clear. 
 W.br., clear. 
 NW. fr., clear. 
 NW.,br.,fair. 
 W. fr.,cleair. 
 N.fr., clear. 
 NE.br., clear. 
 NW.lt., clear. 
 W. br., clear. 
 SE. fr., clear. 
 
 W. Ir. , clear. 
 W.fr.,fair. 
 SE.fr., fair. 
 NW.br., clear. 
 E.br.,fair. 
 E.fr., clear. 
 W.fr., clear. 
 SW.fr., clear. 
 SE.fr., clear. 
 E.fr., clear. 
 
 N.fr., clear. 
 S. br. , clear. 
 W. fr. , clear. 
 Do. 
 
MEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES. 251 
 
 Table I. — Potential on dear and fair days, Boston, Mass., July, 1886, to August, 1888 — Continued. 
 
 Bate. 
 
 9 a.m. 
 
 11 a. m. 
 
 1 p. m. 
 
 3 p. m. 
 
 Means. 
 
 KemarkH. 
 
 1886. 
 
 
 
 
 
 
 
 November 14 
 
 119 
 
 120 
 
 120 
 
 136 
 
 124 
 
 NW. high, clear. 
 
 November 16 
 
 111 
 
 58 
 
 29 
 
 30 
 
 '57 
 
 NW.fr., fair. 
 
 November 19 
 
 132 
 
 241 
 
 225 
 
 210 
 
 - 202 
 
 W.br.,;fair. 
 
 November 21 
 
 150 
 
 226 
 
 240 
 
 256 
 
 218 
 
 W.fr.,fair. 
 
 November 22 
 
 184 
 
 244 
 
 256 
 
 255 
 
 235 
 
 NW.fr., clear. 
 
 November 24 ...... 
 
 60 
 
 136 
 
 195 
 
 195 
 
 146 
 
 NW. high, clear. 
 
 1,030 
 103 
 
 1,852 
 185 
 
 1,558 
 
 1,382 
 
 1,455 
 146 
 
 Means 
 
 November 26 
 
 156 
 
 138 
 
 NW.br., clear. 
 
 255 
 
 326 
 
 345 
 
 332 
 
 314 
 
 November 27 
 
 392 
 
 335 
 
 325 
 
 376 
 
 357 
 
 W. fr. , clear. 
 
 November 28 
 
 375 
 
 406 
 
 441 
 
 390 
 
 403 
 
 W.br., cleat. 
 
 December 1 
 
 32 
 
 51 
 
 52 
 
 42 
 
 44 
 
 SW. high, fair. 
 
 December 2 
 
 75 
 
 69 
 
 69 
 
 64 
 
 69 
 
 W. high, fair. 
 
 December 3 
 
 120 
 
 166 
 
 210 
 
 135 
 
 158 
 
 W. br. , clear. 
 
 December 8 
 
 130 
 
 . 156 
 
 94 
 
 126 
 
 126 
 
 Do. 
 
 December 9 
 
 105 
 
 142 
 
 147 
 
 135 
 
 132 
 
 NW.fr., clear. 
 
 December 10 
 
 225 
 
 105 
 
 195 
 
 145 
 
 168 
 
 W.br., fair. 
 
 December 11 
 
 Sums 
 
 63 
 
 87 
 
 100 
 
 74 
 
 81 
 
 W.br., clear. 
 NW.br., fair. 
 
 1,772 
 177 
 
 1,843 
 184 
 
 1,978 
 198 
 
 1,819 
 182 
 
 1,852 
 
 185 
 
 Means 
 
 December 14 
 
 46 
 
 135 
 
 286 
 
 104 
 
 143 
 
 December 17 
 
 208 
 
 222 
 
 225 
 
 255 
 
 228 
 
 W.br., clear. 
 
 December 19 
 
 67 
 
 95 
 
 113 
 
 94 
 
 92 
 
 W.fr., clear. 
 
 December 21 
 
 20 
 
 47 
 
 61 
 
 20 
 
 37 
 
 SW. high, clear. 
 
 December 25 
 
 191 
 
 414 
 
 229 
 
 153 
 
 247 
 
 NW. high, clear. 
 
 December 28 
 
 62 
 
 148 
 
 112 
 
 89 
 
 103 
 
 W. br. , clear. 
 
 1887. 
 
 
 
 
 
 
 
 January 2 
 
 32 
 
 71 
 
 61 
 
 55 
 
 55 
 
 W. high, fair. 
 
 
 63 
 131 
 
 170 
 411 
 
 140 
 351 
 
 106 
 220 
 
 120 
 
 278 
 
 NW.br., clear. 
 W.fr., clear. 
 
 January 11 
 
 January 12 
 
 Sums 
 
 103 
 
 160 
 
 • 171 
 
 122 
 
 139 
 
 SW.fr., clear. 
 
 923 
 
 1,873 
 
 1,749 
 
 1,218 
 
 1,442 
 
 Means . . 
 
 i January 13 
 
 92 
 
 187 
 
 175 
 
 122 
 
 144 
 
 W.fr., clear. 
 
 70 
 
 127 
 
 120 
 
 86 
 
 101 
 
 January 16 
 
 122 
 
 191 
 
 191 
 
 170 
 
 168 
 
 NW.fr., clear. 
 
 January 18 
 
 42 
 
 90 
 
 99 
 
 80 
 
 78 
 
 W.br., clear. 
 
 January 21 
 
 47 
 
 63 
 
 42 
 
 23 
 
 ' 44 
 
 NW. high, clear. 
 
 January 27 
 
 30 
 
 46 
 
 29 
 
 20 
 
 31 
 
 NW. fr., clear. 
 
 February 4 
 
 .32 
 
 38 
 
 30 
 
 13 
 
 28 
 
 W.br., fair. 
 
 February 5 
 
 51 
 
 103 
 
 70 
 
 34 
 
 64 
 
 NW. fr., clear. 
 
 February 9 
 
 81 
 
 189 
 
 231 
 
 154 
 
 164 
 
 NW.br., clear. 
 
 February 12 
 
 63 
 
 88 
 
 132 
 
 65 
 
 87 
 
 Do. 
 
 February 13 
 
 Sams 
 
 29 
 
 179 
 
 142 
 
 39 
 
 97 
 
 Do. 
 
 567 
 
 1,114 
 
 1,086 
 
 684 
 
 862 
 
 Means 
 
 February 14 
 
 57 
 
 111 
 
 109 
 
 68 
 
 86 
 
 E.fr., clear. 
 
 73 
 
 109 
 
 51 
 
 39 
 
 68 
 
 February 16 
 
 1 
 
 13 
 
 16 
 
 5 
 
 9 
 
 Do. 
 
 February 17 
 
 8 
 
 12 
 
 13 
 
 13 
 
 12 
 
 W.fr., clear. 
 
 February 25 
 
 75 
 
 152 
 
 164 
 
 90 
 
 120 
 
 NW. high, clear. 
 
 February 28 
 
 55 
 
 50 
 
 40 
 
 29 
 
 44 
 
 Do. 
 
 
 62 
 39 
 91> 
 3L 
 15 
 
 110 
 
 129 
 
 198 
 
 90 
 
 42 
 
 100 
 
 110 
 
 350 
 
 65 
 
 31 
 
 85 
 70 
 198 
 32 
 22 
 
 89 
 
 87 
 
 209 
 
 54 
 
 28 
 
 N. br., clear. 
 NW.br., clear. 
 NW.br., fair. 
 NW.fr., clear: 
 W, high, clear. 
 
 March 8 . . . . 
 
 March 12 
 
 Marcli 14...... - 
 
 March 25 
 
 
 450 
 
 45 
 
 905 
 90 
 
 940 
 94 
 
 583 
 58 
 
 720 
 72 
 
 Means 
 
 March 26 
 
 29 
 31 
 56 
 17 
 
 116 
 86 
 
 192 
 21 
 
 65 
 23 
 
 220 
 21 
 
 42 
 
 43 
 
 160 
 
 15 
 
 63 
 
 46 
 
 157 
 
 18 
 
 W. high, clear. 
 NW. br., fair. 
 W. high, clear. 
 W. fr., clear. 
 
 March 27-- 
 
 March 30 
 
 March 31 
 
 
 133 
 33 
 
 415 
 
 104 
 
 329 
 
 82 
 
 260 
 65 
 
 284 
 71 
 
 Means.... 
 
 \ 
 
 ^■ 
 
 
 
 
 
 
252 MEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES. 
 
 Table I. — Potential on clear and fair days, Boston, Mass., July, 1886, to August, 1888 — Continued. 
 
 SUMMARY. 
 
 Ifnmber of days- 
 
 11 a. m. 
 
 Xp. m. 
 
 3 p.m. 
 
 Means. 
 
 (10) 
 
 (10) 
 
 (10) 
 
 (10) 
 
 (10) 
 
 (10) 
 
 (10) 
 
 (10), 
 
 (10) 
 
 (10) 
 
 (4) 
 
 Sums. 
 Means 
 
 336 
 
 246 
 
 1,597 
 
 177 
 
 685 
 
 1,030 
 
 1,779 
 
 92.3 
 
 567 
 
 450 
 
 133 
 
 7,916 
 
 76 
 
 406 
 
 345 
 
 1,710 
 
 286 
 
 521 
 
 1,852 
 
 1,843 
 
 1,873 
 
 1,114 
 
 905 
 
 415 
 
 11,270 
 108 
 
 731 
 
 362 
 
 1,817 
 
 269 
 
 793 
 
 1,558 
 
 1,978 
 
 1,749 
 
 1,086 
 
 940 
 
 329 
 
 11,612 
 111 
 
 349 
 
 396 
 
 2,296 
 
 284 
 
 848 
 
 1,382 
 
 1,819 
 
 1,218 
 
 684 
 
 583 
 
 260 
 
 10, 119 
 97 
 
 456 
 
 339 
 
 1,854 
 
 250 
 
 718 
 
 1,455 
 
 1,852 
 
 1, 442 
 
 862 
 
 720 
 
 284 
 
 10,235 
 
 98 
 
 Date. 
 
 7 a.m. 
 
 8 a.m. 
 
 11 a. m. 
 
 Ip.m. 
 
 3 p.m. 
 
 7p. m- 
 
 11p.m. 
 
 Means. 
 
 11 
 
 
 23 
 
 20 
 
 20 
 
 22 
 
 3 
 
 16 
 
 16 
 21 
 
 
 33 
 35 
 
 20 
 17 
 
 16 
 
 8 
 
 
 
 21 
 
 28 
 
 is 
 
 68 
 
 16 
 
 
 46 
 
 41 
 
 17 
 
 35 
 
 
 31 
 
 43 
 
 
 38 
 
 30 
 
 31 
 
 33 
 
 47 
 
 37 
 
 69 
 
 
 58 
 
 40 
 
 40 
 
 40 
 
 58 
 
 51 
 
 23 
 
 
 31 
 
 69 
 
 60 
 
 74 
 
 80 
 
 56 
 
 13 
 
 
 40 
 
 34 
 
 22 
 
 33 
 
 47 
 
 30 
 
 14 
 
 
 80 
 
 61 
 
 60 
 
 74 
 
 78 
 
 61 
 
 31 
 
 
 43 
 
 40 
 
 23 
 
 35 
 
 35 
 
 34 
 
 257 
 
 
 427 
 
 372 
 
 297' 
 
 354 
 
 416 
 
 365 
 
 26 
 
 
 43 
 
 37 
 
 30 
 
 39 
 
 52 
 
 36 
 
 28 
 
 55 
 
 58 
 
 150 
 
 
 30 
 
 50 
 
 71 
 
 140 
 
 27 
 51 
 38 
 
 75. 
 
 26 
 38 
 30 
 43 
 
 
 
 28 
 
 48 
 
 49 
 
 102 
 
 
 
 
 
 
 
 135 
 
 151 
 
 70 
 
 131 
 
 
 102 
 
 181 
 
 71 
 
 180 
 
 60 
 126 
 
 63 
 123. 
 
 60 
 
 74 
 
 70 
 
 107 
 
 
 
 89 
 133 
 
 68 
 145 
 
 
 
 
 
 157 
 
 170 
 
 58 
 
 
 179 
 
 160 
 
 171 
 
 199 
 
 251 
 
 170 
 
 79 
 
 
 143 
 
 106 
 
 343 
 
 530 
 
 30 
 
 202 
 
 915 
 
 
 1,147 
 
 829 
 
 962 
 
 876 
 
 451 
 
 1,034 
 
 92 
 
 
 . 115 
 
 83 
 
 96 
 
 292 
 
 150 
 
 103 
 
 111 
 
 
 143 
 
 131 
 
 131 
 
 170 
 
 231 
 
 153 
 
 27 
 
 __^_( 
 
 31 
 
 71 
 
 130 
 
 147 
 
 273 
 
 113 
 
 170 
 
 
 199 
 
 180 
 
 146 
 
 171 
 
 149 
 
 169 
 
 63 
 
 
 66 
 
 56 
 
 42 
 
 73 
 
 87 
 
 64 
 
 40 
 
 
 67 
 
 23 
 
 26 
 
 29 
 
 47 
 
 39 
 
 43 
 
 
 47 
 
 23 
 
 19 
 
 31 
 
 72 
 
 39 
 
 25 
 
 
 31 
 
 19 
 
 16 
 
 34 
 
 48 
 
 29 
 
 35 
 
 78 
 
 81 
 
 51 
 
 51 
 
 58 
 
 108 
 
 66 
 
 22 
 
 51 
 
 47 
 
 27 
 
 19 
 
 27 
 
 52 
 
 35 
 
 16 
 
 27 
 
 35 
 
 J5 
 
 16 
 
 31 
 
 32 
 
 23 
 
 552 
 
 156 
 
 747 
 
 596 
 
 596 
 
 761 
 
 1,099 
 
 730 
 
 55 
 
 52 
 
 75 
 
 60 
 
 60 
 
 76 
 
 110 
 
 73 
 
 Kemarks. 
 
 1887. 
 April 10... 
 April 14... 
 April 20... 
 April 22. . 
 
 May2 
 
 May 5 . 
 
 May9 
 
 May 10 
 
 May 13.... 
 May 14 
 
 Sams. 
 Means 
 
 May 15.... 
 May 17 .... 
 May 19.... 
 May 20.... 
 May21 .... 
 Mav22.... 
 
 May23 
 
 June 7 
 
 June 10 
 
 June 11.... 
 
 Sums. 
 Means 
 
 June 12 
 
 June 13 
 
 June 15 
 
 Jane 26 
 
 June28.... 
 
 June 29 
 
 June 30 
 
 July2 
 
 July 3 
 
 July 4 , 
 
 ' Sums. 
 Means 
 
 W. fr., clear. 
 N. fr.,fair. 
 W.fr., clear. 
 SE.fr., clear. 
 E. ft, fair. 
 SE.fr., fair. 
 NE.fr., clear. 
 W. fr., clear. 
 E.fr., clear. 
 Do. 
 
 E. It., fair. 
 SE.fr., clear. 
 NW.fr., clear. 
 W. fr. , clear. 
 E.fr., clear. 
 S.fr., clear. 
 SW.br., fair. 
 W. fr. , fair. 
 E. br., clear. 
 SE.fr., clear. 
 
 Var.fr., clear. 
 SE. fr., clear. 
 E.br.,cl3ar. 
 Var.fr., fair. 
 S.fr., clear. 
 W. fr., clear. 
 
 Do. 
 
 Do, 
 E.fr., fair. 
 SW.br., fair. 
 
MEMOIRS OF THE NATIONAL ACADEMY OP SCIENCES. ' 253 
 
 Table I — Potential on clear and fair days, Boston, Mass., July, 1886, to August, 1888— Continued. 
 
 Date. 
 
 7 a. m. 
 
 9 a. in. 
 
 11a.m. 
 
 1 p.m. 
 
 3 p.m. 
 
 7 p.m. 
 
 11p.m. 
 
 Means. 
 
 Remarks. 
 
 1887. 
 Julys 
 
 41 
 
 52 
 27 
 30 
 12 
 13 
 63 
 93 
 33 
 82 
 
 125 
 - 46 
 39 
 18 
 18 
 19 
 90 
 93 
 45 
 57 
 
 86 
 55 
 21 
 51 
 59 
 27 
 75 
 
 147 
 51 
 
 100 
 
 75 
 35 
 33 
 39 
 59 
 21 
 81 
 120 
 51 
 87 
 
 75 
 27 
 39 
 33 
 63 
 66 
 150 
 120 
 45 
 63 
 
 74 
 21 
 21 
 
 88 
 44 
 26 
 
 81 
 40 
 29 
 34 
 43 
 29 
 92 
 115 
 45 
 73 
 
 E.fr., clear. 
 N. br., clear. 
 N. br.,fair. 
 E. fr., clear. 
 S. ft., fair. 
 SW.fr., clear. 
 SE.fr., clear. 
 N.br., clear. 
 SE.fr., clear. 
 N.fr., clear. 
 
 NW.fr., clear. 
 
 Do. 
 W.fr., clear. 
 SW.br., clear. 
 Var. fr., clear. 
 
 July 14 
 
 July 15 
 
 July 20 
 
 July 26 
 
 July 28. ...:... 
 
 August 1 
 
 August 7 
 
 August 8 
 
 August 13 
 
 Sums 
 
 Means 
 
 
 
 
 
 
 
 
 
 
 
 63 
 
 60 
 
 446 
 45 
 
 550 
 55 
 
 672 
 67 
 
 601 
 60 
 
 681 
 
 68 
 
 179 
 45 
 
 218 
 54 
 
 581 
 58 
 
 August 14 
 
 August 17 
 
 August 19 
 
 August 21 
 
 August 29 
 
 Sums 
 
 Means 
 
 49 
 75 
 74 
 81 
 118 
 
 59 
 
 75 
 
 72 
 
 180 
 
 158 
 
 149 
 
 60 
 
 93 
 
 - 135 
 
 249 
 
 93 
 
 51 
 
 97 
 
 120 
 
 261 
 
 144 
 38 
 69 
 
 153 
 
 298 
 
 78 
 21 
 51 
 79 
 270 
 
 72 
 28 
 35 
 53 
 334 
 
 92 
 
 50 
 
 70 
 
 114 
 
 241 
 
 397 
 79 
 
 544 
 109 
 
 686 
 137 
 
 622 
 124 
 
 702 
 140 
 
 499 
 100 
 
 522 
 104 
 
 567 
 113 
 
 summahy. 
 
 Nnmber of days. 
 
 7 a.m. 
 
 9 a.m. 
 
 11 am. 
 
 I p. m. 
 
 3 p.m. 
 
 7 p.m. 
 
 11 p. m. 
 
 Means. 
 
 (10) 
 
 257 
 915 
 552 
 446 
 397 
 
 ""156' 
 550 
 544 
 
 427 
 1,147 
 747 
 672 
 686 
 
 372 
 839 
 596 
 601 
 622 
 
 297 
 962 
 596 
 681 
 702 
 
 354 
 876 
 761 
 179 
 499 
 
 416 
 451 
 1,099 
 218 
 522 
 
 365 
 
 1,034 
 
 730 
 
 581 
 567 
 
 (10) 
 
 (lO).'. 
 
 (10) 
 
 (5) 
 
 Sums 
 
 Means 
 
 2,567 
 57 
 
 1,250 
 69 
 
 3,679 
 
 82 
 
 3,020 
 
 67 
 
 3,238 
 
 72 
 
 2,669 
 86 
 
 2,706 
 90 
 
 3,277 
 73 
 
 Date. 
 
 9 a.m. 
 
 11 a. m. 
 
 1 p. m. 
 
 3 p.m. 
 
 5 p.m. 
 
 Means. 
 
 Bemarks. 
 
 1887. 
 
 December 13 
 
 December 14 
 
 1888. 
 
 January 12 .... 
 
 January 14 
 
 January 16 
 
 114 
 240 
 
 132 
 126 
 155 
 
 52 
 182 
 
 106 
 124 
 144 
 151 
 133 
 99 
 88 
 127 
 
 117 
 
 109 
 
 106 
 108 
 124 
 110 
 133 
 151 
 103 
 147 
 
 104 
 252 
 
 108 
 119 
 146 
 106 
 133 
 161 
 109 
 143 
 
 124 
 299 
 
 132 
 167 
 172 
 185 
 236 
 ^93 
 114 
 19i 
 
 102 
 216 
 
 117 
 129 
 148 
 138 
 161 
 142 
 95 
 145 
 
 Clear. 
 Do. 
 
 NW.fr., clear. 
 NW.lt., clear. 
 NW.fr., clear. 
 
 Do. 
 N W. br. , clear. 
 
 Do. 
 NW. high, clear. 
 NW. br. , clear. 
 
 N.fr., clear. 
 NW.br., clear. 
 
 Do. 
 W.br., clear. 
 SE.lt., clear. 
 NW.br., clear. 
 
 Do. 
 N. It, clear. 
 W. br., clear. 
 
 Do. 
 
 January 20 
 
 January 21 
 
 January 27 
 
 January 28 
 
 172 
 
 108 
 
 60 
 
 118 
 
 1,225 
 136 
 
 1,206 
 121 
 
 1,208 
 121 
 
 1,381 
 138 
 
 1,813 
 181 
 
 1,393 
 139 
 
 Means 
 
 February 1 
 
 February 2 
 
 February 6 .- 
 
 February 9 
 
 February 13 
 
 February 15 
 
 February 16 
 
 February 24 
 
 March 15 . - 
 
 398 
 188 
 172 
 170 
 743 
 
 86 
 197 
 213 
 
 83 
 102 
 
 392 
 176 
 233 
 128 
 405 
 108 
 170 
 175 
 135 
 107 
 
 254 
 260 
 250 
 122 
 338 
 108 
 121 
 270 
 189 
 108 
 
 208 
 159 
 210 
 112 
 692 
 119 
 192 
 184 
 148 
 118 
 
 257 
 268 
 205 
 142 
 957 
 108 
 367 
 835 
 154 
 115 
 
 303 
 210 
 214 
 135 
 627 
 106 
 209 
 335 
 142 
 110 
 
 March 17 . - 
 
 
 2,352 
 235 
 
 2,029 
 203 
 
 2,020 
 202 
 
 2,142 
 214 
 
 3,408 
 341 
 
 2,391 
 239 
 
 Means 
 
254 ' MEMOIRS OP THE NATIONAL ACADEMY OF SCIENCES. 
 
 Table 1.— Potential on clear and fair days, Boston, Mass., July, 1886, to August, 1888— Oontinued. 
 
 Date. 
 
 9 a. m. ■ 
 
 11 a. m. 
 
 1 p. m. 
 
 3 p. m. 
 
 5 p. m. 
 
 Means. 
 
 Beinarks. 
 
 1888. 
 April 13 
 
 44 
 307 
 122 
 
 46 
 298 
 219 
 
 43 
 148 
 
 88 
 
 39 
 
 20 
 179 
 
 156 
 47 
 
 325 
 96 
 73 
 
 138 
 48 
 80 
 
 23 
 167 
 379 
 
 34 
 127 
 535 
 
 37 
 267 
 106 
 115 
 
 33 
 494 
 433 
 
 41 
 
 468 
 284 
 
 58 
 162 
 163 
 
 57 
 
 65 
 709 
 204 
 
 69 
 746 
 129 
 
 82 
 419 
 
 64 
 
 62 
 
 35 
 371 
 259 
 
 47 
 393 
 253 
 
 59 
 227 
 
 94 
 
 71 
 
 NW.br., clear. 
 E.fr., clear. 
 SE.lt., fair. 
 NW.fr., clear. 
 E.fr., fair. 
 Var.fr., fair, 
 SW.br., clear. 
 E.br., clear. 
 SE.,fr., clear, 
 W.fr., clear. 
 
 NE.fp., clear. 
 E. fr. , clear. 
 few. br. , clear. 
 NW.br., clear. 
 SW.br., clear. 
 NW.fr., fair. 
 E. fr., clear, 
 SB.fr., clear. 
 W.fr., fair. 
 Var. fr., clear. 
 
 NW.fr., clear. 
 W.fr., clear. 
 NW.br., fair. 
 NW.fr., clear. 
 W.br., clear. 
 W.fr., clear. 
 W. br. , clear. 
 
 April 27 
 
 April 28 
 
 May 21 
 
 May 22 
 
 
 
 June 8 . . . 
 
 June 12 
 
 June 23 
 
 Sums . - . 
 
 1,354 
 135 
 
 1,162 
 116 
 
 1,790 
 179 
 
 2,183 
 218 
 
 2, .549 
 255 
 
 1,809 
 181 
 
 Means 
 
 July 2 . 
 
 1,400 
 
 2,100 
 
 352 
 
 81 
 
 261 
 
 665 
 
 1,440 
 
 1,140 
 
 208 
 
 895 
 
 1,160 
 
 2,360 
 
 317 
 
 60 
 
 106 
 
 211 
 
 1,300 
 
 510 
 
 425 
 
 745 
 
 1,000 
 
 1,970 
 
 493 
 
 165 
 
 35 
 
 400 
 
 1,410 
 
 615 
 
 348 
 
 650 
 
 1,110 
 -850 
 563 
 406 
 
 880 
 
 1,230 
 490 
 475 
 630 
 
 400 
 
 1,370 
 
 528 
 
 432 
 
 18 
 
 1, 160 
 
 •1,317 
 
 985 
 
 685 
 
 970 
 
 1,014 
 
 1,730 
 
 451 
 
 229 
 
 84 
 
 663 
 
 1,339 
 
 748 
 
 428 
 
 778 
 
 Julys 
 
 Jaly4 
 
 July 6 . - .. 
 
 July 11 
 
 July 14 
 
 July 16 
 
 July 17 
 
 July 24 
 
 July 25 
 
 
 8,542 
 854 
 
 7,194 
 719 
 
 7,086 
 709 
 
 6,684 
 663 
 
 7,865 
 786 
 
 7,464 
 746 
 
 Means 
 
 July 30 
 
 
 495 
 800 
 265 
 575 
 752 
 530 
 790 
 
 520 
 605 
 258 
 550 
 .585 
 370 
 650 
 
 420 
 510 
 420 
 445 
 725 
 435 
 660 
 
 440 
 515 
 955 
 600 
 640 
 270 
 725 
 
 469 
 670 
 430 
 570 
 680 
 452 
 737 
 
 August 10* 
 
 Auffust 14 
 
 920 
 250 
 680 
 700 
 655 
 860 
 
 August 23 .----. 
 
 
 August 25 
 
 August 30 
 
 
 4,065 
 678 
 
 4,207 
 601 
 
 3,538 
 505 
 
 3,615 
 516 
 
 4,145 
 592 
 
 4,008 
 573 
 
 Means 
 
 SUMMARY, 
 
 No. of days. 
 
 (10) 
 
 (10) 
 
 (10) 
 
 (10) 
 
 (7) 
 
 Sums. 
 Means 
 
 9 a.ln. 
 
 11 a.m. 
 
 1 p. m. 
 
 3 p.m. 
 
 5 p.m. 
 
 Means. 
 
 1,225 
 2,352 
 1,354 
 
 8, 542 
 4,065 
 
 1,206 
 2,029 
 1,162 
 7,194 
 4,207 
 
 1,208 
 2,020 
 1,790 
 7,086 
 3,538 
 
 1,'381 
 2,142 
 2, 183 
 6, 634 
 3,615 
 
 1,813 
 3,408 
 2,549 
 7,865 
 4,145 
 
 1,393 
 2,391 
 1,809 
 7,464 
 4,008 
 
 17, 538 
 390 
 
 15,798 
 336 
 
 15, 642 
 333 
 
 15, 955 
 340 
 
 19,780 
 421 
 
 17,065 
 364 
 
MEMOIRS OP THE NATIONAL ACADEMY OF SCIENCES. 
 
 255 
 
 Table J. — Potential on clear and fair days, St. Louis, Mo., 1861. 
 [A. Wislizenus, M. c, observer.] 
 
 Date. 
 
 1861. 
 .Tanuary 1... 
 January VI. 
 January 18. 
 January 24. 
 January 25. 
 January 27.. 
 February 4. 
 February 5. 
 February 6. 
 February 8. 
 
 Sams .. 
 Means . 
 
 February 20 
 February 26 
 
 March 5 
 
 March 10 
 
 March II 
 
 .March 18... 
 
 March 21 
 
 April 16 
 
 April 19 
 
 April 24 
 
 Sams .. 
 Means .. 
 
 April 28.... 
 
 April 30 
 
 May I 
 
 Maya 
 
 May 8 
 
 May 14 
 
 May 15 
 
 May 16 
 
 May 17 
 
 May 18 , 
 
 Sums .. 
 Means . 
 
 May 22 , 
 
 May 25 
 
 May 27 
 
 Jane 5 
 
 June9 
 
 June 10 
 
 Jane 12 
 
 June 13 . 
 
 June 14 . ; . . . 
 June 16 
 
 Sums ... 
 Means .. 
 
 June 20 
 
 June 21 
 
 Julyl 
 
 July 2 
 
 Julys 
 
 July 4 
 
 July 6 
 
 July 10 
 
 July 11 
 
 July 13...... 
 
 Sums ... 
 Means .. 
 
 6 a.m. 
 
 9 a. ra. 
 
 12 m. 
 
 3 p.m. 
 
 6 p.m. 
 
 9 p.m. 
 
 Meiina. 
 
 38 
 
 57 
 
 76 
 
 31 
 
 24 
 
 40 
 
 44 
 
 52 
 
 07 
 
 57 
 
 42 
 
 55 
 
 42 
 
 52 
 
 24 
 
 38 
 
 34 
 
 24 
 
 29 
 
 17 
 
 28 
 
 31 
 
 40 
 
 24 
 
 38 
 
 52 
 
 42 
 
 38 
 
 116 
 
 76 
 
 57 
 
 38 
 
 42 
 
 34 
 
 60 
 
 15 
 
 31 
 
 42 
 
 36 
 
 57 
 
 45 
 
 38 
 
 45 
 
 45 
 
 64 
 
 34 
 
 45 
 
 36 
 
 45 
 
 55 
 
 47 
 
 45 
 
 42 
 
 52 
 
 50 
 
 48 
 
 31 
 
 45 
 
 24 
 
 29 
 
 17 
 
 15 
 
 27 
 
 4 
 
 17 
 
 15 
 
 34 
 
 29 
 
 n 
 
 18 
 
 411 
 
 463 
 
 438 
 
 348 
 
 402 
 
 332 
 
 398 
 
 41 
 
 46 
 
 44 
 
 35 
 
 40 
 
 33 
 
 40 
 
 47 
 
 40 
 
 45 
 
 11 
 
 38 
 
 38 
 
 36 
 
 17 
 
 29 
 
 45 
 
 17 
 
 22 
 
 . 13 
 
 24 
 
 45 
 
 34 
 
 15 
 
 17 
 
 24 
 
 24 
 
 26 
 
 15 
 
 34 
 
 38 
 
 34 
 
 42 
 
 27 
 
 32 
 
 19 
 
 27 
 
 11 
 
 13 
 
 15 
 
 4 
 
 15 
 
 15 
 
 17 
 
 15 
 
 8 
 
 34 
 
 29 
 
 20 
 
 57 
 
 72 
 
 29 
 
 27 
 
 27 
 
 29 
 
 40 
 
 45 
 
 •27 
 
 27 
 
 29 
 
 29 
 
 34 
 
 32 
 
 24 
 
 36 
 
 13 
 
 13 
 
 19 
 
 22 
 
 21 
 
 15 
 
 . 6 
 
 4 
 
 15 
 
 24 
 
 90 
 
 26 
 
 299 
 
 322 
 
 242 
 
 184 
 
 274 
 
 310 
 
 272 
 
 30 
 
 32 
 
 24 
 
 18 
 
 27 
 
 31 
 
 27 
 
 22 
 
 45 
 
 40 
 
 38 
 
 22 
 
 24 
 
 32 
 
 17 
 
 19 
 
 17 
 
 13 
 
 11 
 
 15 
 
 15 
 
 40 
 
 29 
 
 34 
 
 22 
 
 29 
 
 24 
 
 30 
 
 22 
 
 34 
 
 24 
 
 17 
 
 15 
 
 17 
 
 22 
 
 31 
 
 17 
 
 15 
 
 4 
 
 4 
 
 13 
 
 14 
 
 36 
 
 40 
 
 29 
 
 22 
 
 24 
 
 38 
 
 32 
 
 52 
 
 45 
 
 27 
 
 17 
 
 22 
 
 24 
 
 31 
 
 57 
 
 52 
 
 31 
 
 27 
 
 15 
 
 31 
 
 36 
 
 , 34 
 
 47 
 
 42 
 
 31 
 
 27 
 
 15 
 
 33 
 
 8 
 
 38 
 
 45 
 
 22 
 
 19 
 
 13 
 
 24 
 
 319 
 
 366 
 
 304 
 
 213 
 
 188 
 
 214 
 
 269 
 
 32 
 
 37 
 
 30 
 
 21 
 
 19 
 
 21 
 
 27 
 
 27 
 
 29 
 
 34 
 
 19 
 
 15 
 
 11 
 
 22 
 
 15 
 
 4 
 
 4 
 
 11 
 
 17 
 
 4 
 
 9 
 
 15 
 
 8 
 
 8 
 
 6 
 
 8 
 
 13 
 
 10 
 
 31 
 
 29 
 
 34 
 
 17 
 
 19 
 
 13 
 
 24 
 
 2 
 
 4 
 
 8 
 
 13 
 
 11 
 
 2 
 
 7 
 
 4 
 
 13 
 
 8 
 
 19 
 
 15 
 
 17 
 
 13 
 
 27 
 
 22 
 
 13 
 
 11 
 
 19 
 
 17 
 
 18 
 
 13 
 
 15 
 
 17 
 
 15 
 
 15 
 
 13 
 
 15 
 
 11 
 
 13 
 
 8 
 
 6 
 
 4 
 
 2 
 
 7 
 
 11 
 
 2 
 
 2 
 
 4 
 
 6 
 
 8 
 
 6 
 
 156 
 
 139 
 
 136 
 
 121 
 
 129 
 
 100 
 
 129 
 
 16 
 
 14 
 
 14 
 
 12 
 
 13 
 
 10 
 
 13 
 
 19 
 
 4 
 
 2 
 
 2 
 
 4 
 
 2 
 
 6 
 
 4 
 
 2 
 
 4 
 
 4 
 
 6 
 
 2 
 
 4 
 
 2 
 
 8 
 
 4 
 
 15 
 
 13 
 
 13 
 
 9 
 
 13 
 
 22 
 
 13 
 
 11 
 
 27 
 
 24 
 
 18 
 
 31 
 
 13 
 
 15 
 
 11 
 
 8 
 
 8 
 
 14 
 
 17 
 
 11 
 
 11 
 
 11 
 
 13 
 
 4 
 
 11 
 
 2 
 
 2 
 
 • 2 
 
 2 
 
 8 
 
 4 
 
 3 
 
 17 
 
 15 
 
 15 
 
 22 
 
 24 
 
 19 
 
 19 
 
 11 
 
 15 
 
 17 
 
 13 
 
 22 
 
 13 
 
 •15 
 
 15 
 
 11 
 
 11 
 
 11 
 
 "11 
 
 13 
 
 12 
 
 131 
 
 103 
 
 94 
 
 102 
 
 136 
 
 102 
 
 111 
 
 13 
 
 10 
 
 9 
 
 10 
 
 14 
 
 10 
 
 11 
 
 Kemarks. 
 
 SE.lt., clear. 
 SE.fr., fair. 
 SW. br., clear. 
 
 Do. 
 SE.fr., fair. 
 W. fr. , clear. 
 NW. It, fair. 
 W. fr. , clear. 
 SW.fr., clear. 
 SE.fr., clear. 
 
 NW.br., fair. 
 SE. It., clear. 
 W. fr. , fair. 
 
 Do. 
 SE.fr., fair. 
 
 Do. 
 SE.lt., fair. 
 N. br.jfair. 
 NW.fr., clear. 
 W. It., clear. 
 
 S. It. , clear. 
 SW.lt., clear. 
 NE.fr., clear. 
 SE.fr., fair. 
 W. It., fair. 
 SW.lt., clear. 
 W. br.,fair. 
 N. It. , clear. 
 E. It., fair. 
 SE.lt., fair. 
 
 SE.lt., clear. 
 SW.fr., fair. 
 W. br.,fair. 
 SE.fr., fair. 
 E.fr.,fair. 
 SE.fr., clear. 
 NW. fr. , clear. 
 SE.lt., fair. 
 S. It. , clear. 
 N. br,,fair. 
 
 SW.br., fair. 
 SW.fr., clear. 
 N. br. , fair. 
 NE. fr., clear. 
 SE. Itclear. 
 
 Do. 
 S. It., fair. 
 NW.br., fair. 
 W. fr.jfair. 
 SE.lt., fair. 
 
256 MEMOIRS OF THE IfATIONAL AOADEMr OF SCIENCES. 
 
 Table J. — Potential on clear and fair days, St. Louis, Mo., 1861 — Continued. 
 
 I>at». 
 
 1861. 
 
 July 16 
 
 July 17 
 
 July23 
 
 July 24 
 
 July25 
 
 July 29 
 
 JnlvSO 
 
 July 31 
 
 August 1 . . . 
 August 2 . . . 
 
 Sums . 
 Means 
 
 August 3 . . 
 August 7 . . 
 August 14 . 
 August 15 . 
 August 16 - 
 August 17 . 
 August 23 . 
 August 27 . 
 August 29 . 
 Aiigust 30 . 
 
 Sums . 
 Means. 
 
 August 31 
 
 September 1 .. 
 September 5 . . 
 September 6 . . 
 September 7 .. 
 September 8.. 
 September 9.. 
 September 18. 
 September 19. 
 September 22. 
 
 Sums . 
 Means 
 
 September 23. 
 September 28. 
 
 October 6 
 
 October 7 
 
 October 8 
 
 October 11 ... 
 October 12 ... 
 October 13 ... 
 
 October 14 
 
 October 20 ... 
 
 Sums . 
 Means . 
 
 October 21 ... 
 October 23 . . . 
 October 27 ... 
 October 28 ... 
 November 15 , 
 November 20 . 
 November 27 . 
 December 4 . . 
 December 8 . . 
 December 9 . . 
 
 Sums . 
 Means 
 
 4 
 24 
 22 
 8 
 2 
 2 
 6 
 4 
 4 
 2 
 
 78 
 
 2 
 4 
 4 
 
 27 
 2 
 
 13 
 6 
 6 
 4 
 6 
 
 74 
 
 7 
 
 2 
 ■2 
 4 
 8 
 4 
 6 
 4 
 2 
 2 
 2 
 
 36 
 4 
 
 12 m. 
 
 42 
 4 
 
 11 
 4 
 11 
 34 
 13 
 17 
 
 114 
 
 11 
 
 11 
 
 22 
 2 
 13 
 27 
 15 
 13 
 22 
 31 
 17 
 
 173 
 17 
 
 24 
 
 U 
 
 22 
 
 31 
 
 50 
 
 8 
 
 31 
 
 38 
 
 2 
 
 2 
 
 219 
 22 
 
 56 
 
 13 
 34 
 15 
 11 
 27 
 34 
 90 
 36 
 31 
 27 
 
 318 
 32 
 
 29 
 
 31 
 
 52 
 
 34 
 
 55 
 
 17 
 
 34 
 
 116 
 
 4 
 
 2 
 
 3 p.m. 
 
 6 p. m. 
 
 83 
 
 13 
 2 
 19 
 17 
 19 
 11 
 15 
 8 
 11 
 11 
 
 126 
 13 
 
 11 
 4 
 4 
 4 
 2 
 2 
 4 
 13 
 19 
 
 71 
 
 7 
 
 11 
 4 
 13 
 11 
 24 
 15 
 23 
 15 
 8 
 15 
 
 9 p. m. Means. 
 
 11 
 
 6 
 6 
 
 2 
 
 2 
 
 2 
 
 17 
 
 19 
 
 81 
 
 17 
 2 
 2 
 
 15 
 8 
 
 11 
 
 11 
 2 
 2 
 
 11 
 
 81 
 
 15 
 15 
 24 
 11 
 17 
 22 
 17 
 15 
 13 
 17 
 
 166 
 17 
 
 34 
 45 
 42 
 29 
 27 
 15 
 34 
 50 
 2 
 2 
 
 374 
 
 37 
 
 280 
 28 
 
 138 
 14 
 
 69 
 
 7 
 
 27 
 15 
 13 
 22 
 15 
 27 
 
 8 
 13 
 19 
 
 6 
 
 165 
 16 
 
 15 
 15 
 50 
 27 
 19 
 13 
 35 
 38 
 
 216 
 22 
 
 13 
 11 
 
 17 
 17 
 22 
 19' 
 17 
 11 
 8 
 
 13 
 
 4 
 11 
 4 
 8 
 2 
 4 
 2 
 2 
 13 
 
 63 
 
 143 
 
 14 
 
 17 
 17 
 2 
 
 2 
 11 
 
 4 
 11 
 
 82 
 
 40 
 31 
 19 
 34 
 11 
 29 
 38 
 15 
 22 
 27 
 
 266 
 
 27 
 
 36 
 13 
 15 
 22 
 34 
 36 
 100 
 47 
 2 
 
 313 
 31 
 
 as 
 
 8' 
 
 32 
 3 
 
 11 
 11 
 
 8 
 15 
 
 8 
 
 6 
 15 
 
 •2 
 11 
 22 
 
 109 
 11 
 
 13 
 
 27 
 13 
 24 
 22 
 31 
 38 
 19 
 2 
 
 191 
 19 
 
 10 
 9 
 6 
 6 
 3 
 4 
 4 
 ■8 
 12 
 
 70 
 
 T 
 
 Eemarks. 
 
 11 
 
 5 
 
 11 
 
 20 
 
 16 
 
 13 
 
 14 
 
 8 
 
 7 
 
 9 
 
 114 
 
 11 
 
 9 
 3 
 5 
 10 
 9 
 5 
 5 
 4 
 3 
 6 
 
 59 
 6 
 
 20 
 21 
 14 
 18 
 18 
 22 
 So 
 17 
 21 
 19 
 
 200 
 20 
 
 25 
 24 
 32 
 28 
 34 
 20 
 45 
 51 
 2 
 3 
 
 264 
 26 
 
 NW.fr., fair. 
 SE.lt., fair. 
 If . fr. , clear. 
 SE.lt., clear. 
 S. It,, fair. 
 SW.fr., fair. 
 S. It., clear. 
 SW.lt., clear. 
 NE.lt., fair. 
 N.fr., clear. 
 
 NE.lt., fair. 
 SE. It., clear. 
 NE.lt., fair. 
 
 Do. 
 NE.lt., clear. 
 NE.fr., clear. 
 
 Do. 
 SE.lt., fair. 
 NW.fr., clear. 
 NE.lt., clear. 
 
 SE.lt., clear. 
 SE. f r. , clear. 
 S. It., fair. 
 NW.fr., fair. 
 N.fr., fair. 
 N. fr. , clear. 
 E. f r. , clear. 
 SE.fr., fair. 
 S.fr., clear. 
 SW.lt., clear. 
 
 NE.lt., clear. 
 W. fr.fair. 
 NW.fr., fair. 
 S.fr., fair. 
 SE.fr., clear. 
 SW.fr., clear. 
 W. fr. , clear. 
 S. It. , clear. 
 SW.lt., fair. 
 NE.fr., clear. 
 
 E. It., clear. 
 W.fr., clear. 
 E. It., clear. 
 SE. fr., clear. 
 NW.fr., clear, 
 SW.fr., clear. 
 W. fr. , fair. 
 SE, fr. , clear. 
 S.fr,, fair. 
 Do. 
 
MEMOIRS OP THE NATIONAL ACADEMY OF SCIENCES, 
 Table J. — Potential on clear and fair days, St. Louis, Mo.. 1861 — Continued. 
 
 257 
 
 Date. 
 
 6 a. m. 
 
 9 a. m. 
 
 13 m. 
 
 3 p. m. 
 
 6 p.m. 
 
 76 
 45 
 40 
 29 
 34 
 34 
 85 
 52 
 55 
 22 
 
 9 p. m. 
 
 Means. 
 
 Kemarks. 
 
 1861. 
 
 December 11 
 
 December 12 
 
 December 13 
 
 December 18 
 
 December 19 
 
 December 24 
 
 December 27 
 
 December 28 
 
 December 29 
 
 December 31 
 
 Sums 
 
 76 
 17 
 50 
 34 
 23 
 15 
 19 
 42 
 19 
 45 
 
 34 
 64 
 85 
 . 42 
 36 
 55 
 76 
 50 
 57 
 64 
 
 40 
 50 
 76 
 34 
 22 
 45 
 ' 47 
 55 
 64 
 52 
 
 31 
 
 47 
 116 
 29 
 29 
 17 
 57 
 42 
 42 
 27 
 
 30 
 45 
 34 
 27 
 17 
 15 
 22 
 31 
 34 
 24 
 
 58 
 
 45 
 
 67 
 
 32 
 
 27 
 
 30 
 
 51 
 
 45- 
 
 45 
 
 39 
 
 N.fr., clear. 
 SE.lt., clear. 
 SE.lt., fair. 
 SW. It., clear. 
 SW.fr., fair. 
 SE.fr., clear. 
 E. It. , clear. 
 SE.fr., fair. 
 NW.lt., clear. 
 S. ft., fair. 
 
 339 
 34 
 
 563 
 56 
 
 485 
 48 
 
 437 
 44 
 
 472 
 
 47 
 
 3J9 
 34 
 
 439 
 44 
 
 Means 
 
 MEANS. 
 
 
 6 a. m. 
 
 ga. m. 
 
 12 m. 
 
 3 p.m. 
 
 6 p. m. 
 
 9 p.m. 
 
 Means. 
 
 Sums for 10 days .. 
 Do 
 
 411 
 
 299 
 
 319 
 
 156 
 
 131 
 
 78 
 
 74 
 
 36 
 
 173 
 
 219 
 
 339 
 
 463 
 322 
 366 
 139 
 103 
 
 42 
 114 
 
 56 
 318 
 374 
 563 
 
 438 
 
 242 
 
 304 
 
 136 
 
 94 
 
 83 
 
 126 
 
 81 
 
 . 166 
 
 280 
 
 485 
 
 .348 
 184 
 213 
 121 
 102 
 
 71 
 138 
 
 69 
 165 
 216 
 437 
 
 405 
 274 
 18S 
 129 
 136 
 
 81 
 143 
 
 82 
 266 
 313 
 473 
 
 332 
 
 310 
 
 214 
 
 100 
 
 102 
 
 63 
 
 82 
 
 32 
 
 109 
 
 191 
 
 339 
 
 398 
 272 
 269 
 129 
 111 
 
 70 
 114 
 
 59 
 200 
 264 
 439 
 
 Do 
 
 Do 
 
 Do 
 
 Do 
 
 Do 
 
 Do 
 
 Do 
 
 Do 
 
 Do 
 
 Total sums 
 
 Mean for 1 day. 
 
 2,235 
 
 2,860 
 
 2,435 
 
 2,064 
 
 2,486 
 
 1,874 
 
 2,325 
 
 20 
 
 26 
 
 22 
 
 19 
 
 23 
 
 17 
 
 -'21 
 
 S. Mis. 94 17 
 
258 MEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES. 
 
 Table K. — Potential on clear and fair days, New Raven, Conn., August 1, 1886, to July 31, 1887. 
 
 Date. 
 
 Sa. m. 
 
 11 a. m. 
 
 Ip. m. 
 
 3 p.m. 
 
 Means. 
 
 Bemarks. 
 
 1886. 
 
 11.5 
 
 41.8 
 33.7 
 16.3 
 31.8 
 18.6 
 10.8 
 16.4 
 38.6 
 13.4 
 
 19.6 
 
 ■20.0 
 10.4 
 17.4 
 9.6 
 10.4 
 24.7 
 14.3 
 17.8 
 14.6 
 
 30.9 
 
 38.5 
 10.6 
 13.5 
 9.9 
 32.4 
 33.9 
 17.5 
 14.0 
 17.0 
 
 54.3 
 
 39.3 
 7.0 
 
 ""'9.'7' 
 11. H 
 15. 7 
 15.4 
 
 "'ii'.k.' 
 
 26.6 
 
 32.4 
 15.4 
 15.4 
 15.2 
 15.8 
 31.3 
 15.9 
 3.3.5 
 15.6 
 
 SW. lt.,t^ clouds in 
 
 p. m. 
 SW.lt., clear. 
 NE.lt., clear. 
 Var. It., clear. 
 S.lt., clear. 
 S.lt. 
 W.lt. 
 
 w. 
 
 N.lt. 
 SW.lt. 
 
 NW. It. 
 SW.lt. 
 NW.lt. 
 
 Do. 
 W.lt. 
 
 Do. 
 SW. It, 
 W. fresh.' 
 NW.br. 
 
 NW. 
 
 NE. 
 
 W. 
 
 NW. , , 
 
 NW., A clouds. 
 
 S., -ft; clouds in p. m, 
 
 W. clear. 
 
 NW. clear, tV at 3p. m. 
 
 NW. clear. 
 
 W. clear. 
 
 NW. clear. 
 
 S. clear. 
 N. clear. 
 
 Do. 
 NE. clear, iVatll a.m. 
 S. clear. 
 
 Do. 
 W. clear. 
 SW. clear. 
 
 i 
 
 
 
 Octobers 
 
 
 October 11. . . . 
 
 October 12. .. 
 
 October 23 
 
 October 33 
 
 November 9 
 
 232.8 
 23.3 
 
 158.7 
 19.9 
 
 197.3 
 19.7 
 
 160.3 
 20.0 
 
 197.1 
 19.7 
 
 Means 
 
 November 22 
 
 November 27 
 
 December8 .... 
 
 December9 .|.. 
 
 December 10 
 
 December 11 
 
 December 17 
 
 December 21 
 
 December 25 
 
 1887. 
 .Tannarv 3 .... 
 
 19.2 
 6.5.9 
 38.1 
 56.0 
 67.0 
 ^37.5 
 61.0 
 30.9 
 11.0 
 
 36.0 
 
 18.7 
 57.9 
 33.0 
 46.0 
 52.5 
 
 "i02.'6' 
 59.4 
 14.7 
 
 32.6 
 
 19.3 
 
 18.4 
 44.8 
 28.3 
 65.4 
 40.6 
 34.0 
 49.8 
 11.8 
 
 31.5 
 
 15.4 
 11.8 
 58.0 
 38.2 
 53.4 
 40.4 
 50.6 
 47.5 
 13.1 
 
 34.4 
 
 18.3 
 38.5 
 43.5 
 43.1 
 59.6 
 39.5 
 61.9 
 46.9 
 12.6 
 
 33.6 
 
 Sums. .... .... 
 
 422.6 
 42.3 
 
 416.8 
 - 46.3 
 
 343.9 
 34.4 
 
 362.8 
 36.3 
 
 396.4 
 39.6 
 
 Means 
 
 55.7 
 28.0 
 26.3 
 16.9 
 22.5 
 10.7 
 13.1 
 82.3 
 19.1 
 10.4 
 
 76.9 
 32.2 
 28.5 
 16.8 
 28.5 
 13.0 
 16.6 
 16.0 
 26.0 
 1.4 
 
 59.7 
 28.5 
 26.9 
 14.2 
 24.5 
 20.9 
 12.7 
 13.3 
 36.6 
 6.1 
 
 40.6 
 10.2 
 28.1 
 17.0 
 18.6 
 15.3 
 16.6 
 11.9 
 28.3 
 7.8 
 
 58.2 
 24.8 
 27.4 
 16.3 
 23.5 
 15.0 
 14.5 
 15.6 
 25.0 
 6.4 
 
 January 11 
 
 January 37 
 
 February 9 
 
 February 14 
 
 February 19 
 
 February 25 
 
 March 8 , 
 
 March 26 
 
 April 6 .......... 
 
 
 323.9 
 22.4 
 
 255.9 
 25.6 
 
 233.4 
 23.2 
 
 194.3 
 19.4 
 
 226.6 
 22.7 
 
 Means 
 
 April 8 
 
 28.1 
 7.1 
 18.4 
 16.0 
 25.0 
 24.6 
 27.0 
 27.5 
 
 21.8 
 13.7 
 1.6 
 15.4 
 30.1 
 55.5 
 26.8 
 33.0 
 
 19.5 
 
 5.9 
 
 —12.8 
 
 11.5 
 
 36.5 
 
 10.5 
 
 6.5 
 
 39.5 
 
 21.0 
 16.4 
 
 2.7 
 41.5 
 18.5 
 24.0 
 
 9.1 
 14.0 
 
 22.6 
 10.8 
 2.5 
 81.1 
 25.0 
 28.6 
 17.4 
 28.2 
 
 Mayl3 
 
 May 19 
 
 .Tune 11 ........ 
 
 
 June 29 
 
 June30 
 
 July 2 
 
 
 173.7 
 21.7 
 
 186.9 
 23.4 
 
 117.1 
 14.6 
 
 147.3 
 
 18.4 
 
 156.2 
 19.5 
 
 Means 
 
 SUMMARY. 
 CAptaal readings.) 
 
 Kumber of daya. 
 
 (10) 
 
 (10) 
 
 (10) 
 
 (8) 
 
 Sums (38) ... 
 Means 
 
 232. 8 
 423.6 
 223.9 
 173.7 
 
 1,053,0 
 27.7 
 
 11 a. m. 
 
 158.7 
 416.8 
 255.9 
 186.9 
 
 1,018.3 
 27.5 
 
 Ip. m. 
 
 197.2 
 343.9 
 232.4 
 117.1 
 
 890.6 
 33.4 
 
 3 p.m. 
 
 160.3 
 362.8 
 194.3 
 147.2 
 
 864.6 
 24.0 
 
 Means. 
 
 197.1 
 396.4 
 226.6 
 156.2 
 
 976.3 
 25.7 
 
MEMOIRS OP THE NATIONAL ACADEMY OF 80IEN0ES. 
 
 259 
 
 Table K.~Potential on clear and fair days, New Eaven, Conn., August 1, 1886, to July 31, 1887- 
 
 Oontinned. 
 
 Date. 
 
 1886. 
 
 August 9 
 
 October 4 
 
 Octobers 
 
 Octobers 
 
 October 9 
 
 October 11. . 
 October 12.. 
 October 2a.. 
 October 23-. 
 November 9 
 
 Sums.. 
 Means.. 
 
 November 22 , 
 Nov.ember 27 . 
 Decembers.- . 
 December 9-.. 
 December 10- . 
 December 11. 
 December 17., 
 December 21 . . 
 December 25. . 
 
 1887. 
 January 3 . . 
 
 Sums.. 
 Means . 
 
 January 4 - . . 
 January 11 .. 
 January 27 . . 
 February 9.. 
 February 14 . 
 February 19. 
 February 25 - 
 
 March 8 
 
 March 26 
 
 April 6 
 
 Sums.. 
 Means. 
 
 Aprils .. 
 May 13-. 
 May 19.. 
 June 11 , 
 June 15 . 
 June 29 . 
 June 30 . 
 July 2... 
 
 Sums.. 
 Means . 
 
 .43 
 
 1.26 
 2.19 
 1.05 
 2.09 
 1.18 
 
 .51 
 1.03 
 1.64 
 
 .';6 
 
 12,24 
 1.22 
 
 1.05 
 
 1.71 
 
 .88 
 
 1.33 
 
 1.14 
 
 .95 
 
 .98 
 
 .66 
 
 .87 
 
 1.08 
 
 10.65 
 1.06 
 
 .96 
 1.12 
 
 .96 
 
 1.04 
 
 .96 
 
 .71 
 
 .83 
 
 1.43 
 
 .76 
 
 1.62 
 
 10.39 
 1.04 
 
 1.24 
 
 .66 
 7.40 
 
 .76 
 1.00 
 
 .86 
 1.55 
 
 .98 
 
 14.45 
 1.81 
 
 .74 
 .62 
 .68 
 
 1.13 
 .63 
 .66 
 
 1.16 
 .89 
 .76 
 .94 
 
 8.21 
 
 .8a 
 
 1.02 
 1..50 
 
 .76 
 1.09 
 
 1.64 
 1.26 
 1.16 
 
 .97 
 
 10.28 
 1.14 
 
 1.32 
 1.26 
 1.04 
 1.04 
 1,21 
 
 ;87 
 1.14 
 1.03 
 1.04 
 
 .22 
 
 Ip. m. 
 
 .79 
 
 1.18 
 
 .68 
 
 .81 
 
 .65 
 
 1.42 
 
 1. .')9 
 
 1.10 
 
 .60 
 
 1.09 
 
 9.91 
 .99 
 
 1.06 
 
 .48 
 1.03 
 
 .67 
 ].09 
 1.03 
 
 .55 
 1.06 
 
 .94 
 
 .94 
 
 3 p.m. 
 
 8.85 
 
 10.17 
 1.02 
 
 .96 
 
 1.26 
 
 .64 
 
 .73 
 
 .80 
 
 1.94 
 
 1.54 
 
 1.13 
 
 9.00 
 1.12 
 
 1.03 
 1.15 
 
 .98 
 
 .88 
 
 1.04 
 
 1.39 
 
 .88 
 
 .79 
 
 1.06 
 
 .95 
 
 10.15 
 1.02 
 
 .86 
 
 .55 
 
 -5.10 
 
 .54 
 
 1.46 
 .37 
 .37 
 
 1.40 
 
 .45 
 .06 
 
 SUMMARY. 
 [Relative potential.] 
 
 2.04 
 .91 
 .45 
 
 .64 
 .75 
 .74 
 .97 
 
 1.10 
 
 7.60 
 .95 
 
 .85 
 .31 
 
 1.33 
 .91 
 .90 
 
 1.02 
 .82 
 
 1.00 
 
 1.04 
 
 1.03 
 
 9.21 
 .92 
 
 .70 
 
 .41 
 1.02 
 1.05 
 
 .79 
 1.01 
 1.14 
 
 .76 
 1.13 
 1.22 
 
 9.23 
 .92 
 
 .93 
 
 1.52 
 
 1.08 
 
 1.96 
 
 .74 
 
 .84 
 
 .52 
 
 .50 
 
 .09 
 .01 
 
 Meaua. 
 
