1055 /#JOHNM.f^ I OtlN I) sacA^ CORNELL UNIVEBSnV LIBfAJY 3 1924 074 297 361 All books are subject to recall after two weeks Olin/Kroch Library DATE DUE S"! i-rvrej.-.ij.-v.,.! ,-1. gp^fCoN^ F^SBHP^ m ^mpB ^^g^^ ! 1 GAYLORD PRINTED IN U.S.A. Cornell University Library 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/cu31924074297361 LANDING ON THE WOLF OFF LANDS END. EUROPEAN LIGHT-HOUSE SYSTEMS; EEPOET OF A TOUE OF INSPECTION MADE IN 1873, Major GEORGE H. ELLIOT, Corpg of Engineers, U.S.A., Memlar and Ungineer-Socretarij of thu Light-House Board, Jtnbtr l^c giulbqritii of Hon. WILLIAM A. RICHARDSON, Seci'etary of the Treasury. Illurteated bt 51 Engeavings and 31 Wood-Cuts in the Text. LONDON : LOCKWOOD & CO., 7 STATIONERS'-HALL COURT, LUDGATE HILL. 1875. I- ill ', T J. ii. V.,' ^CORNEi UNIVEFJSITY LIBHARY^ In compliance with current copyright law, LBS Archival Products produced this replacement volume on paper that meets the ANSI Standard Z39.48-1984 to replace the irreparably deteriorated original. 1989 TABLE OF CONTENTS, rago. Extra,ctfrom Light-Honse Board Report for 1873 'J Outward voyage, and deficiency in fog-signals on transatlantic steamers 1"' The Trinity House, London IH I'og-signal experiments near Dover, under direction of Professor Tyndall i^J Extracts from Professor Tyudall's report 2'i Sir Frederick Arrow's remarks on Professor Tyudall's report C'J South Foreland electric ligbts fil Roman pliaros in Dover Castle 7" Examination of the Doty lamp 74 Experiments with lights in Westminster clock- to wcr 75 Trinity-House depot atBlackwall 7i) Improvements iu lamps for light-houses ^0 Inspection-tour of the North Sea lights of England in the Trinity House steam- yacht Vestal tU Iron light-houses off the mouth of tlio Thames t'3 Orfordness lights 101 Depot at Yarmouth ICl Haisborough lights 104 Experiments at night with Haisborough lights 10.1 Newarp ligbt-&hip 11:; Cockle light-ship 11.') Spurn Point lights 11.) Flamborough Head light 11/" Whitby lights ,, Hi Souter Point light K;i Coquet light 1-27 Inner Fame Island lights lol' Longstone light V.i) Return to London IS.! Second tour of inspection. — the southwest coast of England I'-W Light-house depot at IsleofWight IS- Saint Catherine light 13! The Needles light l;-;4 Lights of the Bill of Portland lo.'i The Start light l;!.'> The Eddystone light 1S''> Saint Anthony light 1S.7 Plymouth Breakwater light l:.7 The Lizard lights l;l.> The Wolf light i;.: Rundlestone bell-buoy l-'.4 Seven Stones light-ship ]4.'i Longships light 1-il Godrevy light lJ-< "The Stones" buoy, off Godrevy 14n 4 CONTENTS. age. Holyhead light 149 North Stack fog-signal station 155 South Stack light 156 Visit to Commissioners of Irish Lights, Dublin 158 Howth Bally light 159 Wicklow Head light 160 Gas-apparatus for fixed lights 161 Gas-apparatus for intermittent lights 162 Gas-apparatus for revolving lights 165 Gas-apparatus for group flashing' lights 165 Gjs-apparatus for triform fixed lights 166 Gas-apparatus for triform intermittent lights 167 Gas-apparatus for triform revolving lights 167 Gas-apparatus for triform group flashing lights 167 Experiments -svith the triform gas-light 167 Illuminating powers of gas-lights 169 Cost of gas-light apparatus ; 170 Cost of gas-light apparatus, (triform) 171 Cost of maintenance of gas-lights 171 Illumination of beacons by gas 172 Wigham's gas-gun 174 Visit to Commissioners of Northern Lights, Edinburgh 175 Stevenson's holophone 179 Visit to lens manufactory of Chance, Brothers &Co 183 Visit to Commission des Phares, Paris 184 Dep6t des Phares of Franco. 185 JI. Eeynaud's observations concerning mineral oil 19^ Lens-makers of Paris 20;? Lepaute's observations concerning light-house burners 20'S Light-houses at the mouth of tbo Seine 215 Phare do l'H6pital 217 Feu de port at Honflcur 218 Phare do Fatouvillo 219 Phares de la Hfeve 220 Description of the electric lights at La H6ve 226 III ternational exhibition at Vienna 249 Submarine foundations for harbor light-houses 250 Models of light-houses 250 Light-house apparatus 251 Iron tower for fourth-order light 254 Swedish light-houses 257 Austrian fog-horn 261 Osnaghi's reflectors 262 llclurn voyage 260 LIST OF ILLUSTRATIONS, PLATES. r:::c. Froutispiooe : The "Wolf Hook light-house 1 I. South Foreland, general plan of light-houses Gj II. South Foreland, ground-plan of engine-house f'3 III. South Foreland, lanteru and lens at '^^ IV. Six-wlck Trinity House burner 'f' V. Mapliu^and light-house '. ICO VI. Haisborougb, general plan 10' VII. Upper part of English light-house tOTver 103 VIII. Ventilating window for light-house tower 110 IX. Souter Point, chart of vicinity of 120 X. Souter Point, plan and details of low light-room .at 122 XI. Souter Point, pl.ia of machine-room 122 XII. Souter Point, general plan 124 XIII. Souter point, ground-plan 124 XIV. Souter Point, section of lantern, lens, and low light-room 12,T XV. Souter Point, east elevation 12.) XVI. Coquet Island, chart of vicinity of 123 XVII. The Longstoue light-house l^iO XVIII. The Eddystone light-house l:^ XIX. The Irish ffas-lifiht for light-houRes—lOi, jets 1-".? XX. L.and's End, chart of vicinity of 14 J XXI. Comparative sections of rock light-honses 144 XXII. Holmes's fog-horn apparatus 140 XXIII. South Stack fog or "occasional" light 15G XXIV. Howth Daily g.as light-house 158 XXV. Howth Baily gas light-house IGO XXVI. Wicklow Head gas light-house 162 XXVII. One-hundred-and-eight-jet burner 164 XXVIII. Twenty-eight-jet burner 163 XXIX. Triform burners 172 XXX. Triform lenses 174 XXXI. Swedish light-ship 204 XXXII. Kevolving catadioptric. apparatus for light-ships 20.T XXXIII. Burners of French light-house lamps 209 XXXIV. Interior .adjustments of level in mineral-oil light-house lamps 21 i XXXV. Exterior adjustments of level in mineral-oil light house lamps 212 XXXVI. Mineral-oil lamp of 1845, Lepauto's gas-burner. Doty lamp. ., 214 XXXVII. La Hfeve, elevation aud general plan 220 XXXVIII. La Hfeve, ground plan of machine-room 220 XXXIX. La Hfeve, section of machino-room 230 XL. La Hfeve, front elevation of magueto-electric machine 232 XLI. La Hfeve, side elevation of magneto-electric machine 2:!4 XLII. La Hfeve, plan of magneto-elt!Ct-ic machine 2:33 XLIII. La Hfeve, details of magneto-yljcrriu macbino 240 6 ILLUSTEATIONS. Page. XLIV. La Hfeve, switches 242 XLV. Lii Hfeve, regulators 246 XLV(. Lanterns and lenses for electric and oil lights at Cape Grisaez 24S XLVII. Submarine foundation for harbor light-houses 250 Xi.^lll. Lens for electric light 254 XLIX. Iron tower for fourth-order light 25G L. Austrian fog-trumpet 260 FIGURES. 1 . Uoman pharos in Dover Castle 73 ii. Douglass gas-burner 79 J. Five-gallon oil-can 91 4. Cbinmey-gauge 91! 5. Bnoy-finder at Yarmoutli Ui (i. Bilge-keels of light-ships 104 7. Red cut, Spurn Point .-. i- 110 8. Fastening for red panes, Whitby 119 !'. Lanip-gnard 119 10. G.:ncral view of establishment at Souter Point 120 11. Lens and lanterns, Souter Poiut 124 ]J. Low light-room, Coquet Island 123 1 :!. Filling oil-butts at Saint Catherine's 134 14. lied light, Plymouth Breakwater 133 lo. linndlestone bell-buoy, off Land's End 145 1 i. Ttiree-wick lamp at Holyhead ICO ir. English and American lanterns 154 1 i'. Faraday's wind-guard, North Stack 155 1.1. Diagram illustrating revolving intermittent gas-lights 163 ~0. Stevenson's holophone, vertical section igo ~1. Stevenson's holophone, front elevation leO 1)2. Mineral-oil test, (areometer) 133 23. Mineral-oil test, (flashing point) Igy 24. Sautter's lantern for electric light 207 2o. La Hove, plan of electric light-room 222 26. La Heve, vertical section of electric light -room 223 ;.7. La Heve, lens for electric light 224 28. Swedish light-house, details 257 20. Swedish light-house, details 257 r.O. Osnaghi's reflector for flashing light 262 31. )snaghi's reflector for fixed light 265 PUBLISHER'S PREFACE. The very important and interesting information in regard to the present condition of European seacoast illumination, and its cognate aids to com- merce, which is found in the following pages, was collected by Major Elliot, of the United States Engineers, in 1873. and appearing soon afterwards in the form of a report to the Light- house Board, it attracted much attention and commendation. It will be observed that Major Elliot had extra- ordinary and excellent facilities, and that he made the most of them in obtaining a knowledge of the immense improvements which, in later years, have been made in one of the most important of Govermental services. His report, which may be considered to be a complete exhibit of the state of the lighthouse service at the present time, has not been accessible to the public, and in order to satisfy the demand both in this country and in Europe, from en- gineers, scientists, persons interested in commerce, and general readers, the Publisher issues the pre- sent edition. Kew Yoek, June, 1875. EXTRACT FROM THE REPORT OF THE LIGHT-HOUSE BOARD TO THE SECRETARY OF THE TREASURY FOR THE FISCAL YEAR ENDING 30in JUNE, 1H73. The Ligbt-House Board, during the past year, desirous of acquainting itself minutely with any improvements which of late years may have been introduced into the light-house service in Europe, obtained the sanction of the honorable the Secretary of the Treasury to commission Major Elliot, of the Corps of Engineers of the Army, and engineer- secretary of the Board, to visit Europe and report upon everything which he might observe relative to light-house a^jparatus and the man- agement of light-house systems. He has lately returned, after having gathered information which will prove of importance in its application in our country, as will be evident from his preliminary report. Major Elliot was everywhere received with marked cordiality, and every facility was given him to inspect the various coasts and systems of administration, of which full information was furnished him, together with the drawings and models necessary for a perfect acquaintance with the latest improvements which have been adopted in Great Britain antl on the continent. The special thanks of the Board are due to His Eoyal Highness thci Duke of Edinburgh, the master ; to Sir Frederick Arrow, the De|)uty Master, and the Elder Brethren of Trinity House, for the warmth ot their reception and the marked distinction they conferred upon him iis the representative of the Board ; and to ]M. L6ouce Eeynaud, Inspector- general of the Corps des Fonts et Chaussees and Director of the French light-house service, for his efibrts to make the visit of Major Elliot profitable to his country and agreeable to himself. " Treasury Department, " Office op the Light-House Board, " Washington, September 17, 1873. " Professor Joseph Henry, L. L. D., Chairman : "I have the honor to make a preliminary report of my journey of in- spection of the light-house establishments of Europe, which I have made by direction of the Board, with the approval of the honorable the Secre- tary of the Treasury, and from which I returned a few days since. " 1 sailed on the 30th of April, and, after a pleasant voyage, reached Liverpool on the 10th of May, observing enroute the light-houses on tlio Irish coast, and the light-ships and buoys on the approaches to Liver- pool. " On the 13th of May I arrived at London, and was cordially received by Sir Frederick Arrow, the Deputy Master, and the Elder Brethren of the Trinity House, which has charge of the lights of England and a su- pervisory control over those of Scotland and Ireland. The Trinity House kindly offered me an opportunity of making a tour of inspection of the light-houses, &c., on the coasts of England in the steamers which were about to take the annual supplies, and at the first session after my ai- 10 EUROPEAN LIGHT-HOUSE SYSTEMS. rival a delegation of the elder bretbrea was appointed to accompany me. " I remained in London some weeks to take advantage of this oppor- tunity, and in the mean while my time was occupied in inspecting the depots, lamp-shops, photometric test-rooms, &c., belonging to the Trin- ity House; also plans of light-houses, lenses, and other optical appa- latus used on the coasts of Great Britain. "In company with Professor Tyndall, the scientific adviser, some of the Elder Brethren and the engineer of the Trinity House, I visited Dover to attend the inauguration of fog-sigual experiments, which, under Pro- lessor Tyndall's direction, are now being carried on at an experimental station on the cliffs near the great electric lights of South Foreland. The light-house authorities of Great Britain are fully alive to the necessity for powerful fog-signals, and are anxiously seeking to find the best ma- chine, not only to inform the mariner enveloped in fog of his approach to the coast, but, by distinguishing characteristics of sound, to indicate to him on what part of the coast he is. The Board will remember that Sir Frederick Arrow and Captain Webb, of the Elder. Brethren, visited the United States during the summer of last year to be present at some of our experiments with the steam-whistle, the horn, and the siren at Portland Harbor. I think the Board has been impressed that on coasts ■where fog is habitual, as those of New England, Calitbrnia, and some of the great lakes, fog-signals are fully as important as lights, and the English seem to be approaching a similar conclusion. "Professor Tyndall told me that he intends to make an exhaustive series of experiments with all fog-signals now in use, to determine the best. Both be and the Elder Brethren are especially pleased at the action of our Board in sending an American siren for use in the Dover experiments. In these experiments the signals are observed from sev- eral vessels cruising in the Straits of Dover, at different distances from llie fog-signal station and under varying conditions of wind and weather. The signals tested when I was at Dover were a steam-whistle, an air- whistle, and a trumpet, very much like the American invention of Da- boll, but patented by Professor Holmes, and in use at several English light-stations. The experimenters have since included a cannon and our own siren. The experiments are not yet concluded, and Sir Frederick kindly promised to inform me of the results. "The delay in London gave me an opportunity of examining the lamps invented by Mr. Douglass, the distinguished engineer of Trinity House, which present improvements of the greatest importance as regards both the British lights and those of other countries. Not only is the bril- liancy of the llame very much increased by ingenious methods of pro- moting combustion, but the consumption of oil is actually decreased. In British light-houses and on the continent colza-oil is generally used, 1 hough, for the sake of economy, mineral oil is being rapidly substituted for it, and the French government has made an order for a general change to mineral oil in all the lighthouses of the republic. "When the Trinity House tender had been made ready, I embarked with two of the Elder Brethren (Admiral CoUinson, 0. B., and Captain Weller) to inspect the British lights on the shore of the North Sea, and visited nearly every one on the coast from the mouth of the Thames to the Tweed, (the boundary of Scotland,) including the gas-light at Hais- l)orongh and a new electric light at Souter Point below the river Tyne. At Haisborough the gas-light was established for experimental com- I)arison with an oil-light a few hundred yards from it, there being two towers, as at Cape Ann on the coast of Massachusetts. At Souter Point the electric light is necessary, because the coast near the Tyne is envel- EUROPEAN LIGHT-HOUSE SYSTEMS. 