 1.00 
 1.00 
 1.00 
 1.00 
 1.00 
 1.00 
 1.00 
 1.00 
 1.00 
 1.00 
 
 10.00 
 1.00 
 
 1.00 
 1.00 
 1.00 
 1.00 
 1.00 
 1.00 
 1.00 
 1.00 
 1.00 
 
 1.00 
 
 10.00 
 1.00 
 
 1.00 
 1.00 
 1.00 
 1.00 
 1.00 
 1.00 
 1.00 
 1.00 
 l.-f'O 
 1.00 
 
 10.00 
 1.00 
 
 1.00 
 1.00 
 1.00 
 1.00 
 1.00 
 1.00 
 1.00 
 1.00 
 
 8.00 
 1.00 
 
 No. of days. 
 
 Ha.m. 
 
 1 p.m. 
 
 3 p.m. 
 
 Means. 
 
 (10) 
 
 (10) 
 
 (10) 
 
 (8) 
 
 Sums (38) 
 Means 
 
 12.24 
 10.65 
 10.39 
 14.45 
 
 8.21 
 10.28 
 10.17 
 
 9.00 
 
 9.91 
 
 8.85 
 
 10.15 
 
 .45 
 
 47.73 
 1.26 
 
 37.66 
 1.02 
 
 29.36 
 
 .77 
 
 7.60 
 9.21 
 9.23 
 8.09 
 
 34.13 
 .95 
 
 10-00 
 10.00 
 10.00 
 
 8.00 
 
 38.00 
 1.00 
 
260 
 
 MEMOIRS OF THE KATIO-NAL ACADEMY OP SCIENCES. 
 
 Table L. — Potential on days on which precipitation occurred at the place of observation, Terre Haute, 
 
 Ind., March 30, 1887, to August 35, 1888. 
 
 [Extract from daily journal.] 
 
 Date. 
 
 Kemarks. 
 
 1887. 
 Apr. 1 
 
 Apr. 6 
 Apr. 16 
 Apr. 18 
 
 Apr. 20 
 Apr. 21 
 
 Apr. 22 
 
 Apr. 28 
 
 May 1 
 
 May 2 
 
 May .5 
 
 May 6 
 
 May 11 
 
 May 
 
 17x 
 
 May 
 
 21 
 
 May 
 
 24 
 
 May 
 
 30 
 
 May 
 
 31 
 
 June 
 
 5 
 
 June 
 
 9 
 
 June 
 
 20 
 
 June 
 
 22 
 
 lit, rain and sleet *b, 6 a. m. ; first observation at 8:50 a. m. ; negative potential, 8:50 to 9:15 
 a. m. ; rain te. 9:30 a. m. Threatening weather with negative again at 11:55 a. m. ; It. rain 
 11:56 a. m. to 12 m. ; negative during rain ; variable positive and negative from 12 m. to 
 2:30 p. m., with weather clearing and threatening by turns 
 
 Threatening, with variable positive and negative, from 1 to 5 p. m. ; rained during the night. 
 
 Threatening weather, with a few flakes of dry snow, 11 to 11:02 a. m. ; positive all day. 
 
 Lt. rain and sleet tb. d. u., changed to snow 9:55 a. m. ; hy. snow untU 1 p. m. ; It. snow e. 4 
 p. m. First observation 9 a, m, ; negative until 11:30 a. m. ; variable ^: until 1 p. m. ; pos- 
 itive rest of the day. 
 
 Lt, rain b. 7 a. m., e. 10:44 a. m., 0.03 inch ; variable positive and negative from 9 to 10:15 a. m. 
 Trace of rain from 7 to 7:15 p.m.; negative at 7:10 p. m. ; no other observations after 
 5:45 p. m. 
 
 Threatening at 4 p. m. f negative from 4:30 to 4:50 p. m. ; It. rain b. 5:15 p. m. ; It. and hy. 
 rains all evening ; variable positive and negative from 5:20 to 6:20 p. m. No observations 
 after 6:20 p. m. The potential was very high during the rain, and sparks frequently 
 passed from the needle to the quadrants. 
 
 Eain b. d. n. ; thunderstorm and lightning b. 9:36 a. m. ; e. 11 a. m. Fresh SE. winds before 
 the storm changed to W. and NW. gale during, and then to light variable. After the 
 storm the wind was fresh easterly. Rain e. 11:34 a. m.. High variable positive and nega- 
 tive from 9 a^m. to 12 m. At times during the storm the sky was so dark and threaten- 
 ing that lights had to be used to read the scale, and almost continuous sparks passed 
 between the needle and quadrants. Cloudy from 12 m. to 5:30 p. m. ; then began to 
 threaten : variable positive and negative from 5:40 to 6:25 p. m. ; a few drops of rain at 
 6:37 p.m.; high positive until 7:05 p. m. ; positive and negative 7:05 to 7:09p. m. No ob- 
 servations after 7:15 p. m* Thunderstorm south of the station at 7:06 p. m. with hy. rain ; 
 It. rain began at the station 7:20, e. 8 p. m., 0.01 inch. 
 
 A few drops of rain at 2:55 p. m. ; no observations between 1 and 3 p. m. ; positive at all ob- 
 servations ; lower at 3 p. m. than at any other time observed. , 
 
 Thunderstorm and lightning b. 10:40, e. 11:05 a. m. ; rain and hail b. 11, e. 11:08 a. m. , 0.02 inch. 
 No observations until 11:10 a. m. ; variable positive and negative 11:10 to 11:20 a. m., when 
 it became steady positive. 
 
 Threatening at 9:30 a. m. to 12 m. ; negative from 12 m. to 12:23 p. m. ; then variable posi- 
 tive and negative until 1:10 p. m. Thunder and lightning from 12:10 to 12:55 p. m. ; 
 It. rain from 12:53 to 1 p. m. 
 
 Lt. rain §b. d. n., e. 10:50 a. m. ; variable positive and negative from 9 to 11 a. m. ; negative 
 from 11 a. m. to 12:15 p. m. ; hy. rain from 2 to 2:10 p. m. No observations between 1 and 
 3 p. ro. Fair from 3 to 5 p. m. ; threatening at 5:05 p. m. ; negative from 5:11 to 5:50 p. m. ; 
 then variable J- until 6:40 p.m., when it became steady positive; It. rain 5:20 to 6:30 
 p. m. ; distant thunder at 6 p. m. ; almost continuous sparks ftom 5:55 to 6:10 p. m. 
 
 Threatening at 1 p. m. ; variable positive and. negative from 3 to 5 p. m. ; no observations 
 after 6:30 p. m. ; rain began at 8 p. m. 
 
 Variable positive and negative from 3 to 6 p. m., generally neegative ; thunder and light- 
 ning almost continuous from 3:42 to 4:45 p. m. ; It. rain b. 3:45, e. 4:30 p. m. ; heaviest part 
 of the storm south of the city ; positive from 6 to 7 p. m. ; sparks between the needle and 
 quadrants during the thunder. 
 
 Lt. rain mist 11:31 to 11:33 a. m. and from 12:55 to 1:05 p. m., amount, trace ; positive at all 
 observations and during both rains. 
 
 Variable positive and negative from 10 a. m. to 2:20 p. m. ; negative from 2:20 to 3:10 p m • 
 positive rest of the day ; thunder and lightning from 1:20 to 3 p. m. ; hy. rain from 1-30 to 
 2:40 p. ra. ; sparked from 2:20 to 2:25 p. m. and at 2:55 p. m. 
 
 Threatening at 3:20 p. m. ; variable positive and negative from 3:30 to 4:15 p. m. ; negative 
 from 4:15 to 5:05 p.m.; variable positive and negative 5:05 to 5:30 p.m.; thunder from 
 4:36 to 5:15 p. m. ; electricity sparked during the thunder ; It. rain from 5 to 5:05 p m 
 trace. '' 
 
 Rai n b. d. n., e. 9:30 a. m. ; first observation at 9 a. m. ; variable positive and negative &om 
 9 to 10:32 a. in. ; low positive in afternoon ; no observations after 6 p. m. : thunderstorm 
 from 7:30 to 8:30 p. m. 
 
 Thunder and lightning from 1:05 to 2:40 p. m. ; variable positive and negative from 1 to 3-45 
 p. m., with frequent sparks; hy. rain b. 1:41 p. m., changed to It. rain 2 p. m. e 3-06 b m 
 
 Threatening at 1:30 p. m. ; negative from 3 to 3:45 p. m. ; hy. rain from 3:30 to 3:46 p m 6 04 
 inch ; It. rain from 4:56 to 4:59 p. m. ; negative from 4:57 to 5 p. m. ^ •) • 
 
 A trace of rain at 2 p. m. ; no observations between 1 and 3 p. m. ; positive at all observa- 
 
 Threatening and negative from 12 m. to 12:30 p. m. ; no observations from 12:30 to 2-50 » m • 
 thunderstorm from 1:20 to 2 p. m. ; trace of rain from 1:30 to 1:40 p m 
 
 Variable positive and negative from 11:05 a. m. to 5 p. m. ; trace of rain from 1 to 1-02 r, m ■ 
 negative during the ram. ' ^" ' 
 
 + Ended. 
 
 t Began during night, from about 11 p. m. to daylight. 
 5 Began during night, ended •**. 
 
MEMOIRS OP THE NATIOli^AL ACADEMY OP SCIENCES. 
 
 261 
 
 Table L. — Potential on days on which precipitation occurred at the place of observation, Terre Haute, 
 Ind., March 30, 1887, to August 25, 1888— Continued. 
 
 Date. 
 
 1887. 
 June 30 
 
 July 2 
 
 July 3 
 
 3a\j 4 
 
 July 6 
 
 July 8 
 July 18 
 
 July 21 
 July 22 
 Aug. 4 
 
 Aug. 5 
 Aug. 11 
 
 Aug. 17 
 
 Aug. 21 
 
 Aug. 22 
 Sept. 22 
 
 Kemarks. 
 
 Sept 
 
 26 
 
 Sept. 
 
 27 
 
 Sept. 
 
 29 
 
 Sept. 
 
 30 
 
 Oct. 
 
 10 
 
 Oct. 
 
 11 
 
 Oct. 
 
 20 
 
 Oct. 
 
 23 
 
 Nov. 
 
 9 
 
 Nov. 
 
 19 
 
 Nov. 
 
 23 
 
 Nov. 25 
 
 ISegative from 12 m. to 12:30 p. m. ; It. rain from 1:25 to 2 p. m. ; no obaervations during the 
 lain. Threatening and negative from 4:10 to 4:30 p. m. ; variable positive and negative 
 until 4:48 p. m. ; It.Tain b. 4:26, e. 4:42 p. m. 
 
 Threatening at 3 p. m. ; variable positive and negative from 3:45 to 7:10 p. m. ; distant thun- 
 der at 4:15 p. m. ; trace of rain from 7:06 to 7:07 p. m. ; negative during rain : no observa- 
 tions after 7:10 p. m. 
 
 Trace of rain Irom 10:45 to 10:46 a.m. ; no observations until 11 a.m., after which it was 
 positive. 
 
 Variable positive and negative from 3 to 4:30 p. m. ; distant thunder from 3:30 to 3:35 p. m. ; 
 It. rain b. 3:48, e. 4:20 p. m. 
 
 Variable positive and negative from 10 a. m. to 6 p. ra. (R. E. trains seemed to influence tlie 
 potential); It. rain from 5:19 to 5:55 p. m. ; thunderstorm from 5:32 to 5:58 p. m. ; fre- 
 quently sparlsed during the rain. From 6 to 6:30 p. m. the potential was high positive 
 and sparked so much that readings could not be taken ; distant thunder until 8:30 p. m. ; 
 no observations after 6:30 p. m. ' 
 
 Threatening at 3 p. m. ; thunderstorm and lightning from 3:30 to 6 p. m. ; variable positive 
 and negative from 3:30 to 6:15 p. m. ; It. rain from 4:46 to 5:45 p. m. 
 
 Positive up to 1 p. m. ; no observations from 1 to 2:30 p. m. ; trace of rain from 1:50 to 2 p. m. 
 Negative from 2:30 to 6:45 p. m. ; no observations after 6:45 p. m. Thunderstorm b. 2:05 
 p. m., continued all the afternoon until 8 p. m. ; lightning continued until 9 p. m. ; a trace 
 I of rain from 5:15 to 5:16 p. m. 
 
 Threatening at 1 p. m. ; negative from 3:15 to 5:30 p. m. ; thunderstorm and lightning from 
 3:30 to 7 p. m. ; It. rain from 3:31 to 3:35 p. m. ; hy. rain from 5:50 to 7:05 p. m. ; the poten- 
 tial was not over 1,500 volts ; no observations after 6 p. m. 
 
 Variable positive and negative from 1 to 7 p. m. ; very high potential ; sparked (E. E. trains 
 seemed to have an influence) ; It. rain b. 5:15, e. 5:50 p. m. ; high positive during the rain ; 
 negative just before and just after it. 
 
 Positive until 12 m. ; no observations from 12 m. to 2:30 p.m.; thunder and lightning from 2:20 
 to 6 p. m. ; a trace of rain from 2:20 to 2:25 p. m. ; hy. rain from 4:14 to 5:35 p. m. ; nega- 
 tive from 2:30 to 3:15 p. m. ; variable positive and negative from 4:08 to 4:35 p. m. ; nega- 
 tive from 4:47 to 6 p. m. ; then positive to 7 p. m. 
 
 Thunder and lightning from 12:50 to 3:30 p. m. ; hy. rain from 2:15 to 3:40 p.m. ; high positive 
 from 12:45 to 1:20 p. m. ; variable positive and negative from 1:25 to 4:30 p. m. 
 
 Thunder and lightning from 8 to 10:47 a. m. ; It. rain b. 8:25, e. 9:29 a. m. Observations be- 
 gan at 9 a. m. Variable positive and negative from 9 to 10:45 a. m. ; positive rest of the 
 day ; hy. thunderstorm and rain from 9 p. ui. to 1 a. m. of 12th. 
 
 Lt. rain at intervals from 8:40 a. m. to 12:35 p. ra. Observations taken every half hour from 
 9 a. m. ; the potential was low positive all the time. 
 
 Trace of rain Irom 3:45 to 3:49 p. m. No observations between 1 and 4 p. m. ; positive at all 
 observed tiqies. 
 
 Lt. rain b. d. n., e. 9:45 a. m. ; positive at 9 a. m., the only observation during the rain. 
 
 Trace of rain from 1 to 2:45 p. m. No observations between 12:45 to 3 p. m. ; low positive all 
 day ; insulation poor. 
 
 A high positive potential at 12 m. ; It. drizzling rain b. 12:10 p. m. and continued all day; 
 negative from 3:45 to the last observation at 6:30 p. m. 
 
 Lt. rain mist all night and all day ; negative at 11a. m. and 1 p. m. ; positive at the other 
 observations ; low potential ; insulation very poor. 
 
 Lt. rain mist b. 4:04 p. m., changed to hy.rain at 4:30, e. 5:48 p. m. ; thunder and lightning 
 from 4:30 to 5:10 p. m. ; negative from 4:15 to 4:35 p. m. ; then variable positive and neg- 
 ative until 5:50 p. m. 
 
 A trace of rain from 9:37 to 9:38 a. m. ; positive all the time except for a few minutes at 10:15 
 a. m., when it was negative. 
 
 Lt. rain b. d. n., e. 11:50 a.m.; b. l.,e. 1:50 p.m.; b. 4:02, e. 4:10 p. m. ; negative from 9 to 11 
 a. m. ; variable positive and negative from 11 a. m. to 4:10 p. m. 
 
 Hy. rain b. 4:08 p. m., e. 5:48 p. m. ; positive all day from 9 a. ra. to 3 p. m. No observations 
 between 3 and 5 p. m. ; variable positive and negative from 5 to 5:50 p. m. ; then positive 
 nntil 7 p. m. ; negative and sparks during the rain, which was large drops. 
 
 Threatening at 9 a. m. ; trace of rain from 10:50 to 10:55 a. m. ; positive between 9 and 11 
 a. m. ; variable positive and negative from 11:10 a. m. to 5:30 p. m., with west to north- 
 west gale. 
 
 Threatening, with south gale, at 10:30 a.m.; It. rain b. 1:10, o. 2:15 p.m., 0.02 inch; positive 
 from 10:30 to 11:30 a. ra. ; negative from 12 m. to 1 p. m. ; no observations after i p. m. 
 
 A trace of rain from 8:20 to 8:50 a. m. ; first observation at 9 a. m. ; variable positive jiud 
 negative until 11 a. m. ; rained in the afternoon and evening ; no observations after 1p.m. 
 
 A trace of snow from 8:30 to 9:25 a. m. ; threatening weather the remainder of the day. A 
 cold wave coming; temperature fell from 37° at 8 a. ra. to 30° at 12 m., and to 12° during 
 the night ; west gale winds. Variable positive and negative from 9 to 10 a. m. ; negative 
 500 to 1,000 volts from 10 ^. m. all day. 
 Eain b. 7:50 a.m., e. during night of 24th; amount, 1.08 inches; variable positive and neg- 
 ative all day from 9 a. m. to 5 p. m. 
 Lt. rain b. d. n., e. 2:50 p. m. ; steady negative from 9 a. ra. to 1 p. m. ; positive from 3 to 5 
 and variable positive and negative from 7 to 8 p. ra., followed by rain during the night. 
 
262, 
 
 MEMOIEB OF THE ]!fATrOIfAL ACADEMY OF SCIENCES. 
 
 Table L. — Potential on days on which precipitation occurred at the place of observation, Terre Haute, 
 Ind., March 30, 1887, to August 25, 1888— Continued. 
 
 Date. 
 
 Hemarka. 
 
 1887. 
 Nov. S6 
 
 Dec. 
 
 2 
 
 Dec. 
 
 3 
 
 Dec. 
 
 7 
 
 Dec. 
 
 9 
 
 Dec. 
 
 10 
 
 Dec. 
 
 •15 
 
 Dec. 
 
 ■20 
 
 Dec. 
 
 S3 
 
 Dec. 
 Deo. 
 
 26 
 30 
 
 Dec. 
 
 31 
 
 1888. 
 Jan. 5 
 
 Jan. 
 
 6 
 
 Jan. 
 
 7 
 
 Jan. 
 
 9 
 
 Jan. 12 
 
 Jan. 17 
 
 Jan. 25 
 
 Jau. 30 
 
 Feb. 4 
 
 Feb. 7 
 
 Feb. 8 
 
 Feb. 14 
 
 Feb. 15 
 
 Feb. 24 
 
 Feb. 25 
 
 Lt. rain b. d. n. and continued at intervals all day ; variable positive and negative all day 
 from 9 a. m. to 5 p. ra. ; low potential. 
 
 Lt. rain b. d. n. continued all day, 0.61 inch ; negative from 9 a. m. to 1 p. m. and positive from 
 3 to 5 p. m. ; low steady potential ; no special observations. 
 
 Lt. rain continued all night and e. 1:05 p. m. ; amount, 0.55 inch ; variable positive and nega- 
 tive from 9 a. m. to 12 m. ; positive from 1 to 5 p. m. 
 
 Lt. rain mist b. 7 a. m.,e. 1:30 p.m., 0.07 inch ; variable positive and negative from 9 to 11:30 
 a. m. 
 
 Lt. rain mist from 9:10 a. m. to 4:50 p. m., 0.03 inch ; lowpositive potential at all regular ob- 
 servations ; no negative observed. 
 
 Lt. rain b. 10 p. m. of 9th and continued as a mist all day; amount, 0.72 inch ; no negative 
 observed ; low positive at all the regular observations ; insulation on the 9th and 10th 
 was poor. 
 
 A trace of It. dry snow mist from-e a. ra. to 4:15 p. m. ; variable positive and negative from 
 9:30 to 9:50 a. ra. and from 2:50 to 3:10 p. ra. ; positive the rest of the time; low potential. 
 
 Lt. rain b. 6 a. m., changed to snow 5:50 p. ra., c. 9:15 p. m. ; negative all day from 9 a. m. to 
 5:10 p.m.; then variable positive and negative until 5:35 p. m. ; then high positive during 
 the snow up to the last obseryation at 6:40 p. m. The wind was light easterly all day 
 until5p. m., when it suddenly changed to SW. fiesh ; then at 5:10 p. m. to W. gale. The 
 temperature was 43"= at 5, 35° at 5:10, 32° at 5:30, 28° at 5:50, and 26° at 6:15^ p. m. Amount 
 of ram and snow, 0.61 inch. Sparks between the needle and quadrants during the snow. 
 
 A trace of snow from 11:30 to 11:45 a. m. ; no observations during the snow ; positive at 11 
 a.m. and 1 p.m. 
 
 A trace of snow from 8:50 to 9:30 a. m. ; first observation at 9 a. m. ; no negative observed. 
 
 Lt. snow b. 1:10 p. m. and continued during the night ; low positive all morning ; high posi- 
 tive all afternoon during the snow. Sparks frequently passed between the needle and 
 quadrants. 
 
 The snow changed to rain during the night ; It. rain all day. Variable positive and nega- 
 tive all day from 9 a. m. to 5 p. m. 
 
 Dense fog at 9 a. m. ; It. fog all day ; It.rain mist h. 10:15 a. m.,e. 6:15 p. m. , 0.02 inch. Vari- 
 able positive and negative from 9 to 10 a. m; and from 3 to 5 p. m. 
 
 Lt. rain b. 10 p. m. of the 5th, rained hard during the night; It. rain all day, 1.16 inches. 
 Variable positive and negative all day from 9 a. m to 5 p. m. 
 
 Rained all night, e. 9:45 a. m. ; b. 10:30 a. m., and continued as a light rain until during the 
 night. Variable positive and negative all day from 9 a. m. to .5"p. m. 
 
 A trace of snow from d. n. to 10 a. m. ; just an occasional flake. First observation at 9 a. m. 
 No negative observed during the snow. Low positive at 1 and 3 p. m. No observations 
 between 3 and 4 p. ra. ; It. snow b.4 p.m., e. d. n., 0.02 inch. The dry snowflakes looked 
 like pieces of broken needles i to i of an inch long and very narrow. From 4 to 6 p. m. 
 the potential wa-s variable positive, with an occasional negative. 
 
 Lt. snow b. 12:05 p. m. ; changed to sleet at; 2 p. ra. ; changed to moist snow at 3:30 p. m. ; 
 changed to rain at 5:30 p. ra. ; rain e. d. a. ; amount of melted sleet and snow, 0.21 inch ; 
 amount of rain, 0.30 inch. Positive in the morning. No observations from 11 a. m. to 12 
 m. ; variable positive from 12 m. to 1 p. m. during the snow. No observations from 1 to 2:30 
 p. m. ; negative all afternoon from 2:30 to 6 p. m., during sleet and rain. 
 
 A trace of snow (occasional flakes) from 11:05 a. m. to 5:30 p.m. High variable positive, 
 with sparks, from 10 to 11 a. m. ; low positive the rest of the time observed. 
 
 A trace of snow from d. n. to 10:05 a. m. No observations before 9 a. m. ; positive after that 
 hour; varied from 50 to 1,000 volts. 
 
 Lt. rain mist from 3:30 to 7 p. m., 0.01 inch. Potential positive 800 volts at 1 p. m., 200 at 3 
 p. m., and 600 at 5 p. m. ; no special observations. 
 
 Lt. rain during the night and rain mist all day, changed to snow at 6, e. 8:50 p. m., 0.15 inch. 
 Positive from 9 to 11:30 a. m. ; then variable positive and negative uutil 1p.m.; positive 
 from 3 to 5 p. m. - r , r 
 
 Lt. rain mist from 3:05 to 6:50 p.m., 0.01 inch. Falling positive all moruing; uo observa- 
 tions from 1 to 3 p. m. ; no negative observed iu the afternoon. 
 
 Lt. snow b. 4:55 p. m., e. d. n. ; amount, 0.10 inch. Variable positive iu the a. m. ; no negative 
 observed during the day. 
 
 Lt. rain Ii. 12:10 p. m., changed to sleet 2:45, e. 4:30 p.m., 0,12 inch. Steady positive from 
 
 9 to 11 a. m., began falling slowly ; changed to negative at 12:05 p. m. Variable positive 
 and negative from 12:05 to 3:45 p. m. ; then changed to positive. 
 
 A trace of snow b. d. n., e. 12:20 p. m. First observation at; 9 a. m. ; no negative observed • 
 positive at a!] regular observations, ' 
 
 Lt, rain 8:30 to 8:55 a. m. ; hy. rain from 10:.57 to 11 a. m, ; It, rain from 11 a. m. to 1-20 p m • 
 hy. ram from 3:05 to 5:56 p, m. ; thiiniler-storm from 2:50 to 5:53 p. m. Positive from 9 to 
 
 10 a. m. ; negative at 10:55 a. m. Variable positive and negative with sparks duriuff the 
 hy; ram from 10:55 a, tn to 1 p, m. No observations from 1 to 3:20 p. m. Variable positive 
 and negative from 3:20 to 0:40 p, ni. Sparks during the thunder storm 
 
 Trace of snow b. d. n., e. 8:50 a. m. Positive at 9 a. m, ; variable positive and negative from 
 10 to 11 a. ra. A trace of snow mist from 11:30 a. in. to 8 p, ra, Variable politlve, with 
 sparks, during the snow from 2 to 4 p. m. West gale winds 
 
MEMOIRS OP THE NATIONAL ACADEMY OP SCIENCES. 
 
 263 
 
 Table L. — Potential on days on which precipitation occurred at the place of observation, Terre Haute^ 
 Ind., March 80, 1887, to August 25, 1888— Continued. 
 
 Date. 
 
 Remarks. 
 
 1888. 
 Feb. 27 
 
 Mar; 
 
 1 
 
 Mar. 
 Mar. 
 
 5 
 6 
 
 Mar. 
 
 10 
 
 Mar. 
 
 16 
 
 Mar. 
 
 19 
 
 Mar. 
 
 20 
 
 Mar. 
 
 23 
 
 Mar. 
 
 27 
 
 Apr. 5 
 
 Apr. 9 
 
 Apr. 10 
 
 Apr. 21 
 
 Apr. 30 
 
 May 3 
 May 7 
 
 May 11 
 May 25 
 
 June 1 
 Jane 8 
 
 Jnne 9 
 June 15 
 
 June 21 
 
 June 22 
 June 23 
 
 June 26 
 
 A trace of snow from 1:30 to 8 p. m. No special observations; positive at all regular obser- 
 vations ; higher at 3 p. m. than at any other time. 
 
 Potential positive 60 to 200 volts from 9 to 10 a. ni. ; then rose to a maximum of 800 volts at 
 10:10 a. m. ; then fell gradually to — 25 volts at 10:28 a. m. ; then varied from 60 to 600 
 volts until 1 p. m. No -special observations in the afternoon ; 600 volts at 3 and 400 at 5 
 p. m. ; It. rain from 7:30 to 8 p. m., 0.14 inch; no observations after 5 p. m. 
 
 A trace of snow from d. n, to 9:30 ^. m. ; first observation at 9 a. m. ; no negative observed. 
 
 A trace of snow b. d. n. , e. 11:42 a. m. ; negative at 10:45 and 11:20 a. m, ; positive the rest of 
 the time after 9 a. m. 
 
 Lt. rain b. 1:45 a. m., e. 8:50 a. m. ; variable positive and negative from 9 to 10 a. m. ; It. rain b. 
 3:40 p. m., changed to snowat9,e.9:45.p.m., 0.23 inch. No observations from 1 to 4:30 p.m. 
 Variable positive and negative from 4:30 to 6:30 p. m. ; no observations after that. 
 
 Lt. rain b. 7:45, e. 7:50 a.m. Variable positive and negative from 9 to 10 a. m. ; positive 
 from 10 to 11 a. m. Lt. rain from 11:26 a. m. to 12:40 p. m., 0.29 inch. Negative for a few 
 minutes at 11:45 a. m. 
 
 Positive 150 volts at 9 a. m. ; 30 at 11 a. m. ; 50 at 1 p. m. No observations from 1 to 3 p. m. 
 Lt. rain b. 2:10 p. m., continued all afternodn and evening. Variable positive and nega- 
 tive ; generally negative all afternoon from 3 to 6:30 p. m. Amount of rain, 0.12 inch. 
 
 Rain continued all night o. 11:07 a. m., 0.67 inch. Low potential; variable positive and 
 negative from 10 a. m. to 12:15 p. m. 
 
 No special observations; positive at all regular observations. Lt. snow mist b. 11:45 a. m., 
 changed to sleet 3:50, e. 4:30 p. m. Potential low; 9 a.m., 60 volts; 11 a.m., 50; 1 p.m., 
 30; 3p.m., 400; 5p.m., 60. 
 
 Lt. rain b. 7:50, e. 10:15 a. m. First observation at 8:30 a. m. Variable positive and nega- 
 tive from 8:30 to 10 a. m. ; then positive from 11:30 a. m. to 12:30 p. m. ; then variable posi- 
 tive and negative until 1:10 p. m. No observations after this. Lt, rain b. 3:30 p. m., con- 
 tinued all afternoon and evening. 
 
 Cloudy in a. m. ; low steady positive up to 4 p. m. Began to threaten at 3 p. m. ; thunder 
 and lightning b. 4:30 p. m. was very heavy from 5 to 6:30 p. m., e. 7 p. m. ; hy. rain b. 5:57, 
 e. 7:15 p. m., 0.77 inch. High positive from 4 to 5:30 p. m., with sparks ; negative from 
 5:31 to 5:45 p. m. ; variable positive and negative, often sparking, from 5:45 to 7 p. m., the 
 last observation. 
 
 Lt. rain b. 7:15 a. m., e. 4:50 p. ra., 0.72 inch. Variable positive and negative all day from 9 
 a. in. to 5 p. m., generally negative. ' 
 
 Hy. rain b. d. n, e;9:30 a. m., 1.70 inches. Variable positive and negative from 9 to 11:45 
 a. ra. 
 
 Lt. rain mist from 2:15 to 7:25 p. m. , 0.13 inch. Positive in a. m. ; no ohiservations from 1 
 to 3 p. ra. ; 30 volts at 3 p. m. ; occasional drops of rain ; no observations after 3 p. m. 
 
 Lt. rain b. d. n., e. 11:15 a. m., 0.41 inch. Variable positive and negative from 9 to 10:30 a. m. ; 
 positive from 11 a. m. to 3 p. m. ; negative at 5 p. m. Lt. rain from 5:20 to 8 p. m., 0.01 
 inch; no observation daring the rain. t 
 
 Variable positive and negative from 12:30 to 5:30 p. m. A trace of rain from 9 to 9:15 p. m. 
 and from 10:40 to 11 p.m. ; no observations after 5:30 p. m. 
 
 Lt. rain b. 8:15, e. 9:40 a. m. Negative at 9 a. m. ; positive at 11 a. m. and at 1 and 3 p. m. ; 
 negative from 4:31 to 4:53 p. m. ; variable positive and negative from 4:53 to 5:30 p. m. Lt. 
 rain from 4:35 to 4:58 p.m., 0.13 inch. Lt. rain b. 11:30 p.m., e.d.n. 
 
 Variable positive and negative from 1 to 3 p. m. No observations after 3 p. m. Eain from 
 8:45 p. m. to d. n., 0.46 inch. 
 
 Hy. rain and thunderstorm d. n. ; It. rain from 9 to 11:20 a. m., 1.70 inches. Negative at 9 
 a. m. ; positive at 11 a. m. and at 1, 3, and 5 p. m. Lt. rain from 3:10 to 3:15 p. m. and from 
 3:50 to 4:15 p.m. No observations from 1 to 3 p. m., nor during the rain. 
 
 A trace of rain from 1:15 to 1:20 p. m. No observations between 1 and 3 p. m. ; positive at 
 both those hours. 
 
 Positive from 9 a. m. to 3 p. m. ; variable positive and negative from 4:50 to the last observa- 
 tion at 6:30 p. m. Threatening 5:30 p. m. ; thnnderstorm from 5:35 to 7:20 p. m. ; a trace 
 of rain from 7:05 to 7:20 p. m. and from 8:30 to 9:10 p. m. 
 
 Lt.rain b. 8:25, e. 11:10 a.m. ; b. 12:20, e. 1:50 p.m. Low potential; negative at 
 a. m. ; no special observations. 
 
 Variable positive and negative from 10:30 a. m. to 1 p. m. ; no observations from 1 to 3 p. m. ; 
 positive at 3 and 5 p. m. Thunderstorm from 10:55 a. m. to 3:20 p. m. ; It. rain from 3:05 to 
 3:30 p.m., 0.09 inch; no negative observed during rain. 
 
 Lt. rain from 8 tc^8:20 a. m. Negative from 9 to 10 a. m. Hy. rain b. 9:35, e. 11:35 a. m 
 tant thunder from 10 to 11 ^. m. Variable positive and negative from 10 a. 
 Amount of rain, 0.56 inch. 
 
 No observations before 4 p. ra. Threatening and negative from 4 to 5:20 p.m. 
 positive and negative from 5:20 to 6 p. m. Lt. rain from 4:45 to 6:30 p. m. 
 
 Hy. rain from 2:45 to 3:35 p. m. and from 5:05 to 7:30 p. m., 0.92 inch. Low potential ; posi- 
 tive at 9 and 11 a. ra. and 1 p. m. ; no observations from 1 to 3:30 p. m. ; positive at 3:30 
 and 5 p. m. ; no special observations. 
 
 Lt. rain b. d. n. , e. 8:15 a. m. Low positive from 9:30 a. m. to 1 p. m. ; threatening at 4 p. m. ; 
 variable positive aud negative from 4 to 4:45 p. m. ; It. rain from 4:27 to 4:53 p. m. ; distant 
 thunder at 4:46 p. m. 
 
 9 and 11 
 
 dis- 
 ra. to 12 m. 
 
 Variable 
 
264 
 
 MEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES. 
 
 Table L. — Potential on days on which precipitation occurred at the place of observation, Terre Saute, 
 ■> Ind., March 30, 1887, to August 25, 1888— Continued. 
 
 - D.ate. 
 
 Kemarks. 
 
 June 27 
 
 July 9 
 
 July 14 
 
 July 17 
 
 July 23 
 
 July 26 
 
 July 28 
 
 Aug. 4 
 
 Aug. 12 
 
 Aug. 16 
 
 Aug. 20 
 
 Aug. 21 
 
 Aug. 25 
 
 Hy. rain d. n.,o. 9:20 a.m. ; b. 11:50 a. m.,e. 9 p. m., 3.36 inches. Positive at 9 a. m. ; nega- 
 tive at 11 a. m. ; variable positive aud negative from 12 m. to 6:20 p. m. 
 
 Rained hard during the night; lt.rain b. 8:50, e. 9:15 a. m. Negative at 9 a.m.; variable 
 positive and negative from 9 to 10 a. m. ; positive at 11 a. m. and 1 p. m. ; no observations 
 between 1 and 3 p. m. ; negative at 3 and 5 p. m. Hy. rain from 1:45 to 3:10 p. m. Amount 
 of rain last night and to-day, 1.69 inches. 
 
 Lt.rain mist b. 11:40 a. m.,e. 3:30 p.m.; b. 8, e.€:15 p.m., 0.04 inch. No special observations ; 
 positive at all regular observations; varied from 5 to 250 volts. 
 
 Variable positive and negative from 9 to 10 a. m. Lt. rain from 10:08 a. m. to 2:05 p. m. and 
 from 3:45 to 6:50 p. m. High positive from 10 a. m. to 12 m. ; variable positive and neg- 
 ative from 3:40 to 5:30 p. m. Amount of rain, 0.30 inch. 
 
 Threatening at 10 a. m. Variable positive and negative from 10:15 to 10:30 a. m. ; then pos- 
 itive until 12 m. Thunderstorm from 2:30 to 3:40 pi m. ; It. rain from 2:56 to 3:35 p. m., 
 0.09 inch. No observations from 1 to 2:40 p. m. ; variable positive and negative from 2:40 
 
 . to 5:30 p. m. • 
 
 Threatening at 9 a. m. Negative at 9:50 a. m. ; variable positive and negative until 10 a. m. 
 A trace of rain from 10 to 10:10 a. m. Positive from 10 a. m. to 12 m. Threatening, with 
 variable positive and negative, from 5 to Op. ra. 
 
 Threatening at 12 m. Negative at 12:20 to 12:25 p. m. Thunder and lightning from 12:28 
 to 4:30 p. m. Positive at 12:28 p. m. ; negative from 12:29 to 12:48 p. m. ; then variable 
 positive and negative until 1:30 p. m. ; no observations after this. Hy. rain from 12:33 
 to 3:15 p. m., 0.56 inch. 
 
 Negative from 9:40 to 9:45 a.m. Lt.rain from 10:01 to 11 a.m., 0.13 inch. Thunderstorm 
 from 10:16 to 11:25 a. m. Variable positive and negative from 10 to 11 a. m. ; positive after 
 1 p. m. 
 
 Lt. rain b. 10:30, e. 11:13 a. m., 0.05 inch. First observation at 10:50 a. m. ; negative from 
 10:50 to 11:02 a. m. ; then variable positive and negative until 11:30 a. m. ; then positive. 
 
 Lt. rain mist from 12:40 to 4:10 p. m., from 4:38 to 7 p. m., and from 8:15 to 9:45 p. m., 0.09 
 inch. No negative observed; varied from 50 to 350 volts iu the forenoon and from 10 to 
 200 in the afternoon ; no observations after 5 p. m. 
 
 Rained very hard during the night, e. 3:50 p.m., 2.37 inches. Negative from 9:20 to 11:30 
 a. m. ; positive at 9 a. m., and after 1 to 6 p. m. 
 
 Rain b. d. n., e. 9:30 a. m., 0.45 inch. Variable positive and negative from 9 to 9:20 a. m. ; 
 threatening at 5 p. m., with negative. 
 
 Clear, with variable positive and negative, from 9 to 10 a. m. ; low positive all- morning. 
 Threatening at 4 p. m. ; It. rain from 4:06 to 4:28 p. m., 0.03 inch ; distant thunder from 4:15 
 to 4:40 p. m. Negative from 4:20 to 4:25 p. m. ; insulation poor. 
 
 Date. 
 
 » Precipitation. 
 
 Before. 
 
 Daring. 
 
 
 Kemarks. 
 
 Began. 
 
 Ended. 
 
 <3 
 
 ¥ 
 
 it 
 
 > 
 
 i 
 
 1 
 
 i 
 
 i 
 s 
 
 o 
 
 1887. 
 Apr. 1 
 Apr. 1 
 Apr. 
 Apr. 16 
 Apr. 18 
 Apr. 20 
 Apr. 20 
 Apr. 21 
 Apr. 2-i 
 
 Apr. 22 
 Apr. 22 
 Apr. 28 
 May 1 
 May 2 
 May 5 
 May 5 
 May 5 
 May () 
 May 11 
 
 6 a. m 
 
 11:56 a.m.. 
 During 
 
 11 a. m 
 
 D.n 
 
 7 a. m 
 
 7 p. m 
 
 5:15 p. ra . . . 
 D.n 
 
 6:37 p. m .. 
 7:20 p.m.. 
 2:55 p.m..- 
 
 11 a. ra 
 
 12:53 p.m.. 
 
 D.n 
 
 2 p. ra 
 
 5:20p.m... 
 
 8 p. m 
 
 3:45 p.m... 
 
 9:30 a.m... 
 12m 
 
 
 
 
 
 
 
 
 Lt.rain aud sleet. 
 
 Lt. rain ; threatening after rain. 
 
 Lt. rain. 
 
 Lt. snow, tr. ; dry snow. 
 
 Rain, sleet, and snow. 
 
 L^ rain, 0.03 iuch. 
 
 Trace of rain : no obs. before. 
 
 Hy. raiu. 
 
 Hy. rain and thunderstorm; NW. 
 
 gale; sparks. * 
 Lt.rain, tr. ; sparks. 
 Lt. rain, thunder, 0.01 inch ; sparks. 
 Lt. rain, tr. 
 
 Lt. rain and hail, 0.03 inch ; thunder. 
 Lt.rain; thunder. 
 Lt. rain. 
 Hy. rain. 
 
 Lt. rain ; thunder ; sparks. 
 Lt. vain. 
 Lt.rain; thunder; sparks. 
 
 10 
 
 
 
 .... 
 
 1 
 
 night. 
 11:02 a.m.. 
 
 .... 
 
 -■-- 
 
 
 4p.m 
 
 10:44 a.m.. 
 7:15 p. m.. . 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 D.n 
 
 11:34 !i,.m.. 
 
 6:38 p.m.. 
 8p. m 
 
 
 1 
 
 .... 
 
 .... 
 
 1 
 
 i 
 
 
 .. 
 
 1 
 
 
 
 
 
 .... 
 
 .... 
 
 "i" 
 
 11:08 a.m.. 
 
 
 
 1 
 
 
 
 .... 
 
 10:50 a.m.. 
 2:10 p.m... 
 C:30p. m... 
 
 9p. m 
 
 4:30 p.m... 
 
 .... 
 
 3 
 
 i 
 5 
 
 f 
 
 .... 
 
 ■-■ 
 
 
 
 
 
 
 
 
 
 .... 
 
 .... 
 
 
 
MEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES. 
 
 265 
 
 Table L. — Potential on days on which precipitation occurred at the place of observation, Terre Haute, 
 Ind., March 30, 1887, to August 25, 1888— Continued. 
 
 Date. 
 
 1887. 
 
 May 17 
 
 May 21 
 
 May 24 
 
 May 30 
 
 May 30 
 
 May 31 
 
 June 5 
 
 Jane 9 
 
 June 20 
 
 June 22 
 
 June 80 
 
 June 30 
 
 July 2 
 
 July 3 
 
 July 4 
 
 July 6 
 
 July 8 
 
 July IS 
 
 July 18 
 
 July 21 
 
 July 21 
 
 July 22 
 
 Aug. 4 
 
 Aug. 4 
 
 Aug. 5 
 
 Aug. 11 
 
 Aug. 11 
 
 Aug. 17 
 
 Aug. 21 
 
 Aug. 22 
 
 Sept. 22 
 
 Sept. 26 
 
 Sept. 27 
 
 Sept. 29 
 
 Sept. 30 
 
 Oct. 10 
 
 Oct. 10 
 
 Oct. 11 
 
 Oct. 20 
 
 Oct. 23 
 
 Nov. 9 
 
 Nov. 19 
 
 Nov. 23 
 
 Nov. 25 
 
 Nov. 26 
 
 Dec. 2 
 
 Dec. 3 
 
 Dec. 7 
 
 Dec. 9 
 
 Dec, 10 
 
 Dec. 15 
 
 Dec. 20 
 
 Dec. 23 
 
 Dec. 26 
 
 Dec. 30 
 
 Dec. 31 
 
 1888. 
 
 Jan. 5 
 Jan. 
 Jan. 
 Jan. 
 Jan. 
 Jan. 
 
 Jan. 17 
 
 Jan. 25 
 
 Jan. 30 
 
 Feb. 4 
 
 Feb. 7 
 
 Precipitation. 
 
 Began. 
 
 11:31a.m.. 
 1:30 p.m... 
 
 5 p. m 
 
 D.n 
 
 7:30 p.m... 
 1:41p.m.., 
 3:30 p.m... 
 
 2p. m 
 
 1:30p.m... 
 
 1 p. m 
 
 1:25 p.m... 
 4:26 p.m... 
 7:06 p.m... 
 10:45 a.m.. 
 3:48 p.m... 
 5:19 p.m... 
 4:46 p. m- - - 
 1:50 p.m... 
 5:15 p.m... 
 3:31p.m... 
 5:50 p.m... 
 5:15 p.m... 
 2:20 p.m... 
 4:14 p. m... 
 2:15 p.m... 
 8:25 a.m... 
 
 9p. m 
 
 8:40 a.m... 
 3:45 p.m... 
 
 D.n 
 
 1 p. m 
 
 12:10p.m.. 
 
 All 
 4:04 p. m - - . 
 9:37 a. m . . . 
 
 D.n 
 
 4:02p.m... 
 4:0Hp. m... 
 10:50 a.m.. 
 l:10p.ra... 
 
 4p.m 
 
 8:30 a. ra... 
 7:50 a. m . . . 
 D.n 
 
 All 
 
 All 
 
 D.n 
 
 7 a. m 
 
 9:10a.m... 
 
 All 
 
 6 a. m 
 
 6 a. m 
 
 11:30 a.m.. 
 8:50 a.m... 
 1:10p.m. 
 
 D.n. 
 
 Ended. 
 
 Before. 
 
 1:05 p.m. 
 
 2:40 p.m. 
 
 5:05 p.m.. . 
 
 9:30 a.m... 
 
 8:30p.m... 
 
 3:06p.m.. . 
 
 4:59p.m.. . 
 
 2:01 p.m. .. 
 
 1:40 p.m... 
 
 1:02 p.m... 
 
 2p. m 
 
 4:42 p. m . . . 
 
 7:07 p.m... 
 
 10:46a. ui.. 
 
 4:20 p.m... 
 
 5:55 p. m.- - 
 
 5:45 p. m . . . 
 
 2p.m 
 
 5:16 p. m.. , 
 
 3:35 p.m... 
 
 7:05p.m.. . 
 
 5:50 p. m.. . 
 
 2:25 p.m... 
 
 5:35 p.m... 
 
 3:40p.m... 
 
 9:29 a.m... 
 
 12 mid 
 
 12:35 p.m.. 
 
 3:49 p.m... 
 
 9:45 a. m.. . 
 
 2:45 p. m . . . 
 
 D.n 
 
 Say. 
 
 5:48p.m... 
 
 9:38 a.m... 
 
 1:50 p.m... 
 
 4:10p.m... 
 
 5:48 p.m... 
 
 10:55 a. m . . 
 
 2:15 p.m... 
 
 D.n 
 
 9:25 a. m . - . 
 
 D.n 
 
 2:.50p. m... 
 day. 
 day. 
 
 1:05 p.m... 
 
 1:30 p.m... 
 
 4:50p.m.. . 
 day. 
 
 4:15 p. m... 
 
 9:15 p.m... 
 
 11:45a. m.. 
 
 9:30 a.m... 
 
 D.n 
 
 all day. 
 
 10:15a.m.. I 6:15p.m. 
 
 All day. 
 
 All day. 
 
 D.n 
 
 4p. m 
 
 12:05 p.m.. 
 11:05a'. m.. 
 
 D.n 
 
 3:30 p.m... 
 D.n....... 
 
 3:05 p.m.. 
 
 10 a. m ... 
 
 D.n 
 
 D.n 
 
 5:30 p.m.. 
 10:05 a.m. 
 
 7p. m 
 
 8:50 p.m.. 
 6:50 p.m.. 
 
 
 *^ 91 
 
 During. 
 
 10 
 
 Bemarka. 
 
 Lt. rain, tr. ; mist. 
 
 Hy. rain; thunder: sparks. 
 
 Lt. rain, tr. ; thunder. 
 
 Lit. rain. 
 
 Lt. rain ; thunder. 
 
 Hy. rain; thunder; sparks. 
 
 Hy. rain, 0.04 inch. 
 
 Lt. rain, ir. 
 
 Do. 
 
 Do. 
 
 Do. 
 . Do. 
 Lt. ra'n, tr. ; thunder. 
 Lt. rain, tr. 
 Lt.rain; thunder. 
 Lt. rain ; thunder ; sparks. 
 
 Do. 
 Lt. rain,tr. 
 
 Lt. rain, tr. ; thnndef . 
 Lt.rain; thunder. 
 Hy. rain ; thunder. 
 Lt. rain ; sparks. 
 Lt. rain, tr. ; thunder 
 Hy. rain; thunder. 
 Lt. rain ; thunder. 
 
 Do. 
 Hy. rain ; thunder. 
 ' Lt.rain, mist. 
 Lt.rain, tr. 
 Lt. rain. 
 Lt. rain, tr. 
 Lt.rain, mist. 
 
 Do. 
 Hy. rain ; thunder. 
 Lt.rain, tr. 
 Lt. rain. 
 
 Do. 
 Hy. rain ; sparks. 
 Lt. rain tr. ; NW. gale. : 
 Lt, rain. 
 
 Do. 
 Lt. snow, tr. ; W. gale ; cold wave, 
 Hy. rain, 1.08 inches. ' 
 
 Lt. rain. 
 
 Do. 
 
 Do. 
 Lt. rain, 0.55 inch. 
 Lt.rain, 0.07 inch. 
 Lt. rain, 0.03 inch ; no sp. obs. 
 Lt. rain, 0.72 inch ; no sp. obs. 
 Lt. snow, tr. 
 
 Kain and snow ; sparks ; cold wave. 
 Lt. snow, tr. 
 
 Do. 
 Lt. snow ; sparks. 
 Lt. rain . 
 
 Lt.rain, 0.02 inch; fog. 
 
 Hy. rain, 1.16 inches. 
 
 Lt. rain. . 
 
 Lt. snow, tr. 
 
 Lt. snow ; almost ice. 
 
 Snow, sleet, and rain. 
 
 Lt. snow, tr; sparks. 
 
 Lt. snow, tr. 
 
 Lt. rain, mist, 0.01 inch ; 
 
 Lt. rain and snow. 
 
 Lt. rain, mist, 0.01 inch. 
 
 no sp. obs. 
 
260 
 
 MEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES. 
 
 Table L. — Potential on days on which precipitation occurred at the place of observation, Telrre Haute, 
 Ind., March 30, 1887, to August 25, 1888— Continued. 
 
 Date. 
 
 1888. 
 
 Feb. 8 
 
 Feb. 14 
 
 Feb. 15 
 
 Feb. a4 
 
 Feb. 25 
 
 Feb. 27 
 
 Mar. 1 
 
 Mar. 5 
 
 Mar. 6 
 
 Mar. 10 
 
 Mar. 16 
 
 Mar. 1& 
 
 Mar. 20 
 
 Mar. 23 
 
 Mar. 27 
 
 Mar. 27 
 
 Apr. 5 
 
 Apr. 9 
 
 Apr. 10 
 
 Apr. 21 
 
 Apr. 30 
 
 Apr. 30 
 
 May 3 
 
 May 7 
 
 May 7 
 
 May 11 
 
 May 25 
 
 ■June 1 
 
 June 8 
 
 ,Jnne 9 
 
 June 15 
 
 June 21 
 
 June 22 
 
 June 23 
 
 June 26 
 
 June 27 
 
 July 9 
 
 July 9 
 
 July 14 
 
 July 17 
 
 July 17 
 
 July 23 
 
 July 26 
 
 July 28 
 
 Aug. 4 
 
 Aug. 12 
 
 Aug. 16 
 
 Aug. 20 
 
 Aug. 21 
 
 Aug. 25 
 
 Precipitation. 
 
 Began. 
 
 4:55 p.m.. 
 12:10 p.m.. 
 
 D.n 
 
 10:57 a.m. 
 11:30 a.m.. 
 f?S0p.m.. 
 7:30 p.m.. 
 
 D.n 
 
 D.Ji 
 
 3:40 p.m.. 
 11:26 a.m. 
 2:10 p.m.. 
 
 D.n 
 
 11:45 a. m. 
 7:.'S0a.m.. 
 8:30p.m.. 
 5:57 p.m.. 
 7:15 a.m.. 
 
 D.n 
 
 2:15 p.m.., 
 
 D.n 
 
 5:20p.m.., 
 
 9p. m 
 
 8:15 a. m.. 
 4:35 p.m.. 
 8:45 p.m.. 
 
 D.n 
 
 1:15 p. m.- 
 7:05 p. m ., 
 8:25a. m.. 
 3:05 p.m.. 
 9:35 a.m.. . 
 4:45 p. m . . 
 2:45 p.m.. 
 4:27 p. m . . 
 
 D.n 
 
 D.n. 
 
 1:45 p. m.. 
 11:40 a.m.. 
 10:08 a.m.. 
 3:45 p.m.. 
 2:56 p.m.. 
 
 10 a. m 
 
 12:33 p.m.. 
 10:01a.m.. 
 10:30 a.m.. 
 12:40 p.m.. 
 
 D.n 
 
 D.n 
 
 4:06 p. m.. . 
 
 Total (136) . 
 
 Ended. 
 
 D.n 
 
 4:30 p.m.. 
 12:20 p.m. 
 5:56 p. m.. 
 
 8p. m 
 
 8 p. m 
 
 8 p: m 
 
 9:30 a.m.. 
 11:42 a.m. 
 8:45 p.m.. 
 12:40 p.m. 
 
 D.n 
 
 11:07 a.m. 
 4:30 p.m.. 
 10:15 a.m. 
 
 D.n 
 
 7:15 p. m.. 
 4:50 p.m.. 
 9:30 a.m.. 
 7:25 p.m.. 
 11:16 a. m. 
 
 8p. m 
 
 lip. m ... 
 9:40 a.m.. 
 4:58 p.m.. 
 
 D.n 
 
 4:15 p. m.. 
 1:20 p.m.. 
 9:10 p.m.. 
 1:50 p.m.. 
 3:30 p.m.. 
 11:35 a. m. 
 6:30 p. m . 
 7:30 p.m.. 
 4:53 p.m.. 
 
 9p. m 
 
 9:15 a.m.. 
 3:10 p.m.. 
 8:15 p.m.. 
 2:05 p.m.. 
 6:50 p.m.. 
 3:35 p.m.. 
 10:10 a.m. 
 3:l5p. m.. 
 lla.m ... 
 11:13 a.m. 
 9:45 p.m.. 
 .3:50 p.m.. 
 9:30 a.m.. 
 4:28 p.m.. 
 
 Before. 
 
 46 
 
 is 
 
 T^ 
 
 Vs 
 
 !2i 
 
 59 31 36 
 
 During. 
 
 83 
 
 27 
 
 15 
 
 KemarkB. 
 
 Lt. 
 Lt. 
 Lt. 
 Hy 
 Lt. 
 Lt. 
 Lt. 
 Lt. 
 
 Lt. 
 Lt. 
 Lt. 
 Lt. 
 Lt. 
 Lt. 
 
 Hy 
 Lt. 
 
 Hy. 
 
 Lt. 
 Lt. 
 Lt. 
 Lt. 
 Lt. 
 
 Lt. 
 Hy 
 Lt. 
 Lt. 
 Lt. 
 Lt. 
 Hy 
 Lt. 
 Hy 
 Lt. 
 Hy 
 Hy, 
 
 Lt. 
 Lt. 
 Hy, 
 Lt. 
 Lt. 
 Hy. 
 Lt. 
 Lt, 
 Lt, 
 Hy, 
 Lt. 
 Lt. 
 
 snow, 0.10 inch, 
 rain and sleet. 
 snow, tr. 
 
 . rain ; thunder ; sparks, 
 snow, tr. ; sparks, 
 snow, tr. ; no sp. obs. 
 rain, 0.14 inch, 
 snow, tr. 
 
 Do. 
 rain. 
 
 rain, 0.29 inch, 
 rain, 0.12 inch ; no sp. obs. b. 
 rain, 0.67 inch, 
 snow and sleet, 
 rain. 
 
 Do. 
 . rain ; thunder; 0.77 inch ; sparks, 
 rain, 0.72 inch. 
 . rain, 1.70 inches, 
 rain, mist, tr. ; no. sp. obs. 
 rain. 
 
 rain, 0.01 inch, 
 rain, tr. 
 rain. 
 
 Do. 
 rain, 0.46 inch, 
 .rain, 1.70 inches; thunder, 
 rain, tr. 
 
 rain, tr. ; thnnder. 
 rain. 
 
 rain, 0.09 inch ; thunder. 
 . rain, 0.56 inch ; thunder, 
 rain. 
 
 . rain ; no sp. obs. 
 rain; thunder. 
 . rain, 3.36 inches. 
 , rain, ? 
 
 Do., S 
 rain mist, 0.04 inch ; no. sp. obs. 
 rain. 
 
 . rain, 0.30 inch, 
 rain. 0.09 inch ; thunder, 
 rain, tr. 
 
 , rain, 0.56 inch ; thunder, 
 rain 0.13 inch ; thunder, 
 rain, 0.05 inch. 
 
 rain mist, 0.09 inch ; no sp. obs. 
 . rain 2.37 inches, 
 rain, 0.45 inch, 
 rain, 0.03 inch ; thunder. 
 
 ^1.69 inches. 
 
 SUMMARY. 
 
 ^t^umber of days. 
 
 (50) 
 (2)- 
 (1)- 
 (1)- 
 
 Precipitation. 
 
 Rain 
 
 Rain and sleet 
 Rain and hail 
 Suow 
 
 Before 
 
 
 During 
 
 
 & 
 
 <A 
 
 1 
 
 .C9 
 
 
 
 
 1 
 
 6 
 
 
 S.S 
 
 a 
 
 
 a 
 
 a 
 
 a 
 
 
 
 
 
 
 
 
 ;^ 
 
 'A 
 30 
 
 'A 
 U 
 
 14 
 
 'A 
 
 5 
 
 4 
 
 9 
 
 31 
 
 2 
 
 
 
 
 
 
 
 2 
 
 
 
 
 
 1 
 
 
 
 
 
 1 
 
 
 
 
 
 1 
 
 
 
 
 
 1 
 
 
 
 
 
 1 
 
 
 
MEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES. 
 
 267 
 
 Table M. — Potential on days on which precipitation occurred, New Haven, Conn., August 1, 1886, to 
 
 July 30, 1887. 
 
 [Extracts from daily jonrnaL] 
 
 Date. 
 
 1886. 
 July 30 
 
 July 
 Aug. 
 
 31 
 2 
 
 Aug.* 
 Sept. 
 
 7 
 23 
 
 Oct. 
 
 18 
 
 Oct. 
 
 21 
 
 Oct. 
 
 27 
 
 Oct. 
 
 Nov. 
 
 28 
 6 
 
 Nov. 
 
 10 
 
 Nov. 
 
 12 
 
 Nov. 
 
 17 
 
 Nov. 
 
 18 
 
 Nov. 
 
 23 
 
 Nov. 
 Dec. 
 
 25 
 
 7 
 
 Dec. 
 
 13 
 
 Dec. 
 
 15 
 
 Dec. 
 Dec. 
 Dec. 
 Dec. 
 Deo. 
 Dec. 
 
 16 
 18 
 24 
 27 
 30 
 31 
 
 1887. 
 Jan. 1 
 
 Jan. 
 Jan. 
 Jan. 
 Jan. 
 
 5 
 14 
 15 
 17 
 
 Jan. 
 
 24 
 
 Jan. 
 
 26 
 
 Jan. 
 
 29 
 
 Feb. 
 
 2 
 
 Feb. 
 
 3 
 
 Feb. 
 
 7 
 
 Feb. 
 
 8 
 
 Feb. 
 Feb. 
 
 U 
 15 
 
 Feb. 
 
 18 
 
 Feb. 
 
 22 
 
 Bemarl£u. 
 
 Light rain at 9 a. m. ; potential variable negative at 9 a. m. ; positive at other hours of ob- 
 servation. 
 Light rain at 9 a. m. ; potential positive at all observations. 
 Light rain 12:25 to 12:58 p. m. ; potential low positive at 9 and 11 a. m., zero at 1 p. m., and 
 
 high positive at 3 p. m. 
 Light rain at 1 and 3 p. m. ; potential positive at 9, 11 a. m., and 1 p. m. ; negative at 3 p. m. 
 Light rain about 9:08 a. m. ; potential high positive at 9 a. m. ; low positive at 11 a. m. ; high 
 
 positive at 1 and 3 p. m. 
 Heavy rain at 9 a. ni. ; potential variable from negative to positive at 9 a. m. ; positive at 
 
 other observations. 
 Light sprinkling rain at 11 a. m. ; potential positive at 9, 11 a. m., and 1 p. m. ; negative at 
 
 3 p. m. 
 Light rain at 9, 11 a. m., and 1 p. m. ; potential high negative at 9 a. m. ; positive at 11 a. m. 
 
 and 1 p.m. 
 Light rain at 3 p. m. ; potential positive at all observation hours. 
 Light rain 9:38 to 11 a. m. ; potential variable from positive to negative at 11 a. m. ; positive 
 
 at all other hours of observation. 
 Light rain at 11 a. m. and 1 p. m. ; potential negative at 11 a. m. ; variable from positive to 
 
 negative at 1 p. m. ; high positive at 9 a. m. and 3 p. m. 
 Light rain from 1:03 to 3 p.m.; potential high negative at 3 p.m.; positive at other ob- 
 servations. 
 Light rain all day ; potential variable from positive to negative at 9 a. m. ; high positive alt 
 
 other observations. 
 Light rain at 11 a. m. ; potential variable positive to negative at 11 a. m. ; positive at other 
 
 observations. 
 Light rain at 9, 11 a. m., and 1 p. m. ; potential high negative at 9 a. m. ; positive at other 
 
 observations. 
 Light rain 6 to 8 a. m. and at 3 p. m. ; potential positive at all observations. 
 Light snow at 11 a. m. ; heavy snow at 3 p. m. ; potential negative at 9 and 11 a. ra. ; positive 
 
 at 1 and 3 p. m. ' 
 
 Light rain all day ; potential high negative at 1 p. m. : normal (positive) at 9, 11 a. m., and 
 
 3 p. m. 
 Light rain at ll a. m., 1 and 3 p. m. ; potential positive at 9 and 11 a. m. ; negative at 1 and 
 
 3 p.m. 
 Light snow at 9, heavy snow at 11 a. m. ; potential high positive all day. 
 Light rain all day ; potential negative at 9 and 11 a. m. ; positive at 1 p. m. 
 Dense fog at 9 and 11 a. m. ; light rain at 1 p. m. ; potential positive at all observations. 
 Light snow at 9 and 11 a. m. ; potential positive at all observations. 
 Light snow all day from 1:15 a. m. ; potential high positive at all observations. 
 Snow of 30th turned to sleet at 6 a. m. to-day ; sleet turned to rain at 4 p. m. ; potential 
 
 high negative all day. 
 
 Light rain continued until 1 p. m. ; potential negative at 11 a. m. ; pdsitive at other obser- 
 vations. " 
 
 Light snow 2:10 p. m. to-2:30 p. m. ; potential positive at all observations. 
 
 Light rain 1:35 a. m. to 2 p. m. ; potential negative at 9 a. m. ; positive at other observations. 
 
 Light snow at intervals from 9:25 a. nj. until 6 p. m. ; potential po^tive all day. 
 
 Light rain 7:85 a. m. until 6:55 p. m. ; potential negative at 9 and 11 a.4P- ; positive at 1 and 
 3 p. m. 
 
 Light rain from 8 a. m. to 6 p. m.; potential negative at 9 and 11 a. m. and 1 p. m. ; positi ve at 
 3 p. m. 
 
 Light rain 11:15 a. m. to 12:15 p.m.; light snow 12:15 to 6:30p.m.; heavy snow about 
 3 p. m. ; potential negative at 3 p. m. ; positive at other observations. 
 
 Heavy rain from 12:15 p. m. to during night ; potential negative at 1 and 3 p. m. ; positive 
 at other hours of observation. 
 
 Heavy snow from 7:10 a. m. to 12:30 p. m. ; sleet from 4: 15 to 5 p. m. ; snow 5:30 p.m. to during 
 night ; potential high negative at 9 a. m. ; high positive at other hours of observation. 
 
 Light rain 12:15 to 5:30 p. m. ; potential variable from positive to negative at 3 p. m. ; posi- 
 tive at other hours of observation. 
 
 Light rain 1:15 to 3 p. m. ; sleet from 3 to U p. m. ; potential negative at 9 a. m. and 3 p. m. ; 
 positive at 11 a. m. and 1 p. m. 
 
 Light rain from 11 p. m. of 7th to 3:30 p. m. to-day, and from 6 to 9:30 p. m. ; potential neg- 
 ative at 9 and 11 a. m. ; positive at 1 and 3 p. m. 
 
 Light rain 3:40 to 4:30 p. m. ; potential positive at all observations. 
 
 Rain from 1:50 a. m. to 1:15 p. m. ; rainfall heavy at 9 a. m. ; potential negative at 9 a. m. ; 
 positive at other observations. 
 
 Light snow from 7:40 to 10:45 a. m. ; light rain from 1 to 10:25 p. m. ; potential negative at 9 
 a. m. and 3 p. m. ; positive at 11 a. m. and 1 p. m. 
 
 Heavy snow 7:20 to 10:30 a. m. ; light rain 10:30 a. m. to 1 p. m. ; potential negative at 11 a. 
 m. ; positive at other observations. 
 
268 
 
 MEMOIRS OF THE NATIONAL ACADEMY OP SCIENCES. 
 
 Table M.— Potential on days on which precipitation occurred, New Haven, Conn., August 1, 18>?6, to 
 
 July 30, 1887— Con tiuued. 
 
 Date. 
 
 IBS'? 
 
 
 Feb. 
 
 24 
 
 Feb. 
 
 26 
 
 Mar. 
 
 1 
 
 Mar. 
 
 10 
 
 Mar. 
 
 22 
 
 Mar. 
 
 28 
 
 Apr. 
 Apr. 
 Apr. 
 
 1 
 
 2 
 
 15 
 
 Apr. 
 
 18 
 
 Apr. 
 
 23 
 
 Apr. 
 Apr. 
 May 
 
 2B 
 28 
 
 7 
 
 May- 
 
 21 
 
 May 
 June 
 
 25 
 
 1 
 
 June 
 
 2 
 
 June 
 
 7 
 
 June 
 
 8 
 
 June 
 
 18 
 
 June 
 
 22 
 
 June 
 
 23 
 
 July 
 
 
 
 July 
 July 
 
 16 
 
 18 
 
 July 
 
 21 
 
 July 
 
 23 
 
 July 
 
 23 
 
 July 
 July 
 
 25 
 
 26 
 
 Eemarks. 
 
 Light rain 2:25 to 9:45 a. m. ; potential positive at all observations. 
 
 Heavy snow 10:20 a. m. to 6 p. m. ; potential positive at all observations. 
 
 Light snow 11 a. m. to 1 p. m. ; potential positive at all observations. 
 
 Eain 12:10 a. m. to 12:15 p. m., heavy at 9 a. m. ; potential negative at 9 and 11 a. m. ; posi- 
 tive at 1 and 3 p.m. 
 
 Heavy snow 8:50 to 10:30 a. m. ; light rain 11:20 a. m. to 1 p. m. ; light snow 1 to 6 p. m. 
 potential negative at 9 a. m. ; positive at other observations. 
 
 Light rain began 10:05 p. m. on 27th, ended 10:30 a. m. 28th ; potential negative at 9 ?.. m. ; 
 positive at other observations. 
 
 Light snow began 3:25 a. m., ended 3:10 p. m. ; potential positive at all observations. 
 
 Light snow began d. n., ended 6:05 p. m. ; potential positive at all observations. 
 
 Eain began 4:15 p. m. and continued during the night; potential negative at 3 p. ni. ; posi- 
 tive at other observations. 
 
 Light snow began at 9:40 a. m., turned to sleet at 1:30 p. m. ; sleet ended at 4:30 p. m. ; po- 
 tential negative at 8 and 11 a. m. ; positive at 1 and 3 p. m. 
 
 Light rain began 7 a. m. and continued during the day ; thunder storm about 10 p. m. ; po- 
 tential positive at all observations. 
 
 Light rain about 9:30 a. m. ; potential negative at 7 a. m. ; positive at other observations. 
 
 Light rain 7 to 10:45 a. m. ; potential negative at 7:10 a. m. ; positive at other observations. 
 
 Light rain 3:40 to 4:45 p. m. ; potential negative at 11 a. m. and 3 p. m. ; positive at 7 a. m. 
 and 1p.m. 
 
 Light rain 11:30 a. m. to 1:50 p. m. ; potential negative at 1 and 3 p. m. ; positive at 7 and 
 11 a. m. 
 
 Light rain 4 to 7 a. m. ; potential positive at all observations. 
 
 Heavy rain 12:01 a. m. to 1:30 p. m. ; potential negative at 7 and 11 a. m. ; positive at 1 and 
 3 p. m. 
 
 Light rain 6 a. m. to 2:15 p. m. ; potential positive at all observations. 
 
 Light rain 8:25 to 10 a. m. ; potential positive at all observations. 
 
 Light rain 10:20 a. m. to 12 m. ; potential positive at all observations. 
 
 Light rain 7:22 to 8:30 a. m. ; potential positive at all observations. 
 
 Light rain 1:55 to 2:10 p. m. ; potential positive at all observations. 
 
 Eain 6:55 a. m. ; continued during the day ; rainfall heavy at 11 a. m. and 3 p. m. ; poten- 
 tial negative at 1 and 3 p. m. ; positive at 7 and 11 a. m. 
 
 Light rain 12:05 to 9:45 a. m. ; 12:30 to 1:50 p. m. ; thunder storm from 5:20 to 6:05 p. m. ; po- 
 tential positive at all observations. 
 
 Light rain 6:30 to 7:45 a. m. ; potential positive at all observations. 
 
 Heavy rain with thunder storm 12:45 to 1:20 p. m. ; potential negative at 1 p. m. ; positive 
 at other observations. , 
 
 Light rain 8:15 a. m. to 4:55 p. m. ; rainfall heavy at 3 p. m. ; potential negative at 3 p. m. ; 
 positive at other observations. 
 
 Eain from 7:05 p. m. on 21st to 9:.30 a. m. to-day ; heavy rain at 7 a. m. ; potential nega- 
 tive at 7 a. m. ; positive at other observations. 
 
 Light rain 12:50 to ] p. m., and 3:20 p. m. and during night ; potential positive at all obser- 
 vations. 
 
 Light rain 6:30 to 7:05 a. m. ; potential positive at all observations. 
 
 Light rain with thunder storm 3:55 to 4:45 p. m. ; potential positive at all observations. 
 
 ^ SUMMARY. 
 
 During the year 72 storms, accompanied by precipitation, were noted, occurring between the hours 
 of 7 a. ni. and 3:30 p. m., the time covered by observations. 
 
 Light rain. — During 47 of the storms the precipitation consisted of light rain. In 23 of these the rain- 
 fall began before the first observation of the day; 3 were preceded by negative potentials and 21 by 
 positive. No observations were made during 9 of them. Negative potentials occurred during 25 and 
 positive during 13 of them. After precipitation negative potential was noted only once. 
 
 Heavy rain. — In 9 storms the precipitation consisted of heavy rain; 6 of these began before the first 
 observation and 3 were preceded by positive potentials; negative potentials were noted during all of 
 them. 
 
 Snow.— Snow was the precipitation during 14 of the 72 storms. Of these 14, 7 began before the first 
 obsorvation of the day ; 2 were preceded by negative and 5 by positive potentials. Negative potentials 
 were nolied during 5, and only positive duriug 9 of them. 
 
 Sleet. — The precipitation during 2 storms consisted of sleet. Both began before the first observation 
 and both were accompanied by negative potentials during precipitation. ■ 
 
MEMOIRS OP THE NATIONAL ACADEMY OF SCIENCES. 
 
 269 
 
 Table M. — Potential on days on which precipitation occurred, New Haven, Conn., August 1, 1886, to 
 
 July 30, 1887— Continued. 
 
 Date. 
 
 1886. 
 
 July 30 
 
 July 31 
 
 Aug. 2 
 
 Aug. 7 
 
 Sept. 23 
 
 Oct. 18 
 
 Oct. 21 
 
 Oct. 27 
 
 Oct. 28 
 
 Nov. 6 
 
 Nov. 10 
 
 Nov. 12 
 
 Nov. 17 
 
 Nov. 18 
 
 Nov. 23 
 
 Nov. 25 
 
 Dec. 7 
 
 Dec. 13 
 
 Deo. 15 
 
 Dec. 16 
 
 Dec. 18 
 
 Deo. 24 
 
 Dec. 27 
 
 Deo. 30 
 
 Dec. 31 
 
 1887. 
 
 Jan. 1 
 
 Jan. 5 
 
 Jan. 14 
 
 Jan. 15 
 
 Jar. 17 
 
 Jan. 24 
 
 Jan. 26 
 
 Jan. 29 
 
 Feb. 2 
 
 Feb. 3 
 
 Feb. 7 
 
 Feb. 8 
 
 Feb. 11 
 
 Feb. 15 
 
 Feb. 18 
 
 Feb. 22 
 
 Feb. 24 
 
 Feb. 26 
 
 Mar. 1 
 
 Mar. 10 
 
 Mar. 22 
 
 Mar. 28 
 
 Apr. 1 
 
 Apr. 2 
 
 Apr. 15 
 
 Apr. 18 
 
 Apr. 23 
 
 Apr. 26 
 
 Apr. 28 
 
 May 7 
 
 May 24 
 
 May 25 
 
 June 1 
 
 June 2 
 
 June 7 
 
 June 8 
 
 June 18 
 
 Precipitation. 
 
 Before. 
 
 5s 
 
 li 
 
 Daring. 
 
 be 
 <& 
 
 •a 
 
 5f 
 a 
 
 •g 
 
 Beraarks. 
 
 Lt. rain. 
 
 Do. 
 
 Do. 
 
 Do. 
 
 Do. 
 Hy. rain. 
 Sprinkling, 
 lit. rain. 
 
 Do. 
 
 Do. 
 
 Do. 
 
 Do, 
 
 Do. 
 
 Do. 
 
 Do. 
 
 Do. 
 Lt. snow at 11 a,, m ; hy. at 3 p. m. 
 Lt. rain all day. 
 Lt. rain 11 a. m. to.3 p. m. 
 Lt. snow at 9 a. m. ; by. at 11 a. m. 
 Lt. rain all day. 
 
 Fog at 9 and 11 a. m ; rain at 1 p. m. 
 Lt. snow at 9 a. m. 
 Lt. snow all day ; began 1:15 a. m. 
 Sleet all day. Snow turned to sleet 
 at 6 a. m ; sleet to rain at 4 p. m. 
 
 Lt. rain ; ended 1 p. m. 
 
 Lt. snow. 
 
 Xit. rain. 
 
 Lt. snow. 
 
 Lt. rain. 
 
 Lt. rain; hy. rain. 
 
 Hy. snow. 
 
 Hy. rain. 
 
 Hy. snow. 
 
 Lt. rain. 
 
 Do. 
 
 Do. 
 
 Do. 
 Hy. rain. 
 Sleet. 
 
 Hy. snow, followed by rain. 
 Lt. rain. 
 Hy. snow. 
 Lt. snow. 
 Hy. rain ; It. rain. 
 Hy. rain. 
 Lt. rain. 
 Lt. snow. 
 
 Do. 
 Rain. 
 Lt. snow. 
 Lt. rain. 
 
 Do. 
 
 Do. 
 
 Do. 
 
 Do. 
 
 Do. 
 Hy. rain. 
 Lt. rain. 
 
 Do. 
 
 Do. 
 
 Do. 
 
270 
 
 MEMOIES OF THE NATIONAL ACADEMY OF SCIENCES. 
 
 Table M..— Potential on days on which precipitation occurred. New Haven, Conn., August 1, 1886, to 
 N ^ July 30, 1887— Continued. 
 
 Date. 
 
 Precipitation. 
 
 Bemarka. 
 
 Before. 
 
 Dniing. 
 
 u 
 > 
 
 h 
 
 a 
 
 
 1 
 1 
 
 ii 
 
 o-l 
 
 1 
 
 i 
 
 «5 
 
 1 
 
 o 
 
 1887. 
 June 23 
 Jnne 23 
 July 6 
 July 16 
 July 18 
 July 21 
 July 22 
 July 23 
 July 25' 
 July 26 
 
 
 
 1 
 
 1 
 
 
 
 
 Lt. rain. 
 
 Lt. rain ; hy. rain. 
 
 Lt. rain. 
 
 Do. 
 Hy. rain ; t. s. 
 
 Do. 
 
 Do. 
 Lt. rain. 
 
 Do. 
 
 Do. ; t. 8. 
 
 1 
 
 1 
 
 i 1 
 
 1 
 
 
 1 
 
 
 
 
 
 
 1 
 1 
 
 
 
 
 
 
 
 
 
 1 
 
 
 1 
 
 1 
 1 
 
 
 
 
 
 
 
 
 
 
 i 
 1 
 
 
 1 
 
 
 
 
 
 1 
 
 1 
 
 
 
 
 
 
 
 SUMMARY. 
 
 Eemarks. 
 
 Precipitation. 
 
 Before. 
 
 During. 
 
 1 
 1 
 
 
 121 
 
 > 
 
 a 
 
 1 
 
 i 
 
 1 
 
 1 
 
 i 
 
 1 
 
 
 23 
 6 
 
 3 
 
 
 
 39 
 3 
 
 9 
 
 
 
 25 
 9 
 
 13 
 
 
 
 1 
 
 
 
 Total rains . , . 
 
 29 
 7 
 2 
 
 3 
 2 
 
 
 
 24 
 5 
 
 
 
 9 
 
 
 
 
 34 
 5 
 2 
 
 13 
 
 9 
 
 
 1 
 
 
 
 
 Sleet 
 
 Total (72) 
 
 38 
 
 5 
 
 29 
 
 9 
 
 41 
 
 22 
 
 1 
 
 
 Table N. 
 
 -The potential on days on which precipitation occurred at Columbus, Ohio, March 1, 1886, 
 
 to July 28, 1888. 
 
 Date. 
 
 Precipitation. 
 
 Before. 
 
 During. 
 
 1 
 
 Kemarks. 
 
 Began. 
 
 Ended. 
 
 i 
 
 I! 
 
 
 
 1 
 
 1 
 
 a 
 
 
 1886. 
 Mar. 12 
 Apr. 6 
 Apr. 26 
 Apr. 29 
 May 4 
 May 5 
 May 10 
 May 11 
 May 12 
 May 14 
 May 25 
 
 7 p. m 
 
 D. n 
 
 4 p.m 
 
 6 p.m 
 
 Late p.m.. 
 D. n 
 
 Late p. m.. 
 Late p. m . . 
 Late p. m.. 
 Late p. m . . 
 
 7 p. m 
 
 D.n 
 
 3 p. m 
 
 D.n 
 
 "i' 
 
 4 
 
 "'5' 
 3 
 
 7 
 
 '7" 
 
 7 
 7 
 6 
 8 
 
 
 1 
 
 
 
 
 Lt. snow. 
 
 Do. 
 Lt. rain. 
 
 Do. 
 
 Do. 
 
 Do. 
 Hy. rain, thunder. 
 
 Do. 
 
 Do. 
 
 Do. 
 
 Do. 
 
 1 
 
 
 
 
 
 D.n 
 
 D.n 
 
 2 p. m 
 
 D. u 
 
 .... 
 
 
 
 
 
 
 
 1 
 
 .... 
 
 
 D.n 
 
 
 
 
 
 D.n 
 
 
 
 
 
 D.n 
 
 
 
 
 
 D.n 
 
 
 
 
 
 
 
 
 
 
MEMOIRS OP THE NATIOIS^AL ACADEMY OF SCIENCES. 
 
 271 
 
 Table N. — The potential on days on which precipitation occurred at Columbus, Ohio, March 1, 1886, 
 
 to July 28, 1888— Continued. 
 
 Date. 
 
 1886. 
 May 27 
 July 9 
 July 12 
 July 13 
 July 14 
 July 15 
 July 20 
 July 27 
 July 30 
 Sept. 10 
 Sept. 15 
 Sept. 22 
 Sept. 27 
 Oct. 4 
 Oct. 26 
 Oct. 27 
 Oct. 28 
 Nov. 3 
 Nov. 10 
 
 Nov. n 
 
 Nov. 17 
 
 Nov. 22 
 
 Nov. 23 
 
 Nov. 30 
 
 Dec. 1 
 
 Dec. 13 
 
 Deo. 17 
 
 Dec. 22 
 
 Deo. 23 
 
 Dec. 24 
 
 1887. 
 
 Jan. 5 
 
 Jan. 6 
 
 Jan. 8 
 
 Jan. 14 
 
 Jan. 26 
 
 Jan. 28 
 
 Feb 
 Feb. 
 Feb. 
 Feb. 
 Feb. 
 Feb. 10 
 Feb. 11 
 Feb. 14 
 Feb. fS 
 Feb. 18 
 Feb. 21 
 Feb. 23 
 Mar. 9 
 Mar. 14 
 Mar. 18 
 Mar. 21 
 Mar. 21 
 Apr. 18 
 Apr. 22 
 May 5 
 May 31 
 June 1 
 June 2 
 June 7 
 June 9 
 June 20 
 June 21 
 June 22 
 July 5 
 July H 
 
 Precipitatiou. 
 
 Began. 
 
 3 p.m 
 
 10:25 p. m. 
 11 p. m.... 
 
 7 
 
 Late p. m . . 
 
 D. n 
 
 3:20 p. m . . 
 1:50 p. ni . . 
 1:35 p.m.. 
 2:40 p.m.. 
 
 2 p. m 
 
 6:40 p. m . . 
 AUday ... 
 
 3 p.m 
 
 Late p. m . . 
 AUday ... 
 
 3 p.m 
 
 3p.m 
 
 All day — 
 
 D. n 
 
 AUday — 
 AUday... 
 AUday... 
 
 9 a. m 
 
 D. n 
 
 AUday... 
 AUday... 
 AUday... 
 AUday... 
 AUday... 
 
 Ended. 
 
 5 p. m . .. 
 
 D.n 
 
 D.n 
 
 D.n 
 
 D.n 
 
 10 a. m .. 
 
 6 p. m 
 
 2 p. m — 
 2:20 p.m. 
 3:10 p.m. 
 
 D.n 
 
 D.n 
 
 3:30 p.m. 
 D.n 
 
 5 p. m . 
 
 10 a. m 
 
 11 a,, in 
 12m ... 
 
 AUday... 
 All day ,. . . 
 
 I p.m. 
 
 AUday.., 
 AUday... 
 AU day . . 
 3 p. m 
 
 II a. m . . . 
 AUday ... 
 
 9 a. m 
 
 3 p.m 
 
 I p.m 
 
 9 a. m 
 
 AUday... 
 AUday... 
 
 10 a. m ... 
 
 II a. m ... 
 All day ... 
 
 9 a. m 
 
 9 a.m 
 
 D.n 
 
 D.n 
 
 1 p. m 
 
 I p.m 
 
 AUday ... 
 6p.m 
 
 11 a.m ... 
 
 II a. m ... 
 1 p.m 
 
 1 p. m 
 
 2 p.m 
 
 3:10 p.m.. 
 11 a. m . . . 
 
 3 p. m 
 
 12:30 p.m. 
 12:30 p.m. 
 
 3 p. m . 
 
 3 p. m . 
 
 12m 
 
 D.n 
 
 D.n 
 
 11 a.m ... 
 
 11 a.m ... 
 11:10 a.m. 
 
 11 a.m ... 
 11 a.m ... 
 10 a.m ... 
 10 a. m ... 
 
 4 p. m 
 
 D.n 
 
 D.n 
 
 11:10 a.m. 
 
 12m 
 
 4 p.m 
 
 2:30 p.m. 
 5 p.m 
 
 3 p. m . . . 
 D. n .... 
 1 p.m — 
 
 4 p. m . .. 
 
 Before. 
 
 
 fc£-5 
 <D O 
 
 During. 
 
 
 . 1 
 1 
 1 
 
 Remarts. 
 
 Lt. Iain, thunder. 
 
 Lt. rain. 
 
 Hy. rain, thunder. 
 
 Do. 
 Lt. rain. 
 
 Do. 
 
 Do. 
 Lt. rain, trace. 
 
 Hy. rain, 2.83 inches; thunder. 
 Lt. rain. 
 
 Do. 
 
 Do. 
 
 Do. 
 Trace of rain. 
 Lt. rain. 
 
 Do. 
 
 Do. 
 Lt. rain, mist. 
 
 Do. 
 Lt. snow. 
 JLt. rain, mist. 
 
 Do. 
 
 Do. 
 Lt. snow. 
 Lt. snow. 
 Lt. rain. 
 Lt. snow. 
 
 Do 
 Lt. rain. 
 Lt. rain and snow. 
 
 Lt. snow. 
 
 Do. 
 
 Do. 
 Lt. rain. 
 Lt. snow. 
 ; Lt. rain. 
 
 Do. 
 Lt. rain, thunder, high potential. 
 Lt. rain, mist. i 
 
 Do. 
 Lt. rain. 
 Lt. rain, mist. 
 
 Do. 
 
 Do. 
 
 Do. 
 Lt. rain. 
 
 Do. 
 Lt. rain, mist. 
 Lt. rain. 
 Lt. snow. ' 
 
 Do. 
 
 Do. 
 Lt. rain. 
 
 Do. 
 Hy. rain, thunder. ^ 
 
 Do. -^ 
 
 Lt. rain. 
 
 Do. 
 
 Do. 
 
 Do. 
 
 Do. 
 Hy. rain, thunder. 
 Distant thunder. 
 Lt. rain, high potential. 
 Lt. rain. 
 Lt. rain, thunder. 
 
272 
 
 MEMOIEP OF THE NATIONAL ACADEMY OF SCIENCES. 
 
 Table N The potential on days on which precipitation occurred at Columbus, Ohio, March I, 1886, 
 
 to July 28, 1888— Continued. 
 
 Date 
 
 Precipitation. 
 
 Before. 
 
 Buring. 
 
 t 
 
 Bemarks. 
 
 Began. 
 
 Ended. 
 
 u 
 
 7*S 
 
 n 
 
 1 
 ^ 
 
 1. 
 
 i 
 1 
 
 t 
 
 o 
 
 |2i 
 
 1887. 
 July 8 
 July 18 
 July 21 
 Aug. 11 
 Aug. 17 
 Aug. 22 
 Sept. 6 
 Sept. 7 
 Sept. 22 
 Sept. 27 
 Sept. 28 
 Sept. 30 
 Oct. 10 
 Oct. 11 
 Nov. 14 
 Hov. 15 
 Nov. 24 
 Nov. 25 
 Dec. 20 
 Dec. 29 
 
 1888. 
 Jan. 5 
 Jan. 6 
 Jan. 7 
 Jan. 13 
 Jan. 17 
 Jan. 25 
 Jan. 27 
 Jan. 31 
 Feb. 24 
 Feb. 29 
 Mar. 2 
 Mar. 16 
 Mar. 23 
 Mar. 24 
 Mar. 27 
 Apr. 10 
 Apr. 19 
 Apr. 20 
 Apr. 30 
 May 4 
 May 4 
 May 8 
 May 18 
 May 25 
 June 14 
 June 27 
 July 18 
 
 11:10 a.m.. 
 3 p.m 
 
 lOa.m 
 
 Late p.m.. 
 10:45 a. m.. 
 
 11:50 a.m.. 
 3:10 p.m... 
 10:20 a.m.. 
 D.n 
 
 .... 
 
 1 
 
 8 
 2 
 
 .... 
 
 1 
 .... 
 
 1 
 
 
 
 
 Lt. rain. 
 
 Lt. rain from clear sky. 
 
 Lt. rain. 
 
 Do. 
 
 Do. 
 
 Do. 
 
 Do. 
 Lt. rain, thunder. 
 Lt. rain. 
 
 Do. 
 
 Do. 
 
 Do. 
 
 Do. 
 
 Do. 
 
 Do. 
 
 Do. 
 
 Do. 
 
 Do. 
 
 Do. 
 Lt. snow. 
 
 Lt. rain. 
 
 Do, 
 Lt. snow. 
 Lt. rain. 
 
 Do. 
 
 Do. 
 Lt. snow. 
 Lt. rain. 
 Lt. rain, mist. 
 Lt. rain and sleet. 
 Lt. rain. 
 
 Do. 
 Lt. snow. 
 
 Do. 
 Hy. rain. 
 Lt. rain. 
 
 Do. 
 Lt. snow. 
 Lt. rain. 
 
 Hy. rain, thunder. 
 Lt. rain. 
 Hy, rain 
 
 Do. 
 Lt. rain, mist. 
 Thunderstorm. 
 Lt. rain. 
 
 Do. 
 
 - 
 
 1 
 
 .... 
 
 .... 
 
 
 
 
 11 p. m 
 
 
 1 
 
 
 
 All day... 
 
 
 1 
 
 
 
 
 .... 
 
 9:30 a.m... 
 9 a. m 
 
 Late p. m .', 
 All day ... 
 
 9:40 a. m.- 
 
 i 
 
 
 
 1 
 1 
 
 11 a. m 
 
 D.n 
 
 1 
 
 
 
 
 
 8 
 
 .... 
 
 1 
 
 
 
 
 1 
 1 
 
 1 
 1 
 
 
 
 All day 
 
 
 
 
 
 
 7 p.m 
 
 lOa.m 
 
 1:30 p.m... 
 
 D. n 
 
 11 a. m 
 
 9pm 
 
 4 
 
 ... . 
 
 1 
 
 
 
 D.n 
 
 
 
 
 .... 
 
 5 p. m 
 
 
 
 
 
 10 a.m.... 
 
 17:.Wa. ni _ 
 
 1 
 
 ""i" 
 
 1 
 
 
 
 
 .... 
 
 
 
 
 All day . . 
 
 
 
 D. n 
 
 3 p. m 
 
 11 a. m 
 
 11 a, m 
 
 All day 
 
 2p.m 
 
 
 
 
 1 
 
 
 
 .... 
 
 
 
 11:30 a.m.. 
 3 p. m 
 
 • 
 
 2 
 
 
 1 
 
 
 1 
 
 
 
 
 .... 
 
 11 a. m 
 
 D. n 
 
 11:10 a m 
 
 
 
 
 
 1 n. TTi 
 
 1 
 1 
 1 
 1 
 1 
 
 
 
 1 
 
 ^ 1 
 1 
 
 D. n 1 12m 
 
 All day 
 
 
 
 
 
 
 
 
 
 
 
 D. n 
 
 D. n 
 
 3 p.m 
 
 11 a, m 
 
 D. a 
 
 1:30 p.m... 
 
 1 p.m 
 
 9 a. m 
 
 3 p.m 
 
 D. n 
 
 9:40 a.m.-. 
 
 3 p.m 
 
 1:20 p.m... 
 10:30 a.m.. 
 
 3 p. m 
 
 D. n 
 
 D. u 
 
 9a.m 
 
 3 p.m 
 
 8 a. m 
 
 1 p. m 
 
 Total ( 
 
 9:30 a.m... 
 9:30 a.m... 
 4 p. m ... 
 
 
 
 
 
 .... 
 
 
 
 
 
 
 
 
 
 
 
 
 .... 
 
 .... 
 
 10 3.m .... 
 
 1 
 
 
 
 
 1 
 
 
 3 p.m 
 
 11 a. m 
 
 .... 
 
 .... 
 
 
 
 .... 
 
 .... 
 
 .... 
 
 4 p. m 
 
 
 
 10:30 a.m.. 
 10:30 a.m.. 
 
 1 
 
 
 
 
 .... 
 
 
 
 
 
 
 7 p. m 
 
 
 2 
 2 
 
 
 1 
 1 
 1 
 1 
 I 
 
 12:15 p.m.. 
 
 .... 
 
 .... 
 
 — . 
 
 
 
 .... 
 
 .... 
 
 10 a.m.... 
 10:30 a.m.. 
 
 11 a. m 
 
 1 
 
 1 
 
 1 
 
 .... 
 
 
 
 
 
 
 
 
 
 
 
 54 
 
 2 
 
 A 
 
 
 
 1 
 
 3 p. m 
 
 2p.m 
 
 
 
 
 29 
 
 
 
 124) 
 
 52 
 
 43 
 
 24 
 
 46 
 
 SDTMMAEY. 
 
 
 ■ Before. 
 
 During. 
 
 i 
 
 > 
 
 I 
 
 'A 
 
 o 
 
 4a 
 
 h 
 U 
 
 'A 
 
 a 
 1 
 
 k 
 
 u 
 
 1 
 
 t 
 
 i 
 
 a 
 o 
 •A 
 
 Rain (103) i.... 
 
 Snow (20) 
 
 38 
 13 
 
 1 
 
 52 
 
 42 
 1 
 
 
 43 
 
 23 
 6 
 
 
 29 
 
 23 
 
 1 
 
 
 24 
 
 43 
 2 
 1 
 
 46 
 
 37 
 
 17 
 
 
 
 54 
 
 2 
 
 
 
 2 
 
 Rain and snow (1) 
 
 Total (124) 
 
MEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES. 
 
 273 
 
 Table O. — Potentials on days on which precipitation occurred at Ithaca, N. Y., October^ 1887, to 
 
 August, 1888. 
 
 fExtracIs from daily journal.! 
 
 Date. 
 
 1887. 
 
 Oct. 
 Oct. 
 
 ,5 
 
 7 
 
 Oct. 
 Oct. 
 Oct. 
 
 20 
 21 
 
 2a 
 
 Oct. 
 
 30 
 
 Nov. 
 
 4 
 
 Nov. 
 
 10 
 
 Nov. 
 
 11 
 
 Nov. 
 
 14 
 
 Nov. 
 
 15 
 
 Nov. 
 
 « 
 
 18 
 
 Nov. 
 
 19 
 
 Nov. 
 
 24 
 
 Nov. 
 
 25 
 
 Nov. 
 
 28 
 
 Nov. 
 Dec. 
 
 30 
 3 
 
 Dec. 
 Dec. 
 
 4 
 5 
 
 Dec. 8 
 
 Dec. 
 
 10 
 
 Dec. 
 
 12 
 
 Dec. 
 Dec. 
 Dec. 
 Dec. 
 
 15 
 
 17 
 18 
 20 
 
 Dec. 
 
 23 
 
 Dec. 
 Dec. 
 Deo. 
 Dec. 
 
 23 
 25 
 26 
 
 28 
 
 Dec. 
 
 29 
 
 Deo. 30 
 Dec. 31 
 
 1888. 
 Jan. 1 
 
 llemarL 
 
 Lt. rain 7:30 a. m. to 2:40 p. m. ; no special observations ; negative at 1 p. m. 
 
 Threatening weallier 10:30 a. m. to 2:30 j). ni. ; It. rain 12 m. to 12:10 p. ui, ; no special obser- 
 vations; positive at regular observations. 
 
 Lt. rain 7:30 to 10 p.m. ; negative potential at 9 and 11 a. m. 
 
 Lt.raiu 9:05 a. m. to 12:10 p. m ; no special observations ; negative at 9 a. ni. 
 
 Lt. snow 8:30 a. ni. to 11:30 a. m. ; no special observations ; positive at 9 and 11 a. m. ; If. 
 snow 1:45 to 2:15 p. ni. ; no special observations ; negative at 1 p. m. 
 
 Lt. snow 11:15 a. ui. to 12:10 p. to. ; no special observations ; positive at all regular observa- 
 tions. 
 
 Lt. rain 1:25 to 1:50 p. in. ; weather threatening 10 a. m. to 1:25 p. in. ; positive 9 to 10:50 a. ni. ; 
 positive and negative 10:50 a. m. to 1:20 p. m. ; positive 1:20 to 5 p. m. 
 
 Lt. rain 6:45 to 9:27 a.m.; high positive and negative 9 to 9:27 a. m. ; high positive, with 
 sparks, 9:30 to 10:50 a. m. ; It. rain 11:01 to 11:04 a. m. ; negative 10:50 to 11:10 a. m. ; posi- 
 .tive and negative 11:15 to 11:35 a. ra. ; It. rain 3:20 to 6:40 p. m. ; variable positive and 
 negative 3:20-to 4 p. m. ; potential zero 1:30 to 3:25 p. m. 
 
 Lt. and heavy snow 9 p. ra. on 10th to 10:04 a. ui. to-day ; It. and heavy snow 10:16 a. m. to 
 12:40 p.m. ; It. and heavy snow 1.30 p. m. to during night; high positive all day; often the 
 potential was so high that discharges took place between the needle and quadrants ; 
 during intervals of no precipitation there was a fall in potential. 
 
 Lt. rain 7:30 p. m. to 3 a. m on 15th ; no negative observed up to 5 p. m., though there was a 
 steady fall of potential from 10 a. m. 
 
 Sprinkling rain 3:15 to 7 p. m. ; weather was threatening from 9 a. m, t^, 2:15 ^ . m. ; posi- 
 tive all day, potential low, and variations were slow and small. 
 
 Lt. snow began aud ended during early morning ; potential was positive during the evening 
 of the 17th, bnt there was a fall froai 3 to 5 p. m. 
 
 Lt. snow 9:20 to 9:28 a. m. ; 9:43 to 9:54 a. m. : negative 8:55 to 9:20 a. m. ; positive and nega- 
 tive 9:20 to 9:54 a. m. ; sleet 11:45 a. m. to 2:30 p. m. ; by. snow 2:30 to 4:40 p. m. ; sleet 
 4:40 to 5:56 p. m. ; positive and negative 10 a. m. to 2 p. in. ; positive 2 to 6:.30 p. m. 
 
 Lt. rain 11:40 to 11:54 a. m. ; sleet 11:54 a. m. to 12:40 p. m. ; It. snow 12:40 to 1:40 p. m. ; It. 
 rain 1:40 p. m. and during night ; dense fog from 9 to 11:40 a. m. ; positive aud negative 
 9:40" to 11:47 a. m. ; positive during remainder of the day. 
 
 Hy. rain 10 p. m. and during night; negative 10:41 to 11:05 a. ni.; weather threatening all 
 day and wind southerly. 
 
 Sleet early' a. m. to 10:10 a. m. ; negative was observed during the morning and early even- 
 ing of the 27th and all of this day except from 10:39 to 10:52 a. m., when thejiotential was- 
 positive. 
 
 Heavy snow 8:80 to 11:58 a. m. ; positive all day. 
 
 Rain 6:40 p. m. and during night ; cloudy, threatening weather all day ; negative at 9 to 11 
 a.m. 
 
 Rain 6 p. m. and during night ; positive and negative 9 a. m. to 5 p. m. 
 
 Lt. snow 1:10 to 3:30 p.m. ; cloudy all day; positive and negative all day ; chiefly negative 
 during time of no precipitation; chiefly positive during precipitation. 
 
 Mist 11:10 to 11:20 a.m.; cloudy, threatening weather all day: positive and negative 10:51 
 to 10:57 a. m. ; positive during rest of the day except from 2:13 to 2:24 p. m,, when it was 
 negative. 
 
 Lt. rain all day until 4:45 p. m. ; positive 8 to 8:23 a. m. ; negative 8:24 to 10:20 a. m. ; posi- 
 tive 10:20 a. m. to 5 p. ui.- 
 
 Lt. snow 12:28 to 3:15 p. m. ; snow was very light and fine (trace) ; negative 8:30 to 9:30 a. m. ; 
 positive and negative 9:30 a. m.to 1 p. m. ; positive 1 to 5 p. m. 
 
 Sleet 1:10 to 2:35 p. m. ; weather cloudy and threatening all day ; positive all day. 
 
 Snow 5:05 p. m., continued during night ; positive all day ; weather cloudy. 
 
 Lt. snow all day ; high positive all day. 
 
 Sleet 4:15 p. m. and during night ; weather threatening during evening from 1 p. m. ; high 
 positive all day. ' .,,..■ , i- 
 
 Heavy snow 9:30 to 11:45 a. m. ; positive 9 a. m. to 12 m. ; variable positive aud negative 
 from 1 to 5 p. m. 
 
 Lt. snow 8:30 a. m. to 1:31 p. m. ; positive all day. 
 
 Lt. snow 12:40 to 2 p. m. ; weather cloudy ; positive all day. 
 
 Lt. snow 7:15 to 10 a. m. ; 1:45 p. m. and during night ; positive all day. 
 
 Sleet early a. ni. to 12:45 p. m. ; snow 12:45 to 1:50 p. m. ; negative 7 to. 9 p. m. on 27th ; posi- 
 tive 8 to 9:25 a. m. ; positive and negative 9:25 a. m. to 1 p. m. ; positive 1 to 1:50 p. m. 
 
 Lt. snow all day (trace); high positive all day ; sparks passed immediately upon connect- 
 ing up the electrometer and water dropper. 
 
 Lt. snow early a. m.to 9:45 a.m.; 11:40 a. m. to 1:50 p. m. ; 3:55to4:25p.m. ; positive nil day. 
 
 Lt. snow 9:50 a. m. to 1:05 p. m. ; 2 to 5:40 p. m. ; negative l:05,to 1:40 p. m. 
 
 Lt. rain early a. m. to 9:40 a. m. ; 6:45 to 9:10 p. lu. ; high negative at 9 a. m. ; negative va- 
 riable at 1 to 3 and 5 p. m. ; sparks wereobtained at 9 a. m. ; no observations after 5 p. m. 
 
 S. Mis. 94 18 
 
274 
 
 MEMOIRS OP THE NATIONAL ACADEMY OF SCIElSrOES. 
 
 Table O. — Potential on days on which precipitation occurred at Ithaca, N. T., October, 1887, to 
 
 .August, 1888 — (Jontiuued. 
 
 Date, 
 
 Kemarks. 
 
 1888. 
 Jan. a 
 
 Jan. 
 
 Jan. 
 
 Jan. 
 Jan. 
 
 Jan. 8 
 
 Jan. 9 
 
 Jan. 10 
 
 Jan. 11 
 
 Jan. 12 
 
 Jan. 13 
 
 Jan. 14 
 
 Jan. 15 
 
 Jan. 16 
 
 Jan. 17 
 
 JaB. 18 
 
 Jan. 19 
 
 Jan. 21 
 
 Jan. 22 
 
 Jan. 24 
 
 Jan. 25 
 Jan. 26 
 
 Feb. 1 
 
 Feb. 4 
 
 Feb. 7 
 
 Feb. 8 
 
 Lt. snow 9:20 to 10:55 a. ra. ; 13:30 to 1:35 p. m. ; 2:50 to 3:lt) p. in, ; negative 9:04 to 9:15 a. m. ; 
 positive at all other times until 5 p. m. ; during the light flurries of snow in the afternoon 
 the potential rose between 100 and 200 volts, but did not change to negative; (trace). 
 
 Lt. snow early a. m. to 3:20 p. m. ; negative 9 a. m. to 3 p. m. ; variable positive and negative 
 3 to 5 p. m. ; negative 5 to 6:20 p. ra. ; precipitation from 11 a. m. to 3:20 p. m. was very 
 light and snow was very moist. 
 
 Lt. snow 7:45 to 10:10 a. m. ; 3:04 p. m. and during night ; positive 9 a. m. to 3:20 p. m. ; nega- 
 tive 3:21 to 3:55 p. m. ; positive 3:55 to 5 p. m. 
 
 Lt. snow continued until 9:35 a. m. ; positive 9 to 9:35 a. m. ; precipitation was very light. 
 
 Sleet early a. m. to 2:20 p. m. ; 4 to 4:45 p. m. : negative was observed during the evening of 
 the 5th ; negative 9 a. m. to 2:40 p. m. ; positive 2:40 to 5 p. m. The magnitude of the nega- 
 tive potential increased gradually from 9 a. m. : 9 a. m. — 50 volts ; 9:30 a. m. — 1,300 volts ; 
 10 a. m. —off scale ; 10:30 a. m. — sparks ; sparks continued to pass rapidly, after exposure 
 of the collector, until 2:05 p. m. ; at 2:10 p. m. readings could again be taken and the poten- 
 tial was —5,000 volts ; it lell slowly to zero at 2:40 p. tn., became +100 volts at 2:45 p. m., 
 and continued steady; sleet ended at 2:20 p, m, ; precipitation from 4 to 4:45 p. m. ; didnot 
 seem to affect the potential. 
 
 Lt. snow early a. m. to 10 a. m. ; variable positive and negative 7:30 to 9:31 p. m. on 7th, and 
 8:30 to 11:46 a. m. to-day ; negative 11:47 a. m. to 10 p. m., except variable positive 3 to 3:15 
 p.m. 
 
 Lt. snow early a. m. to 6 p.m.; potential variable positive and nijgative during morning; 
 negative during evening; precipitation very light (trace 1 to 5 p.m.). 
 
 Lt. snow early a. m. to 10:40 a.m.; 12:55 to 2 p.m.; positive 9 to 10:50 a.m.; negative 11 
 a. m#to 12:50 p. m. ; positive 12:55 to 5 p. m. ; snow ended 10:40 a. m. ; potential changed 
 from positive to negative at 10:55 a.m. and remained negative until 12:55 p.m., when 
 snow began again. Although snow continued to fall about 8 miles sonthwest of the sta- 
 tion from 10:40 a. m. to 12 m., the potential at Ithaca did not seem to be affected by it. 
 
 Lt. snow 10 a. m. to 12:10 p. m. ; positive all day; potential was steady before snow fell, but 
 rose rapidly fr&m +950 volts at 9:55 a. m. to +3,450 volts at 10 a. m., when snow began. Af- 
 ter snow ended it fell rapidly to about +750 volts and remained steady, decreasing slowly 
 during the remainder of the day. 
 
 Lt. snow early a. m. to 9:45 a. m. ; positive all day. 
 
 Sleet 10:50 to 11:13 a. m. ; It. rain 11:13 a. m. to 12:10 p. m. ; positive 9 to 11:10 a. m. ; nega- 
 tive 11:13 a. m. to 12:20 p. m. ; positive after. 
 
 Lt. snow early a. m. to 9:30 a. m. ; positive all day. 
 
 Lt. rain earlya. m. to 10:15 a.m.; 12:15 to 2:30 p.m.; It. snow 2:30 to 4:20 p.m.; variable 
 positive and negative all day; positive during snow. 
 
 Lt. snow, early a. m. to 10 a. m. ; positive all morning ; negative during afternoon and 
 night. 
 
 Heavy snow 10:40 a. m. to 4:21 p. m. ; It. rain 4:21 to 5:30 p. m. ; snow 5:30 p. m. and during 
 night; negative 9:17' to 10:05 a. m. ; positive 10:05 a. m. to 4:20 p. m. ; negative 4:22 to 5 p. 
 m. ; no observation after 5 p. m. Potential changed from positive to negative as precipi- 
 tation changed from snow to rain. 
 
 Lt. snow continued from 17th to 12 m, to-day; 4:15 to 8 p.m.; potential positive all day, 
 and increased whenever precipitation became teavier; snow fell all day in sight of the 
 station, but did not seem to affect the potential, except when falling at the station. 
 
 Lt. snow 10:30 a. m. to 2:35 p.m. (trace); positive all day; varied in magnitude during 
 snowfall; at 9 a. m. snow was falling at several points along the horizon, especially in the 
 NW., yet the potential remained steady at Ithaca. 
 
 Lt. snow early a. m. to 11:50 a. m. (trace) ; positive all day ; potential very high and fluctu- 
 ated during snOw. 
 
 Lt. snowS a.m. to 1:15 p. m. (trace) ; potential positive all day; precipitation very light 
 indeed and fluctuations in potential were not great. 
 
 Lt. snow 5:40 p.m. on 23d to 10:45 a. m. to-day; 12:30 to 12:50 p.m.; 2:40 to 4 p. m. (trace 
 from 9 a. m. to 3 p. ra. ; 0.01 of an inch 3 to 4 p. m.) ; positive all day ; fluctuated greatly 
 during snow ; greatest amount of precipitation and highest potentials occurred between 
 3 and 4 p. m. 
 
 Lt. snow 3:40 p. m. and during night ; positive all day. 
 
 Lt. sno w 8:45 a. m. to 5:45 p. ra. (0.01 inch from 9 to 11 a. m., trace 11a. m. to 5 p. m.); poten- 
 tial positive all day, and so high that it was impossible to take any readings on account 
 of sparks, which passed even when the battery was disconnected from the quadrants. 
 
 Lt. snow ln:.iO a. m. to 2:05 p. m. ; 4:30 to 5:20 p. m. ; potential positive all day; fluctuations 
 were not great. 
 
 Sleet early a. m. to 1:50 p. m. ; It. rain 2:30 to r>:;!0 p. ra. ; potential negative all day ; sparks 
 passed between needle and quadrants at 9:35 and' 11:20 a. m., the times of heaviest pre- 
 cipitation. 
 
 Lt. SHOW 2:35 to 3:45 p. m. ; potential positive all day ; it flnctiiated greatly during snow- 
 fall, and sparks were obtained from 3:15 to 3:45 p.m., though there was no perceptible 
 variation in the amount of precipitation. 
 
 Lt. snow 7:30 to 9:45 a. m., heavy 9:45 a. m. to 2:40 p. ra. ; It. snow 2:40 to 3:30 p. m. ; potential 
 rose gradually from +800 volts at 9 a. m. to +2,150 volts at 9:30 p. u\, ; at 9:55 a, ra. there 
 was a sudden rise in potential to iiii>i« than + 5,000 volts; sparks began to pass and contin- 
 ued until 2:40 p. ra., when precipitation decreased in amount; after snow ceased falling 
 the potential remained nearly steady. 
 
MEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES. 
 
 275 
 
 Table O. — Potential on days on which precipitation occurred at Ithaca, N. Y., October, 1887, to 
 
 August, 1888— Continued. 
 
 Date. 
 
 1888. 
 Feb. 10 
 
 Feb. 11 
 Feb. 15 
 
 Feb. 17 
 
 Feb. 18 
 
 Feb. 20 
 
 Feb. aa 
 
 Feb. 25 
 
 Feb. 26 
 
 Feb. 27 
 
 Mar. 1 
 
 Mar. 2 
 
 Mar. 3 
 
 Mar. 6 
 
 Mar. 
 Mar. 
 
 Mar. 11 
 
 Mar. 12 
 
 Mar. 13 
 
 Mar. 14 
 
 Mar. 16 
 
 Mar. 17 
 
 Mar. 2;> 
 
 Mar. 26 
 
 Mar. 28 
 
 Mar. 30 
 
 Apr. 1 
 
 Apr. 2 
 
 Apr, 3 
 
 Apr. 5 
 
 Apr. 10 
 
 Apr. 12 
 
 Remarks 
 
 Lt. snow 3:45 to 7 p. m. (trace) ; potential varied from positive to negative between 12 rn. 
 and 3:45 p. m. ; high positive 3:49 to 7 p. m. ; precipitation very light. 
 
 Lt. siiow 9:20 to 10:10 a. ru. (trace) ; positive all day ; potential fell slowly during BQowfall. 
 
 Lt. snow early a. m. to 6:30 p. m. ; potential positive all day, aud so high that sparks passed 
 and it was impossible to take readings of the electrometer ; the snow drifted heavily as 
 it fell. 
 
 Lt. snow 10:55 p. m to 12 midnight ; potential positive all day ; rose slightly during jfrecipi- 
 tation, which wan very light indeed. 
 
 Lt. snow 12:01 a. m. to 10:40 a. m. ; potential positive all day except 7:40 to 7:50 a. m., when 
 it was negative. 
 
 Lt. rain 7 to 7:20 p. m. : potential variable from positive to negative 9 to 9:30 a. m. and 6:40 
 
 to 7:39 p.m. 
 ' Lt. snow 8:55 to 11:15 a. m. ; negative all day except at 9:30 for 20 sec. a. m., when it was pos- 
 itive ; negative all day on 21st until 11 p. m. 
 
 Sleet early a. m. to 9:30 a. m. ; It. rain 9:30 to 11:54 a. m., 1:50 to 2:32 p. m. ; potential negative 
 8:30 to 11:54 a. m. ; positive 11:54 a m. to 2:32 p. m. 
 
 Heavy snow 11:40 a. m. to 12:25 p. m. ; negative 10 to 10:10 a. ni., 12:44 and 12:50 p. m. ; sparks 
 were obtg,iued during snow. 
 
 Lt. snow l:ii3 to 1:15 p. ui., 2:55 to 3:20 p. m., 3:40 to 4 p. m. ; potential negative 9 to 10 a. m. ; 
 variable from positive to negative 10 to 11 a. m. ; negative 11 a. ra. to 12:40 p. m. ; positive 
 12:40 to 12:55 p. m. ; negative all other times during the day except at 3:45 p. m,, when it 
 was positive. 
 
 Lt. snow 2:55 p. m. and during night ; negiitive 11:44 a. m. to 2:54 p. m. ; variable from posi- 
 
 • tive to negative 2:55 to 6 p. m. 
 
 Sleet early a. m. to 10:30 a. m. ; It. rain 12:45 p. m. and during night ; potential negative 8:45 
 to 10:44 a. m. except at 9:09, when it was positive ; positive 10:44 a. m. to 2 p. m. ; variable 
 from positive to negative 2 to 5 p. m. 
 
 Lt. and heavy snow all day ; potential high positive all day and fluctuated with the amount 
 of precipitation. 
 
 Lt. snow 1 1:25 to 11:40 a. lu. (trace) ; potential positive and pretty steady ; precipitation very 
 light. 
 
 Lt. snow 5 p. m. and during night ; positive all day ; no observations after 5 p. m. 
 
 Lt. snow 11 to 11:30 a. m., 2:30 to 4:45 p. m. ; potential positive all day and fluctuated dur- 
 ing snow. 
 
 Lt. rain 12:35 to 4:20 p. m. ; heavy rain 4:20 to 4:58 p. m. ; heavy snow 4:58 p. m. to during 
 night; potential positive 9 a. m. to 2:15 p.m.; Tariable from positive to negative 2:15 to 
 3:10 p. m. ; positive 3:10 to 7 p. m. At 4:20 p. m. when the rain became heavy there was a 
 sudden increasein potential of more than 1,000 volts; it continued increasing; at4:42p.iu. 
 it was -f 5,000 volts as rain turned to snow ; at 4:58 p. m. it was about +6,000 volts and at 
 5:10 p. m. it was impossible to take readings owingto sparks passing between needle and 
 electrometer ; after 5:20'p. m. it was possible to get sparks J an inch long from a cascade 
 of Leyden jars connected up with the water dropper ; the jars discharged with a very loud 
 report'; a blizzard struck the station at 5.19 p. m. 
 
 Lt. snow continued until 9:30 a.m.; 12:10 p.m. aud during night; potential high positive 
 all day ; impossible to take readings of the electrometer on account of sparks. 
 
 Lt. snow all day; potential very high negative ; impossible to take readings of the elec- 
 trometer ; sparts an inch long were obtained from a cascade of Leyden jars connected with 
 the collector. 
 
 Lt. snow 2:55 to 3.40 p.m.; potential positive all day, and was less during precipitation 
 than when there was none. 
 
 Lt. rain 12:15 to 12:40 p. m. ; It. snow 4:50 to 7 p. m. ; potential variable from positive to 
 negative 8:30 a. m. to 1:22 p. m. : positive 1:22 to 5 p.m.; variable from positive to nega- 
 tive 5 to .5:35 p. m. ; no observations after 5:35 p. m. 
 
 Lt. snow ^arly a. m. to 11:20 a. m. ; potential positive all day ; very high during snow. 
 
 Lt. snow 12:15 to 2:40 p. m. ; negative at 9 and 11 a. m. ; high positive during snow ; varia- 
 ble from positive to negative after 2:40 p. m. , 
 
 Lt. rain early a. m. to 2 p. m. ; potential variable from positive to negative 9 a. m. to 2:30 p. m, ; 
 very high negative at 11 a. m. and 1 p. m. ; no special observation. 
 
 Eain 5:07 p. m. aud during night ; negative at 5 p. m. 
 
 Lt. rain 12:58 to 1:15 p. m. ; It. snow 4' to 4:30 p.m. ; negative at 9 to 11 a. m. and 1 and 3 p. m. ; 
 no special observation. 
 