11 oped bj' a dense volume of smoke, produced by tbe immense number of manufactories on the river between Shields and Newcastle. '• I had excellent opportunities for testing the different varieties of lijjhts in all kinds of weather, and particulai'ly the gas and electric lights in fog. 1 was especially shown the system of marking the posi- tions of rocks and shoals by means of what Trinity House calls "red cuts," i. e. by covering proper sections of the dioptiic apparatus with red glass screens; and at different places on the northeast coast of En- gland I made several boat-excursions at night to test the utility of the system. "After my return from the inspection of the northeast coast 1 embarked with Captain Webb, of the Elder Brethren, at Portsmouth, and in- si>ected the light-houses on the Isle of Wight and the southern coast, and passed around Land's End as far as St. Ives, on the west coast of Cornwall, visiting the celebrated light-house on the Wolf Eock, off hand's End, whicli is the most recent and difiicult of all the English examples of light-house engineering. I regretted that I could not land at the Eddystone light-house, but the sea, filthough usually not so dangerous as at the Wolf, was too heavy when I passed it to make a landing practicable. '• Besides the light-houses on the coast, I jjarticularly observed the light- sliips and the system of buoyage ; and 1 will here mention that the En- glish use revolving apparatus in tjjeir lightships in many cases, and they are found much more useful than fixed lights. I would recommend to the immediate consideration of the Board the propriety of distinguish- ing in this way some of our numerous light-ships off the coast of Massa- diusetts and in Long Island Sound. "The English also find no difiiculty in using fog-signals operated by hot-air engines in their light-shijjs, and I saw several, iu one case hear- ing the signal distinctly at a distance of eight miles. '■ From England I went to France, and had conference with M. Keynaud, VInspecteur General des Fonts ct Gliaussees, and director of the Fiench light-house service, and M. AUard, the chief engineer, who is in charge of the ofQce of the Commission des Phares ; also with the three lens-manufacturers of Paris. " 1 was much interested in seeingour own optical apparatus in all stages of its manufacture ; iu learning the modes adopted by French engineers of testing the lenses, burners, and mineral oil ; and iu examining the most complete depot des phares in the world, where are shown examples of all stages in the progress of the science of light-house illumination, Jroiu the first efforts of Fuesnel, inventor of the system which bears his name, to the latest improvement of the present time. '■I visited the lights at the mouth of the Seine, and the double electric lights of La Heve at Sainte Adresse, near Havre. '■ I atterward proceeded to Vienna and examined the light-hoixse appa- ratus at the industrial exhibition, consisting of models, drawings, and ))hotographs of light-houses from different countries, including our own A i)ackage of these, which I made up a short time before I went to Eu- rope, I was glad to learn, on my return, obtained a dii)loina of honor. "After returning from Vienna I visited several light-housses on the coast of Wales, including two very interesting ones, that at Holyhead ami one at the " South Stack." , '•The first-named, a new one, though quite ready,wasnot lighted until siiine days after my inspection ; it combined all the latest improvements or the English iu regard to lens, lamps, and lantern. "At South Stack is a light which is lowered down the cliff in foggy 12 EUROPEAN LIGIIT-IIOUSE SYSTEMS. ' weatber wbea tbe light is obscured by fog and it is clear below, a plan which I had before thought of as ai)])licable to our lights on the elevated cliffs of the Pacific coast. "I also visited Ireland and Scotland, tbe former by special invitation from the Board of Commissioners of Irish Lights, and I had an excellent opportunity of seeing two of the light-bouses (Howth Baily and Wick- low Head) where tbe illuminant used is gas, of which Professor Tyu- dall when in the United States, expressed so favorable an opinion and which has been applied only by the Irish Board, except in the case I have mentioned, viz, the experimental light at Haisborough, on tbe east coast of England. " These gas-lamps can be increased in an instant, when the weather becomes thick or foggy, from twenty-eight to forty-eight, sixty-eight, or eighty-eight, even to one hundretl and eight jets for dense fog, and the inventor, Mr. Wigham, of Dublin, exhibited to nie apparatus for pro- ducing' a light from three hundred and twenty -four jets in the same lens apparatus. "At Edinburgh I visited the Board of Commissioners of Scottish Lights, and bad an interesting and instructive interview with Mr. Thomas Ste- venson, engineer of the Boai'd and a member of the family of celebrated Scottish engineers. " I also visited the very extensive manufactory of light-house lenses of Chance Brothers & Company, near Birmingham, who are the furnishers 01 light-house apparatus to tbe Trinity House, and who also supply in a large degree the Irish and Scottish Boards, as well as India, China, and South America. Chance Brothers claim that their optical appa- ratus is superior to the French, and they certainly have a great advan- tage in having for the constant supervision of their work a gentleman of high scientific attainments. '• I carried with me a special letter from the honorable the Secretary of State to the ministers and consuls of the United States in Europe, and I received every facility and courtesy from them and Irom the officials of the countries which I visited. "I have full notes of my inspection, and at an early day shall have the honor to present to you a detailed report of what I saw differing from our own system. " In closing this preliminary report, I will say that the great questions which are occupying the attention of the light-house authorities of Europe, and in which the different establishments are in competition with each other, are : " What is the best illuminant ? and '■^What is the best means for producing the most perfect combustion ? "I will only add that while the British and French systems are neces- sarily very much like our own, I saw many details of construction and administration which we can adopt to advantage, (and which I shall exhibit in my detailed report,) while there are many in which we excel. Our shore fog-signuls, particularly, are vastly superior both in number and power. They are in advance of us in using both tbe gas and elec- tric lights in positions of special importance, in the use of azimuthal condensing prisms for certain localities ; in the character of their lamps; in the use of fog signals in light-ships; in their light-ships with revolv- ing lights, and, more than all, in the character of their keepers, who are in service during good behavior until death or superannuation, who arc promoted for merit, and whose lives are insured by the government for the benefit of their families. , ''I am much indebted to Mr. Paul J. Pdz, chief draughtsman to the EUROPEAN LIGIIT-nOUSE SYSTEMS. 13 Board, who accompanied me by its permission and with the approval of the. honorable the Secretary of the Treasury, as ray secretary, and who lias made many skctrl'cs lor the illustration of my report, and who has, in other ways, been of much assistance to me in the execution of the duty assigned me. ''^Vcry respectfully, "GEORGE H. ELLIOT, "ilajor of Engineers U. 8. A., Engineer- Secretary. ^^ REPORT. OUTWARD VOYAGE. As stated in tbe preliminary report of my jdnrney of Dateof8aiim& inspection of the European light-house establishments, I sailed from IfTewTork in the steamship Cuba, of the Canard line, on the 30th of April, 1S73. During the voyage I had many interesting conversations convoisation ■with the commander, Captain McCauley, in regard to the McCauiey '''coS lights of thelJnited States, France, and England. In ref- cruglits:^"'' erence to our own lights he stated that they were in general satisfactory to mariners, and had been of great service to him on many occasions, during his long service in the Cunard Company, especially in running between Boston and New York and between Halifax and Boston. With respect to brilliancy, the English and American Eiaiiancy of lights are, in his opinion, about equal, but those of tliefrMcVana Ea' French he considers superior to either. ^"''' ^°^^^- He said of the electric lights, of which the English and Electric lights French have several, that they penetrated fog much more'*"^'''""'^"^' successfully than the common oil-light, and aids to naviga- tion in fog are, in his opinion, vastly more important than for fair weather. Our fog-signals he praised highly, saying that the steam- Fog-aisnais of whistle at Cape Ann and the siren at Sandy Hook had ^ marSie™!'*'''^'' often been of great service to him, and he confidently relied on hearing them at distances of from six to eight miles. He Fog-signais thought it would be much to the interest of commerce if the giisii coaata. British government would place similar signals at impor- tant points, as the channel approaches to Great Britain were nearly as much subject to fogs as is our eastern coast. Our Nantucket Shoals he considered to be badly lighted, insufficient and called my attention to the fact that on the coasts of tu(!ketsiiol£''"" Great Britain, in similar localities, light-ships are placed at distances of ten to twelve miles apart; such I found afterward to be the case. He thought a light-ship should LigbtsWp need- be placed off the Eose and Crown Shoal, (which is due eastciwa shoai.'"'*' from Sankaty Head, on the Island of Nantucket,) so that a vessel could take a course to it from the Highlands (Cape Cod) light, and thence to the Nantucket New South Shoals light-ship, which he thought should be moved farther out. 16 EUROPEAN LIGHT-HOUSE SYSTEMS. Meeting -witii On the fifth night out from New Tork (the night of the foundSnd°B?nt8 4th of May) we met a steamship on the Banks off New- in a, thick fog. fomjiiiand, but there being at the time one of those dense fogs prevalent at some seasons of the year in that part of the Atlantic, we did not see her, and only knew of her proximity by the sound of her whistle, a fact which impressed Importance of me with the importance of powerful fog-signals on the t'r\'Sna,ni°S stcamships plying between America and Europe on this steamers. much-frequented track * Danger of col- Iq addition to the large number of steamships the num- sof8°dii?gVg3.' ber of sailing-vessels is very great, and the tales of narrow escapes from collision, especially with fishermen anchored on the Banks, which one hears while (enveloped in dense fog) he is steaming along at a high rate of speed, very much impair the confidence which is naturally inspired by vessels like those of the Cunard line and commanders like Captain McCauley ; for it is evident that want of eflcient fog-signals cannot be compensated for by strength of ship or skill of I nsnfflciency officers. The whistles in use are, I am told, frequenSly in- on steamers. sufBcicut in powcr, and, being placed abaft the foresails and in front of the great smoke-pipes, are in such positions that the sound-shadows often cover the precise directions in which it is most essential the warziing should he conveyed. Position and I am of the opiniou that not Only the j)osiroved transmission. To test this inference I had the steamer turned and urged back to our last position of in- audibility. The sounds, as I expected, were distinctly though faintly heard. This was at three miles' distance. At three and three-quarters miles we had the guns fired, both point-blank and elevated. The faintest pop was all that we heard ; but we did hear a pop, whereas we had previously heard nothing, either here or three-quarters of a mile nearer. Wosteamed outto four anda quarter miles, where the sounds were for a moment faintly heard ; but they fell away as we waited, and though the greatest quietness reigned on board, 30 EUEOPEAN LIGHT-HOUSE SYSTEMS. and thougb the sea Mas -without a ripple, -we could hear nothing. We could plainly see the steam-puffs which an- nounced the beginning and end of a series of trumpet-blasts, but the blasts themselves were quite inaudible. "It was now 4 p. m., and my intention at first was to halt at this distance, which was beyond the sonnd-range, but not far beyond it, and see whether the lowering of the sun would not restore the power of the atmosphere to transmit the sound. But, after waiting a little, the anchoring of a boat was suggested, so as to liberate the steamer for other work ; and though loath to lose the anticipated revival of the • sound myself, I agreed to this arrangement. Two men were placed in the boat and requested to give all attention so as to hear the sound if possible. With perfect stillness around them they heard nothing. They were then instructed to hoist a signal if they should hear the sounds, and to keep it hoisted as long as the sound continued. "At 4.45 we quitted them and steamed toward the South Sand Head light-ship. Precisely 15 minutes after we had separated from them the flag was hoisted. The sound had at length succeeded in piercing the body of air between the boat and the shore. " We continued our journey to the light-ship, went on board, and heard the report of the lightsmen. Eeturuing toward the Foreland, in answer to a signal expressing a wish to communicate with us, we manned a boat and pulled to the shore. The exhaustion of the ammunition was re- ported, but the horns and whistle continued to sound. We steamed out to our anchored boat, and then learned that when the flag was hoisted the horn-sounds were heard : that they were succeeded after a little time by the whistle- sounds, and that both increased in intensity as the evening advanced. On our arrival, of course we heard the sounds ourselves. "The explanation giveuaboveof the stoppage of the sound is in perfect harmony with these observations. But we pushed the test further by steaming farther out. At five and three-quarters miles we halted and heard the sounds. At six miles we heard them distinctly, but so feebly that Ave thought we had reached the limit of the sound-range. But while we waited the sound rose in power. We steamed to the Varne buoy, which is seven and three-quarters miles from the signal-station, and heard the sounds there better than at six miles distance. We continued our course out ward to ten miles, halted there, but heard nothing. EUROPEAN LIGHT-HOUSE SYSTEMS. 