 Heavy rain 4 to 6:30 p. m. ; potential variable from positive to negative all day.' 
 
 Lt. rain 4:45 to 5:10^p. m. ; potential negative all day; no special observation. 
 
 Lt. snow 10:35 to 10:55 a. m. ; potential negative all day. 
 
 Lt. rain 9:15 to 11:20 a. m. ; It. rain 5:10 to 6 p. m. ; potential positive 9 a. m. to 1 p. m. ; 
 very high from 11 a. m. %o 1 p. m. ; variable from positive to negative 1 to 4 p. m. 
 
 Lt. rain 8 a. m. to 4:20 p. m. ; positive 9 to 9:20 a. m. ; negative 9:20 a. m. to 4 p. m. ; positive 
 4 to 5 p. m. 
 
 Lt. snow 2:25 to 3:20 p.m. (trace); potential variable from positive to negative 8:45 a.m. 
 to 3 p, m. ; negative 3 to 11 p. m. 
 
276 
 
 MEMOIRS OF THE NATIONAL ACADEMY OP SCIENCES. 
 
 Table O. — Potential on days on which precipitation occurred at Ithaca, N. Y., October^ 1887, to 
 
 August, 1888 — Continued. 
 
 Hemarks. 
 
 1888. 
 Apr. 14 
 
 Apr. 18 
 
 Apr. 19 
 Apr. 20 
 
 Apr. 21 
 
 Apr. 24 
 May 1 
 2 
 
 May 
 
 4 
 
 May 
 
 8 
 
 May 
 
 10 
 
 May 
 
 13 
 
 May 
 May 
 
 13 
 14 
 
 May 
 
 15 
 
 May 
 
 16 
 
 May 
 
 18 
 
 May 
 May 
 
 25 
 27 
 
 May 
 
 28 
 
 May 
 
 29 
 
 May 
 
 31 
 
 June 
 
 2 
 
 June 
 
 10 
 
 June 
 June 
 June 
 
 11 
 15 
 23 
 
 Jnne 
 
 24 
 
 June 
 June 
 June 
 July 
 
 26 
 
 28 
 
 29 
 
 5 
 
 July 
 
 8 
 
 July 
 
 19 
 
 July 
 
 19 
 
 July 
 
 26 
 
 Lt. rain early a. m. to 10:15 a. m. | 11:02 to 11:22 a. m. ; 12:30 to 6 p. m. ; precipitation from 
 3:40 to 6 p. m. was a. mixture of rain and sttow ; potential negative all day-. 
 
 Lt. rain early a. m. to 9 a. m. ; potential negative all day on the 17th ; potential variable 
 from positive, to negative 7:30 to 10 a.m. to-day; very high during precipitation, sparks 
 were obtained 7:45 to 8:35 a. m. 
 
 Lt. rain 5:45 to 5:50 p. m. (trace) ; potential positive 9 to 10:15 a. m. ; negative 10:15 a. m. to 
 6 p. m. 
 
 Lt. snow early a. m. to 10:45 a. m. ; 4:40 to 8 p. m. ; potential negative 9 to 10:45 a. m. ; vari- 
 able from positive to negative 10:45 to 11:30 a. m. ; negative 11:30 a. m. to 5 p. m. ; no ob- 
 servation after 5 p. m. 
 
 Lt. snow 11:02 a. m. to 12 m. (trace); potential negative 9 to 9:40 a. m. ; variable positive to 
 negative 9:40 a. m. to 12:40 p. m. ; negative 12:40 to 5 p. m. 
 
 Light flurries of snow at 9:20 and 9:45 a. m. ; potential negative 9 to 10:55 a. m. 
 
 Rain during early a. m. (trace); potential negative; dense haze during evening of April 30. 
 
 Lt. rain during early a. m. (trace); potential negative during evening of May 1. 
 
 Lt. ram 6:30 to 8:30 a. m. ; potential fell during evening of May 3, but did not change to neg- 
 ative during the time that observations were taken. 
 
 Lt. rain a,a. m. to 12:30 p. m. ; potential variable from positive to negative 9 a. m. to 12 m. ; 
 positive during remainder of the day. 
 
 Lt. rain 1:55 to 2:15 p. ra. ; heavy rain 3:52 to 4:20 p. m. ; thunderstorm ; potential positive 
 
 9 a. m. to 3 p. m. ; variable positive to negative 3 to 4:50 p. m. 
 
 Lt. rain 11:15 a. m. to 12:40 p.m.; thunderstorm; It. rain 4:10 to 4:40 p. m. ; thunderstorm; 
 potential variable positive to negative all day. 
 
 Eain 6:35 to 7:30 p. m. ; potential negative all day. 
 
 Lt. rain 8:30 a. m. to 12:30 p. m. ; potential variable positive to negative 9 a. m. to 12:10 p. m. ; 
 negative 12:10 to 6 p. m. 
 
 Lt. rain 11:30 a. m. to 12:15 p. m. ; heavy rain and hail 1:15 to 1:55 p. m. ; potential negative 
 all day except at 1:30, 2:30, 4:20, and 4:40 p. m., when it was positive ; potential during rain 
 and hail, 1:15 to 1:55 p. m., was variable and so high that sparks were obtained. 
 
 Lt. rain 8:55 to 10 a. m. ; 11:40 a. m. to 12:05 p. m. ; 12:25 to 1:15 p. m. ; 1:50 to 2:50 p. m. ; poten- 
 tial positive 9 to 11:10 a. m. ; variable from positive to negative 11:10 a. m. to 4:10 p. m.; 
 daring the interval of no rain, 12:05 to 12:25 p. m., the potential was highest and variable 
 from positive to negative ; sparks passed almost oontinnally ; the clouds hung so low dur- 
 ing that time that only the base of hills 2 miles away across the valley could be seen ; the 
 hill tops were hidden. 
 
 Lt. rain 10:30 to 10:,=i0 a. m. ; 12:45 to 4:15 p. m. ; potential variable positive to negative 9 
 a. m. to 3:30 p. m. ; positive 3:30 to 5 p. m. 
 
 Lt. rain 4:35 p. m. and daring night ; potential positive all day ; no special observations. 
 
 Lt. rain 7:45 to 8:15 p. m. ; potential variable from positive to negative all day ; no observa- 
 tions after 5 p. ra. 
 
 Lt. rain 8:30 to 9:25 a. m. (trace); potential variable positive to negative 8:50 to 10 a. m. ; 
 positive after ; precipitation was very light but the potential was so high at times that 
 sparks passed between needle and quadrants. 
 
 Lt. rain 9:50 to 10:30 a. m. ; potential negative 9 to 9:30 a. m. ; variable from positive to neg- 
 ative 9:30 to 11:40 a. m. ; positive during rest of the day. 
 
 Lt. rain 3:31 to 4:07 p. m, ; thunderstorm; potential variable positive to negative 9:40 to 
 11:40 a.m.; positive 11:40 a. m. to 3:10 p. m. ; variable from positive to negative (chieily 
 negative) 3:10 to 4:35 p. ra. ; positive after that time. 
 
 Heavy rain 2:25 to 3:30 p. m. ; thunderstorm ; potential variable positive to negative all 
 day, and so high during rain that it was impossible to take readings on account of sparks. 
 
 Lt. rain 9:45 to 11:30 p. m. ; thunderstorm ; no observations ; there was a, fall of potential 
 from 3 to 5 p. m. 
 
 Lt. rain 2 to 3:15 p. m. (trace); potential variable from positive to negative all day. 
 
 Lt. rain 7 to 9:30 a. m. ; observations from 9 to 9:30 a. m. only ; potential positive all day. 
 
 Lt. and heavy rain 12:30 to 2:45 p. m. ; thunderstorm ; potential positive 9 a. m. to 12 lii ■ 
 variable from positive to negative 12 m. to 2:45 p. m. ; positive after that time. ' ' ' 
 
 Lt. rain 2:50 to 4:10 p.m.; thunderstorm ; potential positive dvwing morning ; variable from 
 positive to negative during the remainder of the day. 
 
 Lt. rain 8 to 9:10 a. m. ; observations began at 9 a. m. ; potential positive aU day. 
 
 Lt. rain all day ; potential positive all day. 
 
 Lt. rain continued until 10:10 a. m. ; potential positive all day. 
 
 Lt. rain 12:15 to 12:55 p.m.; thunderstorm; potential variable from positive to negative 
 
 10 a. m. to 2:30 p. m. ; positive at other times during the day. 
 
 Lt.rain 10 p.m. and during night; potential variable from positive to negative 12 m to 5 
 
 p. m. ; no observations after 5 p. m. 
 Lt. rain 2:30 to 5:30 p. m. ; potential variable from positive to negative durin"- the whole 
 
 day. ° 
 
 Heavy rain 2:35 to 2:55 p. m. ; It. rain 3:15 to 3:40 p. m. 
 
 negative all day. 
 Lt. rain 1:05 to 3:28 p. m. ; 5:05 p. m. and during night 
 
 negative 12 m. to 5 p. m. 
 
 potential variable from positive to 
 potential variable from positive to 
 
MEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES. 
 
 277 
 
 Table O. — Potential on days on which precipitation occurred at Ithaca, N. Y., October, 1887, to 
 
 August, 1888 — Continued. 
 
 Date. « 
 
 1888. 
 July 31 
 Aug. 4 
 Aug.^ 8 
 
 Aug. 
 Aug. 
 
 Aug. 11 
 Aug. 12 
 Aug. 13 
 Aug.- 17 
 Aug. 21 
 Aug. 22 
 
 23 
 31 
 
 Hemarkg. 
 
 Lt. rain 2:10 to 2:55 p. m. ; potential variable from positive to negative 12:30 to 4:30 p. m. 
 
 Rain 5:30 to 7:15 p. m. ; thunderstorm ; potential negative at 5 p. m. 
 
 I^t. rain 5:20 to 5:25 p. m. ; fine shower rain from a single isolated cloud ; potential posi- 
 tive all day. 
 
 Lt. rain 12 m. to 12:55 p. m, 0.01 inch ; potential poaitiye all day ; low during precipitation. 
 
 Lt. rain 3 to 10 a. m. ; potential negative at 9 a. m. ; positive during rest of day. 
 
 Lt. rain 8:35 to 10 a. m. ; potential negative at 9 a. m. ; positive during rest of day. 
 
 Lt. rain 8 to 10:45 a. m. ; potential steady positive all day. 
 
 Lt. rain 2:20 p. m. and during night ; potential steady positive all day. 
 
 Lt. rain continued until 10:20 a. m. ; potential low positive at 9 a. m. ; increased slowly dur- 
 ing the day. 
 
 Lt. rain 4 to-4:15 p. m. ; potential negative at 1 p. m. 
 
 Lt. rain 7 to 11 p. m. ; potential negative 3 and 5 p. m. 
 
 Date. 
 
 1887. 
 
 Oct. 5 
 
 Oct. 7 
 
 Oct. 20 
 
 Oct. 21 
 
 Oct. 22 
 
 Oct. 22 
 
 Oct. 30 
 
 Wov. 4 
 
 Nov. 10 
 
 Nov. 10 
 
 Nov. 10 
 
 Nov. 11 
 
 Nov. 15 
 
 Nov. 19 
 
 Nov. 19 
 
 Nov. 24 
 
 Nov. 25 
 
 Nov. 28 
 
 Nov. 30 
 
 Dec. 2 
 
 Dec. 4 
 
 Dec. 5 
 
 Dec. 8 
 
 Dec. 10 
 
 Deo. 12 
 
 Dec. 15 
 
 Dec. 17 
 
 Dec. 18 
 
 Dec. 20 
 
 Deo. 22 
 
 Dec. 23 
 
 Dec. 25 
 
 Dec. 26 
 
 Dec. 26 
 
 Dec. 28 
 
 Dec. 29 
 
 Dec. 30 
 
 Dec. 31 
 
 1888. 
 Jan. 
 Jan. 
 Jan. 
 Jan. 
 Jan. 
 
 Precipitation. 
 
 Began. 
 
 Ended. 
 
 7:.30a.m... 
 
 '12m 
 
 7:30 p.m... 
 9:05 a.m... 
 8:30 a.m... 
 1:45 p.m... 
 11:15 a.m.. 
 1:25 p. m . . . 
 6:45 a.m... 
 11:01a.m.. 
 3:20 p.m... 
 
 All 
 2:15 p.m... 
 9:20 a.m... 
 11:45 a.m.. 
 11:40 a.m.. 
 
 lOp. ni 
 
 Early a. m . 
 8:30 a. m... 
 6:40 p. m.. . 
 
 6 p.m 
 
 1:10p.m... 
 11:10 a. ra.. 
 Early a.m. 
 12:28 p.m.. 
 1:10p.m... 
 5:05 p. m . . . 
 
 All 
 4:15p.m.. . 
 9:30 a.m... 
 8:30 a.m... 
 12:40 p.m.. 
 7:15 a.m.- . 
 1:45p.m.. . 
 Early a.m. 
 
 All 
 Early a.m. 
 9:50 a.m... 
 
 Early a.m. 
 6:45 p.m... 
 9:20 a.m... 
 Early a.m. 
 7:45 a. m.. . 
 
 2:40 p.m... 
 
 12:10 p.m.. 
 
 10 p. m 
 
 12:10 p.m.. 
 
 11:30 a.m.. 
 
 2:J5p.m... 
 
 12:10 p.m.- 
 
 1:50 p.m... 
 
 9:27 a. m . . - 
 
 11:04 a.m.. 
 
 6:40 p. m 
 
 day.- 
 
 7:10 p.m... 
 
 9:54 a. m.. . 
 
 5:o6p. m.. . 
 
 D.n 
 
 D.n 
 
 10:10 a.m.. 
 
 12 m 
 
 D.n 
 
 D.n 
 
 3:30 p.m... 
 
 11:20 a.m.. 
 
 4:45 p. m.. . 
 
 3.15 p.m... 
 
 2:30 p.m... 
 
 D.n 
 
 day. 
 
 D.n 
 
 ll:45a. m.- 
 l:31p.m... 
 
 2p. m 
 
 10 a. m 
 
 D.n 
 
 1:50p.m... 
 day. 
 
 4:25 p. m. 
 
 5:40 p. m . 
 
 9:40 a.m.. 
 9:10 p.m.. 
 3:15 p.m.. 
 3:20 p.m.. 
 10:10 a.m. 
 
 Before. 
 
 > 
 
 
 10 
 
 24 
 
 ■43 « 
 
 2 b 
 
 o o 
 |Zi 
 
 During. 
 
 3« 
 d 0) 
 bit* 
 
 ID h 
 
 a £ 
 
 !2i 
 
 Bemarks. 
 
 Lt. rain. * 
 
 Lt. rain ; no sp'l obs. 
 
 Lt. rain. 
 
 Lt. rain ; no sp'l obs. 
 
 Lt. snow. 
 
 Lt. snow ; no sp'l obs. 
 
 Do. 
 Lt. rain. 
 
 Do. 
 
 Do. 
 
 Do. 
 Hy. snow. . 
 Mist, It. rain. 
 Lt. snow. 
 
 Lt. sno w and sleet. 
 Lt. snow, sleet and It. rain. 
 Lt. rain. 
 Sleet. 
 Hy. snow. 
 Lt. rain. 
 
 Dd: 
 Lt. snow. 
 Mist, It. rain. 
 Lt. rain. 
 Lt. snow. 
 Sleet. 
 Lt. snow. 
 
 Do. 
 Sleet. 
 
 Heavy snow. 
 Lt. snow. 
 
 Do. 
 
 Do. 
 
 Do. 
 Lt. snow and sleet. 
 Lt. snow, tr. ; sparks. 
 Lt. snow. 
 
 Do. 
 
 Lt. rain. 
 
 Lt. rain: spaiks. 
 Lt. snow, tr. 
 Lt. snow ; moist. 
 Lt. snow. 
 
278 
 
 MfeMOmS OF THE NATIONAL ACADEMY OF S0IBN0E8. 
 
 Table O. — Potential on days on which precipitation occurred at Ithaca, N. Y., October, 1887, to 
 
 August, 1888 — Ooutiaued. 
 
 / 
 
 Date. 
 
 1888. 
 Jan. 4 
 
 Precipitation. 
 
 Began. 
 
 Jan. 
 
 6 
 
 Jan. 
 
 8 
 
 Jan. 
 
 9 
 
 Jan. 
 
 10 
 
 Jan. 
 
 10 
 
 Jan. 
 
 11 
 
 Jan. 
 
 13 
 
 Jan. 
 
 14 
 
 Jan. 
 
 15 
 
 Jan. 
 
 16 
 
 Jan. 
 
 17 
 
 Jan. 
 
 18 
 
 Jan. 
 
 19 
 
 Jan. 
 
 21 
 
 Jan. 
 
 22 
 
 Jan. 
 
 24 
 
 Jan. 
 
 25 
 
 Jan. 
 
 26 
 
 Feb. 
 
 1 
 
 Feb. 
 
 4 
 
 Feb. 
 
 7 
 
 Feb. 
 
 8 
 
 Feb. 
 
 10 
 
 Feb. 
 
 11 
 
 Feb. 
 
 15 
 
 Feb. 
 
 18 
 
 Feb. 
 
 20 
 
 Feb. 
 
 22 
 
 Feb. 
 
 25 
 
 Feb. 
 
 20 
 
 Feb. 
 
 27 
 
 Mar. 
 
 1 
 
 Mar. 
 
 2 
 
 Mar. 
 
 3 
 
 Mar. 
 
 6 
 
 Mar. 
 
 t 
 
 Mar. 
 
 8 
 
 Mar. 
 
 11 
 
 Mar. 
 
 12 
 
 Mar. 
 
 13 
 
 Mai-. 
 
 14 
 
 Mar. 
 
 16 
 
 Mar. 
 
 16 
 
 Mar. 
 
 17 
 
 Mar. 
 
 22 
 
 Mar. 
 
 26 
 
 Mar. 
 
 28 
 
 Mar. 
 
 30 
 
 Mar. 
 
 30 
 
 Apr. 
 
 1 
 
 Apr. 
 
 2 
 
 Api. 
 
 3 
 
 Apr. 
 
 5 
 
 Apr. 
 
 5 
 
 Apr. 
 
 10 
 
 Apr. 
 
 12 
 
 Apr. 
 
 14 
 
 Apr. 
 
 18 
 
 Apr. 
 
 19 
 
 Apr. 
 
 20 
 
 Apr. 
 
 20 
 
 Apr. 
 
 21 
 
 Apr. 
 
 24 
 
 3:04 p.m... 
 Early a. m. 
 Early a. m . 
 Early a. m . 
 Early a.m. 
 12:55 p. m.. 
 
 10 a. m 
 
 10:.50a.m.. 
 Early a. m. 
 Early a. m. 
 Early a. m. 
 10:40 a.m.. 
 4:15 p. m.- . 
 11:30 a.m.. 
 Early a. m . 
 8 a. m .. .. 
 Early a. ra . 
 3:40 p.m... 
 8:45 a. m . . . 
 11:30 a.m.. 
 Early a. ra. 
 2:35 p.m.. . 
 7:30 a.m.-. 
 3:45 p.m... 
 9:20 a.m... 
 Early a. m 
 12:01a.m.. 
 
 7 p. m 
 
 8:55 a. m.. . 
 Early a. m. 
 11:46 a.m.. 
 1:03 p.m... 
 2:55 p.m... 
 Early a. m. 
 
 , All 
 11:25 a. m.. 
 5p. m 
 
 11 a. m 
 
 12:35 p.m.. 
 12:10 p.m.. 
 
 All 
 2:50 p.m... 
 12:15 p. m.. 
 4:50 p. Ill . . . 
 Early a. m . 
 12:15p.m.. 
 Early a.m. 
 5:07 p.m... 
 12:58 p.m.. 
 
 4 p. m 
 
 4 p. m 
 
 4:45 p. m.. . 
 10:35 a. m . . 
 9:15 a. m.. . 
 5:10p. m... 
 
 8 a. m 
 
 2:25 p. m . . - 
 Early a. ni . 
 Early a. m. 
 5:45 p. m . . . 
 Early a. ra. 
 4:40]!. m.. . 
 11:02 a. 111.. 
 9:20 a.m... 
 
 Ended. 
 
 D.n 
 
 4:45 p. m.. 
 10 a. m... 
 
 6 p.m 
 
 10:40 a.m. 
 
 2 p. m 
 
 12:10p.ra. 
 12:10 p.m. 
 9:30 a.m.. 
 4:20 p. m.. 
 10 a. m . . . 
 
 D.n 
 
 8p.m 
 
 2:35 p.m.. 
 11:50 a.m. 
 1:15 p.m.. 
 
 4 p.m 
 
 D.n 
 
 5:45 p. m. 
 5:20 p.m.. 
 5:30 p.m.. 
 3:45 p.m.. 
 3:30 p.m.. 
 
 7 p.m 
 
 10:10 a.m. 
 6:30 p. m.. 
 10:40 a.m. 
 7:-,i0p. m.. 
 11:16 a. m. 
 2:30 p. ra.. 
 12:25 p.m. 
 
 4 p. in 
 
 D.n 
 
 D.n 
 
 day. 
 
 11:40 a.m. 
 
 D.n 
 
 4:45 p.m.. 
 
 D.n 
 
 D.n 
 
 day. - 
 
 3:40 p.m.. 
 
 12:40 p.m. 
 
 7 p. m 
 
 11:20 a. m. 
 2:40 p.m.. 
 
 2 p. in 
 
 D.n 
 
 1:15 p. m.. 
 4:30 p. m . . 
 6:30 p.m.. 
 5:10 p.m.. 
 10:,55a.m. 
 11:20 a.m. 
 
 6 p. m 
 
 4:20 p.m.. 
 3.20 p.m.. 
 
 6 p. m 
 
 9 a. m .... 
 5:50 p. ni . . 
 10:45 a.m. 
 
 8 p. m 
 
 12m 
 
 9:45 a.m.. 
 
 Before. 
 
 !jJl.g 
 
 k5 
 
 3f 
 
 <A <£ 
 
 <Q U 
 
 a m 
 
 •^ CO 
 
 o o 
 'A 
 
 Daring. 
 
 
 '%- 
 
 Semarks. 
 
 Lt. snow. 
 Sleet ; sparks. 
 Lt. snow. 
 Lt. snow, tr. 
 Lt. snow. 
 
 Do. 
 Lt. snow ; sparks. 
 Sleet and rain. 
 Lt. snow. 
 
 Lt. snow and It. rain. 
 Lt. snow. 
 
 Heavy snow and rain. 
 Lt. snow. 
 Lt. snow, tr. 
 Lt. snow, tr. ; sparks. 
 Lt. snow, tr. 
 Lt. snow ; sparks. 
 Lt. snow. 
 Lt. snow ; sparks. 
 Lt. snow. 
 Sleet and rain. 
 Lt. snow ; sparks. 
 Lt. and heavy snow ; sparks. 
 Lt. snow, tr. ; + sparks. 
 Lt. snow, tr. 
 Lt. snow ; sparks. 
 Lt. snow. , , 
 
 Lt. rain. 
 Lt. snow. 
 Sleet and rain. 
 Heavy snow ; sparks. 
 Lt. snow. 
 
 Do. 
 Sleet and rain. 
 Lt. and heavy snow ; sparks. 
 Lt. snow, tr. 
 Lt. snow. 
 
 Do. 
 Rain and heavy snow ; sparks. 
 Lt. .snow ; sparks. 
 Lt. snow ; — sparks. 
 Lt. snow. 
 Lt. rain. 
 Lt. snow. 
 Lt. snow ; sparks. 
 
 Do. 
 Lt. rain. 
 
 Do. 
 
 Do. 
 Lt. snow. 
 Heavy rain. 
 Lt. rain. 
 Lt. snow. 
 Lt. rain. 
 
 Do. 
 
 Do. 
 Lt. snow. 
 
 Lt. snow and It. rain. 
 Lt. rain ; sparks. 
 Lt. rain, tr. 
 Lt. snow. 
 
 Do. 
 Lt. snow, tr. 
 Lt. snow. 
 
MEMOIBS OF THE NATIOISTAL ACADEMY OF SCIENCES. 
 
 279 
 
 Table O — Potential on days on which precipitation occurred at Ithaca, N. Y., October, 1887, to 
 
 August, 1888 — Coutinued. 
 
 Date. 
 
 1888. 
 May 1 
 May 2 
 May 8 
 May 10 
 May 12 
 May 12 
 May 13 
 May 14 
 May 15 
 May 16 
 May 18 
 May 25 
 May 37 
 May 28 
 May 29 
 May 31 
 June 2 
 June 11 
 June 15 
 June 23 
 June 24 
 June 26 
 June 28 
 June 89 
 July 5 
 July 8 
 July 18 
 July 19 
 July 26 
 July 31 
 Aug. 4 
 Aug. 11 
 Aug. 12 
 Aug. 13 
 Aug. 17 
 Aug. 21 
 Aug. 22 
 Aug. 23 
 Aug, 31 
 
 Precipitation. 
 
 Began. 
 
 Ended. 
 
 Early a. m. 
 Early a. m. 
 
 8 a. m 
 1:55 p.m. 
 11:15 a.m.. 
 4:10 p.m.. 
 6:35 p. m.. 
 8:30 a.m.. 
 11:30 a.m. 
 8:55 a. in - . 
 10:30 a. m . 
 4:35 p.m.. 
 7:45 p.m.. 
 8:30 a.m.. 
 9:50 a.m.. 
 3:31p.m.. 
 2:25 p.m.. 
 2p. m 
 
 7 a. m . I . . 
 12:30 p.m. 
 2:50 p.m.. 
 
 8 a. m 
 
 12:15p.m. 
 10 p.m... 
 2:30 p.m.. 
 2:35 p.m.. 
 1:05 p.m.. 
 2:10 p.m.. 
 5:30 p.m.. 
 
 12 m 
 
 3 a. m 
 
 8:35 a.m.. 
 
 8 a. m 
 
 2:30 p.m.. 
 
 4 p. m , 
 7p. m 
 
 12:30 p.m. 
 4:20 p. m . . 
 12:40 p. m. 
 4:40 p. m.^ 
 7:.30p.m.. 
 12:30 p.m. 
 l:.55p. m.. 
 2:50 p.m.. 
 4:15 p.m.. 
 
 D.n 
 
 8:15 p.m.. 
 9:25 a. m . . 
 10:30 a. m . 
 4:07 p.m.. 
 3:30 p.m.. 
 3:15 p.m.. 
 9:30 a.m.. 
 2:45 p.m.. 
 4:10 p.m.. 
 9:10 a.m.. 
 All day. 
 
 10:10 a.m. 
 12:55 p.m. 
 
 D.u 
 
 5:30 p.m.. 
 3:40 p.m.. 
 
 D.n 
 
 2:55 p. m . - 
 7:15 p.m.. 
 12:55 p.m. 
 10 a. m .. . 
 
 10 a. m .. . 
 10:45 a.m. 
 
 D.n 
 
 10:20 a.m. 
 4:15 p. m.. 
 
 11 p. m 
 
 Before. 
 
 Total (146) . 
 
 49 
 
 et to 
 
 <a o 
 
 •a 
 
 68 
 
 CD ^ 
 |21 
 
 Buring. 
 
 29 21 
 
 C3 (Q 
 IB 
 
 o o 
 'A 
 
 74 
 
 Remarks. 
 
 51 18 
 
 no ep'l obs. 
 
 Lt. rain, tr. 
 Lt. rain. 
 
 Do. 
 Heavy rain, thunder. 
 Lt. rain, thunder. 
 Lt, rain. 
 
 Do. 
 
 Do. 
 Lt. rain and hail ; sparks. 
 Lt. rain. 
 
 Do. 
 Lt. rain ; 
 Lt. rain. 
 
 Do. 
 
 Do. 
 Lt. rain ; thunder. 
 Lt. rain ; thunder ; sparks, 
 Lt, rain, tr. * 
 Lt, rain ; no sp'l obs. 
 Hy. rain ; thunder. 
 Lt, rain ; thunder, 
 Lt, rain ; no sp'l obs. 
 Lt, rain. 
 
 Do. 
 Lt. rain ; 
 Lt. rain. 
 
 Do. 
 Hy. rain. 
 Lt. rain. 
 
 Do. 
 Lt. rain ; 
 Lt. rain ; 
 Lt. rain. 
 
 Do, 
 Lt, rain ; no sp'l obs. 
 
 Do. 
 
 Do. 
 
 Do.> 
 
 Do, 
 
 thunder. 
 
 thunder, 
 no sp'l obs. 
 
 Storms. 
 
 
 Before. 
 
 During;. 
 
 1 
 
 <3 
 
 > 
 
 ?'S 
 
 
 9) . 
 
 
 
 
 s? 
 
 .sg 
 
 fe 
 
 £ U 
 
 J=>o. 
 
 fi 
 
 ^t 
 
 s> 
 
 
 a 
 
 -j3 
 
 i^a 
 
 ^S 
 
 "S 
 
 
 
 -M 
 
 
 
 MJ= 
 
 j= 
 
 
 
 fi 
 
 
 
 
 o 
 
 
 
 O 
 
 
 
 
 
 ^ 
 
 ^ 
 
 » 
 
 ^ 
 
 ^ 
 
 fen 
 
 ^ 
 
 
 Ksiin .. ... --, 
 
 66 
 64 
 4 
 3 
 4 
 5 
 1 
 
 18 
 24 
 2 
 
 2 
 3 
 
 
 42 
 21 
 
 2 
 2 
 
 1 
 
 6 
 19 
 2 
 
 
 2 
 
 
 16 
 4 
 1 
 
 
 
 
 
 38 
 22 
 2 
 2 
 4 
 5 
 1 
 
 12 
 
 38 
 1 
 
 0' 
 
 
 
 
 Snow 
 
 Sleet 
 
 
 
 Rain and sleet 
 
 Kain and hail . 
 
 
280 
 
 MEMOIRS OF THE NATIONAL ACADEMY OP SCIENCES. 
 
 Table P. — Potential on days on which precipitation occurred at Baltimore, Md., 1885, 1886, and 1887. 
 
 Date. 
 
 Remarks. 
 
 1885. 
 Jan. 1 
 
 Jan. 
 
 4 
 
 Jan. 
 
 5 
 
 Jan. 
 
 6 
 
 Jan. 
 
 11 
 
 Jan. 
 
 12 
 
 Jan. 
 
 15 
 
 Jan. 
 
 16 
 
 Jan. 
 
 17 
 
 Jan. 
 
 2:1 
 
 Jan. 
 
 24 
 
 Jan. 
 
 28 
 
 J'eb. 
 
 1 
 
 Feb. 
 
 4 
 
 Feb. 
 
 Feb. 
 
 9 
 
 Feb. 
 
 W 
 
 Feb. 
 
 13 
 
 Feb. 
 
 14 
 
 Feb. 
 Feb. 
 
 15 
 16 
 
 Feb. 
 
 17 
 
 Feb. 
 
 18 
 
 Feb. 
 
 24 
 
 Feb. 
 
 25 
 
 Feb. 
 
 26 
 
 Feb. 
 
 27 
 
 Mar. 
 
 1 
 
 Mar. 
 Mar. 
 
 
 7 
 
 Mar. 
 
 8 
 
 Mar. 
 
 12 
 
 Mar. 
 Mar. 
 
 14 
 
 No record in a. m. ; variable positive and negative from 12 m. to 1:30 p. m. ; strong positive 
 
 from 3 to 4 p. m. ; then steady po.sitive ; sleet from 12 m. to 1:20 p. m. ; It. snow from 2:40 
 
 to 4:25 p. m. 
 Negative from 7 a. m. all day ; it. snow b. 7 a. ni. changed to sleet 9:15 a. m., changed to rain 
 
 10:20 a. m., changed to sleet 1:30 p. m., e. 6 p. ni. 
 Negative from midnight to 1 p. ra. ; then positive except slight negative at 10 p. m. ; It. rain 
 
 b. 7:25 p. m. 
 Positive in a. m. except negative from 2 to 4 a. m. and from 9 to 9:30 a. m. ; variable strong 
 
 positive and negative from noon niitil 7 p. m. ; then positive ; It. rain all day, c 7:1(/ p. ra. 
 Negative from 10 a. m. to 2 p. m.aud from 10 p. m. to midnight ; positive at other times ; It. 
 
 rain from 12:20 to 2:40 p. m. and from 6:40 p. m. to midnight. 
 Variable negative, with occasional positive, from midnight to 2 p.m.; then positive ; rain 
 
 e. 5:50 a. m. ; It. rain from 12:20 to 12:55 p.m. 
 Strong negative from 5:30 a. m, to noon ; uo record in p. m. ; sleet b. early a. m, changed to 
 
 rain 7:15 a. m., e. 2:15 p. m. ; It. rain from 5:40 to 8:15 p. m. 
 No record in a. ni. ; from noon positive all day excei^t slight negative at 1 and 4 p. m. ; It. 
 
 rain b. early a. m., e. 10 a. m., followed by dense fog all day. 
 Negative from 1 to 6 a. m. ; then weali negative and positive all day ; It. rain b. and e. early 
 
 a. m., followed by clearing weather, with gale, NW. winds. 
 Variable positive from midnight to 9 p.m. except occasional negatives from 10 a, m. to 12 
 
 m. ; variablepositiveanduegativefromOp.m. to midnight ; It. snow b. 6:40 p. m. changed 
 
 to sleet 9:30 p. m. 
 Negative from midnight to 7 a. m. ; then positive, with occasional negative, until 3 p. m., 
 
 then positive; sleet e. 9:40 a.m. ; snow and sleet covered ground 2 inches. 
 Positive untU,,6 a. m. ; then strong -variable positive and negative until 9 a. m. ; then nega- 
 tive until noon ; then strong positive until 8 p. m. ; It. snow b. early a. m., e. 9:20 a. m. 
 Negative from 12 mid. to 1 a. m. and at 4 a. m. ; uo record from 4 a. m. to noon ; then posi- 
 tive ; It. snow before sunrise; cloudy, followed by fair weather. 
 Steady positive until 6 a. m. ; then negative and positive until 8 a. m. ; then positive until 
 
 10:30 a. m. ; then negative and positive until 3 p.m. ;. strong variable positive and nega- 
 tive from 5 to 9 p. m. ; then positive until midnight, except slight negative at 11:30 p. m. ; 
 
 cloudy, It. rain from 6:30 to 7:50 p. m. 
 Slight negative at 2:30 and 4:30 a. m. ; then positive until 6 p. m. ; then variable positive 
 
 and negative until midnight ; It. rain b. and e. before sunrise ; It. rain b. 9:15 p. ui. changed 
 
 to moist snow at 10:30 p. m. 
 Positive until 5:30 a. m. ; negative 5:30 to 7 a. m. ; zero 7 -a,, m. to noon ; positive in p. m. ; 
 
 It snow during the night e. before sunrise, 1 inch. 
 Lt. rain b. 10:05 a. m. changed to by. rain 6 p. m. continued until midniglit, with by. thunder 
 
 and lightning from 10 to 11 \>. m. 
 Positive from noon to 7 p.m., then negative to midnight; rain e. early a.m.; It. snow b. 
 
 7:.50 .1. 111. continued at intervals until 10:20 a. m.'; NW. gale winds in p. m. 
 Variable positive and negative from 11 a. m. to 3 p.m. ; positive at other times; It. snow 
 
 from 11:30 a. m. to 4:35 p. ni.,2 inches. 
 Variable positive until 3 p. m. ; theu variable positive and negative until 9:15 p. m. ; then 
 
 s'eady positive ; It. snow b. 1:15 p. m. continued all day. 
 Positive all day ; It. snow ended shortly after midnight. 
 Negative from midnight to 5 a. m. ; then strong variable positive and negative until 9:30 
 
 a. m. ; then positive ; by. rain during the early morning, ioUowed by snow from 9:50 to 
 
 11:15 a.m.; NW. gale. 
 Positive until 9:30 p. m. ; then strong variable positive and negative until 11:30 p. m. ; cold 
 
 wave; by. snow b. 9 p. m. 
 Positive all day except slight negative at 5 to G a. m. and 7 to 7:30 p. m. ; It. snow ended 
 
 early a. m. 
 Strong variable positive until 8:30 p. m. ; then strong variable positive and negative; It. 
 
 snow b. 3:30 p. m. continued at night. 
 Strong variable positive and negative until 5:30 a. m. ; then variable positive ; hy. snow 
 
 contiiiued all night, e. 0:25 a. m., 7.5 inches. 
 Variable positive all day except slight negative at 4 to 5 a. m. and from 6:45 to 8 p. m. ; It. 
 
 sleet b. 5:50 p. m. changed to snow 7:30 p. m. 
 Positive and negative from 1 to 7 a.m., then positive; It. snow continued durino- uisrht 
 
 ended 10:25 a.m. " *' 
 
 Negative from 6 to 8 a. m. ; strong variable positive and negative from 10 a. m. to 9 n ra 
 
 theu positive ; It. rain at intervals from 10:45 a. m. to 6:20 p. m. ' 
 
 Steady positive all day ; It. rain before sunrise. 
 Positive and negative from 7 to 11 p. m. of 6th ; strong positive and negative from 1 to 5 
 
 a. m. of 7th ; negative at 7 a. m. and 6 to 7 p. m. ; positive at other times ; It. snow b MO 
 
 a. m., e., before sunrise ; It. snow from 8:50 to 10:10 a. ra. 
 Negative and positive from 4:30 to 7 a. m. ; positive at other times ; It. snow from 6 to 6-45 
 
 II. ra. 
 Strong positive and negative variable from 1:30 to 3:30 a. m. and from 10 to 10:30 a. ni • netr- 
 
 ative variable Irom 3:30 to 10 a. m. and from 11 a. m. to 7:30 p. m., then variable positive • 
 
 It. ram beloro sunrise and from 7:50 a. m. to 7:20 p. m., when it changed to snow ' 
 
 Variable positive with occasional negative all day ; It. snow fell at intervals all day 
 Negative from 1 to 2 a. m. ; positive all day ; It. snow, e. early a. ni. 
 
MEMOIRS OP TniB NATIONAL ACADEMY OF SGIENCEB. 
 
 281 
 
 Table P. — Pot&iMal on days on which precipitation occurred at Baltimore, Md., 1885, 1886, and 
 
 1887— Continued. 
 
 Date. 
 
 Remarks. 
 
 1885. 
 Mar, 15 
 
 Mar. 1!) 
 
 Mar. 22 
 Mar. 31 
 
 Apr. 3 
 
 Apr. 4 
 
 Apr. 5 
 
 Apr. 7 
 
 Apr. 8 
 
 Apr. 11 
 
 Apr. 13 
 
 Apr. 15 
 
 Apr. 16 
 
 Apr. 28 
 
 May # 
 
 May 6 
 
 May 7 
 
 May 13 
 
 May 14 
 
 May 17 
 
 May 20 
 
 May 21 
 
 May "^2 
 
 May 23 
 
 May 24 
 
 May 25 
 
 May 26 
 
 May 27 
 
 May 28 
 
 May 29 
 
 May 30 
 
 May 31 
 
 June 4 
 
 June 5 
 
 June 7 
 
 June 8 
 
 June 15 
 
 June 16 
 
 Jaue 17 
 
 Negative with occasional positve from 8 a. m. to 10 p. m. ; strong at 3:30 a. m., 11 a. m., and 
 
 4 to 5 p. m. : It. rain before sunrise and from 3:30 to 3. 45 p. m. ; fog from 7:30 to 10 p. m. 
 Weak variable positive, except strong variable positive and negative from 8:45 to 10:45 
 
 a. m. ; It. snow from 8:25 to 10:45 a. m. 
 
 Variable positive and negative all day : It. snow from 9: 10 a. m. to 2:45 p. m. 
 
 Negative at 6:30 a. m. and variable positive and negative from 2 to 10. p.m.; positive at 
 other times; It. rain from 5:55 to 8:40 p. m. 
 
 Positive until 7 p. m. ; negative until midnight, with strong variations from 10 to 11 p. m. ; 
 rain b. 7:50 p. m., continued during night. 
 
 Negative until noon; positive and negative until 3 p. m., then positive; rain during the 
 early morning; It. sleet from 10:25 to 10:35 a.m. 
 
 Positive until 11:30 p.m. ; very strong po.sitive 8 to 9 p. m. ; strong variable positive and nega- 
 tive from 11:30 p. m. to 1 a. m. of 6th ; It. rain from 11:30 to 11:50 p. m. ^ 
 
 Positive in a. ni. ; positive with occasional negative from noon to 6:30 p. m. ; negative from 
 6:30 to 8 p. ni., then positive; It. rain at intervals from 1:40 to 10:20 p. m. 
 
 Negative and positive from midnight to 7 a. m., tiien positive until noon; It. rain from 12:50 
 to 2:15 p. ni. ; thunderstorm and rain from 3:22 to 5:25 p. m. 
 
 Positive until 1 p. m., then negative and positive until 6 p. m., then steady positive ; It. rain 
 
 b. 10:10 a. m., changed to snow 10:15 a. m., e. 2:25 p. m. ; It. rain from 3:25 to 3:50 j). m. 
 No record in a. m. ; negative and positive until 5:30 p. m., then positive ; It. rain from 11:40 
 
 to 11:45 a. m. ; brisli NW. winds, cloudy. 
 
 Negative at 1 a.m., then positive until 9 a.m., then variable positive and negative until 
 midnight; It. rain from 10:40 a. m. to 12:20 p. m. ; It. rain b. 3:.50 p.m., continued during day. 
 
 Negative and positive until 6 a. m., then weak variable positive ; It. rain, e. early a. m. 
 
 Positive in a. m. ; strong negative from noon to 5 p. m., then positive. ; It. rain from 3:10 to 
 3:55 p. m. 
 
 Strong negative and positive from 11 p. m. of April 30 to 9 a. m. of May 1, then positive to 
 noon ; no record in p. m. ; It. rain at intervals from 7:15 a. m. to 4:50 p. m. 
 
 Slight negative at 7:30, 9:30, and 11 p. m. of 5th, and 2 a. m. and 6 to 7:30 a. m. of 6th ; also 
 at 7 p.m. ; cloudy; It. SE. winds; It. rain b. 8:25 p.m. 
 
 Strong negative with occasional positive from 12:30 to 4 p. m., then positive; It. rain con- 
 tinued, changed to heavy rain in early a. m., e. 4:10 p. m. 
 
 Positive to 3 a.m., then strong negative until 7:30 p.m., then positive; rain from early 
 a. m. to 3:20 p. m. 
 
 Negative and positive from midnight to 7:30 p. m., then positive ; It. rain 6:40 to 7:40 a. m., 
 and from 5:40 to 6 p. m. 
 
 No record in a.m., variable positive in p. m. ; It. rain from 11:15 to 11:20 p. m. 
 
 Negative from midnight to 1 a. m. and from 6:30 to 8 a. m. ; positive at other times until 5 
 p. m., then negative and positive uutil 10 p. m. ; It. rain from 9:'25 to 9:35 p. m. 
 
 Variable positive until 4:30 p. m., then negative and positive until midnight ; It. rain at in- 
 tervals from 6:43 to 10:20 p. m. 
 
 Positive and negative from midnight to 6 a. m., then strong negative until noon, then posi- 
 tive and negative until 6 p.m., then steady negative; rain b. early a. m., e. 9:40 p.m.; 
 fell in heavy showers during the forenoon. 
 
 Positive from noon to 9 p. m. ; steady weak negative at other times; It. rain began and 
 ended before sunrise. 
 
 Weak steady negative in a. m. ; negative and positive fronj noon to 3 p. m., then positive. ; 
 the record does not seem to be good on 23d and 24th. ; It. rain before sunrise, and from 11:10 
 to 11:15 a.m. 
 
 Zero until 10:30 a. m., then variable positive to 12 m. ; It. rain and thunderstorm began 
 about 11 p.m. 
 
 Variable positive in p.m., with slight negative at 4 p.m.; thunderstorm and ram, e. early 
 
 a. m. . , , . . 
 
 Steady positive in a. m. : negative and positive from noon to 4 p. m., then variable positive ; 
 
 It. rain b. 12:45 p. m. and fell at intervals the rest of the day. 
 Variable positive all day, except slight negative from 5 to 5:30 a. m. ; It. rain fell at inter- 
 vals during the morning; cloudy. . , , r o« 
 Steady positive in a.m. ; no record from 12 m. to 2 p.m. ; negative from 2 to 5:30 p.m., then 
 
 •negative and positive; cloudy, with rain from 9:05 a. m. to 10:35 p. m. 
 Negative and positive in a. m. ; positive from noon to 6 p. m., then variable negative ; cloudy 
 
 with It. rain at intervals from early a. m. to 8:40 p. m. 
 Variable negative all a.m., except slight positive at 5:30 a.m.; cloudy, with occasional 
 
 showers all day ; It. thunderstbrm from 3:06 to 3:35 p. m., and from 6:55 to 7:55 p. m. 
 Positive in a. m. ; It. rain and thunderstorm from 3:30 to 5 p. m. 
 Heavy thunderstorm and rain, with hail and high winds from 2:35 to 3 p.m. 
 Positive in a. m. ; It. rain with lightning from 8:55 to 9 p. ni. 
 No record from noon to 2 p. m. ; negative from 2 to 8 p. m. and at 7 p. m., then positive ; It. 
 
 rain at intervals from 9:15 a. m. to 5:40 p. m. 
 Lt. thunderstorm 6 to 7 p. m. ; It. rain 6:15 to 6:35 p. m. 
 Lt. rain 6:40 to 6:43 p. m. and from 7:05 to 8:20 p. m. ; thunder from 7 to 8:30 p. m. ; silent 
 
 lightning until midnight. ^ ~ i ■ j.-i 
 
 Variable positive in p. m. ; hy. rain from 12:15 a. m. to 1 a. m., followed by It. ram until 
 
 8 a. m. ' 1 
 
282 
 
 MEMOIE8 OF THE NATIONAL ACADEMY OP SCIENCES. 
 
 Table P. — Potential on days on which precipitation occurred at Baltimore, Md., 1885, 1886, and 
 
 1887— Continued. 
 
 Remarks. 
 
 1885. 
 June 25 
 
 June 26 
 
 June 27 
 June 28 
 
 July 2 
 
 July 5 
 
 July 6 
 
 July 7 
 
 July 10 
 
 July 13 
 
 July 14 
 
 July 18 
 
 July 20 
 
 July 25 
 
 July 26 
 
 July 27 
 
 July 28 
 
 July 29 
 
 July 31 
 Aug. 1 
 Aug. 2 
 
 Aug. 3 
 
 Aug. 
 Aug. 
 
 Aug. 8 
 
 Aug. 12 
 
 Aug. 
 Aug. 
 Aug. 
 Aug. 
 Aug. 
 
 13 
 14 
 21 
 22 
 23 
 
 Aug. 
 Aug. 
 Aug. 
 
 25 
 26 
 29 
 
 Aug. 
 Aug. 
 Sept. 
 Sept. 
 
 30 
 
 31 
 
 4 
 
 5 
 
 Sept. 
 
 8 
 
 Sept. 
 
 9 
 
 Sept. 
 
 10 
 
 Sept. 
 
 11 
 
 Sept. 
 
 2'2 
 
 Sept. 
 
 23 
 
 Positive until 7 a. m., then negative and positive until 4:30 p. m., then negative to midnight ; 
 
 It. rain from 9:45 a.m. to 4:10 p. in. , 
 
 Steady negative in a. m. ; steady positive after 1 p. m. ; cloudy, with rain from 9:20 to 9:30 
 
 a. m. ; SE. winds. 
 Variable positive in a. m. ; It. rain from 6:15 to 7:20 a. m. and from 1 to 2. 15 p. m. 
 Negative and positive from noon to 5 p.m., then positive; very heavy rain 2:50 to 10:15 
 
 a. m. ; amount 4.47 inches, of which 4.19 inches fell between 2:50 and 7 a. m. ; very severe 
 
 thunder and lightning accompanied the storm about 4 a. m. 
 Strong positive and negative from 11:30 a. ra. to 2 p. m. ; low positive rest of the time ; It. rain 
 
 from 12:35 to 1 p. m. 
 Positive in a. m. ; fair in a. m. ; hy. rain and thunderstorm from 2:08 to 6:5P p. m. 
 Positive and negative from 12 m. to 2 p. m., then positive ; It. rain from early a. ra. to 10:20 
 
 p. m. 
 Positive until 9 a. m. ; then negative until 2:30 p. m. ; then positive ; It. rain from 12:50 to 
 
 1 p. m., from 9:57 to 10 p. m., and from 10:15 to 10:20 p. m. 
 Positive all day except slight negative from 6 to 8 p. m. ; It. rain from 7:10 to 7:20 a. m. and 
 
 from 12:50 to 1 p. m. ; no record during last rain. 
 Variable positive all day ; It. rain from 5:08 to 5:13 p. m. and from 7:36 to 7:45 p. m. 
 Slight negative midnight to 1 a. m. ; strong negative from 3 to 4 a. m. ; steady positive at 
 
 other times ; It. rain b. 12:50 a. m. , ended before sunrise. 
 Positive in a. m. ; It. rain 8:45 to 9:20 p. m. ; thunder 8:30 to 9:30 p. m. 
 Variable positive in a. m., with slight negative at 6 a. m. ; It. rain from 11:50 a. m. to 12:16 
 
 p. m. and from 2:37 to 2:57 p. m. ; silent lightning from 8:40 to 8:50 p. m. 
 Lt. rain from 6:52 to 7:08 p. m. ; lightning from 8:40 to 9:30 p. m. 
 Fair in a. m. ; hy. thunderstorm, with rain at intervals, from 3:10 to 8:15 p. m. 
 Variable positive in p. m. ; It. rain from early a. m. to 7:20 a. m. and from 1:20 to 1:50 p. m. 
 Slight negative to zero until 5 a. m. ; variable positive rest of the time ; It. rain 12:^ to 1:10 
 
 a.m. 
 'Slight negative at 5 a. m. ; strong positive at 11 a. m. ; strong variable positive a^d nega- 
 tive from 12:30 to 2 p. m. ; positive at other times ; It. rain from 11:30 to 11:48 a. m. and 
 
 from 1:05 to 1:20 p. m. ' 
 
 Variable^poaitive in a. m. ; It. rain and thunderstorm 3:05 to 3:40 p. m. 
 Lt. rain fell during early a. m. ; It. rain 8:25 to 9:10 p. m. ; thunder from 8 to 9:30 p. m. 
 Lt. rain before sunrise ; It. rain from 8 to 8:45 p. m. ; It. rain b. 10:10 p. m. ; thunderstorm b. 
 
 6:30 p.m. 
 Lt. rain changed to hy. rain during early a. m. and continued at intervals until 7:30 p. m. ; 
 
 amount of rainfall 3.35 inches ; the thunderstorm whicfi was prevailing at midnight 
 
 e. 3 a. m. ; a thunderstorm occurred between 4 and 7:30 p. m. 
 Variable positive in p. m. ; It. rain during early a, m., followed by clear weather. 
 Variable positive until 9 a. m., then strong variable negative, with occasional positive, until 
 
 midnight; It. rain b. 8:25 a. m. and continued all day. 
 Variable positive all day with slight negative at midnight and at 9:30 to 10 a. m. ; It. rain 
 
 continued at intervals until 11:25 a. m. 
 Variable positive in a. m. ; It. rain from 9:15 to 9:25 a. m., from 10:20 to 10:50 a. m. and from 
 
 3:13 to 3:50 p. m,, with thunder from 3 to 4 p. m. 
 Lt. rain during early a. m. ; It. rain and thunderstorm froia 4:05 to 8:10 p. m. 
 Steady positive in p. m. ; It. rain during early a. m., followed by fair weather. 
 Negative from 6:30 to 8 p. m. of 20th ; variable positive on 21st ; It. rain from 8:45 to 9:05 p. m. 
 Steady positive in a. m. ; It. rain and thunder from 6 to 7:20 p. m. ; It. rain 9:15 to 10:40 p. m. 
 Lt. rain during early a. m. ; It. rain 2:20 to 2:33 p. m. ; thunder from 2 to 2:40 p. m. ; silent 
 
 lightning from 6:55 to 8:30 p. m. 
 Positive in a. m. ; fair in a. m. ; hy. rain and thunder from 3:25 to 7:15 p. m. 
 Positive in p. m. ; It. rain fell during early a. m. , followed by clearing weather. 
 Variable positive all day except slight negative at 9 a. m. and 6 p. m. ; It. rain from 5:50 to 
 
 6 p. ra. and from 7:45 to 9:30 p. m. 
 Positive in a. m. ; It. rain from 10:15 to 11:05 p. ra. ; thunder from 10 to 11 p. m. 
 Positive in p. m. ; It. rain during early a. m. 
 
 Positive in a. m. ; thunderstorm with It. rain at intervals from 3:50 to 7:50 p. m. 
 Positive from noon to 4 p. m. ; then variable positive and negative until 8 p. m?; then posi- 
 tive ; It. rain in early a. m. and from 2:33 p. m., at intervals, until 6 p. m. 
 Negative and positive from 3 to 6 a. m. ; variable positive rest of the time ; It. rain 4:30 to 
 
 7:05 p. m. 
 Variable strong positive and negative 1 to 2 a. m, , from 12 m. to 2 p. ra. ; variable positive at 
 
 otlier times ; It. rain during early a. m. and from 12:35 to 12:45 p. m. ; silent lightning 7:15 
 
 to 10 p. ra. 
 Negative from 1 to 1:45 p. ra. ; variable positive and negative from 6:30 to 9:30 p. ra. ; posi- 
 tive at other times ; It. rain 6:25 to 7:30 p. ra. 
 Negative and positive frora midnight to 4 a. m. ; then positive until noon ; no record in 
 
 p. m. ; It. rain in early a. ni. 
 Negative from 2 to 3 p. m., at 6.30 p. m., and from 10 p. m. to midnight; positive at other 
 
 times; cloudy,, with occasional rains all day. 
 Low negative from 12 to 1 a. m. ; positive rest of the day ; It. rain ended early a. ra. 
 
 i 
 
MEMOIRS OF THE HATIOKAL ACADEMY OP SCIENCES. 
 
 283 
 
 Table P. — Potential on days on which precipitation occurred at Baltimore, Md., 1885, 1886, and 
 
 1887~CoutiQued. 
 
 Date. 
 
 Bemarbs. 
 
 1885. 
 Oct. 2 
 
 Oct. 
 Oct. 
 Oct. 
 
 3 
 4 
 6 
 
 Oct. 
 
 8 
 
 Oct. 
 
 12 
 
 Oct. 
 
 13 
 
 Oct. 
 Oct. 
 
 14 
 21 
 
 Oct. 
 Oct. 
 
 23 
 29 
 
 Oct. 
 
 30 
 
 Nov, 
 
 1 
 
 Nov. 
 Nov. 
 
 2 
 5 
 
 Nov. 
 Nov. 
 
 6 
 
 7 
 
 Nov. 8 
 
 Nov. 
 Nov. 
 
 9 
 13 
 
 Nov. 
 
 Nov. 
 
 18 
 19 
 
 Nov. 
 
 21 
 
 Nov. 
 
 22 
 
 Nov. 
 
 23 
 
 Nov. 
 
 24 
 
 Nov. 
 Nov. 
 Nov. 
 Nov. 
 
 25 
 
 27 
 28 
 29 
 
 Deo. 
 Dec. 
 
 1 
 3 
 
 Dec. 
 Dec. 
 
 Deo. 
 
 13 
 
 Dec. 
 
 14 
 
 Dee. 
 
 23 
 
 Dec. 
 
 31 
 
 1886. 
 Jan. 4 
 
 Variable positive and negative from 7 a. in. to noon ; It. rain 6:57 to 7:15 a. m. ;' It. rain lb. 2:40 
 p. m., continued rest of day ; It. thunder from 9:10 to 9:45 p. m. 
 
 Positive in p. m., except negative at 9 p. m. ; It. rain e. 6:35 a. m. ; It. rain 8:50 to 9:05 p. m. 
 
 Positive all day ; record not good in a. m. ; It. rain at intervals from 6:50 a. ru. to 1:35 p. m. 
 
 Positive until 4 a. m. ; then negative until 6 a. m. ; then strong variable positive and nega- 
 tive until 3 p.m.; then positive, except slight negative at 9:15 p. m. ; It. rain from early 
 a. m. to 2:47 p. m. , 
 
 Positive until 6 a. m. ; then strong variable negative, with occasional positive, until 2 p. m. ; 
 then positive; It. rain from 6:45 a. m. to 1:43 p. m. 
 
 Variable positive until 6 p. m. ; then strong variable negative until midnight ; It. rain b. 
 4:05 p. m. continued during night. 
 
 Strong variable negative until 7 a. ni. ; then variable positive ; rain continued during a. m., 
 e. 1:43 p. m. 
 
 Positive all day, except negative from 7 to 8 p. m. ; It. rain from 6:35 to 7:20 p. m. 
 
 Strong negative from 4:30 to 10 a. m. ; positive at other times ; hy.tain b. early a. m.,6._ 
 11:45 a. m. ; amount, 1.48 inches. 
 
 Variable positive all day; It. rain 8:15 to 8:22 p. m. 
 
 Variable positive in a. m. except slight negative at 11 a. m. ; It. rain during the day, increas- 
 ing to hy. rain after dark; thunder and lightning at 5:45 to 6 p. m. 
 
 Positive in p.m., except negative 6:30 to 7:30 p. m. ; rain ended earlya. m. ; It. rain 11:55 
 
 a. m. to 12:50 p. m. anil from 5:05 to 7:25 p. m. 
 
 Positive in a. m. ; strong variable positive and negative from 4:30 p. m. to midnight ; It. rain 
 
 b. 6:20 p. m. changed to hy^rain about sunset. 
 
 Strong positive and negative until 4:.30 a. m. ; then positive; rain ended early a. m. 
 
 Variable positive all day, with slight negative from 11:30 p. m. to midnight ; It. rain from 
 9:45 to 10:30 p. m. 
 
 Positive all day ; It. rain in early a. m. 
 
 Negative and positive from 8:30 to 5:30 a. m. and from 3 to 4 p. m. ; positive at other times ; 
 It. rains at intervals from 3:55 a. m. to 3:53 p. m. 
 
 Negative from 1 to 2:30 a. m. ; variable positive and negative from 8 a. m. to 3 p. m. ; nega- 
 tive from 10:15 p. m. to midnight ; positive at other times; lain b. 12:35 a.m. and contin- 
 ued at intervals all day. 
 
 Strong positive and negative from 1:30 to 6 a. m. ; then positive ; rain ended early a. ra. 
 
 Slight negative at 9:80 a. m. ; positive and negative from 2:30 to 4:15 p. m. ; positive at other 
 times; It. rain 11:07 a. m. to 4:35 p. m. 
 
 Slight negative from 2 to 3 a. m! ; variable positive rest of the day ; It. rain 9:10 to 9:35 p. ra. 
 
 Negative and positive from 11 a. m. to 4 p. m. ; variable positive at other times ; It. rain be- 
 fore sunrise ; It. rain 10:55 a. m, to 1:40 p. m. 
 
 Negative from 10 p. m. of 20th to midnight and at 6:30 a. va. to-day ; positive at other times ; 
 no record from noon to 2 p. m. ; It. rain 10:50 a. m. to 12:35 p. m. 
 
 Positive in a. m. ; strong variable positive and negative in p. m. ; rain b. 11:30 a. m„ con- 
 tinued all day. 
 
 Strong variable positive and negative from 2 to 5 a. m. ; positive and negative until 1 p, in, ; 
 posili ve 1 to 7 p. m. ; then strong'negative to midnight ; It. rain all day, changed to snow 
 
 9:10 p.m. J „ . . 4. 
 
 Negative until 3 a. m. ; negative and positive until noon ; positive m p. m. ; rained all night 
 
 and ended 11:20 a.m. 
 Positive all dav ; trace of snow 6 to 7:20 p. m. 
 
 Positive all day, except slight negative 2 p. m. ; It. rain 2:50 to 3:15 p. m. 
 Variable positive all day, except negative from 8 to 9 a. in. ; It. rain before sunrise. 
 Positive in a. m. ; negative and positive from noon to 3:30 p.m.; then positive ; It. ram from 
 
 10:25 a.m. to' 6:40 p.m. , • .x, i one 
 
 Variable positive and negative from 6 a. m. to 6 p. m. ; It. rain mist b. early a. m., e. 8:05 p. m. 
 Slight negative at 9 and 11 a. m., and 3 p. m. ; positive at other times ; It. rain and sleet 11:40 
 
 Strong positive and negative from 5 to 7 a. m. ; slight negative at 8 and 10 p. ra. ; positive 
 at other times; It. rain frora 5:15 to 7:40 a. m. ' ,. „ „ „„ . o qo 
 
 Slight negative 10 to 11 p. m. of 8th ; strong variable negative from 11:80 a. m. to 2:30 p. m. 
 to-day slight negative at 11 p.m.; variable positive at other timea^, It. rain before sun- 
 rise : h'y. rain 11:15 a.m. to 1:50 p.m. ; It. rain 9:43 to 10:20 p. m. 
 
 No record until 10:30 a. m. ; then strong negative until 4 p. m. ; then strong positive to 10:30 
 p m ■ then strong negative until 1 a. m. of 14th ; rain b. 7:45 a. m. and continued all day. 
 
 Positive after 1 to 11 a. m., except negative at 4:30 a. m. ; strong negative 12 m, to 3 p.m.; 
 then steady positive ; rained until 3 p. m. 
 
 Slight negative 10 p. m. of 22d and 7 a. m. to-day ; then positive to 3:30 p. m. ; then negative 
 and positive to midnight ; It. rain 6:35 to 6:50 p. m. ,, . ^ , j. 
 
 Strong variable negative from 4 a. m. to noon ; positive m p. va. ; It. rain trom early a. m. to 
 12:45 p. m. 
 
 Steady positive from 9 p. m. of 3d to 12:30 a. m. of 4th ; then variable positive and negative 
 until 6 a. m, ; then strong variable negative, with an occasional weak positive, until 10 
 p. m. ; then slowly rising positive until midnight ; It. rain b. 12:10 a. m., increasing to a 
 heavy rain after daylight, e. 10:20 p. m. ; SE. gale winds. 
 
284 
 
 MEMOIRS OF THE NATIONAL ACADEMY OE SCIENCES. 
 
 Table P. — Potential on days on which precipifation occurred at Baltimore. Md., 1885, 1886, and 
 
 1887— Continued. 
 
 Bate. 
 
 1886. 
 Jan. 5 
 
 Jan. 
 
 6 
 
 Jan. 
 
 8 
 
 Jan. 
 
 9 
 
 Jan. 
 
 10 
 
 Jan. 
 
 25 
 
 Jan. 
 
 27 
 
 Jan. 
 
 28 
 
 Jan. 
 Jan. 
 
 29 
 30 
 
 Jan. 
 Feb. 
 
 31 
 3 
 
 Feb. 
 
 4 
 
 Feb. 
 Feb. 
 
 10 
 11 
 
 Feb. 
 
 12 
 
 Feb. 
 
 J5 
 
 Feb. 
 
 .23 
 
 Feb. 
 
 25 
 
 Feb. 
 
 26 
 
 Mar. 
 
 8 
 
 Mar. 
 
 12 
 
 Mar. 
 
 13 
 
 Mar. 
 
 18 
 
 Mar. 
 
 19 
 
 Mar. 
 
 20 
 
 Mar. 
 
 21 
 
 Mar. 
 
 22 
 
 Mar. 
 
 20 
 
 Mar. 
 
 27 
 
 Remarks. 
 
 Nearly steady positive all day ; a trace of snow from 11 a. in. to 12:40 p. m., followed by 
 colder, clearing weather. 
 
 Weak variable positive all day ; a trace of snow fr(Jm,12:Q5 to 12:35 p. m., followed by clear 
 weather and a cold wave. 
 
 Variable positive until 5:30 p. m. ; then variable positive and negative until 8 p. m. ; then 
 strong, rapidly varying positive and negative until 5 a. m. of 9th ; It. snow b. 6:30 p. m., 
 soon changed to hy. snow, continued all night. 
 
 Strong variable positive and negative from midnight until 5 a. m. ; then negative until 7 
 3. m. ; then variable positive until 5 p. m. ; then variable positive and negative until raid- 
 night; hy. snow d. n., o. 9:45 a. m. ; amt. of snow on 8th and 9th, 9 inches ; heavy gales ; 
 barometer 29 inches. 
 
 Collector frozen during the night ; negative from 10 a. m. to noon ; no record afternoon; 
 SW. to NW. gales ; a trace of snow from 6:10 to 7:55 p. m. ; precipitation on the 16, 17th, 
 18th, 19th, 21st, 24th, and 25th, no record ; collector frozen. 
 
 No record in a. m. ; variable positive from noon to midnight, except from 8:30 to 10 p. m., 
 when it was variable positive and negative ; It. rain b. 8:30 a. m., e. 10:25 p. m. 
 
 Variable all day ; positive until 10:30 a. m. ; then negative until noon ; positive from 12 m. 
 to 2:30 p. m. and from 4 to 8:30 p. m. ; negative from 2:30 to 4 p. m. and from 8:30 to mid- 
 night; It. rain b. 7:55 a.m., continued all day. 
 
 Strong variable positive all day, except negative at 6 to 6:15 a. m., 4:30 to 5 p. m., and from 
 10 p. m. to midnight ; It. rain continued all day. 
 
 Variable positive until 7 a. m. ; zero until noon ; positive in p. m. ; It. rain e. 8:50 a. m. 
 
 Negative. from 1:30 to 6 a,, m. ; then positive until midnight ; It. rain b. 1:10, changeii to snow 
 7:45 a. m., e. 2:10 p. m. 
 
 Lt. snow from 10:30 to 10:55 a. m. and from 7:50 to 10:10 p. m. ; no record. 
 
 A rising positive potential from 1 to 6 a. m. ; then a very strong variable positive until 8 
 a.m.; then variable positive and negative until 5 p.m.; then weak negative until 10 
 p.m.; then strong variable positive until midnight; hy. snow began in -the early a. m., 
 13 inches fell by midnight. 
 
 Strong variable positive from midnight to 4 a. m. ; then variable negative and occasional 
 positive until noon ; no record in p. m. ; snow continued during the night ; e. 12:15 p. m. ; 
 total amount 15 inches, NW. gale. 
 
 Strong variable positive all day, except negative from 9 to 9:15 p. m. ; It, rain b. 10:25 p. m. 
 
 Variable weak positive and negative from midnight until 6 a, m. ; then strong variable nega- 
 tive until 4 p. m. ; then variable positive nntil midnight with slight negative at 10 p. m. ; 
 rained all day ; very heavy rain in the morning. 
 
 Variable positive in a. m. ; no record in p. m. ; rained all day, e. 9:10 a m. of the 13th ; no 
 record on 13th. 
 
 Negative from 6:15 to 6:30 a. m. ; variable strong positive and negative from 4:15 to 5:30 p. m. ; 
 variable positive the rest of the day ; It. rain from 4:15 to 5:05 p. m. 
 
 Negative at 8 a. m. ; weak variable positive and negative from 12 m. to 3 p. m. ; strong from 
 3 to 4 p.m. ; positive rest of the time. ; It. rain from 2:25 to 2:40 p. m. 
 
 Steady positive from midnight to 4:30 a.m. : then very strong positive and negative nntil 
 4:30 p. m. ; variable positive until 9 p. m. ; then variable strong positive and negative until 
 midnight; hy. rain during the greater part of the day. 
 
 Variable positive from midnight to 5. a. m. ; then variable negative until 7 a. m. ; then varia- 
 ble positive until noon ; variable negative afternoon; colder, NW. gale winds; It. snow 
 from 7:15 to 9:50 a. m. • 
 
 Steady positive until 4 a. m. ; then variable strong positive and negative until 3 p. m. ; then 
 variable positive until midnight, except negative from 10 to 10:30 p. m. ; It. snow b. be- 
 fore daylight, e. 11:40 a.m.; amount 2 inches. 
 
 Weak positive nntil 7:30 a. m. ; strong variable negative from 8 a. m. to 3 p. m. ; then weak 
 variable positive and negative until 8 p. m. ; then weak positive until midnight ; It. rain 
 and sleet b. 8:12 a. m., e. 1:40 p."m. 
 
 Weak positive until 7:30 a. m. ; weak negative then until noon ; then weak positive ; It. rain 
 at intervals from 7:50 to 11:15 a. m. 
 
 Variable positive until 8:30^ p. m. ; strong variable positive and negative from 8:50 to 10 
 p. m. ; weak positive and negative from 10:20 p. m. to midnight ; It. rain from 8:20 to 
 9:15 p. m. 
 
 Strong variable positive and negative from 1 to 8 a.m.; weak positive and negative rest 
 of the day ; It. rain before sunrise; cloudy, with E. winds. 
 
 Variable positive and negative all day, with very Ijigh and rapid variations from 7 to 11 
 p. m. ; It. rain b. 8:50 ;i. jp., .and continued all day. 
 
 Variable positive aud negative from midnight to 3:30 a. m. and from 6 to 7 a. m. ; then va- 
 riable positive until 7 p. m. ; strong positive from 7 to 8 p. m. ; then strong negative until 
 10:15 p. m. ; then positive ; It. rain daring the night e. 7:10 a. m. ; It. rain from 7:15 to 
 9:20 p.m. 
 
 Variable negative from 10 a. m. to 4 p. m. ; variable positive rest of the day ; It. rain before 
 sunrise; brisk W. to NW. winds. 
 
 Variable positive and negative until 9 a. m. ; then strong negative until noon ; then stronn- 
 variable positive and negative until midnight ; rain b. 8:50 a. m. and continued all day.'' 
 
 Strong variable positive and negative all day ; chiefly negative in a. m. ; rain continued all 
 night and day ; o. 9:40 p. m. 
 
MEMOIRS OP THE ]!fATIONAL ACADEMY OF 80IENCBS. 
 
 285 
 
 Table P. — Potential on days on which precipitation occurred at Baltimore, Md., 1885, 1886, and 
 
 1887— Continued. 
 
 Bate. 
 
 BemarkB. 
 
 1886. 
 
 Mar. 28 
 
 Mar. 29 
 
 Mar. 30 
 
 Mar. 31 
 
 Apr. 3 
 
 Apr. 4 
 
 Apr. 5 
 
 Apr. fi 
 
 Apr. 7 
 
 A()r. 11 
 
 Apr. 1-2 
 
 Apr. 13 
 
 Apr. 16 
 
 Apr. 17 
 
 Apr. 24 
 
 Apr. 25 
 
 June 30 
 
 July 1 
 
 July 2 
 
 July 10 
 
 July 13 
 
 July 14 
 
 July 15 
 
 July 16 
 
 July 18 
 
 July 21 
 
 July 25 
 
 July 26 
 
 July 27 
 
 July 31 
 
 Aug. • 1 
 
 Aug. 2 
 
 Aug. 7 
 
 Aug. 14 
 
 Aug. 17 
 
 Sept. 15 
 
 Sept. 16 
 
 Sept. 19 
 
 Sept. 21 
 Sept. 22 
 
 VariiibJe positive and negative from midnight to 2 a. m. ; then positive all day. ; It. rain 
 ■b. and e. d. n. 
 
 Variable positive and negative all day ; rain all day ; It. E. winds. 
 
 Strong negative from 7 to 9 a. m. ; strong variable positive and negative from 3 to 9 p. iii. ; 
 variable positive and negative at other times during the day ; rained all day. 
 
 Weak variable negative with an occasional positive all day ; It. rain with occasional heavy 
 showers all day. 
 
 Variable positive and negative all day ; It. rain from 6:35 to 7:10 a. m. ; cloudy, with north- 
 erly winds. 
 
 Negative during a. m. ; no record in p. m. ; It. rain b. early a. m., and continued all day. 
 
 No record in a.m.; variable strong negative and positive from noon to midnight ; rained all day. 
 
 Strong variable negative, with occasional positive from midnight to noon ; weak positive 
 from noon to midnight, except negative from 7 to 8 p. m. ; It. rain during the night and 
 morning, e. 12 m. 
 
 Variable positive all day, except negative from 7 to 8 a. m. and from 4:30 to 7 p. m. ; It. rain 
 from 12:35 to 12:45 p. m. and from 4:45 to 7:10 p. m. 
 
 Weak variable positive and negative from 2 to 8 a. ra. and from 8 p. m. to midnight; weak 
 positive rest of the time ; It. raiu fioru 7:50 to 8:15 a. m. ; briskE. winds. 
 
 Variable positive and negative from midnight to 9 a. m. ; then strong positive until 6 p. m. ; 
 then zero until midnight ; dense fog in morning ; It. rain from 7 to 9:15 p. m. 
 
 Strong variable negative from midnight to 2 a. m. and from 7:30 to 9 a. m. ; then variable 
 positive from 2:30 to 4 p. m. ; variable positive in ji. m., except a slight negative at 5 and 
 11:30 p. m. ; It. showers of rain during the morning and afternoon ; It. thunder at 3:27 p. m. 
 
 Strong variable positive all day, except a slight negative at 8:30 p. m. ; It. rain from 10:15 to 
 11:20 p. m. 
 
 Variable positive all day, except negative at 1 to 1:30 p. m. and 6:30 to 7 p. ra. ; It. rain before 
 sunrise. 
 
 Lt. rain and thunderstorm from 5 to 9 p. m. 
 
 Variable positive and negative from 3 to 9 p. m. ; positive from 9 p. m. to midnight ; It. rain 
 during the early a. m. and from 3:45 to 4:15 p. m. 
 
 Variable positive'aud negative from 4 to 8 p. m. ; variable positive at other times ; It. rain 
 from 5:20 to 5:35 p. m. 
 
 Variable positive in a. m., except slight negative at 7 a. m. ; variable positive in p. m., ex- 
 cept occasional negative from 6:30 to 8 p. m. ; It. rain b. 10 p. m. 
 
 Very strong variable negative from 1:30 a. m.to 5:30 p. m. ; variable, positive after 6 p. m. ; 
 rained all night and all day, e. 6:30 p. m. 
 
 Steady positive until 6 p. m. , except a strong negative from 6 to 6:30 a.m.; variable posi- 
 tive and negative from 6:30 to 8 p. m. ; It. rain from 8:05 to 8:20 p. m. 
 
 Slight negative at 4 and 7 a. m. and strong variable positive and negative from 9 a. m. to 
 I'p. m. ; steady positive in p. m. ; It. rain &om 10:18 a. m. to 1:25 p. m. 
 
 Lt. rain from 10:10 to 10:30 a. m. ; thunderstorm and heavy rain from 3:20 to 4:50 p. m. 
 
 Thunderstorm and hy. rain from 6:20 to 10:45 p. m. ; amount of rain 2.09 inches; tornado of 
 50 yards width and 2 miles length passed over city at 7:10 p. m. 
 
 Lt. rain from 12:30 a. m. to noon. 
 
 Steadv positive in a. m. ; thunderstorm and It. rain from 10:20 to 10:50 p. m. 
 
 Slight negative at 8 p. m. of 20th ; strong variable positive and negative from 1 to 7 a. m. ; 
 weak variable positive and negative from 7 a. m. to 3 p. m., then positive until midnight. ; 
 heavy rain from 1 to 8:15 a. m. 
 
 Steady positive until 6:30 a.m.; then strong negative and positive until 1:30 p. m 
 steady positive ; rain at intervals from 7:08 a. m. to 2:25 p. m. 
 
 Thunderstorm and heavy rain from 4:30 to 11:30 p. m. 
 
 Lt. rain during the morning, followed by clear weather ; silent lightning in the evening 
 
 Hy. thunderstorm and rain from 12:15 a. m, , e. before daylight. 
 
 Variable positive and negative from 2 to 3 a. m. ; variable positive until, 
 light showers all day; silent lightning from 8:30 to 11:30 p. m. 
 
 Steady positive in p. m. ; It. raiu during the early a. m., e. before sunrise. 
 
 Strong steady negative from 2:30 to 7:30 a. in. ; then steady weak negative until noon ; then 
 weS\ variable positive and negative until 3 p.m. ; then positive ; hy.rain began early 
 a. m., changed to It. rain 7:30 a. m., e. 2:20 p. m. ; amount 2.21 inches. 
 
 Steady positive all day : trace of rain-^:03 to 7:55 a. m. 
 
 Lt. rain b. d. u. and e. d. n. ; thunderstorm and It. rain from 3:10 to 5:35 p. m. 
 
 No record' in a. m. ; variable positive and negative from 12 m. to 1 p. m. ; then positive until 
 9 p. m. ; then negative ; It. rain at intervals all day. 
 
 Negative from midnight to 7 a. m. ; then positive and negative until noon ; then positive ; 
 It. rain during 4he night and a. m. ; clear in p. m. , 
 
 Positive until noon ; hy. rain and thunderstorm from 4:35 to 5:25 p. m. ; It. ram and thun- 
 derstorm from 9:30 to 9:50 p. m. 
 
 Steady positive all day; It. rain b. 11:15 p.m. 
 
 Zero from midnight to 9 a. m. ; then variable positive until 9 p. m. ; then variable positive 
 and negative until 11 p.m.; then positive; It. rain e. early a.m.; cloudy day; It. rain 
 from 11:25 to 11:35 p. m. 
 
 then 
 
 Lnoon; cloudy, with 
 
.286 
 
 MEMOmS OF THE NATIONAL ACADEMY OF SCIENCES. 
 
 Table P. — Potential on days on which precipitation occurred at Baltimore, Md., 1885, 1886, and 
 
 1887— Continued. 
 
 Date. 
 
 1886. 
 
 Sept. 29 
 
 Oct. 14 
 
 Oct. al 
 
 Oct. 26 
 
 Oct. 27 
 
 Oct. 28 
 
 Oct. 29 
 
 Oct. 30 
 
 Oct. 31 
 
 Nov. 6 
 
 Nov. 10 
 
 Nov. 12 
 
 Nov. 13 
 
 Nov. 17 
 
 Nov. 18 
 
 Nov. 22 
 
 Nov. 23 
 
 Nov. 24 
 
 Nov. 25 
 
 Nov. 30 
 
 Deo. 4 
 
 Dec. 5 
 
 Dec. 6 
 
 Kemarka. 
 
 Dec. 
 
 Deo. 
 Deo. 
 
 12 
 
 13 
 15 
 
 Dec. 
 
 16 
 
 Dec. 
 
 18 
 
 Dec. 
 
 22 
 
 Deo. 
 
 23 
 
 Deo. 
 
 24 
 
 Dec. 
 
 26 
 
 Dec. 
 
 29 
 
 Dec. 
 
 30 
 
 Dec. 
 
 31 
 
 Variable positive and negative from 11 pi m. of 28tli to 4 a. m. of 29th ; then strong variable 
 
 positive and negative until 7 a. m. ; then positive all day ; raia from 12:48 to 8:45 a. ni. 
 Zero in a. m. ; weak variable positive and negative from noon to midnight ; It. rain from 
 
 2:5.5 to 3:10 p. m. and from 10:50 to 11:31 p. m. 
 Strong negative from 7 to 8 a. m. ; positive rest of the day ; It. rain from 7:50 to 8:45 a. m. 
 Variable positive and negative all day; strong in p. m. ; It. rain at intervals during after- 
 noon and night. 
 Variable positive and negative all day ; It. rains at- intervals during night and all day. 
 Variable positive and negative until 5 a.m.; then positive all day ; It. rain during night, 
 
 ended before sunrise. 
 Positive all day ; It. rain 4 to 4:08 p. m. 
 Strong negative from 2 to 5 a. m. ; negativ<^ from 3 to 4 p. m. and from 11 p. m. to midnight ; 
 
 positive rest of the time ; occasional It. rains during the day. 
 Negative from midnight to 1 a. m. and at 4 p. m. ; positive at other times ; It. rain in early 
 
 a. m. and at intervals from 8:.')0 a. m. to 1:55 p. m. 
 Variable positive and negative from 7 to 8:15 a. m. ; then positive until 3 p. m. ; then strong 
 
 variable positive and negative until midnight ; It. rain from 7:45 to 8:40 a. m. ; It. rain J). 
 
 1:55 p. m., continued all day and night. 
 Negative from 4 to 4:30 a. m. j variable positive all rest of the day ; It. rain before sunrise. 
 Variable positive and negative from & a. m. to midnight ; very strong, chiefly negative, in 
 
 p. m. ; It. rain b. 6 a. m., changing,to hy. rain in the afternoon, e. 10:48 p. m. 
 Steady positive all day except strong positive at 3 p. m. ; It. snow from 2:10 to 3:15 p. m. 
 Slight negative at 2 and 4 a. m. of 16th ; then variable positive until 7 p. m. of 16th ; then 
 
 variable positive and negative until noon of 17th ; then positive ; It. rain during the 
 
 greater portion of the day. 
 Strong variable positive and negative from 6:30 to 8:.30 a. m. ; steady positive the rest of 
 
 the day ; hy. rain-from 7:25 to 9:20 a. m., followed by clearing weather. 
 Variable positive until 5:30 p. m. ; then variable positive iind negative until midnight ; It. 
 
 rain b. 9:45 p. m. 
 Negative from midnight to 6 a. m. and from 8:30 to 9:30 p. m. ; variable positive rest of the 
 
 time ; cloudy day, with rain in the morning and at night. 
 Negative from 2:30'to 4 a. m. ; positive rest of the time ; It. rain in the early morning, 
 titeady positive until noon, except a slight negative at 2:30 and 4 a. m. ; strong variable posi- 
 tive and negative from noon to 7 p. m. ; then positive ; It. rain b. early a. ro., changed to hy. 
 
 rain at 1:30 p. m., e. 7:20 p. m. ; a waterspout on bay at 3 p. m. 
 Variable positive and negative from 8 p. m. of 29th to 4 a. m. of 30th ; then positive until 
 
 noon ; then strong variable positive and negative until 3 p. m. ; then positive ; It. rain 
 
 from 12:10 to 3:30 p. m. 
 No record in a. m. ; positive in p. m. except a, slight negative at 8 p. m. ; It. snow b. 2:05 
 
 p. m., continued at night. 
 Strong variable positive and negative from midnight to 2:30 a. m. and from noon to mid- 
 night ; It. snow continued until 5:15 p. m. 
 Variable positive and negative from midnight to 1 p. m. ; then positive until 8 p. m. ; then 
 
 negative ; It. snow from 7:35 to 8:10 a. m. ; It. rain b. 11:50 a. m., changed to snow 4:25 p. m., 
 
 e. 7 p. ra. ; It. snow b. 11:10 p. m. 
 Negative in a. m. ; positive in p. m. ; snow continued until 12:30 p. m. 
 Positive in a. m. ; variable positive in p. m., with slight negative at 8 and 10 p. m. ; cloudy, 
 
 with It. rains, during the greater part of the day. 
 Variable positive, with negative from 7 to 9 a. m. ; It. rain e. 9:30 a. m. 
 Zero in a. m. ; strong variable positive arid negative until 9 p. m. ; positive 9 to 11 p. m. ; 
 
 negative 11 p. m. to 12 mid. ; It. rain all day, changedto snow 5:10 p. ra., e. 10:50 p. m. 
 Slightly negative, nearly zero, all morning; negative from 12 to 3 p. m. ; then positive; It. 
 
 snow during the early morning, followed by clear weather. 
 Negative from 12:30 to 4:30 a. m. ; then positive until 7 a. m. ; then strong variable negative, 
 
 with an occasional positive, until 6:30 p. m. ; then positive ; rain began before sunrise and 
 
 fell steadily until 7:30 p. m. 
 Positive until 10 a. m. ; then negative, with an occasional positive, until 7 p. m. ; then steady 
 
 positive ; It. rain from 4:15 to 7:10 p. m. 
 Variable positive, with an occasional negative, from 1 p. m. to midnight; fair in a. m. ; It. 
 
 rain from 12:55 p. ra. at intervals until midnight. 
 Variable positive, with an occasional negative, from raidnight to 8 a. m. ; then positive until 
 
 7 p. m. ; then strong negative until 9 p. m. ; then zero until midnight ; It. rain at intervals 
 
 all day until 9:15 p. ra. 
 Steady positive in a. m. ; variable positive and negative from noon until 9 p. ra., with strong 
 
 variations from 4:30 to 5:30 p. ra. ; It. snow b. 1;25 p. m., changed toTiy. snow at sunset, e. 
 
 6:20 p. m. 
 Variable positive until 8 p.m.; then negative and positive until midnight ; It. snow b. 9:45 
 
 p. m. 
 Negative from 1:45 to 2:15 a. m. ; then positive until 12 m. ; then variable weak positive and 
 
 negative until midnight ; It. snow at intervals all day. 
 Strong negative from 12:30 to 5 a. ra. ; then positive and negative until midnight ; strong 
 
 after 8 n. ni. ; snow changed to rain shortly after midnight and continued all day. 
 
MEMOIRS OP THE NATIONAL ACADEMY OP SCIENCES. 
 
 287 
 
 Table P. — Potential on days on which precipitation occurred at Baltimore, Md., 1885, 1886, and 
 
 1887— Coutinued. 
 
 Bate. 
 
 1887 
 
 
 Jau. 
 
 1 
 
 Jan. 
 
 9 
 
 
 fc 
 
 Jan. 
 
 13 
 
 Jan. 
 
 17. 
 
 Jan, 
 
 24 
 
 Jan. 
 
 26 
 
 Jan. 
 
 29 
 
 Feb. 
 
 2 
 
 Feb. 
 
 3 
 
 Feb. 
 
 5 
 
 Feb. 
 
 6 
 
 Feb. 
 
 7 
 
 Feb. 
 
 8 
 
 Feb. 
 
 10 
 
 Feb. 
 
 11 
 
 Feb. 
 
 14 
 
 Feb. 
 
 1.5 
 
 Feb. 
 
 18 
 
 Feb. 
 
 20 
 
 Feb. 
 
 23 
 
 Feb. 
 
 •24 
 
 Feb. 
 
 26 
 
 Feb. 
 
 27 
 
 Mar. 
 
 3 
 
 Mar. 
 
 4 
 
 Mar. 
 
 5 
 
 Semarks. 
 
 Mat. 6 
 
 Rapid vibrations from positive to negative from 8 p. m, of Dec. 31 to 1 a. m. of Jaa. 1 ; tliea 
 variable positive and negative until 4 a. m. ; positive uiitil6a. jn. ; negative iiutil 11 a. m. ; 
 then steady positive nntil miduijjht ; raiu fell steadily during the early moroing, e. 9:15 
 
 a. m. ; It. flurry Of snow 12:25 to 12:35 p. in. 
 
 Steady positive in a. m. ; variable positive in p. m. ; It. snow b. 11:30 a. m. ; changed to 
 sleet at 9:50 to 10:15 p. m. ; e. early a. m. of lOth ; variable positive during the night. 
 
 Variable positive to negative from 6 to 8 a. m.' ; then positive until 7 p. m. ; variable negative 
 until 10 p. m. ; positive until 11:30 p. m. ; variable negative, with occasional positive, uutil 
 6 a. in. of 14th ; It. rain b. H:55 p. m., e. early a. m. of 14th. 
 
 Variable positive from 6 to 10 a. ni., with a slight negative at 7 and 9 a. ni. ; variable posi- 
 tive and negative from 10 a. m. to 5 p.m.; steady positive until midnight ; It. rain b. 10:55 
 a.m., e. 4:40 p. m. 
 
 Variable high positive from 3 to 5 a. m. ; then high variable positive to negative until 1:30 
 p. m. ; then Variable positive until 3 p. m. ; then steady positive until midnight; lb. rain 
 
 b. early a. m. ; changed to snow at 11:45 a. m., e. 2:50 p. m. 
 
 Negative from 8 to 9:30 a. m. ; variable positive the rest of day ; It. rain from 8:50 to 9:30 
 a. m. ; It. snow from 6:50 to 9:35 p. m. 
 
 Steady positive in a. m. ; strong variable positive and negative from 9 a. m. to 5:30 p. m. ; 
 then positive until midnight ; It. raiu from 9:30 a. ra. to 5:30 p. m. 
 
 Low variable positive, with an occasional negative during the night ; with a sudden change 
 to high negative at 5;15 a. m. ; then a gradually falling negative until 7 a. m. ; then steady 
 weak negative until noon; then variable positive aud negative uutil early a. m. of 3d ; 
 snow and sleet in a. m., followed bj; raiu, which fell at intervals during the day. 
 
 Variable positive and, negative until 6 a.m.; then variable positive until 3 p.m.; then 
 variable strong positive and negative uutil 5 p. m. ; then positive until midnight ; It. rain 
 during the early morning and from 2:50 to 4:35 p. m. 
 
 •Zero potential at 1:30 a. m. ; then steady positive until 8 a. m. ; then variable positive until 
 3 p. m. ; variable weak positive to negative 3 to 6 p. m. ; then weak positive until mid- 
 night ; It. snow b. 8:50 a. m. ; changed to rain 3:35 p. m. ; changed to sleet 6:55 p. m., e. 7 
 p. m. ; It. rain b. 10:35 p. m. 
 
 Negative at 2 and 4 a. m. ; positive until noon ; then variable positive and negative until 
 2 p. m. ; then variable positive until midnight, with negative from 5:15 to 5:30 p. m. ; It. 
 rain, continued all night and all day. , 
 
 No record in a.m.; variable positive in p. m. , with negative for 5 minutes at 1:30 p.m.; 
 It. rain e. 8:20 a. m. ; It. rain from 5:45 to 9:40 p. m. 
 
 Variable positive all day, with zero potential at 5 a. m., 9:30 a. m., aud 3:30- p. m. ; negative 
 from 7 to 8 p. m. ; It. rain b. early a. m. ; rained all day; e. at night. 
 
 Variable positive all day, with negative from 6 to 7:30 p. m. ; It. rain 5:30 to 8:35 p. m. 
 
 Weak variable positive and negative from 7:30 to 9 a. m. ; zero potential all afternoon, proba- 
 bly due to gale causing collector to ground itself agaigst the building ; It. rain ifrom 3 to 
 5:30 p. m. . ~ 
 
 Variable positive from 6:30 to 9 a. m. and all afternoon ; variable positive and negative from 
 10 p. m. to midnight ; It. snow b. 6:15 p. m. ; changed to raiu at 10:40 p. m. 
 
 Strong variable negative from midnight to 8 a. m. ; then variable positive until 6 p. ni. ; 
 then variable positive and negative until midnight. ; rained all night, e. 8:15 a. m. 
 
 Negative from 2 to 2:30 a. m. ; steady positive until 6 a. m. ; then variable positive and nega- 
 tive until noon ; no record in the afternoon ; It. rain b. 7:45 a. m. ; changed to heavy rain, 
 hail, and thunderstorm in late p. m. 
 
 Steady positive until 11 a. m. ; then variable positive and negative until 6:30 p. m. ; then 
 positive until midnight ; It. rain b. 11:45 a jn. ; then changed to snow, aud during the rest 
 of the day rain, sleet, and snow fell at intervals; e. early a. m. of 21st. 
 
 Strong variable positive all day, except negative at 4:45 p. m., 6 p. m., 7 to 7:15 p. in., and 
 9 to 9:30 p. m. ; It. snow b. 3:30 p. m. ; changed to rain at 7:30 p. m. ; continued during the 
 
 Strong "variable negative from 1 to 3:30 a. m. ; then steady positive all day ; rain o. before 
 sunrise. , . , , ... , .. 
 
 Steady positive from midnight to 6:30 a. m. ; then strong variable positive and negative 
 until 10:15 p.m.; then steady positive; -heavy snowstorm b. about 5 a. ra. ; changed to 
 rain at 11 a. m. ; e. 9:30 p. m. .^. „ „^ n u. a f 
 
 Steady positive all day, except strong variable positive from 7 to 9 p. m. ; It. flurry ot snow 
 from 7:50 to 8:15 p.m. . . ^ -, ^ , .. ^. r 
 
 Potential low and variable from positive to negative all day ; yam and sleet 4:45 to p. m. ; 
 sleet 10:30 to 11 p.m.; rain 11 p.m. and d.n. . ^, ^ . „^ <-• o on . 
 
 Potential, no record during morning ; positive variable during afternoon; negative »:du to 
 8-40 p m. ; raiu continued from 3d ; turned to snow early a. m. to 1:50 p. m. 
 
 Potential variable positive until 2:40 p. m. ; strong variable from positive to negative, 
 chiefly negative, 2:40 to 7 p. m. ; variable positive 7 to 10 p. ra. ; variable positive to neg- 
 ative 10 pTm. to midnight ; snow 1:20 to 3:30 p. m. ; sleet 3:30 to 7 p. m. ; ram 7 p. m. to 
 
 Potential variable positive to negative, chiefly negative, 12:01 to 2 a.m. ; variable positive 
 2 to 9:45 a. ni. ; strong variable positive to negative 9:45 a. m. to 6:45 p. m. ; variable posi- 
 tive 6:45 p. m. to midnight ; rain continued from 5th ; e. ea'ly a. m. ; threatening rest ot 
 day. 
 
288 
 
 MEMOIRS OF THE NATIONAL ACADEMY OF SOIE^JCES. 
 
 Table P. — Potential on days on which precipitation occurred at Baltimore, Md., 1885, 1886, and 
 
 1887— Continued. 
 
 Date. 
 
 Kemarka. 
 
 1887. 
 Mar. 7 
 
 Mar. 9 
 
 Mar. 10 
 
 Mar. 13 
 
 Mar. 17 
 
 Mar. 18 
 
 Mar. 21 
 
 Mar. 22 
 
 Mar. 24 
 
 Mar. 27 
 
 Mar. 2d 
 
 Mar. 
 
 31 
 
 Apr. 
 
 1 
 
 Apr. 
 Apr. 
 
 2 
 4 
 
 Apr. 
 
 5 
 
 Apr. 
 
 15 
 
 Apr. 
 
 16 
 
 Apr. 
 
 17 
 
 Apr. 
 
 18 
 
 Apr. 
 
 19 
 
 Apr. 
 
 22 
 
 Apr. 
 
 23 
 
 Apr. 
 
 25 
 
 Apr. 
 
 21) 
 
 Apr. 
 
 27 
 
 Apr. 
 
 28 
 
 Apr. 
 May 
 
 29 
 1 
 
 May 5 
 
 May 6 
 May 7 
 
 Potential variable positive 13:01 to 4:30 a. m. ; strong variable positive to negative 4:30 to 
 
 10:30 a. m. ; high variable positive 10:30 a. m. to midnight; rain early a, m. to 2:25 p. m. 
 Potential variable positive, with occasional negative, from 7 p. m. on 8th to 1 a. m. on 9th ; 
 
 variable positive 1 a. m. to 1 p. m. ; strong negative, with occasional positive, 1 p.m. to 
 
 mid. ; rain during afternoon and night. 
 Potential variable po.titive to negative from raid, to 5 a. m. ; low positive and varialile dur- 
 ing rest of day ; rain raid, to early a. m. 
 Potential positive mid. to noon; variable positive 1:30 to 9 p. m. ; strong variable positive 
 
 to negative, chiefly negative, 9 p. m. to 2 a. m. on 14th ; rain 11:10 to 11:25 p. ra. 
 Potential positive mid. to 8 a. m. ; variable positive to negative 7 to 9:45 a. m. ; .variable 
 
 positive 9:45 a. m. to 4:15 p. m. ; variable positive to negative 4:15 to 4:30 p. m. ; variable 
 
 positive 4:30 to mid. ; snow, occasional light snow, after 10:45 a. m. 
 Potential variable positive midnight to noon and 5 p. m. to mid. ; variable positive to nega- 
 tive noon to 5 p. m. ; snow, light flurries, during a. m. 
 Potential variable positive until 5:45 p. m. ; -strong variable positive to negative 5:45 p. m. 
 
 to midnight ; rain 3:10 to 9:45 p. m. ; snow 9:45 p. m. to mid. 
 Potential strong variable positive to negative mid. to 11 a. m. ; low positive rest of day ; 
 
 snow mid. to early a. m. ; rain early a. m, to 11 a. m. 
 Potential variable positive until 10:20 p. m., excepting negative for a few minutes abont 
 
 7:15 and 9:15 a. m., and 9:15 p. ra. ; strong variable positive to negative 10:20 to 11:30 
 
 p. m. ; positive 11:30 p. m. to raid. ; It. rain 10:55 to 11:05 p. m. 
 Low variable positive mid. to noon ; negative for a few minutes about 7:45 a. m. ; variable 
 
 positive to negative noon to 7 p. m. ; strong variable positive to negative 7 p. m..to mid. ; 
 
 rain 7 p. m. to mid. 
 Strong variable positive to negative mid. to 6 a. m. ; variable positive 6 a. m. to 4 p. m. ; 
 
 strong variable positive to negative 4 to 5:30 p. m. ; positive rest of day ; rain mid. to 
 
 early a. m. ; snow 4 to 4:50 p. ra. 
 Strong variable positive, with occasional negative, mid. to 7 a. m. ; strong-variable positive 
 
 to negative 7 a. ra. to 7 p. m. ; variable positive 7 p. m. to mid. ; snow 7:45 a. m. to raid. 
 Potential low variable positiveto negative mid. to 8 p. m. ; variable positive 8 p. m. to 
 
 mid. ; It. snow all day at intervals. 
 Potential variable positive all day ; snow mid. to 8:35 a. ra. 
 Potential low variable positive to negative mid. to 10:45 p. m. ; strong variable negative 
 
 10:45 p. m. to mid.; It. rain 11:15 to 11:55 p. ra. 
 Potential strong negative mid. to 1 a. m. ; positive 1 to 8 a. m. ; low variable positive to 
 
 negative 8 a. ra. to 6 p. m. ; low positive 6 p. m. to mid. ; snow 4:50 to 4:55 p. ra. 
 Potential positive and variable mid. to 7 p. m, ; strong variable positive to negative 7 p. ra. 
 
 to raid. ; thunderstorm 10 to 11 p. m. ; rain 11:05 to mid. 
 Potential variable positive to negative mid. to 8 p. m. ; variations from mid. to 5 a. ra. were 
 
 quite strong ; rain mid. to 12:05 a. ra. ; It. rain 7:40 to 8 a. m; 
 No electrometer record iiiid. to noon ; potential low; positive noon to raid., with negative 
 
 for a few minutes about 7:20 p. m. and from 10:50 to 11:30 p. ra, ; It. rain 6:30 to 7:15 p. m.; 
 
 rain 11:15 p. ra. to mid. 
 Potential strong variable positive and negative all day ; rain at intervals from mid. dur- 
 ing the day to mid. 
 Potential low variable positive and negative mid. to 5 a.m.; variable positive rest of day ; 
 
 rain mill, to early a. ra. ' 
 
 Potential variable positive, occasional zero, raid, to 3 p. m. ; strong variable positive and 
 
 negative 3 to 10 p. m. ; positive 10 p. m. to mid. ; rain 1:35 p. ra. to raid. 
 Potential variable positive to negative raid, to II p. m. ; variation strong 6 to 10 p. m; ; pos- 
 itive 11 p. m. to mid. ; rain at intervals during the day. 
 Potential variable positive, with occasional negative, raid, to 1:45 p. m. ; strong variable 
 
 positive and negative 1:45 p. ra. to mid. ; rain 2:15 p. m. to mid. 
 Potential strong variable positive to negative raid, to 4 a. m. ; positive 4 a. m. to 5 p. m. ; 
 
 variable strong positive and negative 5 to 7 p. m. ; positive 7 p. m. to mid. ; rain mid. to 
 
 early a. m. ; rain 6:30 to 7 p. ra. 
 Potential variable positive to negative 2 to 6 a. m., .^ to 6 p. m., 11 p. m. to mid. ; positive 
 
 rest of day ; rain during early a. m..; rain 5:30 to 7 p. in., 
 Potantial variable positiveto negative mid. to 6 a. m. ; variable positive 6 a.m. to 2:30 p.m. ; 
 
 strong variable positive and negative 2:30 to 6:30 p. m. ; positive rest of day; rain early 
 
 a. m. ; rain 2 to 6:30 p. m. 
 Potential low variable positive and negative all day; rain at intervals all day. 
 Steady positive all day, except it was variable positive from 9 to 11 p. m. ; a trace of rain 
 
 from 10:25 to 11:15 p. ra. 
 Variable positive and negative, with sheet lightning, from 7:30 p. ra. of 4th to 1 a. m. of 5th ; 
 
 no record from 1 to 9 a. ra. ; variable positive from 9 a. m. to 3 p. ra. ; weak variable posi- 
 tive and negative from 3 p.m. to midnight; It. rain, b. early a. m., continued ail day, 
 
 e. d. n. 
 Wealc variable positive and negative from midnight to 11 a. m. ; strong variable positive 
 
 and negative from 11 a. m. to noon ; no record the rest of the day ; It, rain, with light 
 
 thunder, from 4:25 to 5:30 p. ra. ; It. rain b. 10:30 p. m. 
 Rain and thunder on the 7th, 8th, and 9th ; no record. 
 
MBMOIK8 OF THE NATIONAL ACADEMY OF SCIENCES. 
 
 289 
 
 Table P. — Potential on days on which precipitation occurred at Baltimore, Md., 1885, 1886, and 
 
 1887— Continued. 
 
 Date. 
 
 Kemarks. 
 
 1887. 
 May 10 
 
 May 24 
 
 May 27 
 
 May 28 
 May 31 
 
 June 1 
 
 June 2 
 
 Jane 6 
 
 June 7 
 
 June 9 
 June 18 
 
 June 19 
 
 June 20 
 
 June 21 
 June 22 
 
 Jane 23 
 July 5 
 
 July 6 
 July 9 
 
 July 17 
 
 July 18 
 
 July 19 
 
 July 20 
 
 July 21 
 
 July 23 
 July 24 
 
 July 25 
 
 July 26 
 
 July 37 
 
 July 29 
 
 Aug. 2 
 
 Variable positive from midnight to 5 a. m. ; variable positive and negative from 5 to 11 
 
 a. m. ; variable positive until midnight ; It. rain from 7:40 to 8:15 a. m. 
 Steady positive until 9:40 a. m. ; then strong variable positive and negative until 9:30 p. n). ; 
 
 then steady positive until midnight ; It. showers fell at intervals after 9:35 a. in. ; warm, 
 
 sultry, and oppressive. 
 Steady positive from noon to 4 p. m. ; negative from 4 to 4:30 p. m. ; then strong positive 
 
 until 5:30 p. m. ; then steady positive until, midnight ; It. rain from 4:45 to 4:50 p. m. 
 Steady positive from midnight to 7 a. m. ; then wealc variable positive an J negative until 
 
 noon ; no record in the afternoon ; It. rain from 5:30 to 8:20 p. m. 
 Variable positive in a. m,and from 1:30 to 5:30 p. m, ; variable positive and negative from 
 
 11 a. m. to 1:30 p. m, ; variable strong negative from 5:45 p. m. to 2:30 a. m. of June 1 ; It. 
 
 rain, withgale, b. 5:30 p. m., continued all night. 
 Strong negative from midnight to 2:30 a. m. ; strong positive from 2:30 to 3 a. m. ; then weak 
 
 variable positive and negative until 6:30 a. m, ; then variable positive all day ; hy. rain 
 
 during the night, e. 7:35 a. m. 
 Steady positive from midnight to 5:30 a.m. ; strong variable negative from 5:30 to 7 a. m. ; 
 
 then variable positive until noon ; It. rain from 6 to 8 a. m. ; thunderstorm, with rain, 
 
 from 7:35 to 8:20 p. m. ; It. rain, b. 9:50 p. m., e. d. n. 
 Steady positive from midnight to 6:30 a. m., except zero at 4:40 and 6:30 a. m. ; strong vari- 
 able positive and negative from 7 a. m. to noon ; variable positive from noon to 10 p. m. ; 
 
 zero at 10 p. m. ; positive until 11:30 p. m. ; then strong negative until 12:30 a. m. ; It. rain 
 
 from 6:15 a. m. to 1 p. m. and from 11 p. m. 
 Weak variable positive and negative from 12:30 to 10 a. m., except from 2 to 4 a. m., when 
 
 it was strong positive and negative; rain ended during the night ; It. rain from 9:30 to 
 
 9:45 a. m. 
 Steady positive from midnight to noon ; It. rain from 4:50 to 5:50 p. m,, with distant thunder. 
 Hy. rain and thunder 4:35 to 4:r)0 p. m. ; amount, 0.54 inch ; east of the station the storm was 
 
 accompanied by hailstones as large as pigeon eggs. 
 Lt. rain shortly after midnight ; thunderstorm in early a. m. ; hy. thunder at station from 
 
 7 to 8:30 p. m., and thunder and lightning near station until 10 p. m. ; no rain. 
 
 Lt. rain from 7:08 to 7:15 a.m.; thunderstorm, with rain, from 10:45 to 11:30 a.m.; sheet 
 lightning from 8 to 10 p. m. 
 
 Lt. thunderstorm, with rain, from 10:53 to 11:10 p. m. 
 
 Lt. rain at intervals all day ; by. rain b. 6:15 p. m. ; thunderstorm just after noon and again 
 in the evening. 
 
 Eain e. 6:50 a. m. ; It. rain from 7:20 to 7:30 a. m., 3:35 to 3:30 p. m., and from 6:35 to 6:40 p. m. 
 
 Variable positive from midnight to 3:40 a. m. ; then strong variable negative until 8:30 a. m. ; 
 then variable positive and negative until 4 p. m. ; variable positive from 4 to 7 p. m, ; 
 strong variable positive and negative from 7 to 10 p. m. ; then variable positive until mid- 
 night; It. rain from 12:40 to 12:55 a. m. ; hy. rain, b. d. n., e. 10:20 a. m. ; It. rain from 1:50 
 to 3:30 p.m. ; distant thunder from 8 to 9 p.m. , 
 
 Variable positive from midnight to 3 p. m., exc.ipt npgaUve at 10 a. m. ; strong variable posi- 
 tive and negative from 3 to 4:15 p.m.; variable posilive until midnight; It. rain, b. and e. 
 d. n., 0.02 inch ; threatening from 3 to 4 p. m. ; sheet-lightning at 9 p. m. 
 
 Negative from 6:30 to 7:30 p. m. ofStb; variable positivefrom then to8:30a. m. ofOth; strong 
 variable positive and negative from 8:20 a. m. to 4:30 p. m. ; then variable positive until 
 
 8 p. m. ; then steady positive to midnight ; It. rain from 6.58 a. m. to 12:25 p. m., 3:30 to 
 4:15 p. m. ; distant thunder and lightning from 11:37 to 11:50 a. m. 
 
 Lt. rain from 3:06 to 4:30 p. m., with thunderstorm. 
 
 A terrific hail and thunderstorm, with vain, from 5:10 to 5:50 p. m. and from 7:35 to 8:15 
 p. m. ; nailstones one-quarter to one-half inch in diameter from 5:20 to 5:35 p. m. 
 
 Thunderstorm and hy. rain from 2:50 a. m., e. d. u. ; It. rain from 10:30 to 10:,55 a. m. 
 
 Variable positive in a. m. ; strong variable positive and negative from 12 to 1p.m.; vari- 
 able positive from 1 to 5 p. m. ; weak variable positive to negative from 5 to 8 p. m. ; It. 
 rain from 3:50 to 4:05 p. m. . , ,, 
 
 Lt. rain, b. d. n., e. 7:30 a. m. ; heavy rain 9:35 a., m. to 12:.55 p. m., with thunderstorm ; 
 
 amt., 2.70 inches. , ., . , ,, ■,.,,.,„ 
 
 Hy Tain and thunderstorm from 3:18 to 6:15 p. m. ; amt., 1.11 inches ; It. rain b. 11:30 p. m. 
 Lt rain at intervals all night, e. 5:30 a. m. ; It. jain 10:40 to 11:10 a. m. and from 8:1.5 to 
 
 9:55 p. m. ; from noon to 8 p. m. steady positive ; strong variable negative from 8:20 to 
 
 9:40 p. m. ; then steady positive until midnight. 
 A trace of rain in early a. m. ; steady positive. 
 
 Hy. rain and thunderstorm from 7:40 to 10:45 p.m., 1.55 mehes. ,^ ■ n 
 
 Variable positive, except from 2:55 to 3:05 p. m , when it was strong negative ; It. rain from 
 
 3:04 to 3:06 p. m. 
 Trace of rain from 2:25 to 2:35 p. m. ; lightning from 7:40 to 10 p. m. 
 Variable positive all day ; trace of rain from 3:15 to 2:20 p. m. 
 
 S. Mis. 94 19 
 
290. 
 
 MEMOIRS OF THE NATIONAL ACADEMY OP SCIENCES. 
 
 Table P. — Potential on days on which precipitation occurred at Baltimore, Md., 1885, 1886, and 
 
 1887— Continued. 
 
 Date. 
 
 Before. 
 
 
 
 During. 
 
 After 
 
 
 Kemarks. 
 
 i 
 
 8 
 
 £ 
 
 O 
 
 ^Negative. 
 
 
 
 g 
 1 
 
 O 
 
 g 
 
 2 
 
 1 
 
 § 
 
 
 [3 
 
 O 
 
 -q 
 
 3 
 
 1 
 
 ID 
 
 1 
 
 a 
 o 
 
 3 
 
 i 
 
 1 
 
 + 
 
 1885. 
 Jan. 1 
 Jan. 4 
 Jan. 5 ) 
 Jan. 6 I 
 Jan. 11 
 Jan. 11 ) 
 Jan. 12 < 
 Jan. 12 
 Jan. 15 
 Jan. 16 
 Jan. 17 
 Jan. 23 ? 
 Jan. 24 5 
 Jan. 28 
 Feb. 1 
 Feb. 4 
 Feb. 5 
 Feb. 5 ? 
 Feb. 6 ( 
 Feb. 9 i 
 Feb. iO < 
 Feb. 13 
 Feb. 14 ? 
 Feb. 15 5 
 Feb. 16 
 Feb. 17 I 
 Feb. 18 ( 
 Feb. 24 ? 
 Feb. 25 I 
 Feb. 26 ? 
 Feb. 27 5 
 Mar. 1 
 Mar. 2 
 Mar. 7 
 Mar. 8 
 Mar. 121 
 Mar. 13 
 Mar. 14 ' 
 Mar. 15j 
 Mar. 15 
 Mar. 19 
 Mar. 22 
 Mar. 31 
 Apr. 3 ) 
 Apr. 4 5 
 Apr. 4 
 Apr. 5 
 Apr. 7 
 Apr. 8 
 Apr. 11 
 Apr. 13 
 Apr. 15 
 Apr. 15 > 
 Apr. 16 i 
 Apr. 28 
 May 1 
 May 6 { 
 May 7 J 
 May 13 
 May 14 
 May 14 
 May 17 
 May 20 
 May 21 
 May 32 
 
 1 
 
 
 
 
 
 
 
 
 
 
 
 
 Lt. sleet and snow. 
 Snow, sleet and rain. 
 Lt. rain. 
 
 Do. 
 
 Do. 
 
 Do. 
 
 Do. 
 , Do. 
 Sleet and rain. 
 Lt. rain. 
 
 Do. 
 Snow and sleet. 
 Sleet. 
 Snow. 
 Lt. snow. 
 Lt. rain. 
 
 Do. 
 Lt. snow, moist. 
 Lt. snow. 
 
 Lt. and hy. rain ; thunder. 
 Hy. rain and It. snow. 
 Hy. snowN 
 Lt. snow. 
 
 Do. 
 Hy.rain; It. snow. 
 Hy. snow. 
 Lt. snow. 
 Hy. snow. 
 
 Hy. snow, 7.5 inches. 
 Lt. sleet and snow. 
 Lt. snow. 
 Lt. rain. 
 
 Do. 
 Lt. snow. 
 
 Do. 
 Lt. rain and snow. 
 Lt. snow. 
 
 Do. 
 Lt. rain. 
 Lt. rain ; It. fog. 
 Lt. snow. 
 
 Do. 
 Lt. rain. 
 
 Do. 
 
 Do. 
 Lt. sleet. 
 Lt. rain. 
 
 Do. 
 Lt. rain; thunder. 
 Lt. rain and snow. 
 Lt. rain. 
 
 Do. 
 
 Do. 
 
 Do. 
 
 Do. 
 
 Do. 
 
 Do. 
 Hy. rain. 
 Lt. rain. 
 
 Do. 
 
 Do. 
 Trace of rain. 
 Lt. rain. 
 
 Do. 
 Hy. rain. 
 
 
 
 
 
 
 
 
 
 
 
 .... 
 
 
 1 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 1 
 
 1 
 
 
 .... 
 
 
 
 
 .... 
 
 .... 
 
 1 
 
 
 
 
 
 
 , 
 
 
 
 
 
 
 
 
 
 
 1 
 
 1 
 
 1 
 
 — 
 
 .... 
 
 1 
 
 
 
 
 
 
 
 
 1 
 
 
 
 
 
 
 
 1 
 1 
 
 .... 
 
 
 
 1 
 
 
 
 
 
 1 
 
 .... 
 
 1 
 
 1 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 ~ 
 
 .... 
 
 
 
 
 
 
 
 
 
 1 
 1 
 
 
 
 
 .... 
 
 1 
 
 1 
 
 1 
 
 1 
 
 1 
 
 1 
 
 .... 
 
 
 
 
 
 1 
 
 1 
 
 
 
 
 
 
 
 
 - 1 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 .... 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 .... 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 , 
 
 1 
 
 .... 
 
 .... 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 .... 
 
 1 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 1 
 
 1 
 
 .... 
 
 
 .... 
 
 1 
 
 1 
 
 .... 
 
 
 
 
 .... 
 
 .... 
 
 1 
 
 1 
 
 1 
 1 
 
 .... 
 
 
 .... 
 
 -•■ 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 — 
 
 — 
 
 
 
 
 .... 
 
 .... 
 
 .... 
 
 .... 
 
 1 
 
 1 
 
 1 
 
 1 
 
 1 
 
 
 
 
 1 
 1 
 
 1 
 1 
 
 1 
 1 
 
 
 .... 
 
 1 
 1 
 
 1 
 
 1 
 
 1 
 
 
 
 
 
 
 
 
 
 
 
 
 
 1 
 1 
 1 
 
 
 
 
 
 
 
 
 1 
 
 
 .... 
 
 1 
 
 1 
 
 
 
 
 
 
 
 
 
 
 1 
 
 
 
 .... 
 
 1 
 
 1 
 
 
 
 
 
 
 
 
 
 
 
 .... 
 
 1 
 1 
 1 
 
 1 
 1 
 
 .... 
 
 1 
 
 
 
 
 
 
 
 1 
 
 
 
 
 
 1 
 
 1 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 1 
 1 
 
 .... 
 
 .... 
 
 
 
 
 
 1 
 1 
 
 1 
 1 
 
 1 
 
 
 — 
 
 .... 
 
 .... 
 
 1 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 .... 
 
 1 
 1 
 1 
 
 1 
 1 
 
 1 
 1 
 
 
 
 
 
 1 
 
 1 
 
 1 
 1 
 
 
 
 
 
 
 
 
 .... 
 
 1 
 
 .... 
 
 .... 
 
 1 
 
 1 
 1 
 1 
 
 
 .... 
 
 
 1 
 
 1 
 
 .... 
 
 .... 
 
 
 
 
 
 
 ... 
 
 ■■--« 
 
 _. — 
 
 
 
 
 
 
 
MEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES. 
 
 291 
 
 Table P. — Potential on days on which precipitation occurred at Baltimore, Md,, 1885, 1886, and 
 
 1887— Continued. 
 