31 "At eight miles' distance the sound in the evening was at sisnais iicara least as well heard as at two miles in the morning. ThattLeevenSs.'^^ ' this could occur it was necessary, in accordance with the law of inverse squares, that the sound at two miles' distance should have risen in the evening to an intensity at least six- teen times that which it possessed in the morning. " Steaming on to the Varne light-ship, which is situated at the other end of the Varne Shoal, we hailed the master, and were informed by him that up to 5 p. m., nothing had been heard. At that, hour the sounds began to be audible. He described one of them as ' very gross, resembling the bel- lowing of a bull,' -which very accurately characterizes the sound of the large American steam-whistle. At the Varne light-ship, therefore, the sounds had been lieard toward the close of the day, though it is twelve and three-quarters miles from the signal-station. On our return to Dover Bay at 10 p. m. we heard the sounds, not only distinct but loud, where nothing could be heard in the morning. "I have already referred to the winds and currents which wiaiisaiiacTir. establish themselves round the South Foreland. Mr. Holmes Foreiaud. was, as usual, there on July 3, and he informed me that, from the motion of the smoke of some passing steamers and from the sails of sailing-vessels, he could recognize a curious circulation of the air from land to sea. The wind would sometimes hug the cliff to the northeast of the Foreland; then bend around and move toward the South Sand Head light-ship. And, in point of fact, the wind at the light- vessel had been southwest, with a force of 3 nearly the whole of the day; whereas with us it had passed from south- west by west to a dead calm, and afterward to southeast. On shore also it had shifted from southwest to southeast. The atmospheric conditions between the light-vessels and the Foreland were, therefore, different from those between us and the Foreland ; and the consequence was that at the time when we were becalmed and heard nothing tbe light-keepers, with the larger component of a wind of 3 acting against the vsonnds, heard them plainly all day. " But both the argument and the phenomena have a com- ^^^^'f'"^^'""' "' l^lementary side, which we have now to consider. A stratum of air three miles thick on a perfectly calm day has been proved competent to stifle both the cannonade and the horn sounds employed at the South Foreiaud ; while the observa- tions just recorded seem to point distinctly to the mixture of air and aqueous vapor as the cause of this extraordinary phenomenon. Such a mixture could fill the atmosphere with 32 EUROPEAN LIGHT-HOUSE SYSTEMS. an impervious acoustic cloud on a day of perfect optical trans- parency. But, granting this, it is incredible that so great a body of sound could utterly disappear in so short a distance Tivithout rendering any account of itself. Supposing, then, instead of placing ourselves behind the acoustic cloud, we were to place ourselves in front of it, might we not, iu accordance with the law of conservation, expect to receive by reflection the sound that had failed to reach us by trans- mission? The case would then be strictly analogous to the reflection of light from an ordinary cloud to an observer placed between it and the sun. Echoes ob- " My flrst care in the earlv part of the day in question was to assure myself that our inability to hear the sound did not arise from any derangement of the instruments on shore. Accompanied by Mr. Edwards, who was good enough on this and some other days to act as my amanuensis, at 1 p. m. I was rowed to the shore, and landed at the base of the South Foreland cliff. The body of air which bad already shown such extraordinary power to intercept the sound, and which manifested this power still more impressively later in the day, was now in front of us. On it the sono- rous waves impinged, and from it they were sent back to us with astonishing intensity. The instruments, hidden from view, were on the summit of a cliff 235 feet above us, the sea was smooth and clear of ships, the atmosphere was without a cloud, and there was no object in sight which could possibly produce the observed effect. From the per- fectly transparent air the echoes came, at flrst with a strength apparently but little less than that of the direct sound, and then dying gradually and continuously away. A remark made by my talented companion in his note-book at the time shows how the phenomenon affected him. ' Beyond saying that the echoes seemed to come from the expanse of ocean, it did not appear possible to indicate any more definite point of reflection.' Indeed, no such point was to be seen; the echoes reached us, as if by magic, from absolutely invisible walls. " Here, I doubt not, we have the key to many of the mys- teries and discrepancies of evidence which beset this ques- tion. The foregoing observations show that there is no need to doubt either the veracity or capability of the con- ilicting witnesses, for the variations of the atmosphere are more than sufficient to account for theirs. The mistake, in- deed, hitherto has been, not in reporting incorrectly, but iu neglecting the monotonous operation of repeating the ob- servations during a sufficient time. I shall have occasion EUEOPEAN LIGHT-HOUSE SYSTEMS. 33 to remark subsequently on the mischief likely to arise from giving instructions t|) mariners founded on observations of this incomplete character. " The more accurate comprehension of various historic striking cases •■II 1 1 -. .. . 1 . , . **^ non-transrais- occurrences will be rendered possible by these observations, eion ot soomi. In his lecture entitled ' Wirkungen aus der Perne,' the emi- nent Berlin philosopher, Dove, has collected some striking cases of this kind. During the battle of Cassano, on the Adda, between the Due de Vendome and the Prince Eugene, an army-corps stationed under the duke's brother, five miles up the river, failed to join the battle through not hearing the cannonade. In a river-valley, particularly on a warm day, it would, in my opinion, be very perilous to place much dependence upon sound. Near Montereau, on the Seine, during the battle between Napoleon I and the King of Wiirtemberg, which lasted seven hours, no sound of the conflict was heard by Prince Schwartzenberg, thirteen miles up the river. A Prussian oflcer sent thither at noon first heard the cannonade at a distance of four and a half miles from the field of battle. This happened on a day apparently resembling in point of mildness and serenity our 3d of July. In the battle of Liegnitz, where Frederick the Great overthrew Laudon, the sound of the battle was un- heard by Field-Marshal Daun, who was posted on a height four and a half miles from the battle-field. Dove himself recounts the fact of his having failed to catch a single shot of the battle of Katzbach, at four and a half miles distance, while he plainly heard the cannonade of Bautzen, eighty miles away. " The stoppage of the sound in the foregoing cases Dove other instances referred, and doubtless correctly, to the non-homogeneous S eouT aTmlt character of the air. He also notes the exceedingly inter- p^™®' esting observation that in certain clear winter days, when the sun has already attained some ijower, the semaphore is difficult to decipher, the reason being that by the solar warmth upward currents of warm and downward currents of cold air (similar to those of Humboldt on the plain of Antures) are established, and that such days are also un- favorable to the transmission of sound. In another pas- sage, however, he seems to endorse the i^revalent notion that the transparency of the air and its power to transmit sound go hand in hand ; whereas in our experiments days of the highest optical transparency proved themselves acoustically most opaque. " ' Over water,' says Sir John Herschel, ' or a surface of j„^P":^e?acifoL" ice, sound is propagated with remarkable clearness and S. Ex. 54 3 34 EUEOPEAN LIGHT-HOUSE SYSTEMS. Strength ; ' and he refers to the well-known case of Lieu- tenant Foster, who, in the polar e:||iedition of Captain Parry, carried on a conversation across the frozen harbor of Port Bowen, which is a mile and a quarter wide. Bat as regards smoothness, water could hardly be in a better con- dition than the sea between the lren6 and the South Fore- laud on the 3d of July. Still, though aided by reflection froni the sea's surface, the sound was powerless to penetrate the air. And in regard to Lieutenant Foster's observation, there cannot, I think, be a doubt that the extraordinary acoustic transparency of the polar atmosphere is mainly due to the absence of that flocculence which in our observations proved so hostile to the transmission of the sound. To the same cause is, I believe, to be ascribed the hearing of can- nonades at the extraordinary distances of eighty, one hun- dred and eighty, and two hundred miles, mentioned by Sir John Herschel in his essay on sound. Had Humboldt him- self been aware of the observations here recorded, might not his classical observation also have been connected with the vapor raised from the Orinoco by a tropical sun ? Experiments " lu the Celebrated experiments conducted by the commis- r?enoh aTrea^ siou of the Frcuch Bureau des Longitudes in 1822, two sta- ■ des Longitudes, tious wcrc choscn, 11.6 milcs apart, the one at Montlhery, and the other at Villejuif, near Paris. Two remarkable phenomena, which have a special interest in relation to our observations, presented themselves to the observers; the one was that while the report of every gun fired at Mont- lhery was exceedingly well heard at Villejuif, by far the greater number of those fired at Villejuif failed to be heard at Montlhery. In reference to this point Arago, the writer of the report, with that philosophic reserve which he showed in other matters, expressed himself thus : 'Quant aux difK- rences si remarquables d'intensit^ que le bruit du canon a toujours pr^sent^es suivant qu'il se propageait du nord au - sud entre Villejuif et Montlhery, on du sud au nord entre cette seconde station et la premiere, nous ne chercherons pas aujourd'hui 4 les expliquer, parceque nous ne pourrions offrir au lecteur que des conjectures denudes des prenves.' To another phenomenon he also directs attention, offering not only a description, but an explanation : ' Avant de ter- miner cette note, nous ajouterons seulement que tous les coups tir6s ^ Montlhery y 6taient accompagnes d'un roule- ment semblable a celui du tonnerre, et qui durait 20" k 25". Eiende pareil n'avait lieua Villejuif ; il nous est arriv6 seule- ment d'entendre, k moins d'une seconde d'intervalle, deux coups distincts du canon de Montlhery. Dans deux autres EUROPEAN LIGHT-HOUSE SYSTEMS. 35 circonstances le bruit de ce canon a 6t6 accompagn6 d'un roulemeut prolong^. Oes ph^nomenes n'ont jamais eu lieu qu'au moment d' apparition de quelques nuages ; par un ciel completement serein le bruit 6tait unique et instantan6. Ne serait-il pas permis de conelure de 1^ qu'4 Yillejuif les coups multiples du canon de Montlhery r<5sultaient d'6cli08 formes dans les nuages, et de tirer de ce fait un argument favorable k I'explication qu'ont donn6e quelque physi- ciens du roulement du tonnerre?' " It is not here stated that at Montlhery the clouds were seen when the echoes were heard. The explanation of the Montlhery echoes is in fact an inference from observations made at Villejuif. I think that inference requires qualifica- tion . Some hundreds of cannon-shots have been fired at the South Foreland, many of them when the heavens were com- pletely free from clouds, and never in a single case has a ' roulement ' similar to that noticed at Montlhery been ab- sent. It follows, moreover, so hot upon the direct sound as to present scarcely a sensible breach of continuity between the sound and the echo. This could not be the case if the clouds were its origin. A reflecting cloud, even at the short distance of 1,000 yards, would leave a silent interval of five seconds between the sound and the echo. Had such an inter- val been observed at Montlhery it could hardly have escaped record by the philosophers stationed there. " But, to fall back from reasoning upon facts, it is certain Echoes produc-a that air of perfect visual transparency is competent to pro- ^? *™"''i"'^'^- ' duce echoes of great intensity and long duration. I shall have further occasion to refer to such echoes ; for it was not with whistles, nor trumpets, nor guns, that these echoes in our observations reached their greatest development, but with the steam-siren, to be described farther on. The blasts sounded by this instrument number, I believe, about twenty thousand ; but whatever might be the state of the weather, cloudy or serene, stormy or calm, no single blast of the siren failed to be accompanied by echoes of astonishing strength. " The other point referred to, which Arago declined to dis- cuss, presents a grave difficulty. INo attempt, as far as I am aware of, has since been made to solve it, or even to show that a solution is conceivable. I think the foregoing obser- vations might be shown to have some bearing upon the point. Arago makes incidently the significant remark that, on June 22, wben only one out of twelve of the shots fired at Ville- juif was heard, and that feebly, at Montlhery, ' Thygromtoe avait march^ beaucoup a I'humidit^ ; ' and farther on he speaks of the air as 'tout pres da terme de Thumidit^ ex- , 36 EUEOPEAN LIGHT-HOUSE SYSTEMS. tr6me.' I believe myself safe in saying that air thus moving rapidly toward its point of saturation is sure to yield echoes; and the fact that echoes were heard at Montlhery and not at Villejaif is a proof of the different hygrometric condition of the air at the two stations. With the light wind recorded in the report, Montlhery would probably be swathed by vapor from the valley of the Seine. It seems to me by no means impossible to imagine a distribution of vapor sufficient to produce the observed effect; but this is a subject which may be reserved for future investigation. " The observations of July 3, 1 believe, reveal to us the most potent cause of the caprices of the atmosphere as re- gards the transmission of sound. We shall, moreover, find them throwing light upon anomalies subsequently observed, which, without their aid, would be perplexing in the high- est degree. American siren " During my rcceut visit to the United States I was acn^ for ejrpen. f^^Qj-g^ jjy j^q introduction to General Woodruff by Professor Joseph Henry, of Washington. Professor Henry is chair- man of the Light- House Board, and General Woodruff is engineer in charge of two of the light-house districts. I accompanied General Woodruff' to the establishment at Staten Island, and afterward to Sandy Hook, with the express intention of observing the performance of the steam-siren which, under the auspices of Professor Henry, has been introduced into the light-bouse system of the ' United States. Such experiments as were possible to make under the circumstances were made, and I carried home with me a somewhat vivid remembrance of the mechanical effect of the sound of the steam-siren upon my ears and body generally. This I considered to be greater than the similar effect produced by the horns of Mr. Holmes; hence the desire, on my part, to see the siren tried at the South Foreland. The formal expression of this desire was antici- pated by the Elder Brethren, while their wishes were in turn anticipated by the courteous kindness of the Light- House Board at Washington. Informed by Major Elliot that our experiments had begun, the Board forwarded to the corporation, for trial, the noble instrument now mounted at the South Foreland. rriiicipieoftiie "The principle of the siren is easily understood. A mu- sical sound is produced when the tympanic membrane is struck periodically with sufflcient rapidity. The production of these tympanic shocks by puffs of air was first realized by Doctor Eobisou, and his device was the first and simplest su'eu. EUROPEAN LIGHT-HOUSE SYSTEMS. 37 form of the siren. A stop-cock ^vas so constructed that it opened and shut- the passage of a pipe seven hundred and twenty times in a second. Air being allowed to pass inter- mittently along the pipe by the rotation of the cock, 'a mu- sical sound was most smoothly uttered.' A great step was made in the construction of this instrument by Cagniard de la Tour, who gave it its present name. He employed a box with a perforated lid, and above the lid a similarly perfo- rated disk, capable of rotation. The perforations were oblique, so that when wind was driven through, it so im- pinged upon the apertures of the disk as to set it in motion. No separate mechanism was therefore required to move the upper disk. When the perforations of the two disks coin- cided, a puff escaped ; when they did not coincide, the cur- rent of air was cut off. In this way a succession of im- pulses was imparted to the air. The siren has been greatly improved by Dove, and specially so by Helmholtz. Even in its small form the instrument is capable of produc- ing sounds of great intensity. "In the steam-siren, patented by Mr. Brown, of New York, a fixed disk and a rotating disk are also employed, radial slits being cut in both disks instead of circular apertures. One disk is fixed across the throat of a trumpet, ICJ feet long, 5 inches in diameter, where the disk crosses it, and gradually opening out till at the other extremity it reaches a diameter of 2 feet 3 inches. Behind the fixed disk is the rotating one, which is driven by separate mechanism. The trumpet is mounted on a boiler. In our experiments steam of 70 pounds pressure has for the most part been employed. Just as in the siren already described, when the radial slits of the two disks coincide, a puff' of steam escapes. Sound-waves of great intensity are thus sent through the air 5 the pitch of the note produced depending on the rapidity with which the puff's succeed each other ; in other words, upon the velocity of rotation. dead- ened l)y heavy "Ocio&er8. — * * "^ The heavy rain at length reached sound dm US, but although it was falling ail the way between us and ram. the Foreland, the sound, instead of being deadened, rose perceptibly in power. Hail was now added to the rain, and the shower reached a tropical violence. The deck was thickly covered with hail-stones, which here and there floated upon the rain-water, the latter not having time to escape. "We stopped. In the midst of this furious squall both the horn and the siren were distinctly heard ; and as the shower lightened, thus lessening the local noises, the 38 EUROPEAN LIGHT-HOUSE SYSTEMS. sounds so rose in power that we heard them at a distance of seven and a half miles distinctly louder than they had been heard through the rainless atmosphere at five miles. This observation is entirely opposed to the statement of Derham, which hasbeenrepeatedby all writers since his time, regarding the -stifling influence of falling rain upon sound. But it harmonizes perfectly with our experience on the 3d July, which proved water in the state of vapor, so mixed with air as to form non-homogeneous parcels, to be a most potent influence as regards the stoppage of sound. Prior to the violent showers of to-day the air had been in this condition, but the descent of the shower restored in part the homoge- neity of the atmosphere and angumented its transmissive power. " In the cleansed and cool atmosphere the horn-sound ap- peared to improve more than that of the siren, slightly surpassing it at times. The horn-note was of lower pitch ; hence it might be inferred that the change in the atmos- phere favored specially the transmission of the longer waves. " Up to this time the siren had been performing 2,400 revolutions a minute ; the rate was now reduced to 2,000 a minute. The sound immediately surpassed that of the horn. By this experiment the foregoing inference was reduced to demonstration ; a highly instructive result, as it showed an interdependence between aerial reflection and the lengths of the sonorous waves. "At 4 p. m. the rain had ceased, the sun shone clearly out : the air was calm afloat, but west with a force of 2, ashore. At nine miles' distance the horn was heard feebly, the siren clearly ; the howitzer at this distance sent us a loud report. All, indeed, seemed better at this distance than at five and one-half miles ; from which it follows that at this latter distance the intensity of the sound must have been augmented at least threefold by the descent of the rain. ******* " October 10.—* * * We descended the 121adder shaft, and from the lower station listened to the gun, the upper horn, the siren, and the lower horn. The sound of the siren was strikingly distinguished from that of the upper horn by its hardness and almost explosive force. Its echoes also were much louder and longer continued than those of the horn ; and from this alone its greater reach of penetra- tion might be inferred. The noise of the surf, however, at the lower station, interfered seriously with the observa- tions. EUEOPEAN LIGHT-HOUSE SYSTEMS, 39 " October 13. — * * * On steaming toward the axis no echo for some time was generated by the horns, none by the Canadian ■whistle, but long-drawn and distinct echoes came from the south in the case of the siren. When quite abreast of the station the horn-echoes were also heard, but they failed to approach in intensity those of the siren. "Near the shore the wind was now north; farther out it was no doadenms southwest, and we steamed between the two currents. As oriUed to^a^S.""' far as the South Sand Head light-ship all the sounds were heard both through violent rain and through the noise of the paddles. To rain I have never yet been able to trace any deadening power ; indeed such rain as we have hitherto en- countered produced a distinctly opposite effect, and the reason is now intelligible. The siren on the present occa- sion was clearest and loudest, though at times the Cana- dian whistle showed great power. A struggle between the winds continued for some time, the north wind, accompanied by a cool atmosphere, at length prevailing. "Once while halting near the light-ship, when the Fore- superiority of land was hidden in a dense rain-mist, I, being ignorant of siren. """ '" its bearing, immediately found its position from the direc- tion of the sound. "Thomson, the chief lamp-lighter at the South Sand Head, an exceedingly intelligent man, reported that on all occa- sions the sound of the siren had the mastery; and that opinion on this point was unanimous on board the light- vessel. On Friday and Saturday the sounds, he reported, were but faintly heard, being probably impaired by the lo- cal noises. To-day we found during our visit all the sounds very good, that of the siren being particularly intense. " October 14, — * * * At 11.30 a. m. a gun was fired at Error in sup- ° posing a shrill the Foreland ; report distinct. Up to this time the Cana- note to be supe- nor as a signal. dian whistle had been adjusted to produce a shrill note ; it was not heard. The piercing shrillness of this note, when heard at the South Foreland on October 10, suggested its trial to-day. The opinion that a note of this character, which affects an observer close at hand so powerfully and painfully, has also the greatest range, is a common one, and might be true in connection with homogeneous atmosphere. Butin 'fl.occulent' air the shorter waves suffer most from par- tial reflection, exactly as the shorter waves of solar light suffer most in their passage through the suspended matter of the atmosphere. The blue of the firmament is, in fact, the echo of these shorter undulations. 40 EUEOPEAlSr LIGHT-HOUSE SYSTEMS. "According to arrangement, the Canadian whistle Tvas now changed to its old low pitch. It was immediately heard at the Varne buoy. " During the earlier part of this day the atmosphere, which, throughout, was of extreme optical clearness, favored the transmission of the longer sound-waves, corresponding to the deeper sounds. ChaiKes in the "After a lapse of three hours the case was reversed, the th"aame^day. ™ high-pitched sireu being heard when both gun and horns were absolutely inaudible. But even this was not perma- nent. Such changes on the part of the atmosphere have never hitherto been noticed, nor am I aware of a single ob- servation bearing upon this selective stoppage of the sound. Its optical analogies have been already pointed out. The parcels of air and vapor play, to some extent, the same part in scattering the waves of sound as the minute particles sus- IJended in the atmosphere do in scattering the solar light, producing by their preferences in this respect the blue of the sky. ******* DaboU's inven- '■'■ Octoher 15. — * * * To the late Mr. Daboll, of the tionoifos-koms. -Quitg^ Statcs, belongs the credit of bringing large trumpets into use as fog-signals. At Dungeness one of his horns had been erected under his own superintendence ; and wishing to make myself acquainted with its performance, we steamed Horn at Dun- thither to-day. On examining the horn, I was struck by gcnesa. ^^^ similarity in all essential particulars to the horns em- ployed at the South Foreland. Considerable improvements in the working of the horn have been introduced by Mr. Holmes, but the horn itself is substantially that of Daboll. ******* " October 18. — * * * There is no doubt that two days might be chosen on one of which the report of a pocket-pis- tol would be further heard than the report of an 18-pounder on the other. # * * * " October 23. — * * * In the observations of Mr. Ayres to the west of the Foreland, wind and sound were almost in direct opposition ; in those of Mr. Douglass they were by- no means coincident. For a time both directions inclosed an angle of about 45°, and subsequently a greater angle. The Effeotof a thim- difference in the results is nevertheless striking. I may here atSoepher""*'^^ draw attention to the remarkable effect of the rain and thunder-storm observed by Mr. Douglass. He was well in the sound-shadow near Kingsdown coast-guard station. He had sent a fly in advance of him, and the driver had EUEOPEAN LIGHT-HOUSE SYSTEMS. ' 41 been waiting for him for fifteen minutes without once hear- ing either trumpets or gun ; nor had the coast-guardsman on duty heard any sound throughout the day. In fact, the the atmosphere prior to the thunder-storm was in that floc- culent condition to which I have so often had occasion to refer, being composed of non-homogeneous locks of air and vapor. The thunder-storm, which I am assured by Mr. Douglass resembled the descent of a water-spout rather than of an ordinary shower of rain, abolished this condition of things, diminishing the partial echoes, and opening a freer way for the sound through the atmosphere. " In the case of Mr. Ayres, the mastery of the siren over Superiority of '^ the Americiin the gun was very conspicuous ; m the case of Mr. Douglass sireu. also, though the difference was not so great, the siren was heard a mile farther than the gun. « * * * * # « " October 31. — * * * This was an exceedingly thick and squally day, with dense clouds and vapor everywhere. In acoustic opacity it was almost a match for the memo- rable 3d of July. " Steamed with a view of getting dead to windward of station. The siren was clearly heard through all noises. During one particularly heavy squall, when the wind rose to a force of 8, the siren sent us a forcible sound, the horns at the same time being quite inaudible. * « # * mm* " Novemher 21. — * * * The result of the day's obser- Eesnit of m- vations was to prove that the siren suffered far more in nais'fS>m tho^oS- being directed from us than the gun ; this means that "'°"'°'^' the conical trumpet associated with the siren is far more effectual in gathering up the sound and sending it in the direction of the axis than is the cylinder of the gun. " The siren, pointed on us, was heard to-day through the paddle noises at a distance of five miles. " We made various observations in the sound-shadow and near it. The fluctuations in the strength of the sound in- dicated that we were passing through spaces of interference, the sound being sometimes suddenly augmented and some- times suddenly deadened. " In the neighborhood of an acoustic shadow— we need j J2'^*an^aoous" not be in the shadow— and with a wind of a force of 4 *'« ^^*^''"^- against the sound, there are states of the atmosphere in which even the siren with its axis pointed on the observer could not be trusted for a distance of one and a half miles. 