 Date. 
 
 Before. 
 
 Dm- 
 
 IDii, 
 
 After. 
 
 
 
 
 Negative. 
 
 
 
 Kemarks. 
 
 1 
 
 1 
 
 O 
 
 2 
 g 
 
 O 
 
 3 
 
 i 
 
 4. 
 
 g 
 1 
 
 1 
 
 i 
 
 1 
 1 
 
 1 
 
 1 
 
 2 
 
 1 
 1 
 1 
 
 o 
 
 <0 
 > 
 
 •a 
 
 1 
 1 
 1 
 
 u 
 
 1 
 
 i 
 
 % 
 1 
 
 £ 
 
 
 
 o 
 + 
 
 1885. 
 May 23 
 May 24 
 MaV 24 
 May 25? 
 May 26 ( 
 .May 27 > 
 May 28 ( 
 May 29 
 May 30 
 May 31 
 May 31 
 Juue 4 
 June 5 
 June 7 
 June 8 
 June 15 
 June 16 
 June 17 
 June 25 
 June 26 
 June 27 
 June 27 
 June 28 
 July 2 
 July 5 
 July 6 
 July 7 
 July 7 
 July 10 
 July 13 
 July 14 
 July 18 
 July. 24 
 July 25 
 July 26 
 July 27 
 July 27 
 July 28 
 July 29 
 July 31 
 Aug. 1 
 Aug. 1 
 Aug. 2 
 Aug. 2 ) 
 Aug. 3 I 
 Aug. 4 
 Aug. 7 } 
 Aug. 8 ^ 
 Aug. 12 
 Aug. 12 
 Aug. 13 
 Aug. 13 
 Aug. 14 
 Aug. 21 
 Aug. 22 
 Aug. 23 
 Ang. 23 
 Aug. 25 
 Aug. 26 
 Aug. 29 
 Aug. .30 
 Aug. 31 
 Sept. 4 
 Sept. 5 
 
 
 1 
 
 Lt. rain. 
 
 Do. 
 
 Do. 
 Lt. rain; thunder. 
 
 Do. 
 Lt. rain. 
 
 Do. 
 
 Do. 
 
 Do. 
 Rain and thunder. 
 
 Do. 
 Lt. rain ; thunder. 
 Hy. rain, hail, and thunder ; gale. 
 Lt. rain; lightning. 
 Lt. rain. 
 Lt. rain and thunder. 
 
 Do 
 Hy. rain. 
 Lt. rain. 
 
 Do. 
 
 Do. 
 
 Do. 
 Hy, rain; thunder; 4.47 inches, 
 Lt. rain. 
 
 Hy. rain ; thunder. 
 Lt. rain. 
 
 Do. 
 Trace of rain. 
 
 Do. 
 
 Do. 
 Lt. rain. 
 
 Lt. rain ; thunder. 
 Lt. rain. 
 
 Lt. rain and lightning. 
 Hy. rain; thunder. 
 Lt. rain. 
 Trace of rain. 
 Lt. rain. 
 
 Do. 
 Ltl rain ; thunder. 
 Lt. rain. 
 
 Lt. rain and thunder, 
 Lt. rain. 
 
 Lt. rain ; hy. thunder. 
 Hy. rain ; thunder ; 3.35 inches. 
 Lt. rain. 
 
 Do. 
 
 Do. 
 Trace of rain. 
 Lt. rain ; thunder. 
 Lt. rain. 
 
 Lt. rain ; thunder. 
 Lt. rain. 
 
 Do. 
 Lt. rain and thunder. 
 Lt. rain. ^ 
 Lt. rain and thunder. 
 Hy. rain and thunder. 
 Lt. rain. 
 
 Do. 
 lit. rain ; thunder. 
 Lt. rain. 
 
 Lt. rain ; thunder. 
 Lt. rain. 
 
 
 
 
 
 .... 
 
 .... 
 
 .... 
 
 1 
 
 1 
 
 1 
 
 1 
 
 1 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 1 
 
 .... 
 
 1 
 
 1 
 1 
 1 
 1 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 * 
 
 
 
 
 
 
 
 1 
 1 
 
 1 
 
 I 
 
 .... 
 
 
 
 
 
 
 1 
 1 
 
 1 
 I 
 
 
 
 
 
 
 
 1 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 1 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 1 
 
 1 
 
 1 
 
 1 
 
 1 
 1 
 
 
 
 1 
 1 
 
 1 
 
 
 
 
 
 
 1 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 1 
 1 
 
 1 
 
 1 
 
 
 
 
 
 
 
 1 
 
 .... 
 
 1 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 1 
 
 1 
 
 
 
 
 
 1 
 
 1 
 
 1 
 
 .... 
 
 1 
 
 1 
 
 .... 
 
 1 
 
 1 
 
 
 
 
 
 
 
 
 
 
 
 
 1 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 . 1 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 1 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 ' 
 
 
 
 
 
 1 
 1 
 
 
 
 1 
 1 
 
 1 
 1 
 
 1 
 
 1 
 
 
 
 
 1 
 
 .... 
 
 — . 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 ' 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 1 
 1 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 ( 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 .... 
 
 1 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 1 
 
 
 
 
 
 
 1 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 ■ 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 - 
 
 
292 
 
 MBMOIES OF THE NATIONAL ACADEMY OF SCIENCES. 
 
 Table P. — Potential on days on which precipitation occurred at Baltimore, Md., 1885, 1886, and 
 
 1887— Continued. 
 
 Date. 
 
 Before. 
 
 Dnring. 
 
 
 After 
 
 
 Hemarks. 
 
 1 
 o 
 
 jSTegative. 
 
 
 
 o 
 
 i 
 
 o 
 
 i 
 4 
 
 i 
 
 3 
 
 § 
 
 1 
 
 © 
 
 o 
 
 8 
 
 t 
 
 1 
 
 1 
 
 d 
 
 S 
 
 I 
 o 
 
 1 
 
 E 
 1 
 
 03 
 
 S 
 
 o 
 
 + 
 
 CO 
 
 1885 
 Sept. 5 
 Sept. 8 
 Sept. 9 
 Sept- 9 
 Sept. 10 
 Sept. 11 
 Sept. 22 > 
 Sept. 23 ( 
 Oct. 2 
 Oct. 2 ) 
 Oct. 3 ( 
 Oct. 3 
 Oct. 4 
 Oct. 6 
 Oct. 8 
 Oct. 12 > 
 Oct. 13 ( 
 Oct. 14 
 Oct. 21 
 Oct. 23 
 Oct. 29 
 Oct. 29 ) 
 Oct. 30 i 
 Oct. 30 
 Nov. 1 ) 
 Nov. 2 < 
 Nov. 5 
 Nov. 6 
 Nov. 7 
 Nov. 8 ) 
 Nov. 9 ( 
 Nov. 13 
 Nov. 18 
 Nov. 19 
 Nov. 21 
 Nov. 22 ) 
 
 Nov. as ), 
 
 Nov. 24 S 
 Nov. 25 
 Nov. 27 
 Nov. 28 
 Nov. 29 
 Dec. 1 
 Dec. 3 
 Dec. 5 
 Dec. 9 
 Dec. 9 
 Deo. 9 
 Dec. 13 ? 
 Dec. 14 \ 
 Dec. 23 
 Dec. 31 
 
 1886. 
 Jan. 4 
 Jan. 5 
 Jau. 6 
 Jan. 8 } 
 Jan. 9 5 
 Jau. 25 
 Jan. 27 ) 
 Jan. 28 > 
 Jan. 29 ) 
 Jan. 30 
 Feb. 3 ) 
 Feb. 4 I 
 
 Lt. rain. 
 
 Do. 
 
 Do. 
 
 Do. 
 
 Do. 
 
 Do. 
 
 Do. 
 
 Do. 
 
 Do. 
 Lt.rain; thunder. 
 
 Do. 
 Lt. rain. 
 
 Lt. rain ; record not good. 
 Lt. rain. 
 
 Do. 
 
 Do. 
 
 Do. ■ 
 
 Do. ' 
 Hy. rain. 
 Trace of rain. 
 Lt.rain. 
 Hy. rain ; thunder. 
 
 Do. 
 Lt. rain. 
 
 Lt. rain and hy. rain. 
 Hy. rain. 
 Lt. rain. 
 Trace of rain. 
 Lt. rain. 
 
 Do. 
 
 Do. 
 
 Do. 
 Trace of rain. 
 Lt. rain. 
 
 Do. 
 
 Do. 
 Lt. rain and snow. 
 Lt. rain. 
 Trace of snow. 
 Lt. rain. 
 
 Do. 
 
 Do. 
 
 Do. 
 Lt. rain and sleet. 
 Lt. rain. 
 
 Do. 
 Hy. rain. 
 Lt.rain. 
 
 Do. 
 Hy. rain. 
 Lt. rain. ♦ 
 
 Do. 
 
 Lt. to hy. rain. 
 Trace of snow. 
 
 Do. 
 Lt. and hy. snow. 
 Hy. snow. 
 Lt. rain. 
 
 Do. 
 
 Do. 
 
 Do. 
 Lt. rain and snow. 
 Hy. snow. 
 Hy. snow, 15 inches. 
 
 .... 
 
 I 
 
 1 
 
 
 
 
 
 
 
 
 
 — 
 
 .... 
 
 1 
 1 
 
 1 
 1 
 1 
 1 
 
 1 
 
 
 
 
 
 ^ 
 
 
 
 
 
 1 
 
 1 
 
 
 
 
 
 
 1 
 
 
 
 
 
 1 
 
 .... 
 
 
 
 
 
 1 
 
 1 
 
 .... 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 1 
 
 1 
 
 1 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 1 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 1 
 
 .... 
 
 1 
 1 
 1 
 
 1 
 1 
 1 
 
 1 
 1 
 
 ■ 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 1 
 
 
 
 
 
 
 
 
 
 — 
 
 — . 
 
 
 V 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 1 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 1 
 1 
 1 
 
 
 
 
 
 
 
 
 
 1 
 
 1 
 
 .... 
 
 
 
 
 
 
 
 
 
 .... 
 
 "i" 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 1 
 
 .... 
 
 1 
 
 1 
 
 1 
 1 
 
 1 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 4 
 
 
 
 
 
 
 
 
 
 
 
 
 
 .... 
 
 1 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 1 
 
 1 
 
 1 
 
 .... 
 
 .... 
 
 1 
 
 
 
 
 
 
 
 
 
 
 
 
 1 
 1 
 1 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 1 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 1 
 
 
 
 
 
 
 
 
 
 
 
 
 1 
 
 1 
 
 .... 
 
 
 
 
 
 
 
 
 
 1 
 1 
 
 
 
 
 
 
 
 1 
 1 
 1 
 
 .... 
 
 
 
 
 
 
 
 
 
 1 
 
 
 1 
 
 
 
 
 
 
 .... 
 
 1 
 
 
 
 
 
 
 
 1 
 
 
 
 
 
 
 
 
 
 
 1 
 
 1 
 1 
 
 ~ 
 
 
 
 
 
 
 
 
 
 
 
 
 1 
 
 
 
 
 
 
 
 
 1 
 1 
 1 
 1 
 
 1 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 1 
 
 1 
 
 .... 
 
 1 
 
 1 
 
 1 
 
 
 
 
 
 
 
 
 
 
 
 1 
 
 1 
 
 1 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 1 
 
 .... 
 
 1 
 1 
 
 1 
 1 
 1 
 1 
 ] 
 1 
 1 
 
 
 
 
 
 
 
 
 
 
 
 
 
 1 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 .... 
 
 ■-■•. 
 
 .... 
 
 
 
 
 
 
 
 — 
 
 .... 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
MEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES. 
 
 293 
 
 Table 'P.— Potential on days on which precipitation occurred at Baltimore, Md., 1885, 1886 and 
 
 ■ 1887— Continued. ' 
 
 Bate. 
 
 Before. 
 
 During. 
 
 
 A ftor 
 
 
 Kemarks. 
 
 1 
 
 Negative. 
 
 
 
 s 
 
 p 
 o 
 
 o 
 .a 
 
 o 
 
 2 
 
 i 
 
 s 
 
 g 
 
 2 
 
 1 
 
 2' 
 
 g 
 
 3 
 
 1 
 
 
 
 1 
 
 1 
 
 3 
 
 1 
 
 § 
 
 + 
 
 1886. 
 Feb. 10 1 
 Feb. 11 1 
 Feb. 12 ■ 
 Feb. 13 
 Feb. 15 
 Feb. 23 
 Feb. 25 
 Feb. 26 
 Mar. 8 
 Mar. 12 
 Mar. 13 
 Mar. 18 
 Mar. 19 
 Mar. 20 ) 
 Mar. 21 I 
 Mar. 21 
 Mar. 22 
 Mar. 26 ) 
 Mar. 27 ( 
 Mar. 28 
 Mar. 29 ) 
 Mar. 30 > 
 Mar. 31 ) 
 Apr. 3 
 Apr. 4 ) 
 Apr. 5 > 
 Apr. 6 ) 
 Apr. 7 
 Apr. 7 
 Apr. 11 
 Apr. 12 
 Apr. 13 
 Apr. 13 
 Apr. 16 
 Apr. 17 
 Apr. 24 
 Apr. 25 
 Apr. 25 
 June 30 
 July 1 I 
 July 2 5 
 July 10 
 July 13 
 July 14 
 July 14 
 July 15 
 July^ 16 
 July 18 
 July 21 
 July 25 
 July 26 
 July 27 
 July 31 
 Aug. 1 
 Aug. 2 
 Aug. 7 
 Aug. 17 
 Aug. 17 
 Sept. 15 ? 
 Sept. 16 5 
 Sept. 19 
 Sept.- 19 
 Sept. 21 I 
 Sept. 22 i 
 Sept. 22 
 
 
 
 
 
 
 1 
 
 
 Lt. rain. 
 
 Do. 
 
 Do. 
 
 Do. 
 
 Do. 
 
 Do. 
 Hy. rain. 
 Lt. snow. 
 ' Do. 
 Lt. rain and sleet. 
 Lt. rain. 
 
 Do. 
 
 Do. 
 
 Do. 
 
 Do. 
 
 Do. 
 
 Do. 
 
 Do. 
 
 Do. 
 
 Do. 
 
 Do. 
 
 Do. 
 
 Do. 
 
 Do. 
 
 Do. 
 
 Do. 
 
 Do. 
 
 Do. 
 
 Do. 
 
 Do. 
 
 Do. 
 
 Do. 
 Lt. rain ; thiinder. 
 Lt. rain. 
 
 Do. 
 Lt. rain ; thunder. 
 Lt. rain. 
 
 Do 
 
 Do. 
 
 Do. 
 Hy. rain. 
 Lt. rain. 
 
 Do. 
 
 Do. 
 Hy. rain; thunder. 
 Hy> rain 2.09 in. ; thunder; tornado. 
 Lt. rain. 
 
 Lt. rain ; thunder. 
 Hy. rain. 
 Lt. rain. 
 
 Hy. rain ; thunder. - 
 Lt. rain. 
 
 Hy. rain and thunder. * 
 Lt. rain. 
 
 Lt. rain ; lightning. 
 Trace of rain. 
 Lt. rain. 
 
 Lt. rain ; thunder. 
 Lt. rain. 
 
 Do. 
 Hy. rain ; thunder. 
 Lt. rain ; thunder. 
 Lt. rain. 
 
 Do. 
 
 Do. 
 
 
 
 
 
 
 
 
 1 
 
 
 
 
 
 
 
 
 
 
 
 1 
 1 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 1 
 
 
 
 
 
 1 
 1 
 1 
 
 1 
 1 
 
 
 .... 
 
 .... 
 
 1 
 
 .... 
 
 1 
 
 1 
 
 1 
 
 1 
 
 1 
 1 
 1 
 1 
 1 
 
 .... 
 
 
 
 
 
 
 
 1 
 
 1 
 
 
 
 1 
 1 
 
 
 
 
 
 .... 
 
 1 
 
 1- 
 
 1 
 
 1 
 
 1 
 
 1 
 
 1 
 
 1 
 
 1 
 1 
 1 
 1 
 
 1 
 
 1 
 1 
 
 
 
 
 
 
 
 
 
 
 
 
 
 .... 
 
 1 
 
 1 
 
 1 
 
 1 
 
 1 
 
 1 
 1 
 
 1 
 
 
 
 .... 
 
 1 
 
 1 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 1 
 
 " 
 
 
 .... 
 
 1 
 1 
 
 
 
 
 
 
 
 
 1 
 
 1 
 
 1 
 
 1 
 
 1 
 
 1 
 
 .... 
 
 1 
 1 
 1 
 1 
 1 
 1 
 1 
 1 
 1 
 1 
 
 
 
 1 
 
 1 
 
 
 
 
 
 
 
 
 1 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 1 
 
 1 
 
 1 
 1 
 
 1 
 
 1 
 
 .... 
 
 1 
 
 1 
 
 1 
 1 
 
 1 
 I 
 
 1 
 1 
 
 1 
 1 
 
 1 
 1 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 1 
 
 1 
 
 1 
 
 
 
 
 1 
 
 
 
 
 
 
 
 
 
 
 1 
 1 
 
 .... 
 
 1 
 
 1 
 
 
 
 
 
 
 
 1 
 
 1 
 
 1 
 
 
 
 
 .... 
 
 1 
 
 
 
 
 
 
 1 
 
 1 
 
 
 
 1 
 1 
 
 
 
 
 
 
 
 
 1 
 
 .... 
 
 
 
 
 
 
 
 
 
 1 
 
 
 
 
 
 
 
 1 
 
 
 — 
 
 .... 
 
 1 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 1 
 1 
 
 .... 
 
 1 
 1 
 
 1 
 1 
 
 1 
 
 1 
 
 1 
 
 
 
 
 
 
 1 
 
 .... 
 
 1 
 
 
 
 1 
 
 
 
 
 
 
 1 
 1 
 1 
 
 
 
 
 .... 
 
 1 
 
 
 
 
 1 
 
 1 
 I 
 
 .... 
 
 
 
 
 
 1 
 
 1 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 1 
 
 
 
 
 1 
 1 
 
 
 
 1 
 1 
 
 1 
 
 1 
 
 1 
 
 
 
 
 
 1 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 1 
 
 
 
 
 
 
 
 
 1 
 1 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 , 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 1 
 
 1 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 1 
 
 1 
 
 1 
 
 
 
 
 
 
 
 
 
 
 
294 
 
 MEMOmS OP THE NATIONAL ACADEMY OP SCIENCES. 
 
 Table P. — Potential on days on which precipitation occurred at Baltimore, Md., 1885, 1886, and 
 
 1887— Continued. 
 
 Date. 
 
 Before. 
 
 During. 
 
 
 After 
 
 
 EematkB. 
 
 1 
 
 o 
 
 Negative. 
 
 
 
 1 
 
 s 
 
 o 
 
 '3 
 
 s 
 
 
 
 4 
 
 i 
 
 2 
 
 a 
 
 o 
 
 w 
 
 1 
 
 O 
 
 o 
 
 (2; 
 
 £ 
 1 
 
 
 CO 
 
 g 
 
 + 
 
 1886. 
 Sept. 29 
 Oct. 14 
 Oct. 14 
 Oct. 21 
 Oct. 26 ) 
 Oct. 27" } 
 Oct. 28 S 
 Oct. 29 
 Oct. 30 
 Oct. 31 
 Nov. 6 
 Nov. 6 ) 
 Nov. 7 I 
 Nov. 10 
 Nov. 12 
 Nov. 13 
 Nov. 17 
 Nov. 18 
 Nov. 22 ) 
 Nov. 23 I 
 Nov. 23 
 Nov. 24 
 Nov. 25 
 Nov. 30 
 Dec. 4 ) 
 Dec. 5 5 
 Dec. 6 
 . Dec. 6 ) 
 Dec. 7 S 
 Dec. 12 { 
 Dec. 13 i 
 Dec. 15 ) 
 Dec. 16 \ 
 Dec. 18 
 Dec. 22 
 Dec. 23 > 
 Dec. 24 
 Dec. 26 
 Dec. 29^ 
 Dec. 30 
 Dec. 31 > 
 
 1887. 
 Jan. 1 J 
 Jan. ] 
 Jan. 9 ) 
 Jan. 10 S 
 Jan. 13 I 
 Jan. 14 5 
 Jan. 17 
 Jan. 24 
 Jan. 26 
 Jan. 26 
 Jan. 29 • 
 Feb. 2 
 Feb. 3 
 Feb. 3 
 Feb. 5 
 Feb. 5 ) 
 Feb. 6 > 
 Feb. 7 S 
 Feb. 7 
 Feb. 8 
 Feb. 10 
 Feb. 11 
 
 
 
 
 
 
 1 
 
 1 
 1 
 
 1 
 1 
 1 
 1 
 1 
 
 • 
 
 
 Hy. rain. 
 Lt. rain . 
 
 Do. 
 
 Do. 
 
 Do. 
 
 Do. 
 
 Do. 
 Trace of rain. 
 Lt. rain. 
 
 Do. 
 
 Do. 
 
 Do. 
 
 Do. 
 
 Do. 
 Hy. rain. 
 
 Lt. snow ; high positive daring. 
 Lt. rain. 
 Hy. rain. 
 Lt, rain. 
 
 Do. 
 
 Do. 
 
 Do. 
 Lt. rain; by. rain; waterspout. 
 Lt. rain. 
 Lt. snow. 
 
 Do. 
 
 Do. 
 Lt. rain and snow. 
 Lt. snow. 
 Lt. ram. 
 
 Do. 
 Lt. rain and snow. 
 Lt. snow. 
 Hy. rain. 
 Lt. rain. 
 
 Do. 
 
 Do. 
 Lt. and hy. snow. 
 Lt. snow." 
 
 Do. 
 Lt. rain. 
 
 Lt. rain. 
 
 Lt. snow; trace. 
 
 Lt. snow and sleet. 
 
 Lt. snow. 
 
 Lt, rain. 
 
 Do. 
 
 Do. 
 Lt. rain and snow. 
 Lt. rain. 
 Lt. snow. 
 Lt. rain. 
 
 Snow, sleet, and rain. 
 Lt, rain. 
 
 Do. 
 Snow, rain, and sleet. 
 Lt, rain. 
 
 Do. 
 
 Do. 
 
 Do.. 
 
 Do. 
 
 Do. 
 Lt. rain ; gale. 
 
 
 
 
 
 X 
 
 1 
 
 1 
 1 
 
 1 
 
 1 
 
 
 
 
 1 
 
 
 
 
 
 
 .... 
 
 .... 
 
 1 
 
 1 
 
 1 
 
 1 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 1 
 
 1 
 
 1 
 1 
 
 1 
 I 
 1 
 
 .... 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 1 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 1 
 
 .... 
 
 
 
 
 
 
 
 
 
 
 
 
 1 
 
 .... 
 
 
 
 
 
 
 
 .... 
 
 1 
 
 1 
 
 1 
 
 1 
 
 1 
 
 1 
 1 
 
 1 
 
 — 
 
 1 
 
 .... 
 
 .... 
 
 .... 
 
 
 
 
 
 1 
 
 1 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 1 
 
 1 
 
 .... 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 .... 
 
 1 
 
 1 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 1 
 
 1 
 
 .... 
 
 1 
 
 " 
 
 
 
 
 
 
 
 
 1 
 
 1 
 
 1 
 
 .... 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 1 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 1 
 
 1 
 
 
 
 
 
 1 
 1 
 
 1 
 1 
 
 1 
 
 1 
 
 ---- 
 
 .... 
 
 .... 
 
 .... 
 
 1 
 
 
 
 .... 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 1 
 1 
 
 1 
 1 
 
 — 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 .... 
 
 
 
 . 
 
 
 
 
 
 
 
 
 
 1 
 
 1 
 
 1 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 .... 
 
 1 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 1 
 
 1 
 
 1 
 1 
 
 .... 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 .... 
 
 1 
 
 1 
 
 
 
 
 
 
 
 
 
 
 1 
 1 
 
 — 
 
 
 
 
 
 
 
 
 
 
 1 
 
 
 
 
 
 
 
 
 
 
 
 
 .... 
 
 1 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 .... 
 
 .... 
 
 1 
 
 1 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 1 
 
 
 
 
 
 
 
 1 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 .... 
 
 .... 
 
 1 
 
 1 
 
 
 
 
 1 
 
 
 
 
 
 
 
 
 
 
 
MEMOIRS OP THE NATIONAL ACADEMY OP SCIENCES. 
 
 295 
 
 Table P. — Potential on days on which precipitation occurred at Baltimore, Md., 1885, 1886, and 
 
 1887— Continued. 
 
 Date. 
 
 Before. 
 
 Dui-mg. 
 
 
 After 
 
 
 Kemarks. 
 
 1 
 
 Negative. 
 
 
 
 1 
 
 o 
 
 i 
 
 2 
 
 g 
 g 
 
 4 
 
 J 
 
 3 
 
 s 
 g 
 
 3 
 
 •g 
 
 1 
 
 H 
 
 o 
 
 > 
 1 
 
 In 
 
 g 
 =1 
 
 e 
 
 a 
 o 
 
 1 
 
 o 
 + 
 
 1887. 
 Feb. 14 ? 
 Feb. 15 ( 
 Feb. 18 
 Feb. 18 
 Feb. 20 ) 
 Feb. 21 I 
 Feb. 23 ) 
 Feb. 24 I 
 Feb. 26 
 Feti. 27 
 Mar. 3 
 Mar. 3 1 
 Mar. 4 < 
 Mar. 5 ) 
 Mar. 6 5 
 Mar. 7 
 Mar. 9 > 
 Mar. 10 ( 
 Mar. 13 \ 
 Mar. 14 5 
 Mar. 17 \ 
 Mar. 18 ( 
 Mar. 21 \ 
 Mar. 22 5 
 Mar. 24 
 Mar. 27 ) 
 Mar. 28 5 
 Mar. 28 
 Mar. 31 1 
 Apr. 1 [ 
 Apr. 8 ) 
 Apr. 4 
 Apr. 5 
 Apr. 15 
 Apr. 16 
 Apr. 17 
 Apr. 18 1 
 Apr. 19 i 
 Apr. 22 ? 
 Apr. 23 S 
 Apr. 25 ] 
 Apr. 26 J 
 Ap*. 26 
 Apr. 27 
 ,Apr. 27 
 Apr. 28 
 Apr. 28 
 Apr. 29 
 May 1 
 May 5 
 May 6 
 May 7 
 May 8 
 May 9 
 May 10 
 May 24 
 May 25 
 May 25 
 May 26 
 May 26 
 May 27 
 May 28 
 May 31 ) 
 June 1 S 
 June 2 
 
 
 
 
 
 Lt. snow and rain. 
 Lt. rain. 
 
 Do. 
 Hy. rain; hail; thunder. 
 Lt. rain; snow. 
 Snow, sleet, and rain. 
 Lt. snow and rain. 
 Lt. rain. 
 
 Hy. snow ; It. rain. 
 
 Trace of snow ; high positive during. 
 Lt. rain and sleet. 
 Sleet and rain. 
 Rain and snow. 
 Snow, sleet, and rain. 
 Lt. rain. 
 Hy, rain. 
 
 Do. 
 Lt. rain. ^ 
 Hy. rain. 
 Lt. rain. 
 Lt, snow. 
 
 Do. 
 Lt. rain and snow. 
 Snow and rain. 
 Lt. rain. 
 Hy. rain. 
 
 Do. 
 Lt, snow. 
 
 Do. 
 
 Do. 
 
 Do. 
 Lt. rain. 
 Lt. snow. 
 Lt. rain ; thunder. 
 Lt. rain. 
 
 Do. 
 
 Do. 
 
 Do. 
 
 Do. 
 
 Do. 
 Hy. rain. 
 
 Do. 
 Lt. rain. 
 
 Do. 
 
 Do. 
 
 Do. 
 
 Do. 
 J Do. 
 Trace of rain. 
 Lt.rain; sheet lightning. 
 Lt. rain ; thunder. 
 
 Do. 
 
 Do. 
 Lt.rain. 
 
 Do. 
 
 Do. 
 
 Do. 
 Hy. rain ; thunder. 
 Lt. rain.-' 
 
 Hy. rain ; thunder. 
 Lt. rain. 
 
 Do. 
 Hy. rain. 
 
 Do. 
 Lt, rain. 
 
 
 
 
 
 
 
 
 
 
 
 
 .... 
 
 .... 
 
 1 
 
 
 
 1 
 
 
 .... 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 .... 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 1 
 
 
 .... 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 1 
 
 .... 
 
 .... 
 
 
 
 
 
 
 
 
 
 .... 
 
 .... 
 
 1 
 
 1 
 
 1 
 
 1 
 
 1 
 1 
 
 
 .... 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 .... 
 
 1 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 1 
 
 
 
 
 
 
 
 — 
 
 — 
 
 
 
 .... 
 
 1 
 
 
 
 
 1 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 1 
 
 
 .... 
 
 
 
 
 
 
 
 
 
 1 
 
 1 
 
 .... 
 
 
 
 
 
 1 
 
 1 
 
 
 
 
 
 
 
 
 
 1 
 
 1 
 
 1 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 1 
 
 1 
 
 
 
 
 
 
 
 1 
 
 
 
 .... 
 
 1 
 
 1 
 
 1 
 
 
 
 
 
 
 
 
 
 
 
 
 
 — 
 
 1 
 
 
 
 .... 
 
 .... 
 
 I 
 
 1 
 
 1 
 
 1 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 1 
 
 1 
 1 
 
 1 
 1 
 
 1 
 
 1 
 
 1 
 1 
 
 1 
 
 1 
 1 
 
 1 
 
 
 
 
 1 
 
 
 
 
 
 1 
 
 1 
 
 1 
 
 
 
 
 
 " 
 
 
 
 
 1 
 
 .... 
 
 .... 
 
 
 
 
 
 
 
 
 .... 
 
 " 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 1 
 
 1 
 
 .... 
 
 ■ 
 
 
 
 
 
 
 
 .... 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 1 
 
 
 .... 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 1 
 
 1 
 
 
 
 
 .... 
 
 1 
 
 ■ 
 
 
 
 
 
 
 
 
 1 
 
 
 .... 
 
 
 
 
 
 
 
 
 
 
 
 
 .... 
 
 .... 
 
 1 
 1 
 
 1 
 1 
 
 1 
 1 
 
 1 
 1 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 1 
 
 1 
 
 
 — 
 
 1 
 
 1 
 
 1 
 
 1 
 
 .... 
 
 
 
 
 
 .. . 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 .... 
 
 1 
 
 
 
 
 .... 
 
 1 
 
 1 
 1 
 
 1 
 1 
 
 
 
 
 
 
 
 
 
 1 
 1 
 1 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 — 
 
 
 
 
 
 
 
 
 
 
 
 
 
296 
 
 MEMOIRS OF a:flE NATIONAL ACADEMY OF SCIENCES. 
 
 Table P. — Potential on days on which precipitation occurred at Baltimore^ Md., 18_8S, 1886, and 
 
 1887— Continued. 
 
 Date, 
 
 Before. 
 
 During. 
 
 
 After 
 
 
 Kemarks. 
 
 1 
 
 s 
 
 1 
 
 UTegative. 
 
 
 
 g 
 
 13 
 O 
 
 oi 
 
 § 
 J 
 
 o 
 
 s 
 
 g 
 
 E3 
 
 4 
 
 3 
 
 B 
 o 
 
 1 
 
 3 
 
 "3 
 
 s 
 g 
 
 o 
 
 6 ■ 
 
 1 
 
 P 
 o 
 
 I 
 o 
 
 a 
 o 
 
 O 
 + ' 
 
 1887. 
 June 2 \ 
 June 3 ( 
 June 6 
 June 7 
 June 7 
 June 9 
 June 18 
 June 19 
 June 19 
 June 20 
 June 20 
 June 21 \ 
 June 22 S 
 June 22 \ 
 June 23 S 
 ■Tune 23 
 July 5 
 .July 5 
 July 5 
 July 5 
 Julv 6 
 July 9 
 July 17 
 ,July 18 
 July 19 
 July 19 
 July 20 
 July 21 
 July 21 
 .luly 23 
 July 23 ) 
 July 24 S 
 July 34 
 July 24 
 July 25 
 July 26 
 July 27 
 July 29 
 July 29 
 Aug. 2 
 
 
 
 
 
 
 
 
 
 Hy. rain ; thunder. 
 Lt. rain. 
 
 Do. 
 Hy. rain. 
 Lt. rain. 
 
 Lt. rain and thunder. 
 Hy. rain ; hail and thunder. 
 Lt. rain ; thunder. 
 Hy. rain ; thuuder. 
 Lt. rain. \ ^ 
 Lt. rain and thunder. 
 Lt. rain ; .thunder. 
 
 Do.'^ 
 Hy. rain ; thunder. 
 Lt. rain. 
 
 Do. ' 
 
 Do. 
 Hy. rain. 
 Lt. rain. 
 Thunderstorm. 
 Lt. rain. 
 Lt. rain ; thunder. 
 
 Do. 
 Hy. rain; hail and thunder. 
 Hy. rain and thunder. 
 Lt, rain. 
 
 Do. 
 
 Do. 
 Hy. rain ; tbuuder 2.70 iuches. 
 Hy. rain; thunder 1.11 iuches. 
 Lt. rain. 
 
 Do. 
 
 Do. 
 
 Do. 
 Trace of rain. 
 
 Hy. rain ; thunder 1.55 inches. 
 Lf. rain. 
 Trace of rain. 
 Lightning. 
 Trace of rain. 
 
 "■" 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 1 
 
 
 
 1 
 1 
 1 
 
 
 
 
 
 
 
 
 
 1 
 
 1 
 
 .... 
 
 
 
 
 
 
 
 
 1 
 
 1 
 
 1 
 
 
 1 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 " 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 1 
 1 
 
 1 
 1 
 1 
 
 
 
 1 
 1 
 
 1 
 
 I 
 1 
 1 
 
 1 
 
 1 
 
 / 
 
 
 
 
 1 
 
 
 
 
 
 .... 
 
 i 
 
 
 
 
 
 
 
 ----' 
 
 1 
 
 
 
 
 
 
 
 1 
 
 1 
 
 .... 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 1 
 
 1 
 
 
 
 
 
 1 
 
 1 
 
 1 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 1 
 
 .... 
 
 1 
 
 .... 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 1 
 
 
 1 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 1 
 
 
 
 
 
 Table Q, — Potential on days on which precipitation occurred at Washington, D. C, October 1, 1887, 
 
 to August 31, 1888. 
 
 Date. 
 
 1887. 
 Oct. 18 
 
 Oct. 
 
 2» 
 
 Oct. 
 
 24 
 
 Oct. 
 
 25 
 
 Oct. 
 
 26 
 
 Oct. 
 Oct. 
 Nov. 
 
 27 
 28 
 10 
 
 Hemarks. 
 
 Lt. rain.b. d n.,e. 7:50 a.m., h. 4:10 p. m., e. 5:05 p. m.,b. 6:06 p. m.,e. 9:15 p.m.; no special 
 observations ; positive at all regular observations. 
 
 Lt. raiu, b. 7:45 a. m., e. 9:.50 p. m., 1.14 inches ; variable positive and negative all day, 9 a. 
 ni. to 5 p. m. 
 
 A trace of rain from 4:30 to 4:35 a. ra., from 2 to 2:30 p. m., and from 6:35 to 8:45 p. m. ; no 
 special observations ; positive at all regular observations. 
 
 Sleet, b. 8:45a. m., changed to rain 9:25 a. m., e. 4:.50 p. m. ; It. rain, b. 6 p. m., e. 8:30 p. m., 0.22 
 inch ; variable positive and negative all day. 
 
 Lt. rain from 10:10 to 11:25 a. m. and from 1:30 to 8:3C p. m., 0.02 inch ; no special observa- 
 tions ; positive at all regular observations. 
 
 Lt. drizzling rain all day ; no negative observed. 
 Do. 
 
 Lt. rain from 8:30 a. m. to 2 p. in., 0.30 inch ; variable positive and negative from 9 a. m. to 
 1:30 p.m. 
 
MEMOIRS OF THE NATIONAL ACADJEMY OP SCIENCES. 
 
 297 
 
 Table Q. — Potetitial on days on which precipitation occurred at Washington, D. C, October 1, 1887, to 
 
 August 31, 1888 — Continued. 
 
 Date. 
 
 ■ 1887. 
 Nov. 11 
 
 Nov. 
 
 14 
 
 Nov. 
 Nov. 
 Dec. 
 Dec. 
 
 19 
 
 'i8 
 2 
 
 8 
 
 Dec. 
 
 10 
 
 Dec. 
 
 15 
 
 Dec. 
 
 17 
 
 Dec. 
 
 20 
 
 Dec. 
 
 26 
 
 Dec. 
 
 28 
 
 Deo. 
 
 31 
 
 1888. 
 Jan, 1 
 
 Jan. 
 
 6 
 
 Itemarks. 
 
 Jan. 9 
 
 Jan. 13 
 
 Jan. 17 
 
 Jan. 23 
 
 Jan. 25 
 
 Jan. 29 
 
 Jan. 31 
 
 Feb. 4 
 
 Feb. 7 
 
 Feb. 8 
 
 Feb. 9 
 
 Feb. 10 
 
 Feb. 11 
 
 Feb. 20 
 
 Feb. 27 
 
 Mar. 1 
 
 Mar. 2 
 
 Mar. 5 
 
 Mar. 13 
 
 Mar. 14 
 
 Mar. 16 
 
 Mar. 20 
 
 Mar. 21 
 
 Mar. 22 
 
 A trace of snow from 2:15 to 2:30 p. m. ; no observations between 1 and 3 p.m.; positive at 
 those hours. 
 
 Positivefrom9a. m. to3p. m. ; no observations from 3 to 5 p. m. ; positive at 5 p.m.; noobser- 
 vations after this; It. rain ifrom 4:40 to 4:45 p. m. and from 5:35 to 11:55 p. m,, 0.10 inch. 
 
 Lt. rain, b. 8:50 a. m., e. 2:45 "p. m. ; variable positive and negative from 9 a. m. to 1:45 p. m. 
 
 Lt. rain from 8 a. m. to 1:35 p. m. ; variable positive and negative from 9:30 a. m. to 1:35 p. m. 
 
 A trace of snow from 8:10 to 9:05 a. m. ; positive at 9 a. m. ; no other observations. 
 
 Lt. rain from 7:47 to 9:20 a. m. and from 10:.55 a. ra. to 12:10 p. m., 0.01 Inch ; no special ob- 
 servations; positive at all regular observations. 
 
 Lt. rain, b.d.n.,e. 9:55 a.m. ; negative from 9 to 9:30 a. m. ; It. rain from 12:05 to 2:45 p. m., 
 from 3:14 to ."1:20 p. m., and from 9:50 to 10:35 p.m. ; variable posirtive and negative from 
 1:30 to 5 p. m. ; amount of rain, 0.89 inch. ^ 
 
 Hy. rain from 3:25 a. m. to 2:48 p. m., 0.93 inch ; variable positive and negative from 9 a. m. 
 to 12:35 p. m. 
 
 Threatening at 9 a. m. ; hy. snow from 1 to 9:10 p. m., 0.64 inch of melted snow ; variable 
 positive an4 negative from 10 a. m. to the last observation, at 5:20 p. m. 
 
 Lt. rain, b. 9 a. m., changed to sleet at 10:20 a. m., e. 9:50 p. m., 0.57 inch ; variable posi- 
 tive and negative from 9:50 a. m. to the last observation, at 5:15 p. m. 
 
 A trace of snow from 3:48 to 7 p. m. ; no observation after 1 p. m., except at 5 p. m,, when it 
 was positive. 
 
 Hy. rain from 3:10 a. m. to 1 p. m., 0.63 inch ; variable positive and negative from 9 a. m. to 
 12:30 p. m. 
 
 Threatening at 9 a. m. ; negative at 1 p. m. ; positive at the other regular observations ; no spe- 
 cial observations ; hy. snow, b. 12:40 p.m., changed to sleet 5:45 p. m., e. 7 p. m.,0.42 inch. 
 
 Hy.rain, b. d. u.,i!. 2:30 p. m., 0.85 inch ; negative at 9 and 11a. m.and 1 p. m. ; positive at 
 3 and 5 p. m. ; no special observations. 
 
 Variable positive and negative from 9 to 10 a. m., with threatening weather ; a trace of 
 rain from 11:20 to 11:45 a- m., from 4:40 to 4:45 p. m., and from 5:15 to 5:45 p. m. ; nega- 
 tive and positive dnring first rain ; no observations during others. 
 
 Lt. snow and rain from 10:55 a. ra. to <1. n., 0.31 inch ; positive at 9 a. m. ; no observations be- 
 tween 9 and 11 a. m. ; variable positive and negative at 11 a. m. and 1 and 3 p. m. ; posi- 
 tive at 5 p. m. 
 
 Bain and sleet, b. d.n.,e. 12:45 p.m., 0.70 inch; generally negative at 9 and 11 a. m.and 1 
 p. m. ; no observations at 3 p. m. ; positive at 5 p. ra. 
 
 Lt, snow and sleet, b. 2:45 a. m., e. 5:30 p. m., 0.26 inch ; variable positive and negative all 
 day, 9 a. m. to 5 p. m, 
 
 A trace of snow Irom 1.35 to 1:45 p. m. ; positive at 9 and 11 a. m. and 1 p. m. ; variable 
 positive and negative at 3 p. m. 
 
 Hy. snow from 1:35 to 8:16 p. m., 0.60 inch ; positive at 9 and 11 a. m. and 1 p. m. ; no obser- 
 vations from 1 to 3 p. ra. ; variable positive and negative at 3 and 5 p. m. 
 
 Negative at 4:55 p. m. ; high positive 5:10 to 5:20 p. m. ; no observations after this ; It. snow 
 from 6 to 8:35 p. m., 0.03 inch. 
 
 Lt. rain from 3:30 to 7:10 a. m., 0.15 inch ; a trace of rain from 1:55 to 2:10 p. m. ; no special 
 observations during the day ; positive at all regular observations. 
 
 Lt. rain from 1:40 a. m. to 9:10 p. m., 0:48 inch ; negative at 9 a. m. ; positive at U a. m., and 
 1, 3, and 5 p. m. ; no special observations. 
 
 Lt. rain mist, from 6:20 a. m. to 12:10 p. m., 0.03 inch ; positive from 9 a. m. to 5 p. m. 
 
 Lt. rain, b. 8:20 a. m., e. 12:15 p. m., 0.40 inch ; variable positive and negative from 9 a. m. 
 to 1 p. m. 
 
 A trace of snow from 6:25 a. m. to 12:50 p. m. ; positive all day. 
 
 Lt. snow and sleet from 1:10 a. m. all day., 0.16 inch; high positive from 9 a.m.tolp. 
 m. during snow ; negative from 2 to 7 p. m. , during snow and sleet. 
 
 Sleet and rain, b. d. n., e. 4:40 p. m., 0.42 inch ; variable positive and negative from 9 a. m. 
 to I p. m. 
 
 Lt. rain, b. 5:30, e. 7:30 a. m. ; b. 11:40 a. m.,e. 12:30 p.m.; b. 2:50, e. 3:10 p. m. ; b.5:05, e. 
 5:07 p. m. ; 0:10 inch ; no special observations ; positive at all regular observations. 
 
 Lt. snow from 6:25 to 11:30 a. m,, 0.06 inch; variable positive and negative from 9 to 10 
 a. m. ; positive rest of the time. 
 
 A trace of rayi from 1:15 to 2:25 p.m.; no special observations; positive at regular obser- 
 vations. - t , L J.. 
 
 A trace of rain 12:45 p. m. ; no special observations ; positive at the regular observations. 
 
 Lt. and hy. snow from 6:15 a. m. to 9:40 p. m., 0.42 inch; variable positive and negative 
 from 9 a. ni. to 3 p. m. 
 
 A trace of snow from 11:40 a. m. to 8:30 p. m. ; positive all day. 
 
 A trace of snow from 9 to 10 a. ra. ; positive all day. 
 
 Threatening and negative at 4:58 p. m. ; It. rain from 5:45 to 7:20 p. m. ; no observation 
 after 5 p. m. 
 
 Lt. rain from 5:30 a. m. to 2:15 p. m., 0.44 inch ; negative from 9 to 11 a. m. ; variable posi- 
 tive and negative from 11 a. m. to 12 m. 
 
 Lt. rain from^ 3:45 to 7:50 a. m. and from 1:35 to 4:15 p. m., 0.50 inch ; positive from 9 a. m. 
 to 1 p. ra. ; no observations from 1 to 1:45 p. m. ; variable positive and negative from 1:45 
 to 4 p. m. 
 
 A trace of snow from 6:20 to 7:50 a. m., and from 2:55 to 3:30 p. m. ; positive all day. 
 
298 
 
 MKMOIRS OF THK NATIONAL ACADEMY OP SCIENCES. 
 
 Table Q. — Potential on days on which precipitation occurred at Washington. D. C, October 1, 1887, 
 
 to August 31, 1888— Con tiaued. 
 
 Date." 
 
 Remarks. 
 
 1888. 
 Mar. ii 
 Mar. 26 
 
 Mar. 
 Mar. 
 
 27 
 
 29 
 
 Apr. 
 
 5 
 
 Apr. 
 
 10 
 
 Apr. 
 
 12 
 
 Apr. 
 Apr. 
 Apr. 
 Apr. 
 Apr. 
 May 
 May 
 May 
 May 
 May 
 
 14 
 
 15 
 
 16 
 
 19 
 
 23 
 
 1 
 
 4 
 
 8 
 
 10 
 
 11 
 
 May 
 
 12 
 
 May 
 
 14 
 
 May 
 
 18 
 
 May 
 
 23 
 
 May 
 May 
 May 
 
 24 
 25 
 
 26 
 
 May 
 
 30 
 
 May 
 
 31 
 
 Jane 
 
 14 
 
 Jane 
 Juue 
 June 
 
 16 
 23 
 26 
 
 Jane 
 
 27 
 
 Jane 
 
 28 
 
 Jane 
 
 29 
 
 July 
 
 5 
 
 July 
 
 9 
 
 July 
 July 
 
 10 
 19 
 
 July 
 
 30 
 
 Aug. 
 Aug. 
 
 4 
 
 8 
 
 Aug. 
 
 17 
 
 Aug. 
 
 18 
 
 Aug. 
 
 21 
 
 Aug. 
 
 27 
 
 Aug. 
 
 31 
 
 A trace of snow from 4 to 11:15 a. in. ; positive all day. 
 
 Hy. rain began d. n., e. 11 a, m. ; It. rarn from 2:40 p. m. to d. n., 0.69 inch ; negative from 9 
 a. m. to 12 m. ; variable positive and negative from 12 m. to 3 p. m. 
 
 Negative at 3:15 p. m. ; It. rain b. 5:30 p. m., e. d. n. ; no observations after 5 p. m. 
 
 Lt. rain from 8:50 to 10:20 a, m., 0.21 inch. ; no special observations; positive at the regular 
 observations. 
 
 Lt. rain from 5:20 a. m. to 12:05 p. m., 0.28 inch ; thunderstorm from 9:30 to 10:30 a. m. ; vari- 
 able positive and negative from 9 a. m. to 1 p. m. 
 
 Lt. and hy. rain from 1:45 a. m. to 6:40 p. m., 0.77 inch. ; variable positive and negative from 9 
 a. m. to 3 p. m., and all day on the 9th. 
 
 A trace of rq,in from 12:28 to 12:32 p. m. ; negative from 12:09 to 12:26 p. m. ; positive rest of 
 the time. 
 
 Lt. rain early a. m. to 11:10 a. m. ; potential variable ne ative all day. 
 
 Negative at 5:38 p. m. ; no observations after this ; It. rain from 8:15 to 11:20 p. ra., 0.12 inch. 
 
 Lt. rain from 7:40 to 9:20 a. m., 0.05 inch. ; variable positive an^ negative from 9 to 9:10 a. m. 
 
 Negative at 3 p. m. ; no other observations until 5 p. m. ; It., rain from 3:25 to 3:35 p. m. 
 
 Lt. rain b. d. n., e. 9:10 a. m., 0.34 inch; negative at 9 a. m. ; no spefiial observations. 
 
 Lt. rain from 7:10 to 10:35 a. m., 0.10 inch ; variable positive and negative from 10 to 11 a. m. 
 
 Negative at 3 p. m. ; no observations after 5 p. m. ; It. rain from 8:10 to 10:25 p. m. 
 
 Variable positive and negative from 10 a. m. to 12 m. ; It. rain from 10 p. m. to d. n. 
 
 Lt. rain from 8:40 to 10:45 p. m. ; negative at 3 p. m. ; no observation after 5 p. m. 
 
 Lt. rain b. 6 a. m., e. 11:05 a. ni.,b. 1:50 p. m., e. 4:30 p. m., 0.27 inch. ; no special observa- 
 tions; negative at 3 p. m. ; positive at the other observations. 
 
 Lt. rain from 3:45 to 9:10 p.m., 0..'i5 inch; low positive all day; high positive at 5 p. m. ; 
 no special observations. " 
 
 Lt. rain from 9:40 to 11:35 a.m., and from 6:30 to 8 p.m., 0.14inoh; no special observations ; 
 positive at the regular observations. 
 
 Lt. rain from 3:45 to 11:50 a. m., and from 1:35 to 1:55 p. m., 0.37 inch ; no special observations ; 
 negative at 9 and 11 a. m. 
 
 Lt. rain from 2:30 a. m. to 4:40 p. m., 0.74 inch ; positive at the regular ; no special observa- 
 tions. 
 
 Lt. rain b. d. n., c. 7:45 p. m., 0.68 inch ; positive at the regtilar; no special observations. 
 
 Negative at 1p.m.; It. rain from 3:05 to 3:25 p. m. ; no special observations. 
 
 Lt. rain 2:35 to 4:10 a. m. ; It. rain from 4:50 to 5:15 p. m. ; negative at 9 a. m. and 5 p. m. ; no 
 special observations. 
 
 Lt. rain 8:40 to 9:25 a. m., and from 4:12 to 8:15 p. m., 0.12 inch ; positive at 9 a. m. and 3 and 
 5 p. m. ; no other observations. 
 
 Lt. rain 4:30 a. m. to 2 p. m., and from 5:30 to 8:30 p. m., 0.45 inch; negative at 11a.m. and 1 
 p.m. 
 
 Negative from 4:28 to 4. '40 p. m. ; variable positive and negative from 4:40 to 5:05 p. m. ; 
 hy. rain from 4:40 to 5:0T p. m., 0.40 inch; thunderstorm from 4:34 to 5 p. m. 
 
 Lt. rain from 4:03 to 7:10 p. m., 0.22inch; no special observations ; positive at 3 and5 p. m. 
 
 Negative at 1 and 3 p. m. ; no special observations ; It. rain from 3:16 to 5:35 p. m., 0.69 inch. 
 
 Lt. rain in early a. m., and from 11:25 to 11:27 a. m. ; positive from 9 a. m. to 5 p. m. ; no ob- 
 servations from 11:25 to U:30 a.m. 
 
 Lt. rain from 10:10 to 10:25 a. m., and from 2:05 tu 8:10 p. ra., 0.10 inch. ; no special observa- 
 tions: negative at 1 p. m.; positive at the other observations. 
 
 Hy. rain b. d. n., e. 10:50 a. m. ; It. rain from 4:20 to 5:10 p. m., 1.34 inches; no special 
 observations ; positive at 9 and 11 a. ni., and 1 and 3 p. m. ; negative at 5. p. m. 
 
 Eaiuod d. n., e. 9:12 a. m., b. 11:25 a. m., e. 12:40 p. m., 0.53 inch ; negative at 9 a. m. ; posi- 
 tive at otlier observations ; no special observations. 
 
 No special observations; positive at 9 and U a. in., and 1 p. m. ; negative at 3 and 5 p. m. ; 
 It. rain 2:15 to 5:35 p. ra., 0.02 inch. 
 
 Lt. rai 11 from 8:35 a. m. to hl5 p. ra. and 3:15 to 3:20 p. m., 0.46 inch ; positive at regular; no 
 speciul observations. 
 
 Lt. rain b. d. n., e. 12 m. ; negative at 9 and 11 a. in. ; positive at 1, 3, and 5 p. m. 
 
 Lt. rain from 10:55 a. m. to 7:50 p. m., 0.06 inch ; variable positive aud negative at 11 a. m. 
 and 3 p.m.; positive at 9 a. m., and 1 and 5 p. iii. ; no special observations. 
 
 Lt. rain from 12:05 to 3:10 p. m. ; negative at 11 a. m. ; variable positive and negative at 3 
 p. m. ; no special observations. 
 
 Light rain 8:40 to 8:50 p. ra. ; negative potential at 5 p. m. ; no special observations. 
 
 Hy. rain with thunder from 4:50 to 8:25 p. in., 0.79 inch; positive at 3 p. m. ; negative at 5 
 p. 111. ; no special observations. 
 
 Positive at 1 and 3 p. m. ; negative at 5 p. ra. ; no special observatious ; It. rain frora 1:58 to 
 4:50 p. m., 0.03 inch ; distant thunder at 5 p. m. 
 
 Lt. rain from 7:10 to 9:47 a. m. and from 5:45 to 7:35 p. m., 0.17 inch; no special observa- 
 tions; negative at 11 a. m. ; positive at other observations. 
 
 Lt. rain 11:50 to 11:55 a. m. ; 1:20 to 1:.50 p. ra. ; 3:45 to 4:05 p. m., and 5:45 to 6:20 p. ra., 0.89 
 iuoh ; potential less than 10 volts all day ; negative at 3 p. ra. 
 
 Lt. rain from 3:45 to 6:10 p. ra., 0.17 inch; distant thunder at 4:45 p. m. ; variable positive 
 aud negative froin 4:45 to 5:30 p. m. ; noobserv.ations frora 3to4:45 p. m. ; positive at 3p. m. 
 
 Lt. rain frora 1:,52 to 3:25 p. in., 0.08 inch ; no special observatious ; positive at 1 aud 5 p. m ; 
 variable positive and negative at 3 p. m. 
 
MEMOIRS OP THE NATIONAL ACADEMY OP SCIENCES. 
 
 299 
 
 Table Q. — Potential on days on which precipitation occurred at Washington, D. C, October 1,1887, 
 
 to August 31, 1388— Continued. 
 
 Date. 
 
 Precipitation. 
 
 Ended. 
 
 Before. 
 
 
 at w 
 IS O 
 
 a ® 
 i2! 
 
 Dnring. 
 
 Bemarka. 
 
 188^. 
 
 Oct. ■ 18 
 
 Oct. 20 
 
 Oct. 2S 
 
 Oct. 24 
 
 Oct, 25 
 
 Oct. 26 
 
 Oct. 27 
 
 Nov. 10 
 
 Nov. 11 
 
 Nov. 14 
 
 Nov. 19 
 
 Nov. 28 
 
 Dec. 2 
 
 Dec. 8 
 
 Dec. 10 
 
 Dec. 15 
 
 Dec. 17 
 
 Dec. 20 
 
 Dec. S6 
 
 Dec. 28 
 
 Dec. 31 
 
 1888. 
 Jan. 1 
 Jan. 6 
 Jan. 9 
 Jan. 13 
 Jan. 17 
 Jan. 23 
 Jan. 25 
 Jan. 29 
 Jan. 31 
 Feb. 4 
 Keb. 7 
 Feb. 8 
 Feb. 9 
 Feb. 10 
 Feb. 11 
 Feb. 20 
 Feb. 27 
 Mar. 1 
 Mar. 2 
 Mar. 5 
 Mar. 13 
 Mar. 14 
 Mar. lt> 
 Mar. 20 
 Mar. 21 
 Mar. 22 
 Mar. 24 
 Mar. 26 
 Mar. 26 
 Mar. 27 
 Mar. 29 
 Mar. 31 
 Apr. 5 
 Apr. 10 
 Apr. 12 
 Apr. 14 
 Apr. 15 
 Apr. 16 
 Apr. 19 
 Apr. 23 
 May 1 
 May 4 
 May 8 
 "May 10 
 
 4:10p,m... 
 
 7:45 a.m... 
 
 2 p. m 
 
 8:45 p.m... 
 
 10:10 a.m.. 
 All 
 All 
 
 8:30 a.m... 
 
 2:15 p. m . . . 
 
 4:40 1), ra . . . 
 
 8:50 a. ra... 
 
 8 a. m 
 
 8:10 a.m... 
 7:47 a. m . . . 
 
 D.n 
 
 3:25 a. m . . . 
 1 p. m 
 
 9 a. m 
 
 3:48 p.m... 
 3:40 a.m... 
 12:40 p.m.. 
 
 9:15 p.m.. 
 
 9:5ffp.m.. 
 
 8:45 p.m.. 
 
 8:30 p.m.. 
 
 8:30 p.m.. 
 day. 
 (lay. 
 
 2 p. m 
 
 2:30 p.m. . 
 
 11:55 p. m. 
 
 2:45 p. m.. 
 
 1:35 p.m.. 
 
 9:05 a.m.. 
 
 12:10 p.m. 
 
 10:35 p.m. 
 
 2:48 p.m.. 
 
 9:10 p.m.. 
 
 9:50 p.m.. 
 
 7 p. m 
 
 1 p. m 
 
 7 p. m 
 
 D.n 
 
 11:20 a.m.. 
 10:55 a. m . . 
 
 D.n 
 
 2:45 a.m. .. 
 1:35 p.m... 
 1:35 p.m... 
 
 6 p. m 
 
 1:55 p. Ill - . . 
 1:40 a. m... 
 6:20 a.m... 
 8:20 a. ra... 
 6:25 a.m... 
 All 
 
 D.n 
 
 5:30 a.m... 
 6:25 a.m... 
 1:15 p.m.-. 
 12:45 p.m.. 
 6:15 a. m . . . 
 11:40 a.m.. 
 