42 EUEOPEAN LIGHT-HOUSE SYSTEMS. Horns, whistles, and guns, under those circumstances, are simply nowhere. General re- "A brief review of our proceedings Will aid the memory of the reader who has taken the trouble of going over the fore- going pages. DaboU's horn had been highly spoken of by writers on fog-signals. A third-order apparatus of the kind has been reported as sending its sound to a distance of from seven to nine miles against the wind, and to a distance of twelve to fourteen miles with the wind. Holmes had im- proved upon DaboU, and with an instrument of Holmes of Commence- tj^e first Order our experiments were made. They began on the 19th of May, 1873. Whistles were also employed on this occasion, but those tested were speedily put out of court. uaS^Bs""'*"™^ At a distance of two miles from the Foreland they became useless. At three miles' distance the horns also became useless. At a distance of four miles, with paddles stopped Gun effective, and all ou board quiet, they were wholly unheard. The 12 o'clock gun fired with a 1-pound charge at the Drop Fort in Dover was well heard on May 19, when the horns and whistles were inaudible. On this first day we noticed the sudden and surprising subsidence of the sound as we ap- proached the acoustic shadow lying beyond the line joining the end of the Admiralty pier and the South Foreland. On the 20th of May the permeability of the atmosphere by sound had somewhat increased, but the steam-whistle failed to pierce it to a depth of three miles. At four miles the horns, though aided by quietness on board, were barely heard. By careful nursing, if I may use the expression, the horn-sounds were carried to a distance of six miles. The superiority of the 18-pounder gun, already employed by the Trinity House, over horns and whistles, was on this day so decided as almost to warrant its recommendation to the exclusion of all the other signals. "S'othing occurred on the 2d of June to exalt our hopes of the trumpets and whistles. The horns were scarcely heard at a distance of three miles ; sometimes, indeed, they failed to be heard at two miles. By careful nursing, keeping everything quiet on board, they were afterward carried to a distance of six miles. Long previously they had ceased to be of use as fog-signals. Considering the demands as to sound-range made by writers on this subject, the demonstrated incompetence of horns and whistles of great reputed power to meet these demands was not encour- aging. EUEOPEAN LIGHT-HOUSE SYSTEMS. 43 "OntheSd of June the atmosphere had changed sur- June 3, acoustic prisingly. It -was loaded overhead with clouds of a dark ™°°p'^®'"'5'- and threatening character ; the sounds, nevertheless, were heard at a distance of three and three-fourths miles through the paddle-noises, while with quietness on board they were heard beyond nine miles. " On June 10 the acoustic transparency of the air was also very fair, the distance penetrated being upward of eight and three-fourths miles. A large horn employed on this day was heard at a distance of five miles through the pad- dle-noises. The subsidence of the sound near the boundary of the acoustic shadow on the Dover side of the Foreland was today sudden and extraordinary, affecting equally both horns and guns. We were warned to-day that the suprem- snpremacy of „ j^, . , • T J -i gnn not invaria- acy of the gun on one occasion by no means implied its bie. supremacy on all occasions; the self-same guns which on the 20th had so far transcended the horns, being today their equals and nothing more. " The 11th of June was employed in mastering still fur- ther the facts relating to the subsidence of the sound east and west of the Foreland, the cause of this subsidence being in part due to the weakening of the sonorous waves by their divergence into the sound-shadow, and in part, no doubt, to interference. " The atmosphere on the 25th of June was again very defective acoustically. The sounds reached a maximum dis- tance of six and a half miles. But at four miles, on returning from the maximum distance, the sound was very faint. The guns to-day lost still further their pre-eminence ; at five and a Guns inferior. half miles their reports were inferior to the sound of the horn. No sounds whatever reached Dover Pier on the 11th, and it was only toward the close of the day that they suc- ceeded in reaching it on the 2oth. Thus by slow degrees the caprices of the atmosphere made themselves known to us ; showing that even within the limits of a single day the air, as a vehicle of sound, underwent most serious variations. " The 26th of June was a far better day than its predeces- sor, the acoustic range being over nine and one-quarter miles. The direction of the wind was less favorable to the sound on this day than on the preceding one,' plainly prov- ing that something else than the wind must play an impor- tant part in shortening the sound-range. " On the 1st of July we experimented upon a rotating horn, juiy 1, rotating and heard its direct or axial blast, which was found to be the strongest, at a distance of ten and one-half miles. The sounds to-day were also heard at the Varne light-ship, which 44 EUROPEAN LIGHT-HOUSE SYSTEMS. is twelve and three-quarters miles from tlie Foreland. The atmosphere iiad become decidedly clearer acoustically, but not so optically, for on this day thick haze obscured the ■white cliffs of the Foreland. In fact, on days of far greater optical purity, the sound had failed to reach one-third of the distance attained to-day. By the light of such a fact, any attempt to make optical transparency a measure of acoustic transparency must be seen to be delusive. On the 1st of i2.iiioh Ameri- July a 12-iuch American whistle, of which we had heard a highly favorable account, was tried in the place of the 12- inch English whistle ; but, like its predecessor, the perform- ance of the new instrument fell behind that of the horns. An interval of twelve hours suflQced to convert the acousti- cally clear atmosphere of the 1st of July^into an opaque one ; for on the 2d of July even the horn-sounds, with pad- dles stopped and all noiseless on board, could not penetrate farther than four miles. " Thus each succeeding day provided us with a virtually new atmosphere, clearly showing that conclusions founded upon one day's observations might utterly break down in the presence of the phenomena of another day. This was most impressively demonstrated on the day now to be refer- red to. The acoustic imperviousness of the 3d of July was found to be still greater than that of the 2d, while the opti- cal purity of the day was sensibly perfect. The cliffs of the Extraordiuary Forelaud could be sccu to-day at ten times the distance at acoustic opacity i,. i i.ii ■with optical which they ceased to be visible on the 1st, while the sounds were cut off at one-sixth of the distance. At 2 p. m. neither guns nor trumpets were able to pierce the transparent air to a depth of three, hardly to a depth of two miles. This ex- traordinary opacity was proved to arise from the irregular admixture with the air of the aqueous vapor raised by a powerful sun. "This vapor, though perfectly invisible, produced what I have called an acoustic cloud impervious to the sound, and from which the sound-waves were thrown back as the waves of lightare from an ordinary cloud. The waves thus refused Echoes from transmission produced by their reflection echoes of extraor- traneparent air. binary strength and duration. This I may remark is the first time that audible echoes have been proved to be reflected from an optically transparent atmosphere. By the low- ering of the sun the production of vapor was checked, and the transmissive power of the atmosphere restored to such an extent that, at a distance of two miles from the Foreland, at 7 p. m. the intensity of the sound was at least thirty-six times its intensity at 2 p. m. Nothing requiring any notice EUROPEAN LIGHT-HOUSE SYSTEMS. 45 here occurred on July 4, wlien oar summer experiments ended. " On October 8 the observations were resumed, a steam- October s, ex- siren and a Canadian whistle of great power being added sumcclh 'siren/'' to the list of instruments. A boiler had its steam raised to a pressure of 70 pounds to the square inch. On opening a suitable aperture this steam would issue forcibly in a con- tinuous stream, and the sole function of the siren was to convert this stream into a series of separate strong puffs. This was done by causing a disk with twelve radial slits to rotate behind a fixed disk with the same number of slits. When the slits coincided a puff escaped ; when they did not coincide the outflow of steam was interrupted. Each puff of steam at this high pressure generated a sonorous wave of great intensity, and the successive waves followed each other with such rapidity that they linked themselves together to a musical sound so intense as to be best described as a continuous explosion. "During the earlier part of October 8 the optical trans- sound im- parency of the air was very great ; its acoustic transparency, ^"^ ° ^ ™°' on the other hand, was very defective. Clouds blackened and broke into a rain and hail shower of tropical violence. The sounds, instead of T)eing deadened, were improved by this furious squall ; and, after it had lightened, thus less- ening the local noises, the sound was heard at a distance of seven and one-half miles, distinctly louder than it had been heard through the preceding rainless atmosphere at a dis- tance of five miles. Thus at five miles' distance the inten- sity of the sound had been at least doubled by the rain, a result obviously due to the removal by condensation and precipitation of that vapor, the mixture of which with the air had been proved so prejudicial to fog-signaling. We Depenacnoe bo- established this day a dependence between the pitch of a pIn™r.-Sive po^- uote and its penetrative power, the siren generating iSO^'- waves, being slightly inferior to the horns; while generating 400 waves a second it was distinctly superior. The chaage in the atmosphere had been one favorable to the transmission of the larger waves. The maximum range on October 8 was nine miles. On October 9 the transmissive power had diminished, the maximum range being seven and one-half miles. On both these days the siren proved to be superior to the horns, and on some occasions superior to the gun. "On the 10th and 11th, our steamer having disappeared, ^^octoberio ana we made land-observations. We found the duration of the aerial echoes to be for the siren and the gun 9 seconds, for the horns G seconds. The duration varies from day to day. 46 EUROPEAN LIGHT-HOUSE SYSTEMS. We sought to estimate the influence of the violent wind ■which had caused our steamer to forsake us upon the sound, and found that the sound of the gun failed to reach us in tJieTrSii*^*"'^'^'^® cases at a distance of 550 yards against the wind; the sound of the siren at the same time rising to a piercing intensity. To leeward the gun was heard at five times, and certainly might have been heard at fifteen times, the dis- tance attained to windward. The momentary character of the gun-sound renders it liable to be quenched by a single puff of wind; but low sounds generally, whether momentary or not, suffer more from an opposing wind than high ones. We had on the 13th another example of the powerlessness of heavy rain to deaden sound. " On the 14th the maximum range was ten miles, but the atmosphere did not maintain this power of transmission. It was a day of extreme optical clearness, but its acoustic clearness diminished as the day advanced. In fact the sun was in action. We proved to-day that by lowering the pitch of the Canadian whistle its sound, which had previously Pitch and pene- been inaudible, became suddenly audible. The day at first *™*'™' was favorable to the transmission of the longer sound-waves. After the lapse of three hours the case was reversed, the. high-pitched siren being then heard when both gun and horns were inaudible. But even this state of things did not continue, so rapid and surprising are the caprices of the atmosphere. At a distance of five miles, at 3.30 p. m., the change in the transmissive power reduced the intensity of the sound to at least one-half of what it possessed at 11.30 a. m., the wind throughout maintaining the same strength and direction. Through all this complexity the knowledge obtained on July 8 sheds the light of a principle which reduces to order the apparent confusion. October 15; '' October 15 was spent at Dungeness in examining the Dabou shorn, performance of DaboU's horn. It is a fine instrument, and its application was ably worked out by its inventor ; still it would require very favorable atmospheric conditions to enable it to warn a steamer before she had come danger- ously close to the shore. The directiou in which the aerial echoes return was finely illustrated to- day, that direction being always the one in which the axis of the horn is pointed. October 16 ;bu- " The IGth was a day of exceeding optical transparencv, pononty of the , „ j.- -^ m, • Biren, but 01 great acoustic opacity. The maximum range in the axis was only five miles. On this day the howitzer and all the whistles were clearly overmastered by the siren. It was, moreover, heard at three and a half miles with the KUEOPEAN LIGHT-HOUSE SYSTEMS. 47 paddles going, while the gun was unheard at two and a half miles. With no visible object that could possibly yield an echo in sight, the pure aerial echoes, coming from the more distant southern air, were distinct and long-continued at a distance of two miles from the shore. Near the base of the Foreland cliff we determined their duration, and found it to be 11 seconds, while that of the best whistle-echoes was 6 seconds. On this day three whistles, sounded simul- taneously, were pitted against the siren, and found clearly inferior to it. On the 17th four horns were compared with the siren, and found inferior to it. This was our day of greatest acoustic transparency, the sound reaching a maxi- mum of fifteen miles for the siren, and of more than six- teen for the gun. The echoes on this day were audible for a longer timethan on any other occasion. They continued for 15 seconds ; their duration indicating the atmospheric depth from which they came. " On October 18, though the experiments were not di- rected to determine the transmissive-power of the air, we were not without proof that it continued to be high. From 10 to 10.30 a. m., while waiting for the blasts of the siren at a distance of three miles from the Foreland, the contin- ued reports of what we supposed to be the musketry of skirmishing parties on land were distinctly heard by us all. We afterward learned that the sounds arose from the Eifle - practice rifle-practice on Kingsdown beach, five and a half miles "^^ ■'i^'^^. away. On July 3, which, optically considered, was a far more perfect day, the 18-pounder howitzer and mortar failed to make themselves heard at half this distance. The 18th was mainly occupied in determining the influence of pitch and pressure on the siren-sound. Taking the fluctu- ations of the atmosphere into account, I am of the opinion that the siren, performing from 2,000 to 2,400 revolutions a minute, or, in other words, generating from 400 to 480 waves per second, best meets the atmospheric conditions. We varied the pressure from 40 to 80 pounds on the square inch, and though the intensity did not appear to rise in proportion to the pressure, the higher pressure yielded the hardest and most penetrating sound. " The 20th was a rainy day with a strong wind. Up to a ,,oototer .20^ ^|; distance of five and a half miles the siren continued to be rough weather. heard through the sea and paddle noises. In rough weather, indeed, when local noises interfere, the siren-sound far transcends all other sounds. On various occasions to-day it proved its mastery over both gun and horns. On the 21st, when the deputy master paid us a visit, the wind was 48 EUEOPEAN LIGHT-HOUSE SYSTEMS. strong and the sea high. The horn-sounds, with paddles going, were lost at four miles; the siren continued service- able up to sis and a half miles. The gun to-day was com- pletely overmastered. Its puffs were seen at the Foreland, but its sound was unheard when the siren was distinctly heard. Heavy rain failed to damp the power of the siren. The whistles were also tried to-day, but were found far in- ferior to the siren. October 22; si- "On the 22d it blew a gale, and the Galatea quitted us. wh?n\?c?i'noi8''e8 Wo made observations on land on the influence of the wind interfere. ^^^ ^^ j^^^^ Doiscs. The Shelter of the coast-guard station at Cornhill enabled us to hear gun-sounds which were quite inaudible to an observer out of shelter ; in the shelter also both horn and siren rose distinctly in power, but they were heard outside when the gun was quite unheard. As usual, the sound to leeward was far more powerful than those at equal distances to windward. The echoes from the cloud- less air were to-day very fine. On the 23d, in the absence of the steamer, the observations on the influence of the wind were continued. The quenching of the gun-sounds, in particular to windward, was well illustrated. All the sounds, gun included, were carried much farther to lee- ward than to windward. The effect of a violent thunder- eoumi iu rain, storm and downpour of rain in exalting the sound was noticed by the observers both to windward and to leeward of the Foreland. In the rear of the siren its range to-day was about a mile. At right angles to the axis, and to wind- ward, it was about the same. To leeward it reached a dis- tance of seven and one-third miles. " On the 24th, when observations were made afloat in the steamtug Palmerston, the siren exhibited a clear mastery over gun and horns. The maximum range was seven and three-quarters miles. The wind had changed from west- southwest to southeast, then to east. As a consequence of this the siren was heard loudly in the streets of Dover. On the 27th the wind was east-northeast ; and the siren- sound penetrated everywhere through Dover, rising over the moaning of the wind and all other noises. It was heard at a distance of six miles from the Foreland, on the road to Folkestone, and would probably have been heard all the way to Folkestone had not the experiments ceased. Afloat and in the axis, with a high wind and sea, the siren, and it only, reached to a distance of six miles ; at five miles October 23; in- it was heard through the paddle-noises. On the 28th fur- flueuce of pitcb. ° '- , . r, n • ■, ther experiments were made on the influence of pitch ; the siren, when generating 480 waves a second, being found EUEOPEAN LIGHT-HOUSE SYSTEMS. 49 more effective than when generating 300 waves a second. The maxiiniiLQ range in the axis to-day was seven and one- half miles. " The 29th of October was a day of extraordinary optical transparency, but by no means transparent acoustically. The gun was the greatest sufferer. At first it was barely heard at five miles, but afterward it was tried at five and one-half, four and one-half, and two and one-half miles, and was heard at none of these distances. The siren at the same time was distinctly heard. The sun was shining strongly, and to its augmenting power the enfeeblement of the gun-sound was probably due; wind from east southeast to east-northeast. At three and one-half miles subsequentl j*, dead to windward, the siren was faintly heard; the gun was unheard at two and three-fourths miles. On land Mr. ]-)ouglass heard the siren and horn sounds to windward at two to two and one-half miles ; to leeward Mr. Edwards heard them at seven miles, while Mr. Ayres, in the rear of the instraments, heard them inland at a distance of five miles, or five times farther than they had been heard on October 23. " The 30th of October furnished another illustration of October 3o ; at- ,,^,, „,, , . ,., .n , ' 1 mospliere thick the fallacy of the prevalent notion which considers optical but acoustically and acoustic transparency to go hand in hand. The daj- '^'''"'P''"^" was very hazy, the white cliffs of the Foreland at the greater distances being quite hidden ; still the gun and siren sounds reached on the bearing of the Varne light- vessel to a dis- tance of eleven and one-half miles. The siren was heard through the paddle-noises at nine and one-fourth miles, while at eight"aud one half miles it became efficient as a signal with the paddles going. The horns were heard at six and one-fourth miles. This was during calm. Subse- quently, with a roaring wind from the north-northwest, no sounds were heard at six and one-half miles. At South Sand Head the siren was very feeble, the gun and horns being inaudible. The wind was here across the direction of the sound. On land, the wind being also across, the siren was heard only to a distance of three miles northeast of the Foreland ; in the other direction it was heard plainly on Folkestone Pier, eight miles distant; such was the in- fluence of the wind. Both gun and horns failed to reach Folkestone. "Wind, rain, a rough sea, and great acoustic opacity ^^o«t°^f^ 3'^' ^^J; characterized October 31. Both gun and horns were un-to^veryvmfa™,- heard three miles away. The siren at the same time was clearly heard. It afterward forced its sound with great S. Ex. 54 i xen. M) EUROPEAN LIGHT-HOUSE SYSTEMS. power llirougb a violent rain-squall. Wishing the same in- dividual judgment to be brought to bear on the sounds on both sides of the Foreland, in the absence of our steamer, ■which had quitted us for safety, I committed the observa- tions to Mr. Douglass. He heard them at two miles on the Dover side, and on the Sandwich side, with the same in- tensity, at six miles. "A gap, employed by me in preparing this report, and by the engineers in making arrangements for pointing the siren in any required direction, here occurs in our observa- tions. They were, however, resumed on November 21, "When comparative experiments were made upon the gun and siren. Both sources of sound, when employed as fog- signals, will not unfrequently have to cover an arc of 180°, and it was desirable to know with greater precision how the sound in windy weather is affected by the direction in which the gun or siren is pointed. Effector Chans- '• The gun, therefore, was in the first instance pointed on iiiR the liue of -■„■,, ' , -,„■,, ■, . direction of si- US and flrcd, then turned and nred along a line perpendicn- lar to that joining us and it. There was a sensible, though small, difference between the sounds which reached us in the two cases. A similar experiment was made with the siren, and here the falling off, when the instrument was ])ointed perpendicular to the line joining us and it, was very considerable. This is what is to be expected, for the trumpet associated with the siren is expressly intended to gather up the sound and project it in a certain direction, while no such object is in view in the construction of the gun. Hence any deviation from that direction must, in the case of the siren, be attended with a greater weakening of the sound than in the case of the gun. The experiments here referred to were amply corroborated by others made on No- vember 22 and 23. "On both of these days the Galatea's guns were fired both Aerial echoes, to windward and to leeward. The aerial echoes in the latter case were distinctly louder and longer than in the former. " In front of the Cornhill coast-guard station, and only one and one-fourth miles from the Foreland, the siren, on the 21st, though pointed toward us, fell suddenly and con- siderably in power. Before reaching Dover Pier it had ceased to be heard. The wind was here against the sound : butthiSjthoughitcontributedtotheeffect, could notaccoant for it, nor could the proximity of the shadow accountfor it. To these two causes must have been added a flocculent atmos- phere. The experiment demonstrates conclusively that there are atmospheric and local conditions which when com- EUROPEAN LIGHT-HOUSE SYSTEMS. 51 biued prevent our most powerful iustruments from making more than a distant approacli to the performance wliicli writers on fog-signals have demanded of them. " On November 24 the sound of the siren pointed to Novemiici a ■ ^ cnmparii?rm i t Windward was compared at equal distances in front of and y'"<'Ti'-:;"i ""'i , , . leewmodiic'tiniii behind the instrument. It was louder to leeward in the rear o*' sound. than at equal distances to windward in front. Hence in a wind the desirability of pointing the instrument to wind- ward. The whistles were compared this day with the siren deprived of its trumpet. The Canadian and the 8-inch wliistles proved the most effective, but the naked siren was as well heard as either of them. As regards opacity, the 25th of November almost rivaled the 3d of July. The gun I'ailed to be heard at a distance 2.8 miles ; it yielded only a faint crack at two and one-half miles. This, as on July 3, was when the air was calm. A revival of the wind subse- quently brought with it a revival of the sound. "While the velocity of sound has been the subjectsof refined i"tcnaity of and repeated experiments, I am not aware that since the publication of a celebrated paper by Doctor Derham, in the ^^^•^'"'"^'^ ra- Philosophical Transactions for 170S, any systematic inquiry has been made into the causes which affect the intensity of sound in the atmosphere. Derham's results, though ob- tained at a time when the means of investigation were very defective, have apparently been accepted with unquestion- able trust by all subsequent writers; a fact which is, I think, in some part to be ascribed to the aimori probability of his conclusions. ''ThnsDoctor Robinson, whomlhavealreadvqnoted, * * Dr. iiobiuson a * relying apparently upon Derham, says: 'Fog is a powerful damper of sound;' and he gives a physical reason why it must be so. ' It is a mixture of air and globules of water, and at each of the Innumerable surfaces where these two touch, a portion of the vibration is reflected and lost.' And he adds further on, ' The remarkable power of fogs to deaden the re- port of guns has been often noticed.' "Assuming it, moreover, as probable that the measure of ' a fog's power in stopping sound' bears some simple