 9 a. m 
 
 5:45p. m... 
 5:30 a.m... 
 1:35 p.m... 
 2:55 p. m . . . 
 
 4 a. m 
 
 D.n 
 
 2:40 p.m... 
 5:30 p. m . . . 
 8:50 a.m... 
 
 9 D. m 
 
 5:20 a. m-.. 
 1:45 a.m... 
 12:28 p.m.. 
 Early a.m. 
 8:15 p.m... 
 7:40 a.m... 
 3:25 p.m... 
 
 D.n 
 
 7:10 a. m . . . 
 8:10p.m... 
 
 10 a. m 
 
 8:40 p.m... 
 
 2.30 p.m.. 
 5:45 p. m.. 
 D.n 
 
 12:45 p.m. 
 5:30 p.m.. 
 1:45 p.m.. 
 8:10 p.m.. 
 8:35 p. m.. 
 2:10 p.m.. 
 9:10 p.m.. 
 12:10 p.m. 
 12:15 p. m. 
 12:50 p.m. 
 day. 
 4:40 p.m. . 
 5:07 p.m.. 
 11:30 a.m. 
 2:25 p.m.. 
 12:46 p.m. 
 9:40 p.m.. 
 B:30p.m.. 
 
 10 a. m ... 
 7:20 p.m.. 
 2:15 p.m.. 
 4:15 p.m.. 
 3:30 p.m.. 
 11:15 a.m. 
 
 11 a. m ... 
 
 D.n 
 
 D.n 
 
 10:20 a.m. 
 9:30 p.m.. 
 12:05 p.m. 
 6:40 p. m.. 
 12:32 p.m. 
 11:30 a.m. 
 11:20 p.m. 
 9:20 a.m.. 
 3:35 p.m.. 
 9:10 a.m.. 
 10:35 a.m. 
 10:25 p. m . 
 
 D.n.- 
 
 10:45 p.m. 
 
 A 
 
 No sp. obs. Lt. rain. 
 
 Hy. rain, 1.14 inches. 
 
 Nosp. obs. Lt. rain. 
 
 Sleet and rain, 0.22 inch. 
 
 Lt. rain, 0.02 inch. No sp. obs. 
 
 Lt. drizzling rain. 
 
 Do. 
 Lt. rain, 0.30 inch. 
 Lt. snow, tr. No sp. obs. 
 Lt. rain, 0.10 inch. No sp. obs. 
 Lt. rain. 
 Do. 
 Lt. anovr, tr. 
 
 Lt. rain, 0.01 inch. No sp. obs. 
 Lt. rain, 0.89 inch. 
 Hy. rain, 0.92 inch. 
 Hy. snow, 0.64 inch. 
 Lt. raiu and sleet, ,0.57 inch. 
 Lt. snow, tr. No sp. obs. 
 Hy. rain, 0.63 inch. 
 
 Hy. snow and sleet, 0.42 inch. No sp. 
 obs. , 
 
 Hy. rain, 0.85 inch. 
 
 Lt. rain. No sp. obs. 
 
 Lt. snow and rain, 0.31 inch. No sp. obs. 
 
 Lt. rain and sleet, 0.70 inch. 
 
 Lt. snow and sleet, 0.26 inch. 
 
 Lt. snow, tr. No sp. obs. 
 
 Hy. snow, 0.60 iach. No sp. obs. 
 
 Lt. snow, 0.03 inch. , 
 
 Lt.rain, tr. No sp. obs. 
 
 Lt. rain, 0.48 inch. 
 
 Lt. rain, mist, 0.03 inch. No sp. obs. 
 
 Lt. rain, 0.40 inch. 
 
 Lt. snow, tr. 
 
 Lt. snow and sleet, 0.16 inch. 
 
 Sleet and rain, 0.42 inch. 
 
 Lt. rain, 0.10 inch. No sp. obs. 
 
 Lt. snow, 0.06 inch. 
 
 Lt. r^in, tr. No sp. obs. 
 
 Do. 
 Hy. snow, 0.42 inch. 
 Lt. snow^ tr. 
 
 Do. 
 Lt. rain. 
 
 Lt.rain, 0.44 inch. 
 Lt. rain, 0.50 inch. No sp. obs. 
 Lt. snow, tr. 
 
 Do. 
 Hy. rain, 0.50 inch. 
 Lt.rain, 0.19 inch'. 
 Lt. rain. 
 Lt. rain, 0.21 inch. No sp, obs. 
 
 Lt. rain and thunder. 
 
 Lt. and by. rain, 0.77 inch, 
 
 Lt. Tain, tr. 
 
 Lt. rain. 
 
 Lt. rain, 0.12 inch. 
 
 Lt, rain, 0.05 inch. 
 
 Lt. rain. 
 
 Lt. rain, 0.34 inch. 
 
 Lt. rain, 0.10 inch. 
 
 Lt. rain. 
 
 Do, 
 
 Do. 
 
300 
 
 MEMOIRS OP THE NATIONAL ACADEMY OP SCIENCES. 
 
 Table Q. — Potential on days on which precipitation occurred at Washington, D. G., October 1, 1887, to 
 
 August 31, 1888 — Continued. 
 
 Date. 
 
 Precipitation. 
 
 Before. 
 
 During. 
 
 1 
 
 1 
 
 Remarks. 
 
 Began. 
 
 Ended. 
 
 1-1 
 
 m 
 
 ^ ID 
 
 II 
 
 || 
 
 o o 
 S5 
 
 © 
 
 <i5 
 
 i 
 
 i 
 
 1888. 
 May 11 
 May 12 
 May 14 
 May 18 
 May 23 
 May 24 
 May 25 
 May 26 
 May 30 
 May 30 
 May 31 
 June 14 
 June 16 
 June 23 
 June 26 
 June 27 
 Jane 28 
 June 29 
 July .5 
 July 9 
 July 10 
 July 19 
 July 30 
 Aug. 4 
 Aug. 8 
 Aug. 17 
 Auk. 18 
 Aug. 18 
 Aug. 21 
 Aug. 27 
 -Aug. 31 
 
 6 a. m 
 
 3:45 p.m... 
 9:40 a.m... 
 3:45 a.m... 
 2:30 a.m... 
 
 D.n 
 
 3:05 p.m... 
 4:50 p.m... 
 8:40 a.m... 
 4:12p.m... 
 4:30 a.m... 
 4:40 p.m... 
 4:03 p.m... 
 3:16 p.m... 
 11:25 a.m.. 
 10:10 a.m.. 
 
 D.n 
 
 D.n 
 
 2:15 p.m... 
 8:35 a.m... 
 
 D.n 
 
 10:55 a.m.. 
 ,12:05 p.m.. 
 8:40p.in... 
 4:50 p.m... 
 1:58 p.m... 
 7:10 a.m... 
 5:45 p. m... 
 ll:.50a. m.. 
 3:45 p.m... 
 1:52 p.m... 
 
 Total 
 
 4:30 p.m... 
 9:10 p.m... 
 11:35 a.m.. 
 1:55 p. m... 
 4:40 p. m. .. 
 7:45 p.m... 
 3:25 p.m... 
 5:15 p.m. .. 
 9:25 a.m... 
 8:15 p.m... 
 8:30 p.m... 
 5:07 p.m... 
 7:10 p.m... 
 5:3.'jp.m... 
 11:27 a.m.. 
 8:10 p.m... 
 5:10 p.m... 
 12:40 p.m.. 
 5:35 p.m... 
 3:20 p.m... 
 
 12m 
 
 7:50 p.m... 
 3:10p.m... 
 8:."i0p. m... 
 8:20p.m... 
 4:50 p. m. .. 
 9:47 a.m... 
 7:35 p.m... 
 6:20 p.m... 
 6:10p.m... 
 3:25 p. m... 
 
 (96) 
 
 1 
 
 .... 
 
 1 
 1 
 
 "l 
 "l 
 
 .... 
 
 1 
 .... 
 
 1 
 
 'i' 
 
 46 
 
 
 
 
 1 
 
 
 
 Lt. rain, 0.27 inch. 
 
 Lt. rain, 0.55 inch. No sp. obs. 
 
 Lt. rain, 0. 14 inch. No sp. obs. 
 
 Lt. rain, 0.37 inch. 
 
 Lt. rain, 0.74 inch. No sp. ohs. 
 
 Lt. rain, 0.68 inch. No sp. ohs. 
 
 Lt. rain. 
 
 Do. 
 Lt. rain, 0.03 inch. No sp. obs. ^ 
 Lt. rain, 0.09 inch. No sp. obs. 
 Lt. rain, 0.45 inch. 
 Hy. rain, 0.40 inch. Thunder. 
 Lt. rain, 0.22 inch. No sp. obs. 
 Lt. rain, 0.69 inch. No sp. obs. 
 Lt. rain, tr. 
 
 Lt. rain, 0. 10 inch. No sp. ohs. 
 Hy. rain, 1.34 inches. 
 Lt. rain, 0;53 inch. 
 Lt. rain, 0.02 inch. Nosp. obs. 
 Lt. rain, 0.46 ingh. No sp, obs. 
 Lt. rain. 
 
 Lt. rain, 0.06 inch. No sp. obs. 
 Lt. rain. 
 
 Do. 
 Hy. rain, 0.79 inch. Thunder. Nosp. obs. 
 Lt. rain, 0.03 inch. Thunder. Nosp. obs. 
 Lt. rain. 
 
 Lt. rain, 0.17 inch. 
 Lt. rain, 0.89 inch. No sp. obs. 
 Lt. rain, 0.17 inch. Thunder. Nosp. ohs. 
 Lt. rain, 0.08 inch. No sp. ohs. 
 
 
 
 
 
 .... 
 
 .... 
 
 
 
 
 1 
 
 
 
 
 
 
 
 
 2 
 
 8 
 
 .... 
 
 1 
 
 
 1 
 
 
 
 ... . 
 
 
 
 .... 
 
 
 
 
 
 1 
 1 
 
 i 
 
 
 
 .... 
 
 
 
 
 .... 
 
 
 
 
 
 
 .... 
 
 1 
 1 
 
 1 
 1 
 
 
 
 
 .. . 
 
 .... 
 
 .... 
 
 
 .... 
 
 
 
 
 1 
 1 
 1 
 
 I 
 
 
 .... 
 
 
 
 
 
 1 
 
 .--. 
 
 .... 
 
 7 
 21 
 
 29 
 
 1 
 
 15 
 
 
 I 
 1 
 I 
 
 50 
 
 .... 
 
 .... 
 
 
 
 31 
 
 3 
 
 Note. — Of the 31 during which no negative was observed, special observations were made during only 1 storm, 
 and it was light rain (tr.). 
 
 Precipitation. 
 
 Before. 
 
 I. 
 Il 
 
 'A 
 
 Ml* 
 
 Dnring. 
 
 Eain(74) , 
 
 Rain and sleet (4) 
 Eain and snow (1) 
 Sleet and snow (3) 
 Snow (14) 
 
MEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES. 
 
 301 
 
 Table E. — Potential on days on which precipitation occurred at Boston, Mass., December 1, 1887, to 
 
 August 31, 1888. 
 
 Date. 
 
 Kemarka. 
 
 1887. 
 Dec. 15 
 
 1888. 
 Jan. 13 
 
 Jan. 17 
 
 Jan. 26 
 
 Feb. 4 
 
 Feb. 8 
 
 Feb. 10 
 
 Feb. 11 
 
 Feb. 20 
 
 Feb. 25 
 
 Mar. 12 
 
 Mar. 13 
 
 Mar. 14 
 
 Mar. 21 
 
 afar. 26 
 
 Mar. 28 
 
 Mar. 29 
 
 Apr. 2 
 
 Apr. 5 
 
 Apr. 11 
 
 Apr. 12 
 
 Apr. 14 
 
 Apr. 16 
 
 Apr. 18 
 
 Apr. 20 
 
 Apr. 21 
 
 May 
 
 1 
 
 May 
 
 5 
 
 May 
 
 9 
 
 May 
 
 12 
 
 May 
 
 15 
 
 May 
 
 16 
 
 May 
 
 17 
 
 May 
 
 19 
 
 May 
 
 26 
 
 May 
 
 28 
 
 June 
 
 11 
 
 June 
 
 14 
 
 June 
 
 15 
 
 June 
 
 20 
 
 June 
 
 21 
 
 June 
 
 26 
 
 July 
 
 19 
 
 July 
 
 20 
 
 July 
 
 23 
 
 July 
 
 27 
 
 Rain began at 12 m. and continued during remainder of the day; potential positiTe at all 
 regular observations, except 3 p. m., wheu»it varied from positive to negative. 
 
 Snow began early a, m. ; turned to sleet, then to rain during the evening ; raiu continued 
 during the night ; potential negative at 9 a. m. and 5 p. m. ; positive at other regular ob- 
 servations. 
 
 Snow 9:50 to 10:50 a. m., 4:30 p. m., and daring uight; potential positive all day, decreasing 
 slowly. 
 
 Suow began early a.m.; turned to rain before 4 a.m.; rain ended 10:15 a.m.; potential 
 negative at 9 a. m. ; positive at other regular observations. 
 
 Snow began 12:50 p.m.; turned to sleet during evening; sleet continued during night; 
 potential positive during day ; insulation bad daring p. m. * 
 
 Lt. rain 2:30 p. m. and during night; potential positive all day. 
 
 Lt. snow 4:15 p. u). and during night; potential positive all day. 
 
 Sleet 10:30 a. m. to 2:30 p. m. ; snow 2:30 p. m. and during night ; potential positive at 9 a, m. 
 and 5 p. m. ; negative 11 a. m., 1 and 3 p. m. 
 
 Lt. rain 2 p. m. and duripg night ; potential positive all day. 
 
 Lt. snow 12:30 to 2:30 p. m. ; sleet 2:30 to 3:30 p. m. ; It. rain 3:30 p. m. and during night ; po- 
 tential positive at 9 and 11 a. m. and 1 p. m. ; negative at 3 and 5 p. m. 
 
 Snow early a. m. and during night ; potential positive at 9 a. m. ; negative at 11 a. m. and 1, 
 3, and 5 p. m. 
 
 Snow midnight to 10:45 a. m. ; 4:30 p. m. and during night ; potential positive all day. 
 
 Snow midnight to 10:30 a. m. ; potential positive all day. 
 
 Lt. rain early a. m. and during night ; potential positive 9 a. m. and 3 and 5 p. ni. ; negative 
 at 11 a. ra. and 1 p. m. 
 
 Lt. snow 12:50 to 2:30 p. m. ; rain 2:30 to 4:40 p. m. ; sleet 4:40 p. m. and during night ; poten- 
 tial positive 9 and 11a. m., 1 and 3 p. m. ; negative at 5 p. m. , 
 
 Lt. rain early a. m. to 10:30 a. m. ; potential positive all day. 
 
 Eain 11:30 a. m. to 12:55 p. m. ; potential positive all day. 
 
 Lt. rain early a. m. to 11:30 a. m. ; potential negative at 9 a. m. ; positive at all other obser- 
 vations. 
 
 Lt. rain 2:55 p. m. and during night ; potential positive at 9 and 11 a. ni. and 1 p. m. ; van- 
 able negative at 3 and 5 p. ra. 
 
 Lt. rain early a. m. to 10:30 a. m. ; potential positive at all observations. 
 
 Lt. rain 2:15'to 2:50 p. m. ; 4:45 p. m. and during night ; potential positive at 9 and 11 a. m. 
 and 3 p. m. ; negative at 1 and 5 p. m. 
 
 Lt. rain 12:40 to 4:30 p. m. ; potential variable negative to positive at 9 a. m. and I p. m. ; 
 negative at 3 p. m. ; positive at 11 a. m. aud 5 p. m. 
 
 Rain 12:50 to 12:55 p. m. ; potential high; negative at 1p.m.; positive at other observations. 
 
 Lt. rain 12 m. to 2:50 p. m. ; potential negative at 11 a. m. and 1p.m.; positive at other ob- 
 servations. 
 
 Lt. rain 3:45 p. m. and daring night ; potential negative at 5 p. m. ; positive at all other ob- 
 servations. , ,. , i. , -,-, 
 
 Snow early a. m. to 10:30 a. m. ; It. rain 10:30 a. m. to 12:40 p. m. ; potential negative at 11 
 a. m. ; positive at all other observations. 
 
 Lt. rain 11:57 a. m. to 12:50 p. m. ; potential positive at all observations. 
 
 Lt. rain early a. m. to 9:45 a. m. ; potential positive at all observations. 
 
 Rain early a. m. to 10 a. m. ; potential positive at all observations. 
 
 Lt rain early a. m. to 12 m. ; potential positive at all observations. 
 
 Lt. rain early a. m. to 1:10 p. m. ; potential negative at 11 a. m. ; positive at all other obser- 
 vations. 
 
 Light sprinkling rain after 5 p. m. ; potential negative at 3 p. m. 
 
 Light spiinkling rain 1 to 5 p. m. ; potential negative at 1, 3, and 5 p, m. 
 
 Lt. rain early a. m. to 4 p. m. ; potential positive at all observations. 
 
 Lt. rain 8:55 a. m. to 12:40 p. m. ; potential low positive at all observations. 
 
 Lt. rain 2 p. m. and during night; potential positive all day ; insulation bad. 
 
 Rain 12:30 to 12:50 p. m. ; potential positive at all observations. 
 
 Lt. rain 9:'f0 a. m. to 5:30 p. m. ; potential positive at 9 a. m. ; variable from positive to neg- 
 ative at all other observations. ,. i„ -i- J. ,, 
 
 Rain 9:10 to 10:20 a. m. ; potential variable positive to negative at 9 a. m. ; positive at all 
 other observations. j. ^i, •*• 
 
 Lt. rain 9:40 a. m. to 12:40 p. m. ; potential variable positive to negative at 11 a. m. ; positive 
 at all other observations. 
 
 Lt. rain 12:40 to 1:30 p. m. ; potential positive at all observations. 
 
 Lt. rain 2 to 6 p. m. ; potential positive at all observations. 
 
 Lt. rain 8:50 1i) 11:15 a.m.; potential zero at 9 a. m. ; variable positive to negative at 11 
 a. TO. ; positive at all other observations. 
 
 Eain 2:10 to 2:40 p. m. ; potential positive at all observations. 
 
 Rain 4:20 to 4:28 p. m. ; potential positive at all observations. 
 
 Lt. rain 8:55 a. m. to 3:40 p. m. ; potential positive 9 a. m. and 5 p. m. ; no observations at 11 
 a. m.,1 and 3 p.m. 
 
302 
 
 MBMOIES OF THE NATIONAL ACADEMY OF SCIENCES. 
 
 Table R. — Potential on day^ on which precipitation occurred at Boston, Mass., December 1, 1887, to 
 
 August 31, 1888 — Continued. 
 
 Date. 
 
 Kemarks. 
 
 July 31 
 
 Aug. 4 
 Aug. 6 
 
 Aug. .9 
 Aug. 12 
 
 Aug. 13 
 Aug. 16 
 
 Aug. 17 
 Aug. 21 
 
 Potential variable positive from 7 to 11 a. m. ; variable negative from 11 a. m. to 3 p. m. ; 
 
 variable positive from 3 to 11 p. m. ; variable positive and negative from 11 p. m, to 3 
 
 a. ra. of Aug. 1 ; variable positive all day of Aug. 1 ; It. rain, b. 7:50 p. m. of July 31 and 
 
 continued most of the night. 
 Lt. rain from 8:45 to 8:55 a. m. ; potential variable positive from 7 to 8:40 a. m. ; variable 
 
 positive and negative from 8:40 to 9 a. m. ; variable positive all rest of tlie day. 
 Lt. rain, b. d, n., e. 10:20 a. m. ; It. rain, b. 3:20 p. m., contintied to d. n. of 7th; no record 
 
 until 11a.m. of 6th ; variable positive and negative from 1 to 2 p. m. ; negative from 4 to 
 
 6:30 p. m. ; zero potential the rest of the time. 
 Lt. rain, b. and e. d. n. ; zero potential all night. 
 Lt. rain f om 9:40 a. m. to 1:10 p. m. ; variable positive from 7 to 11 a. m. ; steady positive 
 
 the rest of the day. 
 Rain, b. d. n., e. 11:20 a. m. ; b. 2:40, e. 3:10 p. m. ; steady positive all the time. 
 Lt. rain, b. and e. d. n. ; variable positive from 1 to 11 p. m. of 15th ; variable negative 
 
 from 11 p. m. of 15th to 1 a. m. of 16th; variable positive all dayof 16tb, except negative 
 
 from 9:25 to 9:40 p. m. ; It. rain from 9:45 to 10 p. m. 
 Variable positive from 6 to 11 a. m. ; variable positive and negative from 11 a. m. to 11 
 
 p. m. ; It. rain from 2:45 to 4:05 p. m. and from 8:40 to 9:10 p. ni. 
 Potential zero during the nights of 20th, 2lst, and also 21st, 22d ; variable positive from 7 
 
 a. m. to 5 p. m. of 21st ; hy. rain from 5:25 p. m. of 21st to 1:28 a. m. of 22d. 
 
 Date. 
 
 Precipitation. 
 
 Before. 
 
 During. 
 
 1 
 1 
 
 Hemarks. 
 
 / 
 
 Began. 
 
 Bnded. 
 
 
 t 
 
 i 
 
 r 
 
 o 
 'A 
 
 1. 
 
 o 
 'A 
 
 6 
 
 i 
 
 6 
 
 I 
 
 1887. 
 Dec. 15 
 
 1888. 
 Jan. 13 
 Jan. 17 
 Jan. 17 
 Jan. 26 
 Feb. 4 
 Feb. 8 
 Feb. 10 
 Feb. 11 
 Feb. 20 
 Mar. 12 
 Mar. 13 
 Mar. 14 
 Mar. 21 
 Mar. 26 
 Mar. 28 
 Mar. 29 
 Apr. 2 
 Apr. 5 
 Apr. 11 
 Apr. 12 
 Apr. 12 
 Apr. 14 
 Apr. 16 
 Apr. 18 
 Apr. 20 
 Apr. 21 
 May 1 
 May 5 
 May 9 
 May 12 
 May 15 
 May 16 
 May 17 
 May 19 
 May 26 
 
 12 m 
 
 Early a.m. 
 9:50 a.m... 
 4:30 p.m..- 
 Early a. m. 
 12:.50p.m.. 
 2:30 p.m... 
 4:15 p. m... 
 10:30 a.m.. 
 
 2p.m 
 
 Early a.m. 
 
 D. n 
 
 D. n 
 
 10:50 a.m.. 
 D. n 
 
 1 
 
 1 
 
 
 1 
 
 1 
 
 
 
 Bain. 
 
 Snow; sleet; rain. 
 Snow. 
 
 Do. 
 Snow and rain. 
 Snow and sleet. 
 Lt. rain. 
 Snow. 
 
 Sleet and snow. 
 Bain. 
 Snow. 
 
 Do. 
 
 Do. 
 Bain. 
 
 Snow ; rain ; sleet. 
 Bain. 
 
 Do. 
 
 Do. 
 
 Do. 
 
 Do. 
 
 Do. 
 
 Do. 
 
 Do. 
 
 Do. 
 
 Do. 
 
 Do. 
 Snow; rain. ~ 
 Eain. 
 
 Do. 
 
 Do. 
 
 Do. 
 
 Do. 
 
 Do. 
 
 Do. 
 
 Do. 
 
 Do. 
 
 
 
 .... 
 
 
 
 1 
 1 
 
 .... 
 
 
 
 10:15 a.m.. 
 D.n 
 
 1 
 
 
 
 1 
 
 
 
 
 1 
 1 
 1 
 
 i 
 
 .... 
 
 D. n 
 
 D.n 
 
 D.n 
 
 D.n 
 
 .... 
 
 1 
 1 
 1 
 
 .'.'.'. 
 
 .... 
 
 .... 
 
 .... 
 
 1 
 
 10:45'a.m.. 
 10:30 a.m.. 
 
 D. n 
 
 D. n 
 
 
 
 
 "i' 
 
 — 
 
 Early a. m. 
 Early a. m . 
 12:50 p.m.. 
 Early a.m. 
 11:30 a.m.. 
 Early a. m . 
 2:55 p. in . . . 
 Early a. m - 
 2:15 p.m... 
 4:45 p.m... 
 12:40p.m.. 
 12:50p. m-. 
 
 12m 
 
 3:45p.m... 
 Early a. m. 
 ll:.^7a. m.- 
 Early a. m . 
 Early a.m. 
 Early a.m. 
 Early a.m. 
 
 D. n 
 
 1 p. m 
 
 Early a. m . 
 8:55 a.m... 
 
 
 
 
 
 
 
 1 
 
 1 
 
 
 
 .... 
 
 .... 
 1 
 
 .... 
 
 10:30 a.m.. 
 12:55 p.m.. 
 11:30 a.m.. 
 D. n 
 
 1 
 
 
 .... 
 
 
 
 
 
 1 
 . 1 
 
 
 
 .... 
 
 
 
 10:30 a.m.. 
 2:50 p.m... 
 D. n 
 
 1 
 
 
 1 
 
 .... 
 
 4f 
 3f 
 
 
 1 
 
 .... 
 
 1 
 
 
 1 
 1 
 
 
 
 4:30 p.m... 
 12:55 p.m.. 
 
 .... 
 
 
 
 .... 
 
 1 
 1 
 
 2:50 p.m... 
 D. n 
 
 12:40 p.m.. 
 12:50 p.m.. 
 
 .... 
 
 1 
 
 1 
 1 
 
 .... 
 
 
 
 .... 
 
 I 
 1 
 1 
 1 
 
 .... 
 
 9:45 a.m... 
 lOa.m .... 
 
 12m 
 
 1:10p.m... 
 D. n 
 
 1 
 1 
 1 
 1 
 
 
 
 
 
 
 
 
 
 
 
 
 
 1 
 
 
 2i 
 
 
 1 
 
 
 
 5p. m 
 
 4 p. m 
 
 12:40 p.m.. 
 
 1 
 1 
 1 
 
 
 1 
 1 
 
 1 
 
 .. . . 
 
 
 
 
 
 
 
 
 
 
 
 
 
MEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES. 
 
 303 
 
 Table R — Potential on days on which precipitation occurred at Boston, Mass., December 1, 1887, to 
 
 August 31, 1888 — Continued. 
 
 Date. 
 
 Precipitation. 
 
 Before. 
 
 During. 
 
 1 
 
 1 
 1 
 
 RemaikB. 
 
 Began. 
 
 Ended. 
 
 k 
 
 g 
 
 
 t 
 
 1 
 
 
 i 
 
 1 
 
 1 
 a 
 o 
 
 1888. 
 May 28 
 June 11 
 June 14 
 June 15 
 June 20 
 June 21 
 June 26 
 July 19 
 July 20 
 July 23 
 July 27 
 July 31 
 July 4 
 Aug. 6 
 Aug. 6 
 Aug. 12 
 Aug. 13 
 Aug. 13 
 Aug. 16 
 Aug. 16 
 Aug. 17 
 Aug. 21 
 
 2p. m 
 
 12:30 p.m.- 
 9:40 a.m... 
 9:10 a.m... 
 9:40 a.m... 
 12:41) p. ni..^ 
 
 2p.m 
 
 8:50 a. m--. 
 2:10 p.m... 
 4:20 p.m... 
 8:55 a. m . - . 
 7:50p.m... 
 8:45 a.m... 
 Early a. m . 
 3:20 p.m... 
 9:40 a.m..- 
 Early a. m . 
 3:40 p.m..- 
 
 D. n 
 
 9:45 p.m... 
 3:40 p.m.. 
 5:25 p.m... 
 
 Total 
 
 D.n 
 
 
 
 
 
 Rain. 
 
 Do. 
 
 Do. 
 
 Do. 
 
 Do. 
 
 Do. 
 
 Do. 
 
 Do. 
 
 Do. 
 
 Do. 
 
 Do. 
 Rain. Photo. leoord begun. 
 Rain. 
 VDo. 
 
 Do. 
 
 Do. 
 
 Do. 
 
 Do. 
 
 Do.. 
 
 Do. • 
 
 Do. 
 Hy. rain. 
 
 12:50 p.m.. 
 5:30 p.m.. . 
 
 .... 
 
 .... 
 
 .... 
 
 1 
 
 10:20 a.m.. 
 12:40 p.m.. 
 
 .... 
 
 4 
 
 
 .... 
 
 1 
 
 1:30 p.m... 
 
 
 
 .... 
 
 I 
 
 ' ^ '^ 
 
 
 
 11:15 a.m.. 
 2:40 p.m... 
 
 1 
 
 
 
 1 
 
 
 
 .... 
 
 4:28 p.m... 
 3:40p.m... 
 
 D.n 
 
 8:55 a.m.. . 
 10:20 a.m.. 
 
 D.n 
 
 l:10p.m-.. 
 11-20 a ra 
 
 .... 
 "l 
 
 .... 
 
 
 
 8 
 
 
 
 1 
 1 
 
 
 
 .... 
 
 1 
 
 
 
 J- 
 
 30 
 
 "\ 
 
 1 
 1 
 
 1 
 
 
 
 
 3:10 p m 
 
 
 
 
 
 D. n 
 
 
 1 
 
 i 
 4 
 
 13 
 
 
 
 lOp.m .... 
 9:10 p.m... 
 D. D 
 
 (58) 
 
 20 
 
 
 
 
 .... 
 26 
 
 5 
 
 1 
 
 23 
 
304 
 
 MEMOIES OP THE liTATIONAL ACADEMY OP SCIENCES. 
 
 Table B.^Potential before and during precipitation, St. Louis, Mo., 1861. 
 
 [A. Wializenns, M. D., observer.] 
 
 Date. 
 
 Precipitation. 
 
 Before. 
 
 Dnring. 
 
 Eemarks. 
 
 Began. 
 
 Ended. 
 
 
 43 
 
 1^ 
 
 i 
 
 ID 
 
 1 
 
 . 6 
 
 i 
 
 1 
 
 1 
 
 1861. 
 Jan. 13 
 Jan. 15 
 Jan. 16 
 Jan. 17 
 Jan. 23 
 Feb. 1 
 Feb. 2 
 Feb. 3 
 Feb. 10 
 Feb. 13 
 Feb. 14 
 Feb. 15 
 Feb. 16 
 Feb. 17 
 Feb. 18 
 Feb. 23 
 Feb. 24 
 Mar. 3 
 Mar. 8 
 Mar. 16 
 Mar. 17 
 Mar. 19 
 Mar. 25 
 Mar. 26 
 Mar. 29 
 Apr. 3 
 Apr. 6 
 Apr. 7 
 Apr. 8 
 Apr. 11 
 Apr. 12 
 Apr. 20 
 Apr. 23 
 Apr. 27 
 Apr. 29 
 May 3 
 May 5 
 May 6 
 May 9 
 May 11 
 May 11 
 May 12 
 May 19 
 May 20 
 May 23 
 May 24 
 May 29 
 May 31 
 June 1 
 June 1 
 June 3 
 June 4 
 June^ 6 
 June 7 
 June 11 
 June 23 
 June 24 
 June 25 
 June 27 
 June 28 
 Jane 29 
 July 5 
 July 7 
 July 15 
 July 19 
 
 12m 
 
 11:45 a.m.. 
 
 8 a. m 
 
 8p. m 
 
 12m 
 
 D. n 
 
 11 a. m 
 
 12 m . - . . 
 
 D. n 
 
 
 
 1 
 1 
 1 
 1 
 1 
 
 
 
 1 
 
 Lt. drizzling rain. 
 Hy. rain. 
 Lt. snow. 
 
 Do. 
 Drizzling rain and hy. snow. 
 Drizzling rain. "" 
 Trace ot snow. 
 Trace of snow ; clear. 
 Hy. rain and thunder. 
 Light rain ; mist. 
 Light rain and snow. 
 Lt. snow. 
 
 Do. 
 
 Do. 
 Lt. rain. 
 
 Hail, rain, and thunder; gale. 
 Lt. snowflakes, 
 Lt, rain. 
 
 Do. 
 
 Do, 
 Lt, snowflakes. 
 
 Lt. rain and snow. i 
 Thunder and hy. rain. 
 
 Do. 
 Thunder and rain. 
 Lt. rain. 
 
 Do. 
 Lt. rain ; thunder. 
 Lt. rain. 
 
 Do. 
 Hy. rain, 
 
 Lt, shower ; negative after rain, 
 Lt, rain ; thunder. 
 Lt rain. 
 
 Do. 
 
 D, n 
 
 .... 
 
 .... 
 
 .... 
 
 .... 
 
 10p,m 
 
 
 
 D, n 
 
 
 
 10 a. m 
 
 11:05 a.m.. 
 
 1 
 
 
 .... 
 
 1 
 
 1 
 1 
 1 
 
 
 .... 
 
 .... 
 
 8 a. m 
 
 10 a.m.... 
 All 
 D. n ... 
 
 
 
 
 D. n 
 
 day. 
 H a. m 
 
 .... 
 
 1 
 1 
 1 
 
 
 
 All dav. 
 
 
 
 
 
 D. n 
 
 7pm 
 
 2 p. m 
 
 
 
 
 
 
 1 
 
 1 
 1 
 
 .... 
 
 4 a. m 
 
 6:45 a. m . . . 
 D. n 
 
 4 a. m 
 
 D. n 
 
 9 a. m . 
 
 
 
 16 
 
 1 p.m 
 
 18m 
 
 Early a.m. 
 
 1 
 1 
 1 
 1 
 
 
 ,... 
 
 
 
 
 .... 
 
 
 
 
 
 
 
 
 1 
 
 1 
 1 
 
 -.., 
 
 6p.m 
 
 9 a. ni 
 
 D. n 
 
 • 7 a. m 
 
 D. u 
 
 6 a. m 
 
 10 a. m 
 
 lOa.m .... 
 
 All 
 6 a. m 
 
 D. n 
 
 D. u 
 
 lla.m 
 
 .... 
 
 .... 
 
 1 
 
 .... 
 
 .... 
 
 5p.m 
 
 2p.,m 
 
 1 
 1 
 
 
 
 
 
 1 
 
 1 
 
 
 
 
 
 
 day. 
 3:30 p.m .. 
 
 1 
 1 
 
 
 
 
 
 
 
 ... . 
 
 
 1 
 
 
 6ai.m 
 
 D. n 
 
 8p. m 
 
 3 D. m . 
 
 4 p. m 
 
 2 p.m 
 
 9 p. m . 
 
 1 
 
 1 
 
 
 
 
 
 
 1 
 1 
 
 — 
 
 
 
 
 
 Do. 
 
 7 a. m 
 
 2:30 p.m... 
 
 .... 
 
 1 
 3 
 1 
 
 Lt. rain ; thunder. 
 
 
 
 
 9p.m 
 
 D. n 
 
 9 p. m 
 
 D, n 
 
 3p.m 
 
 12m 
 
 D. n 
 
 9 a. m 
 
 D. n 
 
 3:45 p.m... 
 5 1). m 
 
 i 
 "i 
 
 .... 
 
 .... 
 
 Lt. rain ; thunder. 
 
 Do. 
 Lt. rain ; mist. 
 Lt. rain, mist, and thunder. 
 Lt, rain. 
 
 Do. 
 
 Do, 
 Thunder and rain. 
 Lt. rain. 
 
 Do. 
 Lt. rain ; thunder. 
 Lt. rain. 
 
 Do. 
 Thunder and rain. 
 
 Do. 
 Hy. rain and thunder. 
 
 Do. 
 Lt. rain ; mist. 
 Lt. rain. 
 
 Do, 
 
 Do, 
 
 Do, 
 , Do, 
 Thunder and rain. 
 
 Do. 
 Lt. rain. 
 
 Do. 
 
 .... 
 
 1 
 
 
 
 
 
 1 
 
 1 
 1 
 
 
 
 
 ^ -- 
 
 
 ... - 
 
 8:45p.m... 
 
 9 p. m 
 
 8 a. m 
 
 8:30 a.m... 
 5:30 a.m... 
 
 8 p, m 
 
 All 
 
 6p, m 
 
 7a.m 
 
 2:30 p.m... 
 
 Ip. m 
 
 5:45 a, m . . . 
 12 m 
 
 9 p. m 
 
 
 
 10 p.m. .. 
 
 
 
 2 p. m 
 
 
 1 
 1 
 
 
 Ip. m 
 
 
 
 .... 
 
 
 9 a. m 
 
 9 p.m 
 
 1 
 
 
 
 1 
 
 
 .... 
 
 day. 
 7p. m 
 
 1 
 
 
 
 il 
 1 
 .... 
 
 .... 
 
 
 4 p. m 
 
 
 
 
 
 
 7 p. m 
 
 
 11 a, m 
 
 1 
 
 
 
 1 
 
 1 
 1 
 
 
 
 12 m 
 
 11 a. m 
 
 7 a. m 
 
 All 
 
 12 m 
 
 5p. m 
 
 2 p. m 
 
 8ii,m 
 
 12:30 p.m.- 
 
 
 
 .... 
 
 
 11:15 a.m.. 
 
 
 
 9:30 a.m... 
 day. 
 6 p. m 
 
 "i 
 
 .... 
 
 .... 
 
 .... 
 
 
 1 
 1 
 1 
 
 1 
 
 "i" 
 1 
 
 
 9p. m 
 
 
 
 3p.m 
 
 
 
 9 a. m 
 
 
 
 
 .... 
 
 
 
 
MEMOIRS OP THE NATlOI^fAL ACADEMY OF SCIENCES. 305 
 
 Table S. — Potential before and during jarecipitation, Ht. Louis, Mo., 1861 — Gontinued. 
 
 Date. 
 
 Precipitation. 
 
 Before. 
 
 Daring. 
 
 
 
 
 
 
 
 Began. 
 
 Ended. 
 
 1 
 
 
 1 
 
 1 
 
 1 
 
 1 
 
 t 
 
 1 
 
 i 
 
 a 
 
 Bemarks. 
 
 1861. 
 July 21 
 July 28 
 Aug. 5 
 Aug. 8 
 Aug, 12 
 Aug. 19 
 Aug. 21 
 Sept. 2 
 Sept. 3 
 Sept. 10 
 Sept. 14 
 Sept. 15 
 Sept. 20 
 Sept. 25 
 Oct. 2 
 Oct. 4 
 Oct. 5 , 
 Oct. 10 
 Oct. 15 5 
 Oct. 16 
 Oct. 17 
 Oct. 22 
 Oct. 25 
 Nov. 3 
 Nov. 19 
 Nov. 22 
 Dec. 3 
 Deo. 7 
 Dec. 21 
 Dec. 22 
 
 12 m ..^--- 
 
 4 p.m..... 
 
 
 
 
 
 Trace of rain. 
 
 Thunder. 
 
 Thunder, rain, and gale. 
 
 Thunder; rain. 
 
 Lt. rain ; mist. 
 
 Lt. rain. 
 
 Thunderstorm and rain. 
 
 Do. 
 Lt. rain. 
 
 Lt. rain ; zero potential. 
 Thunder and rain. 
 Thunder and rain ; zero potential. 
 Lt. rain, tr. 
 Lt. rain. 
 Lt. rain ; zero potential. 
 
 Do. 
 Lt. rain ; thunder. 
 Lt. rain ; zero potential. 
 
 Do. 
 Lt. rain. 
 
 Lt. rain, zero potential. 
 Lt. rain. 
 
 Do. 
 
 Do. 
 Hy. rain ; thunder. 
 Lt. rain. 
 Lt. snow. 
 Lt, rain. 
 Lt. snow. 
 Lt. rain and snow. 
 
 4 p.m. 
 Ip. m . 
 12:15 p. 
 3p. m . 
 D. n .. 
 
 
 
 
 
 1 
 1 
 1 
 
 .... 
 "i 
 
 
 1:15 p.m... 
 
 .... 
 
 2 
 
 m.. 
 
 1 
 
 1 
 
 .... 
 
 
 
 
 
 11 a. m 
 
 D. n 
 
 D. n 
 
 1 
 
 
 
 1 
 1 
 
 1 
 
 3p.m 
 
 9:.30p.m--- 
 
 .... 
 
 1 
 
 1 
 1 
 1 
 1 
 •1 
 1 
 1 
 
 .... 
 
 Ip. m . 
 7 p. m 
 
 
 2p. m 1- -- 
 
 
 
 D. n 
 
 
 
 11 a. m 
 
 12m 
 
 
 
 1 
 
 
 7p. m . 
 3p. m . 
 3p. m . 
 D. n.. 
 
 
 10 p. m 
 
 
 
 
 1 
 1 
 1 
 1 
 1 
 
 "i' 
 1 
 
 "'i" 
 1 
 1 
 1 
 
 .... 
 
 1 
 1 
 
 .. • • 
 
 46 
 
 
 
 
 
 .... 
 
 .... 
 
 
 12 mid 
 
 
 
 
 10 a. m 
 
 1 
 
 
 
 
 5 p. m 
 
 All 
 
 D. n 
 
 
 1 
 
 .... 
 
 "'i' 
 
 day. 
 D. n 
 
 1 
 
 
 2p.m. 
 
 S-6p, m . 
 
 D. n . 
 
 3:30 p. 
 
 
 
 1 
 1 
 
 
 .... 
 
 D. n 
 
 8 a.m 
 
 .... 
 
 .... 
 
 
 
 
 1 
 
 
 
 1 
 
 1 
 1 
 1 
 1 
 
 .... 
 
 11 a.m 
 
 11 a. m 
 
 7 a. ui . 
 
 12 m . . 
 
 
 
 
 
 
 .... 
 
 .... 
 
 7:15 a.m... 
 7 n. m 
 
 .... 
 
 .... 
 
 .... 
 
 1 
 
 D. u.. 
 9a.m . 
 D. n .. 
 3p. m . 
 9:10 a. I 
 
 Tc 
 
 
 8 a. m 
 
 10 a.m 
 
 1 
 
 
 
 
 1 
 
 
 
 
 10 a. m .... 
 
 D. n 
 
 D. a 
 
 95) 
 
 1 
 
 28 
 
 
 
 
 n... 
 itdl/ 
 
 9 
 
 1 
 
 58 
 
 9 
 
 1 
 1 
 
 40 
 
 
 
 
 
 
 
 
 
 - 
 
 
 Precipitation. 
 
 Before. 
 
 Daring. 
 
 
 
 u 
 
 1 
 
 1^ 
 II 
 
 i 
 
 ! 
 
 h 
 1 
 
 i 
 
 36 
 
 1 
 3 
 
 a 
 
 o 
 
 35 
 
 10 
 
 1 
 
 
 
 Ea 
 
 Snc 
 
 
 
 
 
 23 
 4 
 1 
 
 8 
 
 1 
 
 49 
 7 
 2 
 
 9 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 S. Mis. 94 5 
 
 SO 
 
 
 
 *Ze] 
 
 "opol 
 
 ential 
 
 in7 
 
 cases 
 
 
 
 
 
 
 
306 
 
 MEMOIRS OP THE NATIONAL ACADEMY OF SCIENCES. 
 
 Table T. — Precipitation and negative potential at the Royal Observatory, Greenwich, England, 
 
 1879 to 1886," inclusive. 
 
 Months. 
 
 1879, 
 January . . . 
 February . 
 
 March 
 
 April 
 
 May 
 
 June 
 
 July 
 
 August 
 
 September ' 
 October ... 
 November . 
 December . 
 
 Total 
 1880, 
 January . . . 
 February . 
 
 March 
 
 April 
 
 May 
 
 June 
 
 July 
 
 August 
 
 September 
 October ... 
 November . 
 December . 
 
 Total 
 
 1881, 
 January . . . 
 February.. 
 
 March . 
 
 April 
 
 May 
 
 June 
 
 July - 
 
 August 
 
 September 
 October . . . 
 November . 
 December . 
 Total 
 
 1882. 
 January.. . 
 February . 
 
 March., 
 
 April 
 
 May 1 
 
 June 
 
 July 
 
 August 
 
 September 
 October . . . 
 November , 
 December . 
 Total 
 
 1883. 
 January . . . 
 February.. 
 
 March 
 
 April 
 
 May 
 
 June 
 
 July 
 
 August 
 
 September 
 October . . . 
 November . 
 December . 
 Total 
 
 Negative and precipi- 
 tation. 
 
 Rain. Mist. Snow. 
 
 
 11 
 12 
 14 
 14 
 14 
 13 
 14 
 10 
 
 3 
 
 115 
 
 4 
 
 9 
 
 4 
 
 15 
 
 9 
 
 SO 
 
 21 
 
 11 
 
 12 
 
 18 
 
 8 
 
 12 
 
 143 
 
 
 11 
 
 8 
 10 
 18 
 10 
 22 
 18 
 17 
 
 9 
 
 8 
 13 
 
 144 
 
 10 
 15 
 13 
 19 
 13 
 15 
 11 
 20 
 18 
 
 153 
 
 11 
 12 
 
 5 
 10 
 11 
 13 
 16 
 15 
 13 
 11 
 15 
 
 9 
 
 141 
 
 11 
 
 Pffecipitation and no negative. 
 
 Bain. 
 
 
 1 
 
 2 
 3 
 7 
 6 
 5 
 3 
 6 
 1 
 2 
 36 
 
 23 
 
 
 3 
 1 
 1 
 
 
 
 
 1 
 
 4 
 1 
 6 
 4 
 21 
 
 3 
 2 
 2 
 1 
 
 1 
 6 
 3 
 5 
 4 
 3 
 7 
 37 
 
 30 
 
 Kain 
 
 less 
 
 than .01. 
 
 2 
 
 6 
 
 40 
 
 25 
 
 20 
 
 38 
 
 38 
 
 Mist. 
 
 
 1 
 1 
 1 
 
 2 
 1 
 
 2 
 
 2 
 4 
 14 
 
 
 2 
 4 
 1 
 1 
 1 
 2 
 1 
 4 
 2 
 2 
 2 
 22 
 
 
 3 
 3 
 3 
 4 
 o 
 
 
 6 
 3 
 5 
 3 
 1 
 33 
 
 Snow, 
 
 11 
 
 Negative 
 
 and no 
 precipita- 
 tion. 
 
 13 
 
 29 
 
 34 
 
 29 
 
 1 
 
 1 
 4 
 4 
 4 
 2 
 2 
 
 3 
 
 1 
 22 
 
 Precipita- 
 tion 
 and no 
 record. 
 
 16 
 
 
 2 
 
 2 
 
 
 1 
 7 
 
 
 
 28 
 
 
 
 2 
 1 
 1 
 1 
 1 
 
 3 
 
 
 1 
 10 
 
MEMOIES OF THE NATIONAL ACADEMY OP SCIENCES. 
 
 307 
 
 Table T.— Precipitation and negative potential at the Royal , Observatory, Greenwich, England, 
 
 1879 to 1886, inclusive — Continued. 
 
 Months. 
 
 1884. 
 
 January 
 
 February . . . 
 
 March 
 
 April 
 
 May 
 
 June , 
 
 July 
 
 August 
 
 September . 
 
 October 
 
 November.. 
 December . . 
 
 Total . 
 
 1885. 
 
 January 
 
 February... 
 
 March 
 
 April 
 
 May 
 
 June 
 
 July 
 
 August 
 
 September . 
 
 October 
 
 November . . 
 December .. 
 
 Total . 
 
 1886. 
 
 January 
 
 February... 
 
 March 
 
 April 
 
 May 
 
 June 
 
 July 
 
 August 
 
 September . 
 
 October 
 
 November . . 
 December . . 
 
 Total . 
 
 Negative and precipi- 
 tation. 
 
 Hain, Mist. Sncw 
 
 8 
 
 11 
 
 10 
 
 15 
 
 7 
 
 16 
 20 
 11 
 7 
 8 
 7 
 9 
 
 129 
 
 7 
 
 15 
 
 6 
 
 14 
 
 21 
 
 7 
 
 4 
 
 13 
 
 12 
 
 10 
 
 9 
 
 7 
 
 125 
 
 13 
 
 3 
 
 6 
 
 17 
 
 14 
 
 9 
 
 14 
 
 6 
 
 7 
 
 10 
 
 11 
 
 18 
 
 128 
 
 14 
 
 Precipitation and no negative. 
 
 36 
 
 28 
 
 29 
 
 Kain 
 
 less 
 than, 01 
 
 40 
 
 32 
 
 29 
 
 Mist. 
 
 1 
 ) 
 
 3 
 
 2 
 1 
 3 
 6 
 12 
 4 
 5 
 
 
 38 
 
 24 
 
 25 
 
 Snow. 
 
 19 
 
 Negative 
 and no 
 precipita- 
 tion. 
 
 14 
 
 20 
 
 Precipita- 
 tion 
 and no 
 record. 
 
 
 
 
 
 
 
 
 
 5 
 14 
 
 
 
 19 
 
 SUMMAKT. 
 
 Tear. 
 
 Negative and precipi- 
 tation. -, 
 
 Precipitation and no negative. 
 
 Negative 
 
 and no 
 precipita- 
 tion. 
 
 Precipita- 
 tion 
 and no 
 record. 
 
 Rain. 
 
 Mist. 
 
 Snow. 
 
 Eain. 
 
 Ha-m 
 
 less 
 
 than .01. 
 
 Mist. 
 
 Snow. 
 
 1879 
 
 115 
 143 
 144 
 153 
 141 
 129 
 125 
 128 
 
 
 
 
 
 1 
 1 
 8 
 14 
 
 11 
 
 2 
 
 7 
 2 
 
 7 
 1 
 2 
 
 7 
 
 36 
 23 
 21 
 37 
 30 
 36 
 28 
 29 
 
 40 
 25 
 
 20 
 38 
 
 38 
 
 40 : 
 
 32 
 29 
 
 7 
 7 
 14 
 22 
 33 
 38 
 24 
 25 
 
 11 
 4 
 5 
 
 4 
 5 
 2 
 
 19 
 
 13 
 29 
 34 
 29 
 22 
 6 
 14 
 20 
 
 5 
 
 1 
 28 
 
 5 
 10 
 
 6 
 19 
 
 5 
 
 1880 
 
 1881 
 
 1882 
 
 1883 
 
 1884 
 
 1885 
 
 1886 
 
 Total 
 
 1078 
 
 24 
 
 39 
 
 240 
 
 262 
 
 170 
 
 50 
 
 167 
 
 79 
 
308 
 
 MEMOIRS OF THE NATIONAL ACADEMY OP SCIENCES. 
 
 Table U. — Negative potentials without precipitation, Terre Haute, Ind., March 30, 1887, to August 
 
 31, 1888. 
 
 Date. 
 
 Remarks. 
 
 1887. 
 Mar. 30 
 
 Apr. 3 
 
 Apr. 4 
 
 Apr. 14 
 
 Apr. 15 
 
 Apr. 29 
 
 May 3 
 
 May 20 
 
 May 25 
 
 May 26 
 
 May 27 
 
 May 28 
 
 June 1 
 
 June 2 
 
 June 7 
 
 June 16 
 
 June 17 
 
 June 23 
 
 June 25 
 
 July 5 
 
 July 9 
 
 July 14 
 
 July 16 
 
 July 19 
 
 July 26 
 
 July 27 
 
 July 28 
 
 July 29 
 
 July 30 
 
 Aug. 2 
 
 Aug. 3 
 
 Observations began 12:30 p. m. ; positive until 3 p. ra. ; steady negative from 4 to 7 p. m., 
 with threatening weather ; It. rain predicted by S. O. ; rain in the Ohio Valley and Ten- 
 nessee and in Illinois ; station northeast of a low pressure. 
 
 Observations from 10:30 a. m. to 12 m. ; negative for a few minutes at 11:50 a. m., with fair 
 weather; It. rain predicted by S. O. ; east of a low ; rain in the lake region. 
 
 Cloudy in a. m. with positive ; W. br. winds ; steady negative from 4 to 6:30 p. m., with W. 
 gale and threatening ; fair predicted by S. O. ; southwest of a low and in northeast edge 
 of a high ; rain in the lower lakes. 
 
 Variable positive and negative from 2:30 to 3:30 p. m. ; 8teady_positive rest of the day ; 
 threatening from 2:30 to 3 p.m.; fair predicted by S. O. ; rain in Ohio, Tennessee, and on 
 the laltes. 
 
 Variable positive and negative all day ; clouds varied from clear to threatening ; W. br. 
 to gale winds; fair by S. O. ; rain on the lakes and in Arkansas. 
 
 Variable positive all day, except for a few seconds, at 11:10 a. m., when it was negative; 
 NW. gale to br. winds ; perfectly clear ; fair by S. O. ; rain in the lake region. 
 
 Threatening with variable positive and negative from 9 to 10 a. m. ; steady positive from 
 then to 7 p. m., with cloudy weather; rain durinu; the night. 
 
 Clear in a. m., with negative from 9 to 9:30 a. m. ; then positive all day ; fair in p. m. ; rain 
 on 21st. ; S. O. predicted fair, followed by rain. 
 
 Negative for a short time at 3 p.m. ; fair; S. O. predicted fair in northern with local rains 
 in southern Indiana. This negative may have been due to an open window. 
 
 Negative from 8:50 to 9:05 a. m. ; positive rest of the day ; wind west; It. at 9 a. m. ; W. 
 gale at 12 m. ; clear in a. m. ; fair in p. m. ; rain in the east ; S. O. fair. 
 
 Negative from 9 to 9:20 a. m. ; perfectly clear in a. m. ; NW. It. winds ; fair in p. m. ; simi- 
 lar day to yesterday. 
 
 Clear in a. m. ; fair in p. m, ; conditions similiar to 26th and 27th ; potential zero at 9 a. m. ; 
 negative at 3 p. m. for a . few moments and positive the rest of the day ; NW. It. to fr. 
 winds. 
 
 Threatening at 12 m. ; thitnder in the west from 12:45 to 1 p. m. ; negative for a short time 
 at 12:45 p. m. and again at 2:15 p. m. ; positive the rest of the day ; thunder in the west at 
 4:05 p. m., had no influence on the electrometer ; rained during the night of the 2d. 
 
 Southwest of a low ; rain in the lower lake region, Missouri Valley, and Tennessee ; S. O. fair ; 
 threatening with negative for a few moments at 2:45, 3:31, and 4:18 p.m.; positive the 
 rest of the time. 
 
 Threatening in p. m. with negative from 6 to 6:15 p. m. ; positive the rest of the time ; S. O. 
 fair ; rain in the upper lake region. 
 
 Perfectly clear ; negative 9:36 to 9:37 a. m. ; positive rest of the day ; W. It. to fresh winds ; 
 rain in the upper lake region ; S. O. fair. 
 
 Perfectly clear ; negative from 9:35 to 9:40 a. m. ; W. It. ; rain on the lakes ; S. O. fair; draft 
 blew from room outward. 
 
 Threatening at 11 a. m. ; negative at 11:30 a. m. and from 12 m. to 12:15 p. m. ; positive rest of 
 the day ; W. gale winds ; rain in the upper Mississippi Valley ; S. O. fair. 
 
 Threatening at 11 a. m. ; negative for a short time at 11:15 a. m. ; positive rest of the time ; 
 rain in the Ohio Valley and Tennessee. 
 
 Fair weather ; SW. It. ; negative at 6:01 and 6:38 p. m. while a R. R. train was passing ; posi- 
 tive rest of the time ; lain in the Ohio Valley, Tennessee, and lake region ; S. O. fair. 
 
 Negative for a lew moments at 12 m. ; W. fr., and cloudy ; NW. gala at 5 p. m. ; rain in the 
 Ohio Valley, and Tennessee, and the lake region ; S. 0. fair ; station south of a low. 
 
 Negative from 12:36 to 12:41 p. m. ; positive the rest of the time ; clear weather ; "W. It. 
 winds; rain in Michigan ; S. 0. fair. 
 
 Temperature 100°; negative with an occasional positive from 1 to 7 p. m. ; the wind was 
 gusty from It. to fresh and variable in direction, SW., NW., W.,E.,SE.,and S. ; threatened 
 at 4 p. m. for a short time ; rain in the lake region and upper Mississippi Valley ; S. O. fair. 
 
 Threatening with negative at 10:55 and 11:12 a. m. ; positive the rest of the time ; NE. fresh 
 winds ; rain in Tennessee and upper lake region. 
 
 Clear all day with about one-tenth clouds ; negative at 10:51, 10:.'i6, 10:58, and at 11:40 a. m., 
 and from 12:45 to 3 p. m., and at 5 p. m. ; positive the rest of the time ; it seemed that 
 the change of the potential was due to the R, R. train passing ; W. It. winds ; rain in 
 Kentucky, Tennessee, and Michigan; S. O. fair. 
 
 Negative from 10:35 to 10:40 a. m. and from 1 to 1:15 and at 2:50 p. m. ; positive the rest of 
 the time; fair weather; It. variable winds; rain in the Ohio Valley, Kentucky, Tennes- 
 see, and Michigan ; S. O. fair. 
 
 Positive all day ; negative at 6:50 p. m. while a train was passing ; clear weather ; N. It. 
 winds. 
 
 Negative at 12:10p.m. while a train was passing; clear weather; rain in the Mississippi 
 Valley, Tennessee, and Michigan; S.O. fair. 
 
 Clear day ; It. haze ; fresh NW. winds ; negative at 10:3'> a. m. and from 11:10 to 11:14 a. m., 
 while trains were passii^ ; rain in the Ohio Valley and lake region ; S. O. fair. 
 
 Perfectly clear ; NE. to E. gale to brisk winds ; negative at 10 and 11 a. m., 1, and 3:30 to 
 3:45 p. m., and at 4:30 p. m. ; positive at 9 a. m., 12 m., and 3 and 4 p, m. ; rain in Ky., 
 Tenn., and Mich. ; S. O. fair. 
 
 Clear day ; negalive from 12 m. to 1 p. m. and at 6 p. m. ; It. E. winds ; rain all around ex- 
 cept in the Ohio Valley ; S. O. fair. 
 