rela- tion to its opacity for light. Dr. Robinson, adopting a sug- gestion of Mr. Alexander Cunningham, states that 'the dis- tance at which a given object, say a flag or pole, disap- l)ears may be taken as a measure of the fog's power' to ob- struct the sound. This is quite in accordance with prev- alent notions, and, granting that the sound is dissipated, as assumed, by reflection from the particles of fog, the con- 52 EUROPEAN LIGHT-HOUSE SYSTEMS. elusion follows that the greater the number of the reflecting particles the greater will be the waste of sound. But the number of particles, or, in other words, the density of the fog, is declared by its action upon light ; hence the optical opacity will be a measure of the acoustic opacity. These opiniona " This I Say esprcsscs the opinion generally entertained ; ^eous" " '"^"° 'clear still air' being regarded as the best vehicle for sound. We have not, as stated above, experimented in really dense fogs, but the experiments that we have made entirely de- stroy the notion that clear weather is necessarily better for the transmission of sound than thick weather. Some of our days of densest acoustic opacity have been marvelously clear optically, while some of our days of thick haze have shown themselves highly favorable to the transmission of sound. "Were the physical cause of the -sound-waves that above assigned, did that waste arise in any material de- gree from reflection at the limiting surfaces. of the particles of haze, this result, as I have already pointed out, would be inexplicable. FaiUu^' rain as "Again, Dcrliam, as quoted by Sir John Ilerschel, says "" "'"="""'"■■ that ' falling rain tends powerfully to obstruct sound.' Wo have had repeated reversals of this conclusion. Some of our observations have been made on days when rain and hail descended with a perfectly tropical fury, and in no single case did the rain deaden the sound. In every case, indeed, it had precisely the opposite effect. i\i:iius 8D01V. " But falling snow, according to Derham, offers a more se- rious obstacle than any other meteorological agent to the transmission of sound. We have not extended our observa- oiMCTvation ou tious attheSouthForelaudintosuowy weather. But I may be t:i>.'.Mer(io(,iace. pg^yji^^ed to Tcfcr to au obscrvatiou of my own which bears- directlyupon this point. On Christmas night, 1859,Ireached Chamouni, through snow so deep as to obliterate the road- fences. On the 2Gth and 27th it fell heavily. During a lull in the storm I reached the Montanvert, sometimes breast- deep in snow. On the 29th the entry in my journal is5 'Snow, heavy snow ; it must have descended through the entire night, the quantity freshly fallen is so great.' Dr. Derham had referred to the deadening effect produced by a coating of fresh-fallen snow upon the ground, alleging that when the surface was glazed by freezing the damping of the sound disappeared. " Well, on December 29, I took up a pot;itiou beside the Mer de Glace, with a view to determine its winter motion, and sent my assistants across the glacier with instructions to measure the displacement of a transverse line of stakes EUEOPEAN LIGHT-HOUSE SYSTEMS. i.)d planted previously iti the snow. I was standing at the time beside my theodolite, with snow 4 feet deep around me. A storm drifted up the valley, darkening the air as it ap- proached. It reached us, the snow falling more heavily than ever I had seen it elsewhere. It soon formed a heap on my theodolite; still through the telescope I was able to pick up at intervals the retreating forms of my men. Here there was a combination of thick snow in the air and of soft fresh snow on the ground, such as Derham had hardly en- joyed. Through such an atmosphere, however, 1 was able with my unaided voice to make my instructions audible for half a mile, while the experiment was rendered reciprocal by one of my men making his voice audible tome. * * • * « * * " The real enemy to the transmission of sound through ^"on-iiomo?c- ,, , , , T.-..1-. •.1 ,-. neous vapor tl.o the atmospnere h.as, I thmk, been clearly revealed by the cause of aconsi.o foregoing inquiry. That enemy bas been proved to be not"^''" ^ rain, nor hail, nor baze, nor, I imagine, fog or snow; not water, in fact, in either a liquid or a solid form, but water in a vaporous form, mingled with air, so as to render it acous- tically turbid and tlocculent. This acoustic turbidity often occurs on days of surprising optical transparency. Any system of measures, therefore, founded on the assumption that the optic and acoustic transparency of the atmosphere go hand in band must prove delusive. " There is but one solution of this difSculty : it is to make the source of sound so powerful as to be able to endure con- siderable loss by partial reflection and still retain a sufficient residue for transmission. Of all the instruments hitherto t,,?"?,?''""*-' '^ examined by us the siren comes nearest to the fulfillment of this condition. Its establishment upon our coast will, in my opinion, prove an incalculable boon to tlie mariner. * « # * * # * '' We had, as already stated, been favored with thunder, xocxpcrimrTus hail, rain, and haze, but not with dense fog. All tlie more ii.'usc tog. anxious was I to turn the recent excellent opportunity to account. On Tuesday, December 9, 1 therefore telegraphed to the Trinity House, suggesting some gun-observations. A prompt reply informed me that such observations would be made in the afternoon at Blackwall or in its neighborhood. * * * ■ » * # * " Slowly, but surely, wo thus master this question. And rogs this shows what instructive results are to be obtained in connection with the transmission of sound through the atmosphere from a mode of observation accessible to all. "This opportune fog enabled us to remove the last of a Errors ro- * *■ ^ moved. cojigeries of errors which, ever since the year 1708, have attached themselves to this question. As regards phonic coast- signals, we now know exactly where we stand; and, through 'the application of this knowledge to maritime pur- poses, a meteorological phenomenon, which was bewailed in London as an unmitigated evil, may in the end redound to the advantage of the public. " Since the publication of the first notices of this investi- rortiaua guns gation various communications have reached mo, to one or miles througii two of which I should like to refer. The Eev. George H. '''="^''^''=- Hetling, of Fulham, has written to me with a circumstan- tiality which leaves no room for doubt, that he has heard the Portland guns at a distance of forty-four miles througii a dense fog. " The Duke of Argyll has also favored me with the fol- Sfatemont of „ ... . r. . -^ •, till! Uuko of Ar. lowmg account of his own experience. Coming as it does gv"- from a disciplined scientific observer, it is particularly val- uable. ' This fact [the x^ermeability of fog by sound] I have long known, from having lived a great part of my life within four miles of the town of Greenocli, across the Frith. Ship-building goes on there to a great extent, and the ham- laeriug of the calkers and builders is a sound which I have been in the habit of hearing with every variety of distinct- ness, or of not hearing at all, according to the state of the atmosphere ; and I have always observed on days when the air was very clear, and every mast and spar was distinctly seen, hardly any sound was heard, whereas ou thick and foggy days, sometimes so thick that nothing could be seen, every clink of every hammer was audible and appeared sometimes as close at hand. This has been long a very familiar experience with me.' "It is hardly necessary for me to say a word to guard Tim real bar. '^ , ner to transmis- myself against the misconception that I consider sound to sion. be assisted by the fog itself. Fog I regard as the visible result of an act of condensation, which removes the real barrier to transmission, that barrier beuig aqueous vapor so mixed with air as to render it acoustically flocculent or turbid. The fog-particles appear to have no more iniiuence upon the waves of sound than the suspended matter stirred up over the banks of Newfoundland has upon the waves of the Atlantic. T)G EUROPEAN LIGHT-HOUSE SYSTEMS. Superiority of "Au absolutely unifomi superiority on all days cannot bo the siren. conceded to any one of the instruments subjected to exami- nation ,: still, our observations have been so numerous and long-continued as to enable us to come to the sure conclu- sion that, on the whole, the steam-siren is beyond questioii the most powerful fog-signal which has hitherto been tried in England. It is specially powerful when local noises, such as those of wind, rigging, breaking waves, shore-surf, and the rattle of pebbles have to be overcome. Its density, quality, pitch, and penetration render it dominant over such noises after all other signal-sounds have succumbed. " I do not hesitate to recommend the introduction of the siren as a coast-signal. Change in " It will be desirable iu each case to confer upon the in- ITesirabilr' ^"'^^ strumeut a power of rotation, so as to enable the person in charge of it to point its trumpet against the wind, or in any other required direction. This arrangement has been made at the South Foreland, and it presents no mechanical diffi- culty. It is also desirable to mount the siren so as to per- mit of the depression of its trumpet 15° or 20° below the horizon. PraitioD of fog- " In selecting the position at which a fog-signal is to be signal. mounted, the possible influence of a sound-shadow, and the possible extinction of the sound by the interference of the direct waves with waves reflected from the shore, must form the subject of the gravest consideration. Preliminary trials may in most cases be necessary before fixing on the precise point at which the instrument is to be placed. siron, with '' '^^^ ^0''^ °^ the sircu which has been longlinown to sci- compresseii air. eutiflc meu is workcd with air, and it would be worth while to try how the fog-siren would behave supposing com- pressed air to be substituted for steam. Compressed air might also be tried with the whistles. * * ^ iioiiinson's " ^^ fog-sigual hitherto tried is able to fulflll the condi- rZlioa'by anytionlaiddowubyDr. Kobinson, ^ * * uamelj, 'that all iog-8ignai. fog-signals should he distinctly audible for at least four miles tinder every circumstance.^ Circumstances may arise to pre- vent the most powerful sounds from being heard at half this distance. What may with certainty be affirmed is, that in almost all cases the siren, even on steamers with paddles going, may be relied on at a distance of two miles ; in the great majority of cases it may be relied upon at a distance of three miles, and in the majority of cases at a distance greater than three miles. EUROPEAN LIGHT-HOUSE SYSTEMS. 57 " Hap[)ily, the experiments thus far made are perfectly sipuiia mo^t ,..,.,. ,, , ., . , efficient during concurrent in indicatmg that at the particular time when log. fog-signals are needed, that is, during foggy weather, the air in which the fog is suspended is in a highly homogeneous condition ; hence it is in the highest degree probable that in the case of fog we may rely upon these signals being effective at much greater distances than those just men- tioned. " I say ' probable,' while the experiments seem to render this result certain. Before pronouncing it so, however, I should like to haA'e some experience of warmer fogs than those in which the experiments have hitherto been made. That the fog-particles themselves are not sensibly injurious to the sound has been demonstrated ; but it is just possible that in warm weather the air associated with the fog may not be homogeneous. I would recommend the experiment necessary to decide this point to be made on some of the fogs of the early summer. "I amcautiousnottoinspire the mariner with a confidence Bistnncn at which may prove delusive. When he hears a fog-sigual heliiouui bohtala. ought, as a general rule, at all events until extended expe- rience justifies the contrary, to assume the source of sound to be not more than two or three miles distant, and to take ])recautions accordingly. "Once warned, he may, by the heaving of the lead or some other means, be enabled to check his position. But if he errs at all in his estimate of distance, it ought to be on the side of safety. "Unless very cogent practical reasons can be adduced in intcrvr.is i>e- •'=''• twccii blasts. its favor, I should stronglj" deprecate a lengthened interval between the siren-blasts. My own small experience has shown me how harassing to the mariner are some of our revolving lights with a long period of rotation. No light, in my opinion, ought to be obscured for more than 30 sec- onds, and the interval between the two blasts of our fog- signal ought not to be longer. "With the instruments now at our disposal, wisely estab- lished along our coasts, 1 venture to believe that the saving of property in ten years will be an exceedingly large mul- tiple of the outlay necessary for the establishment of such signals. The saving of life appeals to the higher motives of humanity." General Duane, of the Corps of Engineers of the Army Eepnit from . ., , -.^ T-. 1 T ^ /• General Duauc. and light-house engineer of the ISew England coast, for- warded to the Light- House Board on January 12, 1872, a 58 EUROPEAN LIGHT-HOUSE SYSTEMS. report which corroborates the results of Professor Tyndall's experiments, some ofwhich were foreshadowed ia his treatise on Sound, published in 18G7. This report contains much practical information in regard to fog-signals, and it is to be regretted that it has not been published. The following are extracts from General Duane's report: i-oi-Ri'nais on " Thcro are six steam fog-whistles on the coast of Maine. tLo Maine cuast. rpj^ggg jj^ye bceu frequently heard at a distance of twenty miles, and as frequently cannot be heard at the distance of two miles, and this with no perceptible difference iu the state of the atmosphere. sisnai some- " The sigual is often heard at a great distance in one iuT^e dfrtctlon* direction, while in another it will be scarcely audible at the distance of a mile. This is not the effect of wind, as the signal is frequently heard much farther against the -wind than with it. For example, the whistle on Cape Elizabeth can always be distinctly heard in Portland, a distance of nine miles, during a heavy snow-storm, the wind blowing a gale directly from Portland toward the whistle. p,,it impi-no- "The most perplexing difficulty, however, arises from s™rronD.Lg"tiie the fact that the signal often appears to be surrounded by sigual- jj, |jg](-^ varying in radius from one to one and a half miles, from which the sound aiipears to be entirely absent. ivnmii lost for " Thus, lu moviug dircctly from a station, the sound may i'anc^^ud thcu ^6 audiblc for the distance of a mile, is then lost for about ictoTcred. ^^iQ sauie distancc, after which it is again distinctly heard for a long time. This action is common to all ear-signals, and has been at times observed at all the stations, at one of which the signal is situated on a bare rock twenty miles from the main-land, with no surrounding objects to affect the sound. All attempts to re enforce the sound by means of reflectors have hitherto been unsuccessful. Upon a large scale sound does not appear, on striking a surface, to be reflected after the manner of light and heat, but to roll along it like a cloud of smoke. * » if * * * * roniiiuoiis of " From an attentive observation during three vears of the tljo atmospbcte. „ . , , . _ „ , fog-signals on this coast, and from the reports received from captains and pilots of coasting-vessels, I am convinced that in some conditions of the atmosphere the most power- ful signals will be at times unreliable. « ***** # Kifli'iiion ai- " yow, it frequently occurs that a signal, which under or- ecim'^Muni. jjjj^ry circumstauces would be audible at the distance of fifteen miles, cannot be heard from a vessel at the distance EUROPEAN LIGHT-HOUSE SYSTEMS. 59 of ii single mile. This is probably due to the reflectioa mentioned by Humboldt. " The temperature of the air over the land where the log- signal is located being very different from that over the 8ea, the sound, in passing from the former to the lattoi', undergoes reflection at their surfaces of contact. Tlie cor- rectness of this view is rendered more probable by the fact that when the sound is thus impeded in the direction of the sea, it has been observed to be much stronger inland. " When a vessel approaches a signal in a fog a diflcuitv Difficulty in ... « 1 *' (k'terniiinnirporti- is sometimes experienced in determining the position oi the tiouoi tiiosigimi. signal by the direction from which the sound appears to proceed, the apparent and true direction being entirely different. This is undoubtedly due to the refraction of sound passing through media of different density. " Experiments and observation lead to the conclusion rvenson lor Dm that these anomalies in penetration and direction of sound to exist. from fog-signals are to be attributed mainly to the want of uniformity in the surrounding atmosphere, and that snow, rain, fog, and the force and direction of the wind have much less influence than has generally been supposed." "While this report is passing through the press, Sir Fred- ericli has also kindly sent me a copy of his memorandum to the Elder Brethren of the Trinity House concerning the re- l)ort of Professor Tyndall, and ifc will be found below. 3IEMOEAKDUJJI BY SIE FEEDEEICK ARROTf, THE DEPUTY MASTER OF THE TRINITY HOUSE, UPON DE. TY'NDALL'S REPORT ON THE EXPERIMENTS AT SOUTH FORELAND. '•At the close of a series of important investigations, undertaken with the desire of adding to the safety of navi- gation round our seaboard, to which a committee of the Elder Brethren, acting in conceit with the corporation's scientiiic adviser, have devoted many months of careful attention, it will be convenient, now that the report of Dr. Tyndall has been presented to the board, to consider how faV the conclusions arrived at may be practically and use fully applied. "Before entering, however, upon the subject-matter of the report, it is due to the members of the committee, who have Ireely sacrificed their time and comfort during a protracted l)eriod, that the board should record its acknowledgment of their careful prosecution of a long and arduous duty. 60 EUROPEAN LIGHT-HOUSE SYSTEMS. And if this acknowledgment is due to the members of the committee, much more is to be accorded to their distin- guished scientific guide, Dr. Tyndall, -who at great incon- venience to himself, with serious encroachment on his valu- able time, and frequently some personal discomfort, has applied himself to this investigation with characteristic liatience and perseverance. Step by step, after repetitions almost wearying to those unversed iu such trained and dis- passionate habits of procedure, the conditions affecting the traveling-power of sound have become clearer and clearer, old errors have been corrected, and a great advance has been made toward arcurately estimating the value of sound- signals; and the important knowledge has been acquired that the seaman's greatest enemy affords in itself aid to mitigate its worst evils. " To Mr. Douglass also and his assistants much credit is due for the very thorough and efiQcient manner iu which they performed their duties in connection with this inquiry, and Mr. Douglass's assistance as a practical observer ou board the yachts has throughout the experiments been of great service. " Observations at sea were commenced on the 19th of Miiy, 1873, after some months previously employed by the engineering department iu mounting the requisite instru- ments, (the selection of which was based upon the report of the committee who had visited the fog-signal establishments of the North American seaboard,) and iu making such arrangements as wore suggested by the experience of the Elder Brethren and Mr. Douglass or by the views of Dr. Tyndall on the subject. From that time to the 21st of Feb- ruary, 187-1, on shore and at sea the observations have been going on at short intervals, and frequently for weeks together. "Foremost among the practical results is the important fact before alluded to, viz, that fog does not impede the transmission of souud, (as has long been supposed ;) indeed, it is shown that a foggy atmosphere is a highly favorable condition for the traveling of the sound-wave; further, during heavy, blinding rain or snow storms the passage of sound through the air is not obstructed ; indeed, the observations of the committee in the former case record an increase in the power of the souud either during or immedi- ately after a rain-storm ; while the evidence of Dr. Tyndall of his Alpine experience with regard to falling snow may be accepted as proving the latter. It may safely be concluded. EUEOPEAN LIGHT-HOUSE SYSTEMS. 61 tlierefore, that whenever the state of the weather is such as to render sound-signals necessary, the atmospheric condi- tions are most fa%'orable for their efificient application, and it may also be concluded that, under the conditions of weather above referred to, the range of the signals will .be much greater than the limit laid down in the report as the result of the general observations. " Turning to the action of the wind upon sound, the report confirms all previous experience, and shows that the most powerful sound fails to penetrate the opposing force of a strong wind to any considerable distance; but it is satis tory to be assured that even against a moderate gale and unfavorable conditions for sound-transmission signals may be relied on for sending sound to a distance of two or three miles, and, under ordinary conditions of fog, considerably farther. Having regard, however, to the variability of the sound-range of the same instrument on different days, attributable to the varying conditions of the atmosphere, it is not possible to assert positively that any signal has an absolute range which may be relied upon at all times. The practice of the Elder Brethren of not publishing in their notices of fog-signals a maximum range of audibility, or of accepting isolated instances as everyday occurrences, is therefore amply justified. Happily long ranges are not very necessary, inasmuch as the mariner does not need to hear a sound-signal at ten, fifteen, or twenty miles. Dr. Tyndall quotes, in relation to this part of the subject, an opinion expressed by our late scientific adviser, Professor Faraday, that ' a false promise to the mariner would be worse than no promise at all.' The Brethren need scarcely be reminded that in so saying our dear and venerated friend was simply giving utterance to the standard axiom of the Trinity House, as old, perhaps, as the corporation itself, viz, that safety is only to be found in certainty, and that anything which does not secure the latter condition is a foe, rather than a friend, to the mariner. " Bearing in mind, therefore, the liability to atmospheric interference under ever-varying conditions, as shown in the report, attention mast next be directed to the instruments used in the investigation and the conclusions arrived at with regard to each of them, so far as the inquiry has now advanced. "The instruments tried were the American siren, Holmes's ti-iimpets, American, Canadian, and English steam-whistles, a:i(l fclu-ee guns. The effects obtained trom all these instru- ments have varied in a remarkable manner at different C2 EUROPEAN LIGHT-HOUSE SYSTEMS. times, but for general efficiency there is no doubt that the American siren takes the first phice. It has shown the greatest penetrative power, especiallj' where local noises have to be overcome, but at present it has the drawback ot being worked by steam at the high pressure of 70 pounds, which is not only a serious element of danger, but entails considerable expense for fuel and labor. Mr. Douglass, however, tells us that the caloric-engine will work the siren, and he confidently anticipates being able to do away with steam altogether, and so to render this instrument a safe, economical, and efficient signal for general adoption. " The air-trumpet has also shown itself to be an efficient instrument, superior to the whistles and sometimes equal- ing the siren. Its chief advantage is that it is blown by means of the caloric-engine at something over 20 pounds' pressure, and can be worked without skilled labor, and, avoiding the danger attendant upon the employment of steam or gunpowder, combines safety with economy ; and its clear, musical note may be an element of distinctiveness capable of being developed so as to make it ultimately of some service in this respect. In actual practice there are one or two drawbacks to the use of reed-instruments, such as the difficulty of tuning, liability of reeds cracking, &c. Such contingencies are not likely to arise in regard to the siren, and if the economy and simplicity of working by meaiis of the caloric-engine can bo also applied to the more powerful siren, it seems clear that the result will be highly advantageous as a most useful combination of power, safety, and economy well suited for fog-signal purposes. JSfever- theless the satisfactory performance of the trumpets during the late trials fully justifies their present employment as fog-signals. "Not so much can be said in favor of whistles. Through- out the trials their marked inferiority to the other instru- ments has been rotiorded. The American whistle, yielding a harsh roar, when close at hand was deafening, but its sound failed to penetrate to any useful distance.* The Ca- nadian whistle appears to have been better, but it also failed in general effective ])ower, although occasionally it Avas heard a great distance, even obtaining superiority over the other instruments, but this was of very rare occurrence. As a rule, the whistles were behind the siren, trumpet, and gun, and seem to have been dependent, more than the other instruments, on exceptional atmospheric conditions for * Tliis statement does not agvee with our expcrieiico in tlie pr.ac'.ical nsc of a largo number of steam fog-^vllistles on 1 lie scaooast of the Uuiteil States.— E. EUROPEAN LIGHT-nOUSE SYSTEMS. 63 yielding their best results. The general conclusion seems to be that for i)ractical purposes the steam-whistles, as at present tried, are not proved to be advantageous as fog- signals. " With respect to the usefulness of guns, it appears from the report that they possess certain disadvantages, viz, the short duration of the sound, the liability of that sound to be quenched by local noises, and its comparative ina- bility to cope with an opposing wind. Dr. Tyndall never- theless ranks the gun as a first-class signal, an opinion which long experience of its use confirms. The gun, as a signal, is well known to mariners, while the flash is also said to be of service in thick weather. With regard to the guus used in the experiments, it appears that the short 5J- inch howitzer, with a 3-pound charge, is superior to the long 18-pounder or the 13-inch mortar with the same charge, the howitzer having generally yielded a louder and more effective report. The subject of a special gun for fog-signal purposes is now under consideration, and it seems probable that both in effective power and facility of working, the gun may be rendered considerably more serviceable than hitherto. "From the foregoing observations it will be seen that at present there are three kinds of instrument practically avail- able for future service as fog-signals, viz, the siren, the trum- pet, and the gun, and as further experience is gained with regard to these instruments, it may reasonably be expected that great improvement will be made in them and that the future results to be obtained from them will surpass those now recorded. " It will be well now to consider brieflj- one or two points in connection with the selection of a site for, and the instru- ment to be used as a fog-signal, when the locality has been determined upon. In the investigations the question as to the height above the sea at which it is desirable that a sig- nal should be placed has received some attention, and the results show that it is advantageous that such signals should be placed at a considerable height above the sea-level in or- der to