MEMOIES OP THE N ACTIONAL AtSADEMY OF SOIENCBS. 
 
 309 
 
 Table U. — Negative potentials without precipitation, Terre Haute, Ind., March 30, 1887, to August 
 
 31, 1888— Continued. 
 
 Date. 
 
 1887. 
 
 Aug. 
 
 9 
 
 Aug. 
 
 14 
 
 Aug. 
 
 18 
 
 Aug. 
 Aug. 
 Aug. 
 
 19 
 20 
 30 
 
 Sept. 
 
 1 
 
 Sept. 
 Sept. 
 Sept. 
 
 2 
 3 
 5 
 
 Sept. 
 
 8 
 
 Sept. 
 
 10 
 
 Sept. 
 Oct. 
 
 23 
 5 
 
 Oct. 
 
 6 
 
 Oct. 
 
 7 
 
 Oct. 
 
 8 
 
 Oct. 
 
 18 
 
 Oct. 
 
 21 
 
 Oct. 
 
 22 
 
 Oct. 
 
 29 
 
 Oct, 
 
 31 
 
 Nov. 
 
 1 
 
 Nov. 
 
 2 
 
 Nov. 
 
 3 
 
 Nov. 
 
 4 
 
 Nov. 
 
 5 
 
 Nov. 
 
 6 
 
 Nov. 
 
 8 
 
 Nov. 
 
 12 
 
 Nov. 
 
 13 
 
 Nov. 
 
 14 
 
 Kemarka. 
 
 Clear weather ; SE. It. winds ; variable positive and negative from 4 to 6;30 p. m. ; once the 
 negative seemed to be the result of a passing train, but at other times it was negative when 
 no train was passing; rain ia the upper laltes; S.O.fair. 
 
 Variable positive and negative, with threatening weather after 4 p.m. ; rain in the Ohio 
 Valley and lalies, at Indianapolis and Springfield ; S. 0. It. rain. 
 
 Threatening ; negative at 3 p. m. while a train was passing ; rain in the lower lake region ; 
 S. O. fair. 
 
 Clear day ; negative at 6 p. m. while a train was passing ; S. O. fair. 
 
 Hazy weather ; negative all afternoon ; It. W. winds ; rain on the 21st. 
 
 Negative from 5:30 to 5:55 p. m. and at 6:1.5 p. m. ; cir.-str. clonds forming ; rain in Missouri ; 
 southwest of a high. 
 
 Negative for 5 minutes at 9 a. m. and from 5:50 to 5:55 p. m. ; positive the rest of the day ; 
 rain in the lake region and Missouri Valley ; S. O. fair, followed by rain. 
 
 Negative at 10:35 a. m. ; fair weather ; SW. fr. 
 
 Threateniug, with negative from 9 to 9:10 a. m. ; S. O. It. rain. 
 
 Negative from 10:15 to 10:45 a. m. ; cir.-cu. clouds ; rain in the upper Mississippi Valley and 
 lake region. 
 
 Negative for a few moments at 3:16 p. ra. while a train was passing; varied from negative 
 to positive from 3:30 to 4 p. m. ; rain in Ohio and Michigan ; S. O. fair. 
 
 Threatening, with negative at 11 a. ni. ; rain in Ohio Valley and lake region and at Indian- 
 apolis; S. O. fair. 
 
 Negative at 1, 3:05, and 3:12 p. m. ; N. fr. cloudy ; rain all around. 
 
 Potential varied from positive to negative from 9 to 10 a. m. ; clear weather; light variable 
 wind; station east of high ; train was switching in yard adjoining the Institute ; gen- 
 erally clear at surrounding stations. 
 
 Potential varied from positive to negative during whole evening ; cloudy weather ; light 
 S. wind; station neither in a high nor a low ; trains passing seemed to have no effect on 
 electrometer readings; rain fell in Upper Miss. Valley and at Chicago after 3 p. m. 
 
 Potential varied from positive to negative from 11 a. m. to 1 p. m. ; fair in a. m., cloudy in 
 p. m. ; fresh S. wind ; station east of low ; rain fell in Michigan all day. 
 
 Potential variedfrom positive to uegative9a.m. to 12m.; cloudy weather ; lights. wind; sta 
 tion south of low; rain fell at Springfield and Chicago. 111. , and throughout the Northwest. 
 
 Potential varied from positive to negative from 9 to 9:30 a. m. ; cloudy, tlireatening weather ; 
 light variable wind; station neither in a high nor a low ; rain fell in Tennessee all day 
 and in Michigan during afternoon. 
 
 Potential variable from positive to negative all dav ; generally clear weather ; high W. to 
 NW. wind ; station west of low ; light rain at Chicago before 3 p. m. 
 
 Potential negative at 9 a. m. ; cloudy, threatening weather; light E. to S. wind; station 
 neither in a high nor a low ; It. rain at St. Louis all day ; heavy rain at Chicago after 
 3 p. m. 
 
 Potential variable positive to negative all morning ; cloudy, threatening weather ; high N. 
 toNW. wind; station south of a high; It. rain at Indianapolis, Cincinnati, Columbus, 
 and Chicago all day. 
 
 Potential varied from positive to negative after 5:45 p.m.; clear weather ; lights, wind; 
 station neither in a high nor a low ; potential became negative about sunset, as smoke 
 settled over the city and haze and fog began to form ; generally clear weather at sur- 
 rounding stations. T T,i OTl 
 
 Potential varied from positive to negative about 5 p. m. and after clear weather ; light SE. 
 wind; potential began to vary about sunset, when fog, haze, and smoke began to form ; 
 generally clear weather at surrounding stations. 
 
 Potential variable from positive to negative about 9 a. ra. and from 5 to 7:15 p. ra. ; station 
 neither in high nor low; clear weather ; light S. wind ; light fog and haze in a. m. and 
 again at night ; clear during middle of day ; generally clear at surrounding stations. 
 
 Potential variable positive to negative about 3 p. m. ; hazy weather ; light S. wind ; station 
 south of a low; generally clear at surrounding stations. 
 
 Potential varied from positive to negative about 3 p. m. ; clear weather ; brisk NW. wind ; 
 station east of high ; It. rain at all Michigan stations during the whole day ; clear at nearer 
 
 stations. , j j- ■ t -ui. 
 
 Potential variable from positive to negative 9 to 10 a. m. ; clear day ; toggy m ». m. ; lignt 
 SW wind; station neither in high nor low; clear at surrounding stations. 
 
 Potential negative at 4:05 p.m.; clear weather; light SW. wind; station neither m high 
 nor low; clear at surrounding stations. ,• , t.t 
 
 Potential variable positive to negative 3 to 4:30 p. ra. ; hazy weather ; light N. wind ; sta- 
 tion neither in high nor low ; clear at surrounding stations. 
 
 Potential variable positive to negative all day; clear weather ; light N. wind; station south 
 of a high; generally clear at surrounding stations. c< • j ;. j.- 
 
 Potential negative at 5 p. m. ; cloudy, threatening weather; fresh S. wind ; station south 
 of a low; cloudy at neighboring stations; light rain in Michigan during afternoon. 
 
 Potential variable from positive to negative during the afternoon; cloudy, threatening 
 weather; fresh W. wind; station south of a low ; light rain at Indianapolis and Nash- 
 ville during the day. 
 
310 
 
 MEMOIRS OP THE NATIOITAL ACADEMY OF SCIENCES. 
 
 Table U. — Negative potentials without precipitation, Terre Haute, Ind., March 30, 1887, to August 
 
 31, 1888— Continued. 
 
 Date. 
 
 188 
 Nov. 
 
 17 
 
 Nov. 
 
 18 
 
 Nov. 
 
 22 
 
 1888. 
 Feb. 9 
 
 Feb. 
 
 17 
 
 Mar. 
 
 3 
 
 Mar. 
 
 28 
 
 Apr. 
 
 12 
 
 Apr. 
 
 20 
 
 Apr. 
 
 23 
 
 Apr. 
 
 24 
 
 Apr. 
 
 26 
 
 Apr. 
 
 28 
 
 May 
 
 19 
 
 May 
 
 23 
 
 .June 
 
 13 
 
 June 
 
 25 
 
 July 
 
 18 
 
 July 
 
 26 
 
 Aug. 
 
 1 
 
 Aug. 
 
 14 
 
 Aug. 
 
 15 
 
 Aug. 
 
 21 
 
 Aug. 
 
 31 
 
 Remarks. 
 
 Potential variable positive to negative 11:30 a. m. to 12:30 p. m. ; clear weather ; brisk W. 
 wind; station neither in a high nor alow ; It. rain throughout Miohiganall day; clear at 
 nearer stations. 
 
 Potential negative at 5 p. m. ; hazy weather ; fresh S. wind ; station south of a low ; It. rain 
 throughout the Northwest, Mich., Wis. ; rain began here at 8:30 a. tn. on 19th. 
 
 Potential varied from positive to negative 4:30 to 5:30 p. m. ; cloudy weather; brisk S. 
 wind ; station east of a low ; light rain at Cairo, 111., during the evening ; cloudy at sur- 
 rounding stations. * 
 
 Potential variable from positive to negative 3 to 3:10 p. m. ; fair weather; fresh N. wind ; 
 
 station within a high ; It. rain at Louisville, Ky. ; Cairo, 111. ; St. Louis, Mo. ; and in 
 
 Michigan. 
 Potential variable positive to negative about 5p.m.; cloudy weather ; fresh W. wind ; sta- 
 tion south. of a low ; It. rain at St. Louis about noon. 
 Potential variable positive to negative 10 a. m. to 12:30 p. m. ; cloudy, threatening weather ; 
 
 brisk to high W. wind ; station south of a low ; heavy snow at all surrounding stations. 
 Potential negative at 9 a. m. ; cloudy weather ; gentle N. wind; station neither in a high 
 
 nor a low ; rain at all surrounding stations during the whole day. 
 Potential negative at 9 a. m. ; clear weather ; fresh N. wind ; station within a high ; generally 
 
 clear weather at surrounding stations. 
 Potential negative about 1 p. m. ; cloudy weather ; frfesh N. wind ; station within a high ; 
 
 It. rain at Chicago all day ; clear at southern stations. 
 Potential negative about 1 p. ra. ; clear weather ; brisk N. wind ; station neither in a high nor 
 
 a low ; cloudy at surrounding stations. 
 Potential variable positive to negative 10 to 11 a. m. ; clear weather ; light N. wind; station 
 
 south of a high; generally clear at surrounding stations. 
 Potential variable positive to negative 9 a. ra. to 1 p. m. ; hazy weather ; fresh S. wind ; 
 
 station neither in a high nor a low ; It. rain at Springfield, 111., and St. Louis about noon. 
 Potential negative at 11 a. ra. ; clear with light haze: light SW. wind ; station neither in 
 
 a high nor a low ; rain fell all day in Mississippi valley. 
 Potential negative at 9 a.m. ; fair weather; fresh N. wind; station within a high ; rain fell 
 
 in Tennessee during the morning. 
 Potential negative 9. a. m. to 1 p. ui. ; cloudy, threatening weather ; fresh SE. wind; station 
 
 within a low; rain fell at all surrounding stations daring the day. 
 Potential negative at 9 and 11 a. m. ; fair weather; brisk southerly wind ;' station neither 
 
 in a high nor a low ; rain fell at Chicago and in Tennessee during the day. 
 Potential negative at 9 a. m. ; threatening weather; light S. wind ; station neither in a high 
 
 nor a low ; rain fell at all surrounding stations during the day. 
 Potential negative about 5 p. m. ; fair weather; fresh W. wind; station south of a low; 
 
 rain fell at all surrounding stations during the day. 
 Potential negative at 5 p. m. ; threatening weather ; fresh NE. wind ; station neither in a 
 
 high nor a low ; rain fell at Springfield, III., and in Tennessee during the day. 
 Potential negative at 5 p. m. ; threatening weather ; fresh SW. wind ; station south of high ; 
 
 rain at surrounding stations during the day ; thunderstorm raging in sight of station ; 
 
 no precipitation here. 
 Potential variable positive to negative at 5 p. ra. ; cloudy weather ; It. SW. wind ; station 
 
 west of a high; rain at Chicago and in upper lake region during the afternoon. 
 Potential variable positive to negative about 5 p. m. ; cloudy weather; fresh S. wind ; sta- 
 
 tion neither in a, high nor a low; rain at Memphis aud Chicago during the day. 
 Potential variable positive to negative at 5 p. m. ; cloudy weather; light NW. wind ; sta- 
 tion north of a low ; heavy rain at ludiauapolis and stations east all day. 
 Potential negative at 11 a. m. and 1 p. m. ; cloudy weather ; gentle variable wind ; station 
 
 west of a low ; rain fell at Cincinnati, Louisville, and Columbus ; heavy rain at Indian- 
 apolis during the early morning. 
 
MEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES. 311 
 
 Table V. —Negative potentials without precipitation, Ithaca, N. Y., October, 1887, to August, 1888. 
 
 1887. 
 Oct. 27 
 
 Nov. 12 
 
 Nov. 16 
 
 Nov. 23 
 
 Nov. 27 
 
 Nov. 29 
 
 Dec. 6 
 
 Dec. 16 
 
 Dec. 19 
 
 Dec. 21 
 
 1888. 
 Feb. 21 
 
 Feb. 28 
 
 Feb. 
 
 29 
 
 Mar. 
 
 15 
 
 Mar. 
 
 20 
 
 Mar. 
 
 21 
 
 Mar. 
 
 23 
 
 Mar. 
 
 24 
 
 Mar. 
 
 29 
 
 Mar. 
 
 31 
 
 Apr. 
 
 4 
 
 Apr. 
 
 6 
 
 Apr. 
 
 7 
 
 Apr. 
 
 8 
 
 Apr. 
 
 11 
 
 Potential negative at 9 a. m., positive at other obaervaiions ; threatening weather ; fresh 
 SE. wind all day ; station in anticyclonic area ; from 3:1.5 to 4:10 p. m. rain was seen fall- 
 ing ESE. of station ; rain fell at Albany, N. ¥., and in Canadian lower lake regions be- 
 tween 7 a. m. and 3 p. m. 
 
 Potential negative from 9 to 9:30 a. ra. ; cloudy weather ; high NW. wind ; station west of 
 an area of low pressure ; rain ended before 7 a. m. at' this station ; rain fell in Canadian 
 lower lalie regions between 7 a. m. and 3 p. m. 
 
 Potential negative at 9 a. m. ; cloudy weather ; brisk NW. wind; station east of a low; 
 precipitation in the upper lak* regions and at Montreal, Canada, between 7 a. m. and 3 
 p. m. 
 
 Potential variable positive to negative from 10:30 a. m. to 1 p. m. ; hazy weather ; gentle 
 S. wind ; station in anticyclonic area ; precipitation at Eocheater and Albany, N. Y., be- 
 tween 7 a. ni. and 3 p. m. 
 
 Potential negative from 9 a, m. until 1p.m.; fair weather ; fresh S. wind ; station south of 
 a lo w ; precipitation quite heavy throughout the lower lake regions during the whole day. 
 
 Potential variable from positive to negative all day ; generally clear weather ; fresh NW. 
 wind; station within anticyclonic area; snow fell at Erie, Pa., Oswego, N.Y., and at 
 Canadian lower lake stations all day. 
 
 Potential negative from 2:15 to 2:54 p. m. ; clear weather ; light S. wind ; station north of 
 a high ; rain before 7 a. m. at Buffalo, N. Y. ; generally clear at surrounding stations dur- 
 ing the day. 
 
 Potential negative all day ; cloudy weather ; brisk NW. wind ; station between two lows ; 
 precipitation at this station during early a. m. ; cloudy weather at surrounding stations ; 
 rain on 17th at Buffalo, N. Y., Erie, Pa., and Cleveland, Ohio. 
 
 Potential negative at 10:50 a. ra. and 12:05 p.m. ; positive at all other times during the day ; 
 cloudy weather ; brisk NW. wind ; station between two lows ; snow fell all day at Cana- 
 dian lower lake stations. 
 
 Potential negative all day ; cloudy, threatening weather ; brisk NW. wind ; station west of 
 a low ; snow fell all day at Oswego, Rochester and Buffalo, N. Y., Erie, Pa., and Canadian 
 lower lake stations. 
 
 Potential variable positive to negative all day ; cloudy weather ; fresh N. wind; station 
 
 south of a low ; snow fell from 7 a. m. until 3 p. m. at Oswego, N. Y., and Canadian lower 
 
 lake stations. 
 Variable potential from positive to negative 11 a. m. to 7 p. m. ; cloudy weather ; brisk 
 
 NW. wind; station north of a high; snow fell all day within sight of the station, but 
 
 none fell at the station ; snow fell all day at Canadian lower lake stations. 
 Potential variable from positive to negative all day ; light N. wind ; station neither in a 
 
 high nor a low ; snow fell at Canadian lower lake stations from 7 a. m. to 3 p. m. 
 Potential variable from positive to negative from 9 to 10:30 a.m.; positive remainder of 
 
 day ; cloudy weather; fresh N. wind ; station north of a high ; bqow at Canadian lower 
 
 lake stations at intervals during the day. 
 Potential variable from positive to negative all day ; cloudy, threatening weather ; brisk S. 
 
 wind; station east of a low; rain fell at Oawago, Rochester, and Buffalo, N. Y., Erie, 
 
 Pa., and at all Canadian lower lake stations during the whole day. 
 Potential variable from positive to negative all day ; cloudy, threatening weather ; brisk 
 
 to high S. and MW. wind ; station east and south of a low ; It. snow and rain at Oswego, 
 
 Rochester and Buffalo, N. Y., and Erie, Pa. ; snow at Canadian lower lake stations during 
 
 the whole day. . 
 
 Potential variable positive to negative all day; fair weather; brisk NW. wind ; station 
 
 west of a low ; It. snow at Oswego, Rochester, and Buffalo during the whole day. 
 Potential variable from positive to negative all day ; fair weather ; brisk NW. wind ; sta- 
 
 .tion west of a low; It. snow at Oswego, Rochester, and Buffalo, N.Y., from 7 a.m. to 3 p. 
 
 "m. ; snow contiuned at Oswego after 3 p. m. 
 Potential negative all day; cloudy to clear weather; brisk NW. wind; station west of a 
 
 low ; It snow all day at Rochester, N. Y., and Toronto, Canada. 
 Potential negative all day; cloudy to clear weather; brisk NW. wind; station west of a 
 
 low ; light snow from early a. ra. to 3 p. m. at Rochester and Canadian lower lake sta- 
 
 Potential variable from positive to negative all day ; clear weather ; fresh NW.wind; sta- 
 tion west of a high ; rain in upper lake region during the afternoon ; rain at this sta- 
 tion began at 9:15 a. m. of 5th. , , . , „„ . , , 
 Potential variable from positive to negative all day; clear weather; brisk NW. wind; sta- 
 tion west of a low; generally clear weather at surrounding stations; faint aurora was 
 observed during the night. . i,- u i- i-i- 
 Potential negative all day ; clear weather ; brisk NW. wind ; station east of a high; iigbt 
 
 rain at Oswego, N.Y., between 7 a.m. and 3 p.m. j. e t ■ -u 
 
 Potential negative all day ; clear weather ; fresh to brisk NW. wind ; station east ot a bigh ; 
 
 quite heavy rainfall between 9 a. 'm. and 3 p. m. at Rochester and Oswego, N. Y. 
 Potential variable from positive to negative all day; cloudy weather; brisk NW. wind ; 
 station west of a low; It. rain at Oswego, Rochester, and Buffalo, N.Y., trie, Pa., and 
 Canadian lower lake stations between 7 a. m. and 3 p. m. 
 
312 
 
 MEMOIRS OF THE NATIONAL ACADEMY OP SCIENCES. 
 
 Table Y. — .S'egative potentials icitliout precipitation, Ithaca, N'. T., October, 1887, to 
 
 1888— Continued. 
 
 Kemarks. 
 
 1888. 
 
 Apr. 13 
 
 Apr. 15 
 
 Apr. 16 
 
 Apr. 17 
 
 Apr. 22 
 
 Apr. 23 
 
 Apr. 25 
 
 Apr. 20 
 
 Apr. 27 
 
 Apr. 28 
 
 May 5 
 
 Ma.y 6 
 
 May 7 
 
 May 17 
 
 May 19 
 
 "May 21 
 
 June 1 
 
 June 4 
 
 June 7 
 
 June 12 
 
 June 30 
 
 July 11 
 
 July 15 
 
 July 25 
 
 Aug. 2 
 
 Aug. 5 
 
 Aug. 14 
 
 Aug, 25 
 
 Potential variable from positive to negative all day ; clear in a. m. ; cloudy at night ; fresh 
 
 NW. wind during a. m. ; llght^. wind during p. m. ; station east of a low ; It. rain at Ca- 
 nadian lower lake stations during the afternoon and evening. 
 Potential negative all day ; cloudy weatder ; fresh NW. wind ; station east of a low ; It. 
 
 rain and snow at Albany, N. Y., Erie, Pa., and Oliio lower lake stations during the 
 
 morning and afternoon. 
 Potential variable from positive to negative all day ; clear to fair weather ; brisk NW. wind ; 
 
 station west of a low ; It. rain at New York «Sty and stations in its vicinity between 7 a. 
 
 m. and 3 p. m. ; faint aurora at night. 
 Potential nagative all day ; clear to cloudy weather ; fresh NW. wind ; station east of low; 
 
 It. rain and snow at all Canadian and New York lower lake stations during morning and 
 
 evening. 
 Potential variable from positive to negative all day; clear to fair weather; fresh NW. 
 
 wind ; station between two lows ; snow fell all day about twenty miles west of station ; 
 
 no snow at lower lake stations. 
 Potential variable from positive to negative all day; fair to cloudy weather ; brisk NW. 
 
 wind-; station west of a low ; snow fell all day about twenty miles west of station ; also 
 
 at New York city and stations in that vicinity. 
 Potential variable from positive to negative all day ; clear weather ; light N. wind ; station 
 
 north of a high ; no precipitation recorded at surrounding stations ; cloudy weather at Ca- 
 nadian lower lake statious. 
 Potential variable from positive to negative all day; clear weather ; light NW. wind; sta- 
 tion west of a high; fair weather at surrounding stations. 
 Potential variable from positive to negative all day ; clear weather ; light NW. wind; sta- 
 tion in anticyclonic area ; clear at surrounding stations. 
 Potential negative 9 to 9:30 a. m. ; clear weather ; light NW. wind ; station neither in high 
 
 nor low ; clear at surrounding stations. 
 Variable positive to negative during p. m. ; fair weather ; fresh to brisk W. wind ; station 
 
 soutli of low ; fair at surrounding statious ; rain along Atlantic coast. 
 Negative at 1 p. in. ; clear weather ; fresh N. wind ; station uorth of high ; fair at surround- 
 ing stations. 
 Variable positive to negative during p.m. ; cloudy weather ; fresh NW. wind ; station east 
 
 of low; rain at nearly all the Canadian, New York, and Ohio lower lake stations from 
 
 9 a. m. to 3 p.m. 
 Variable positive to negative all day; fair weather; fresh N. wind ; station north of high ; 
 
 rain general over whole country. 
 Variable positive to negative all day ; cloudy, threatening weather; fresh NW. wind ; sta- 
 tion west of low ; cloudy, threatening weather at surrounding stations ; heavy rains at all 
 
 stations before 7 a. m. 
 Variable positive to negative during the day ; positiveat night ; clear weather ; fresh NW. 
 
 wind ; station west of high ; brilliant aurora on night of 20th ; heavy rains in NW. 
 
 (northwestern dist.) and South Atlantic stations. 
 Variable positive to negative all day ; clear weather ; brisk NW. wind ; station west of low; 
 
 rain in early morning ; rain at Ohio and Canadian lower lake stations during the day. 
 Variable positive to negative 10 a. m. to I p. m. ; clear weather ; fresh NW. wind ; station 
 
 east of high ; cleat at surrouudiug stations all day. 
 Variable positive to negative all day; cloudy weather ; fresh NW. wind; station east of 
 
 high ; rained 10 miles south of station during a. m, ; also at Oswego and Eochester, N. Y. , 
 
 and Erie, Pa. 
 Variable positive to negative 9 to 10 a. m. ; fair weather ; fresh N. wind ; station north of a 
 
 high ; rain at Oswego and Rochester during early morning ; fair during rest of day. 
 Variable positive to negative 9 to 11 a. m. ; clear weather ; fresh NW. wind ; station west or 
 
 a high ; rain fell at nearly all lower lake stations during the evening. 
 Negative 1 to 3 p. m. ; clear to cloudy weather ; fresh SW. wind ; station south of low ; rain 
 
 fell at nearly all lower lake stations during the whole day. 
 Variable positive to negative 11 a. m. and 1 p. ra. ; hazy weather ; fresh NW. wind ; station 
 
 neither in a high nor a low ; clear at all surrouudiug stations. 
 Variable positive to negative 9 to 11 a. m. ; fair weather ; fresh NW. wind ; station west of 
 
 a high; raiu fell at Montreal, Canada, and in upper lake regions during day and at all 
 
 lower lake stations during night. 
 Variable positive to negative 9 a. m. ; clear weather ; gentle oast wind ; station neither in 
 
 a high nor a low ; fair to cloudy weather at surrounding stations ; rain fell at Pittsburg, 
 
 Pa., and at Ohio lake stations. 
 Negative at 3 p. ra. ; fair and cloudy weather ; light NW. wind ; station south of low ; fair 
 
 to cloudy weather at surrounding stations during the day ; raiu fell at Albany, New York 
 
 City, and many Atlantic coast stations after 8 p. m. 
 Negative at 11 a. m. ; clear weather; light NW. wind ; station neither in high nor low ; 
 
 rain fell at Rochester and Oswego, N, Y., and Canadian lower lake stations during 
 
 night. 
 Negative at 9 a.m.; clear weather; fresh W. wind ; rain fell at Kingston and Montreal, 
 
 Canada, during the evening. 
 
MEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES. 313 
 
 Table y^.— Negative 'potentials without ■precipitation, Baltimore, Md., 1885, 1886, a»^ 1887. 
 
 Date. 
 
 i8a5. 
 
 Jan. 10 
 
 Jan. 21 
 
 Jan. 29 
 Feb. 2 
 Feb. :^ 
 
 Feb. 8 
 Feb. 11 
 Feb. 19 
 
 Feb. 20 
 Mar. 3 
 
 Mar. 10 
 
 Mar. 16 
 
 Mar. 18 
 
 Mar. 21 
 
 Mar. 24 
 
 Mar. 25 
 
 Mar. 26 
 
 Mar. 30 
 
 Apr. 1 
 
 Apr. 21 
 Apr. 22 
 
 Apr. 24 
 Apr. 25 
 Apr. 29 
 
 May 8 
 
 May 9 
 
 May 15 
 
 May 16 
 
 May 19 
 
 June 2 
 
 June 11 
 
 June 13 
 
 Jane 20 
 
 June 24 
 
 July 20 
 Aug. 15 
 Aug. 17 
 Sept. 16 
 Sept. 18 
 Sept. 25 
 
 Sept. 26 
 
 Sept. 28 
 Oct. 16 
 
 Oct. 18 
 
 Oct. 26 
 
 Oct. 27 
 
 Oct. 28 
 Dec. 18 
 
 Dec. 24 
 Dec. 26 
 
 HemarkH. 
 
 Variable positive ivith occasional negative from 10 p. m. of 9th to 12 m. of 10th ; clear : NW. 
 
 brisk winds. 
 No record in a. m. ; weak positive and negative from 12 m. to 8 p. m., then positive : clear ; 
 
 cold -wave and gale coming. 
 Positive, except negative at 10 p. m. ; cold; clear; rising temperature. 
 Slight negative at noon and at 8 p. m. ; positive at other times ; brisk NW. winds ; cloudy. 
 Negative from 9 to 11 a. m. ; variable positive at other limes ; fresh E. to NE. winds ; fair ; 
 
 ice 111 harbor. 
 Slight negative at 7 a. ra. ; positive at other times ; cloudy ; It. NE. winds. 
 Negative from midnight to 11 a. m., then positive ; clear ; cold wave ; brisk NW. winds. 
 Variable positive all day, except positive and negative from 9 to 11 p. m. ; clear ; cold NW. 
 
 winds. 
 Positive with occasional negative ; brisk NW. winds; cold and clear. 
 Variable positive in p. m. to 8:30 p. m., then positive and negative until 3 a. m. of 4th ; It. S. 
 
 winds; cloudy. 
 Positive until 8 p.m.; negative 8 to 8:30 p.m., then variable positive; clear and warm; 
 
 It. variable winds, shifting to brisk NW. winds in the late p. m. 
 Positive, with occasional negative, all day; fair; cold wave coming; winds changing to 
 
 brisk NW. 
 Variable positive, with occasional negative, all day ; clear ; cold wave ; fresh NW. winds. 
 Negative and positive from 10 p.m. of 20th to 11 p.m.of2l8t; cold; fair; gale ; NW. winds. 
 Positive with negative all day ; fair and cold ; brisk NW. winds. 
 Positive with slight negative all day ; warmer ; fair ; fresh NW. winds. 
 Same as 25th. Kain on 27th. 
 
 Negative at 1:30, 6, and ftom 7 to 7:30 a. m. ; positive at other times ; fair ; It. W. winds. 
 Negative from 7 to 9 a. m. and from 5 p. m. of 1st to 1 a. m. of 2d ; positive at other times ; 
 
 fair; cold ; It. winds. 
 Variable positive all day, except slight negative at 7:30 a. m. ; clear ; It. S. to SE. winds. 
 Positive, except negative 8 to 9 a. m., and positive and negative from 6 p. m. of 22d to 9 a. m. 
 
 oi"23d; clear; warm ; It. SE. winds. 
 Negative and positive all day ; warm ; cloudy ; It. SE. winds. 
 Positive, with occasional negative, all day ; cloudy ; It. NE. to SE. winds. 
 Variable negative from 7 to 11 a.m.; variable positive at other times ; clear and cool ; 
 
 gale ; NW. winds, reaching a maximum at 7:30 a. m. 
 Slight negative at 7 and 9 a. ra. ; positi^'e at other times ; cloudy ; threatening ; NE to NW. 
 
 winds. 
 Variable positive all day, except negative from 6 to 7 a. m. and from 4:30 to 6:30 p. m. ; 
 
 cloudy ; fresh SE. veering to NW. winds. 
 Steady positive in a. m. ; variable positive with slight negative in p. m. ; clear; brisk NE. 
 
 to NW. winds. 
 Positive and negative in a. m. ; no record in p. m. ; clear ; warm ; fresh NE. to SE. winds. 
 Positive and negative in a. m. ; positive in p. m. ; warm ; fair ; SE. to S. winds. 
 Positive, with slight negative at midnight and at 7 p. m. ; fair ; brisk NW. winds. 
 Variable positive all day, except slight negative at 12 m. ; clear; warm SE. to SW. winds. 
 Zero to slight negative steady from noon 13th to noon 14th ; record not good ; brisk SE. 
 
 winds on 13th ; brisk NW. winds on 14th ; fair. 
 Variable positive all day, except slight negative from 6 to 6:30 a. m. ; fair ; It. W. to fresh 
 
 SE. winds. 
 Low steady negative potential from 9 a. m. to 2 p. m. ; positive at other times; fair; It. 
 
 variable winds. 
 Positive low and steady, except slight negative from 5:30 to 6:30 p. m. ; fair ; very warm. 
 Variable positive all day, except slight negative at 6 p. m. ; cool ; fair ; fresh N. winds. 
 Positive, except slight negative at 7 a. m. ; clondy and warm ; E. to S. winds. 
 Variable posiiive all day, except slight negative from 4 to 5 p. m. ; clear; fresh NW. winds. 
 Variable positive, with slight negative at7 a. m. ; clear; fresh S. winds 
 Negative from 8 to 8:30 a. m. and from 8 to 9 p. ni. ; positive at other times ; clear ; It. vari- 
 able winds. 
 Negative from 8 to 9 a. m. ; positive rest of the time ; cloudy ; dense haze in a. m. ; clear in 
 
 p. m.; It. variable winds. 
 Slight negative at midnight, 9 a. m,, and 6 to 7 p. m, ; positive at other tinaes. 
 Variable positive, except slight negative at 8, 10 p. m., midnight, and also 7 p. m. of 17th ; 
 
 fair weather ; It. variable winds. 
 Negative from 4 to 5 a. m. and from 7 to 8 a. m. ; positive at other times ; dense fog in a. m., 
 
 followed bj' clear weather. 
 Variable positive, except slight negative at 8 p. m. of 25th and from 8 to 9 a. m. of 26th ; 
 
 clear; It. N. winds. 
 Variable positive and negative from midnight to 10 a. m. ; positive at other times ; dense 
 
 fog, clearing away by noon. 
 Negative and positive from 2 to 8 a. m. ; positive at other times ; dense fog until 10 a. m. 
 Negative from 6 to 9 a. m. and at 11 p. m. ; positive at other times ; warm ; fair ; It. vari- 
 able winds. 
 Variable positive, with occasional negative, all day ; fair ; NW. winds. 
 Variable positive and negative from 8 a. m. of 26th to 7 a. m. of 27th ; clear ; brisk NW. 
 
 winds. 
 
314 
 
 MEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES. 
 
 Table W. — Negative potentials without precipitation, Baltimore, Md., 1885, 1886, and 1887- 
 
 Continued. 
 
 188C 
 Dec. 
 
 30 
 
 1886. 
 Jan. 2 
 
 Jan. 
 
 3 
 
 Feb. 
 
 19 
 
 Feb. 
 Feb. 
 
 20 
 22 
 
 Mar. 
 
 1 
 
 Mar. 
 
 2 
 
 Mar. 
 Mar. 
 
 3 
 10 
 
 Mar. 
 
 15 
 
 Mar. 
 
 16 
 
 Mar. 
 
 17 
 
 Mar. 
 
 23 
 
 Mar. 
 Apr. 
 
 25 
 
 1 
 
 Apr. 2 
 Apr. 9 
 
 Apr. 
 
 21 
 
 Apr. 
 
 22 
 
 Apr. 
 
 23 
 
 Apr. 
 
 26 
 
 Apr. 
 
 27 
 
 Apr. 
 
 29 
 
 May 
 
 2 
 
 July 
 
 3 
 
 July 
 
 5 
 
 July 
 
 8 
 
 July 
 
 9 
 
 July 
 
 12 
 
 July 23 
 
 Aug. 10 
 
 Aug. 21 
 Sept. 17 
 Sept. 26 
 
 Sept. 30 
 Oct. 7 
 Oct. 8 
 Oct. 16 
 
 Oct. 
 
 Oct. 19 
 Oct. 23 
 Oct. 25 
 Nov. 20 
 Dec. 2 
 Dec 3 
 
 Dec. 10 
 Dec. 21 
 
 Eemarks. 
 
 Negative from 7 to 9 a. m. ; variable positive at other times; warmer, fair weather ; SE. 
 winds. 
 
 Variable positive and negative from midnight to 2 a. m. and at 7 a. m. ; variable positive 
 the rest of the time ; clear weather ; It. winds, mostly easterly. 
 
 Variable positive all day, except negative from 4:30 to 5 a.m.; cloudy weather ; falling ba- 
 rometer; SE. to NE. winds. 
 
 Negative at 5 a. m. ; variable positive and negative from 2 to 8 p. m. ; positive rest of the 
 time ; rapidly falling barometer ; fair weather ; S. winds during the day, changing to 
 brisk, and to galeNW. winds at sunset; cold wave approaching. 
 
 Variable positive and negative all day ; fair and cold ; NW. gale. 
 
 Negative from 1 to 1:30 a. m. and from 5 to 5:30 p. m. ; positive rest of the time ; clear and 
 warmer ; NW., backing to S. winds. 
 
 Variable positive from midnight to 5 p. m. ; variable negative, with an occasional positive, 
 from then until midnight ; clear and cold ; NW. brisk to gale winds. 
 
 No record in a. m. ; variable positive and negative in p. m. ; clear and cold ; NW. brisk to 
 gale winds. 
 
 Variable positive and negative all day ; clear; brisk to gale NW. winds. 
 
 Negative from 4:15 to 4:30 a. m. ; variable positive , rest of the day ; fair weather ; fresh NE. 
 winds. 
 
 Negative from 7 to 8 a. m. and at 3 and 6 p. m. ; variable positive rest of the time; clear, 
 with a warm wave ; max. tempt., 71° ; SW. winds. 
 
 Negative at 6:30 a. m. ; variable positive and negative from 11 a. m. to 4 p. m. ; positive 
 rest of the time ; fresh SW. winds, veering at noon to br. NW. winds ; clear and warm. 
 
 Variable positive all day, except negative from 10 p. m. to midnight ; clear and cooler; fr. 
 NW. winds; lunar corona from 7 p. m. to midnight. 
 
 Variable positive and negative from 12 m. to 4 p. m. ; variable positive in a. m. and p. m. ; 
 cloudy ; brisk NW. winds. 
 
 Variable positive and negative all day ; warmer weather ; smoky; It. SW. winds. 
 
 Weak variable positive and negative from 6 a. m. to 7 p. m. ; positive at other times ; clear; 
 brisk SW. winds. 
 
 Weak variable positive and negative all day ; fair, followed by cloudy weather ; brisk SW. 
 winds. 
 
 Variable positive all day, except negative from 9 to 9:15 p. m. ; clear weather ; rising tem- 
 perature. 
 
 Variable strong positive all day, except negative from 8:30 to 11 p. m. ; cloudy and threat- 
 ening followed by clear weather. 
 
 Variable positive all day, except slight negative at 11 a. m. ; clear and warm, with varia- 
 ble winds. 
 
 Variable weak positive and negative all day ; clear and warm ; falling barometer ; SW. 
 winds. 
 
 Variable positive and negative all day ; cloudy and threatening ; E. winds. 
 
 Variable positive andnegative all day ; cool and cloudy; fresh SE. to NE. winds. 
 
 Variable positive, with an occasional negative ; fair and cool ; fresh E. winds. 
 
 Variable positive in p. m., with occasional negative; clear; SE. winds. 
 
 Variable positive all day, except a slight negative at 4 p.m. ; fair weather; northerly winds. 
 
 Steady positive all day, except slight negative at 9:15 p. m. ; clear and warm ; NW. winds. 
 
 Weak positive and negative all day; clear followed by cloudy weather; N. to NE. winds. 
 
 Weak variable positive, with negative from 7 to 8 a. m. ; cloudy weather ; SE. winds. 
 
 Variable positive all day, except slight negative at 4 a. m., 5, and 10 p. m. - clear ; NE. to 
 SE. winds. » 
 
 Weak variable positive all day, with negative from 6 to 7 a. m. and from 5 to 8 p. m. ; cloudy 
 followed by clear weather ; N. winds. 
 
 Positive all day, with a slight negative at 7 a. m. ; cloudy ; falling barometer ; southerly 
 winds. ' 
 
 Variable positive all day, except slight negative at 6 p. m. ; fair and cool ; E. winds. 
 
 Variable positive all day, except negative from 7 to 8 p. m. ; heat lightning at 7:30 p. m. 
 
 Steady positive all day, except negative from 1 to 2 p. m. ; slightly warmer, cloudy weather ; 
 S. to SW. gale. 
 
 Positive, except slight negative, at 1 and 6 p. m. ; clear and cool ; SE. to NE. wind. 
 
 Clear and cool ; It, NE. winds ; positive, except occasional negative, at 2 and 6 p. m. 
 
 Similar to 7th. 
 
 Variable positive and negative from 6 a. m. to noon ; positive rest of the time; fair, with 
 cold wave. 
 
 Variable positive all day, except occasional negative from 7 to 10 p.m.; clear, with warm 
 wave. 
 
 Variable positive all day, with negative from 5 to 8 a. m. ; cloudy, followed by fair weather. 
 
 Slight negative at 6 p. m. ; clear ; variable winds. 
 
 Slight negative at 7 a. m. ; fair ; variable winds. 
 
 Variable positive all day, except negative from 6 to 6:30 a. m. ; cold ; fair; SW. winds. 
 
 Variable positive and negative from 12 m. to 4 p. m. ; clear ; cold NW. gale. 
 
 Variable positive and negative from 12 m. to 3 p. m. ; cold NW. gale ; collector seems to have 
 been frozen in a. m. of 2d and 3d. 
 
 Variable positive all day, except negative from 9 to 10 p. m. ; clear; It. variable winds. 
 
 Negative from midnight to 2 a. m, ; positive rest of the day; clear; It. variable winds. 
 
MEMOIRS OF THE NATIONAL AOADEMi' OP SCIENCES. 
 
 315 
 
 Table W. — Negative potentials without precipitation, Baltimore, Md.^ 1885, 1886, and 1887- 
 
 Oontinued. 
 
 Bate. 
 
 Rem arts. 
 
 1887. 
 
 Jan. 
 
 10 
 
 Jan. 
 
 21 
 
 Jan. 
 
 22 
 
 Jan. 
 
 31 
 
 Feb. 
 
 16 
 
 Mar. 
 
 2 
 
 Mar. 
 
 12 
 
 Mar. 
 
 14 
 
 Mar. 
 
 16 
 
 Mar. 
 
 2ri 
 
 Mar. 
 
 29 
 
 Apr. 
 
 7 
 
 Apr. 
 
 10 
 
 Apr. 
 
 13 
 
 Apr. 
 
 21 
 
 May 
 
 3 
 
 May 
 
 4 
 
 May 
 
 13 
 
 May 
 
 16 
 
 May 
 
 17 
 
 May 
 
 18 
 
 May 
 
 19 
 
 June 
 
 11 
 
 June 
 
 14 
 
 June 
 
 17 
 
 July 
 
 14 
 
 July 
 
 15 
 
 July 
 
 28 
 
 Variable positive and negative from 11 a. m. to 4 p. m. ; snow ended early a. m., followed by 
 
 fair weather ; NW. gale. 
 Negative from 7 to 8:30 p. m. ; positive at other times ; cloudy and mild ; brisk SW. winds. 
 Negative from 6:30 to 8:30 p. m. ; positive at other times ; mild and fair. 
 Slight negative at 9 a. m; positive all day ; clear ; It. SE. winds ; lunar corona 7 to 8 p. m. 
 Negative from 6:30 to 8 a. m. and from"5:30 to 5:45 p. m. ; positive rest of the time; dense 
 
 fog in a. m., followed by threatening, cloudy weather. 
 Variable positive, with occasional negative, all day; warmer, fair weather; SE. to NE. 
 
 wiuds. 
 Negative from 7 to 11 a. m. ; positive at other times ; clear ; brisk NW. winds. 
 Variable positive, with negative from 4:30 to 5:30 p. m. ; cloudy, with brisk NW. winds. 
 Variable positive and negative from 8 a. m to 5 p. m. ; fair, witlrbrisk NW. winds. 
 Negative from 10 a. m. to 12 m. ; positive rest of the day; fair; severe NW. gale. 
 Variable positive and negative all day ; fair ; brisk to high NW. winds. 
 Variable positive and negative all day. ; cloudy; warmer; easterly winds. 
 Positive all day, except negative at 1 and 3 a. ni. ; clear and warm wave. 
 Slight negative in early a. m. ; then positive; fair; easterly winds. 
 Slight negative at 1:30 a. m. ; then positive; clear; warmer; southerly winds. 
 Positive, with occasional negative, all day ; fair, with S. to SE. winds. 
 Positive, with occasional negative, all day; fair, with SE. winds; rain a. m.,5fch. 
 Variable positive and negative all day ; clear and cool ; E. wiuds. 
 Positive and negative all day; falling barometer; SE. winds; fair. 
 Positive and negative all day ; falling barometer; northerly changing to SE. winds ; warm 
 
 and hazy. 
 Positive, with occasional negative ; cloudy ; NE. to SE. winds. 
 Positive, with occasional negative ; clear; NE. to SE. winds. 
 Variable positive and negative from 9 a. m. to 6 p.m. ; positive rest of the time; clear; gale; 
 
 E. winds. 
 Positive and negative in a. m.-; positive in p. m. ; clear ; NE. to SE. winds. 
 Weak positive and negative all day ; warm ; max. tempt. 93° ; fair ; W. winds ; silent light- 
 ning at night. 
 Variable positive and negative from 4 p. m. to midnight ; clear and warm ; It. N. winds. 
 Variable positive all day, with negative from 6 to 7 p. m. ; clear ; It. SE. to NE. winds. 
 Positive all day, except sudden and strong negative from 3:30 to 5:30 p. m. ; dense fog in a. 
 
 m. ; clear in p. m. ; It. SE. winds. 
 
316 
 
 MBMOmS Ol' THE NATIONAL ACADEMY OF SCIENCES. 
 
 Table W. — Negative potentials without precipitation, Baltimore, Md., 1885, 1886, and 1887- 
 
 Continued. 
 
 STJMMAEY OF NEGATIVE 'WITHOUT PEECIPITATION. 
 
 Month. 
 
 Winds brisk to gale, 
 NW. 
 
 Winds light to fresh, 
 
 NE. to SE. 
 
 (Sea breeze.) 
 
 Cloudy. Clear. 
 
 Cloudy. Clear. 
 
 Winds light to fresh, 
 S. 
 
 Cloudy. Clear. 
 
 No 
 
 marked 
 
 condition 
 
 Other 
 
 causes. 
 
 1885. 
 
 January , 
 
 February 
 
 March , 
 
 April 
 
 May 
 
 June , 
 
 July 
 
 August 
 
 September 
 
 October , 
 
 November 
 
 December 
 
 . 1886. 
 
 January 
 
 February 
 
 March 
 
 April 
 
 May 
 
 June 
 
 July 
 
 August 
 
 September 
 
 October 
 
 November 
 
 December 
 
 1887. 
 
 January 
 
 February 
 
 March 
 
 April 
 
 May 
 
 June 
 
 July 
 
 Total (126) . . 
 Rain next day (26) 
 
 37 
 
 19 
 3 
 
 23 
 4 
 
 23 
 4 
 
 
 
 
 
 
 
 
 
 
 *3 
 
 
 
 
 
 
 
 
 
 
 
 + 1 
 
 
 
 
 
 
 tl 
 
 
 
 
 
 tl 
 u 
 
 ' Dense fog. 
 
 t Lightning. 
 
 tFog. 
 
MEMOIES OF THE NATIONAL ACADEMY OF SCIENCES. 
 
 317 
 
 Tablk X. — Negative potentials without precipitation, Washington, D. C, October, 1887, to August, 
 
 1888, 
 
 Hemaika. 
 
 1887. 
 Nov. 8 
 
 Nov. 
 
 1886 
 Jan. 
 
 26 
 
 Mar. 
 
 19 
 
 Apr. 
 
 2 
 
 Apr. 
 
 7 
 
 Apr. 
 
 20 
 
 Apr. 
 
 27 
 
 Apr. 
 
 28 
 
 Apr. 
 
 30 
 
 May 
 
 17 
 
 May 
 
 21 
 
 Jnne 
 
 11 
 
 June 12 
 
 July 2 
 
 July 16 
 
 July 17 
 
 July 18 
 
 July 27 
 
 July 28 
 
 Aug. 30 
 
 Potential variable positive to negative at 11 a. m. and 1 p. m. ; cloudy during a. m. ; hazy 
 during p. m. ; liglit SW. wind ; station in antioyclonic area ; light rain at Norfolk, Va., 
 during the afternoon about 3 p. m. 
 
 Potential negative at 1 -p. m. ; cloudy all day ; light NE. wind ; station east of a low ; 
 ■ heavy rain in Ohio Valley during the evening ; rain at this station on the 10th. 
 
 Potential negative 9 to 11 a. m. and 1 to 3 p. m. ; fair weather ; brisk NW. wind ; snow at 
 
 Pittsburg, Pa., during the day ; at this station at 8 a. m. on 27th. 
 Potential variable positive to negative at-9 a. m. ; clear weather; light S. wind ; rain at H 
 a. m. on 20th at this station ; rain all day on 19th in Ohio Valley. 
 
 Potential negative at 1 p. in. ; fair weather ; fresh NW. wind ; station east of a high ; gen- 
 erally clear weather at neighboring stations ; light rain in Tennessee. 
 
 Potential variable from positive to negative at 3 p. m. ; cloudy weather ; brisk W. wind ; 
 station south of a high ; fair weather at surrounding stations. 
 
 Potential negative at 11 a. m. and 1 and 3 p. m. ; fair weather ; brisk NW. wind ; station 
 east of a high j rain in lake regions and at Philadelphia, Atlantic City, and Norfolk. 
 
 Potential negative at 5 p. m. ; clear weather, with light haze; light NE. wind; station 
 neither in a high nor alow; cl#ar throughout eastern part of the country ; rains through- 
 out the western part. 
 
 Potential variable positive to negative at 5 p. m. ; clear weather, with light haze ; light 
 SE. wind; station neither in a high nor a low; clear in eastern part of country; rain 
 . and snow throughout the West. 
 
 Potential variable positive to negative at 9 and 11 a. m. ; dense haze ; calm in a. m. ; light 
 S, wind in p. m. ; station within a low ; quite heavy rain and snow throughout lower 
 lakes and Ohio Valley; light rain at Pittsburg, Pa., about 4 p. in. 
 
 Potential variable positive to negative at 1 p. m. ; clear weather ; light NW. wind ; rain 
 throughout the Northwest, Mississippi Valley, lake regions, and Ohio Valley ; light rain 
 at Pittsburg, Pa. 
 
 Potential variable positive to negative 1 p. m. ; fair weather ; light SE. wind ; station 
 north of a low ; rain fell at all stations in Virginia, North Carolina, and TeunesBee. 
 
 Potential negative at 3 p. m. ; variable positive to negative at 5 p. m. ; clear weather ; brisk 
 NW. wind; rain fell at Pittsburg and Philadelphia, Pa., Atlantic City. N. J., and Nor- 
 folk, Va. 
 
 Potential variable positive to negative from 11 a. m. to 5 p. m. ; clear weather ; light east- 
 erly wind ; fair weather at surrounding stations ; rain in Gulf States and throughout the 
 West. 
 
 Potential variable positive to negative at 3 p. m. ; clear weather j light E. wind; gen- 
 erally clear weather at surrounding stations. 
 
 Potential variable positive to negative 1 to 5 p. m. ; clear weather, with light haze ; light 
 easterly wind ; rain fell througliout South Atlantic and Gulf States during the night. 
 
 Potential variable positive to negative at 11 a. m. and 3 p. m. ; clear weather ; light SE. 
 wind; station in antioyclonic area ; rain fell in Ohio Valley and at Pittsburg during day 
 and night. 
 
 Potential variable positive to negative at 1 p. m. ; clear weather ; brisk SE. wind ; station 
 south of low ; rain fell at Pittsburg and in Ohio Valley during the day, and at Baltimore 
 
 Potential variable positive to negative at 3 p. m. ; cloudy weather ; fresh NE. wind ; sta- 
 tion in antioyclonic area ; rain fell at Norfolk, Baltimore, Atlantic City, Philadelphia, 
 and Ohio Valley during the day. ^ , „-„ • , ^ ^■ 
 
 Potential variable positive to negative at 11 a. m. ; fair weather ; fresh NE. wind ; station 
 neither in high nor low ; rain fell at Lynchburg, Va., and vicinity during the evening. 
 
 Potential variable positive -to negative at 9 a. m. ; clear weather ; light S. wind ; sta- 
 tion neither in high nor low ; rain feU at Lynchburg, Va., and Upper Ohio VaUey during 
 the night. 
 
318 MBMOIES OF THE NATIOJS'AL ACADEMY OF SOIENOBS. 
 
 Table T. — Negative potentials without precipitation, Boston, Mass., December, 1887, to August, 1888. 
 
 Date. 
 
 1887. 
 Dec. 29 
 
 1888. 
 Jan. 3 
 
 Jan. 
 
 11 
 
 Jan. 
 
 18 
 
 Jan. 
 
 24 
 
 Feb. 
 
 28 
 
 Mar. 
 
 6 
 
 Mar. 
 
 7 
 
 Mar. 
 
 8 
 
 Mar. 
 
 23 
 
 Mar. 
 
 24 
 
 Mar. 
 
 31 
 
 Apr. 
 
 4 
 
 Apr. 
 
 7 
 
 Apr. 
 
 9 
 
 Apr. 
 
 24 
 
 Apr. 
 
 25 
 
 May 
 
 3 
 
 May 
 
 8 
 
 June 
 
 9 
 
 June 
 
 13 
 
 June 
 
 S7 
 
 July 
 
 12 
 
 Aug. 
 
 29 
 
 Remarka. 
 
 Potential negative at 11 a.m., 3 and 5 p. m. ; clear weather all day ; brisk NW. wind ; It. 
 snow fell at Northfield, Vt., Albany, and New York City, N. Y., during the day. 
 
 Potential negative at 1, 3, and 5 p.m. ; cloudy weather ; gentle NW. wind; station neither 
 in a high nor a low ; It. snow fell at Northfield, Vt., 3,11 day. 
 
 Potential negative at 11 a. ra., 1 and 3 p. m.; clear weather; fresh W. wind; station east 
 of a high; It. snow at Yarmouth, N. S., all day; clear at nearer stations. 
 
 Potential negative at 11 a. m. ; cloudy weather; light NW. wind ; station west of a low ; 
 snow at Nortlifield, Vt., Portland, Me., and Nantucket, Mass., all day. 
 
 Potential negative at 9 and H a. m. ; clear weather ; brisk NW. wind ; station east of high ; 
 snow at Northfield, Vt., and in Nova Scotia during the day. 
 
 Potential negative at all five observations ; clear weather ; brisk NW. wind ; station east of 
 high; snow in Nova Scotia all day, 
 
 Potentia,! negative at 11 a. ra. ; cloudy in a. m. ; clear during p. m. ; brisk NW. wind ; sta- 
 tion west of a low ; rain fell at Portland, Me., about noon. 
 
 Potential negative at9, 11 a. m., and 3 p. m. ; clear weather ; brisk W. wind; station neither 
 in a high nor a low ; snow in northern New York and at Eastport, Me., all day. 
 
 Potential negative at 9, 11 a. m., 1 and 3 p. m. ; cloudy weather; high E. wind; station 
 south of low ; snow fell at Eastport, Me., and northern New York all day. 
 
 Potential negative at all five observations; clear weather ; high SW. wind; station west of 
 low ; rain fell at Eastport and Portland, Me., Albany, N. Y., and New London, Conn., dur- 
 ing the day. 
 
 Potential negative at all five observations; perfectly clear weather; brisk SW. wind ; sta- 
 tion east of a high; It. snow fell in northern New York, Quebec, Canada, and in Nova 
 Scotia during the day. 
 
 Potential negative at 11 a. m., 1, 3, and 5 p. m. ; fair weather ; brisk to high W. wind; sta- 
 tion neither in a high nor alow ; snow fell at Montreal, Canada, Northfield, Vt., and East- 
 port, Me., all day. 
 
 Potential negative for a few minutes about 11 a. m. ; clear weather ; brisk W. wind ; sta- 
 tion within a high ; dust clouds were raised by wind in vicinity of station about 11 a. m. ; 
 clear all day at surrounding stations. 
 
 Potential negative at all five observations ; clear weather ; high W. wind ; station neither in 
 a high nor a low; fair weather at surrounding stations. 
 
 Potential negative at 3 p. m. ; clear weather (perfectly) ; fresh NW. wind ; station within 
 a high; dust clouds raised by wind about 3 p. m. ; clear at neighboring stations; rain 
 throughout Gulf States, Ohio Valley, and lake regions. 
 
 Potential ?ero at 11 a. m. ; negative at 1 p. ra. ; cloudy weather ; brisk NW. wind ; station 
 east of a high ; rain at Northfield, Vt., about noon ; fair at stations south and cloudy at sta- 
 tions north of Boston. 
 
 Potential negative at 11 a. m.; clear weather ; fresh NW. wind ; station within a high ; nega- 
 tive reading without a visible cloud and no wind to raise dust ; no other negative values 
 seen during day ; generally clear weather throughout eastern part of country. 
 
 Potential negative at 1 p. m. ; clear weather ; fresh NW. wind ; station east of a low ; no dust 
 recorded; clear weather at neighboring stations ; rain in upper lakes; rain in this dis- 
 trict on morning of 4th. * 
 
 Potential negative at 3 and 5 p.m.; cloudy weather ; brisk SW. wind ; station east of a low ; 
 dust clouds during p. m. ; rain all day throughout the North Atlantic districts and lower 
 lakes. 
 
 Potential negative at 5 p.m.; clear weather ; fresh S. wind ; station east of a low ; rain in 
 St. Lawrence Valley during the day ; throughout New England on 10th. 
 
 Potential negative at 5 p. m. ; cloudy weather; fresh SW. wind ; station north of a high ; 
 rain fell during night at Albany, N. Y., Northfield. Vt., and Portland, Me. 
 
 Potential negative at 1 and 3 p. m. ; clear weather ; brisk NW. wind ; station west of a low ; 
 rain fell at Block Island, R. I. , New York City, and southern stations during the evening ; 
 dust clouds from 1 to 3 p. m. 
 
 Potential negative at all five observations ; clear weather; high W. wind ; station south of 
 a low; light haze all day, with dust clouds; rain fell at Eastport, Me., Northfield, Vt., 
 and in New York City during the day. 
 
 Potential negative at 3 p. m. ; clear weather ; brisk W. wind ; station south of a low; fair 
 weather at neighboring stations. There is every reason to think that the negative po- 
 tentials were caused by dust. There was a high NW. wind on 28th, the ground was 
 thoroughly dried and the brisk W. winds today no doubt raised dust clouds. The nega- 
 tive potential occurred simultaneously with the greatest force of the wind. 
 
arY821 '^°'"*" ""'*"'™"y '-*™T 
 "ifipHiiiiiiiSliiimimfe, °' atmospheric electri 
 
 o.in,an^ ^^24 032 182 580 
 
'^%^^: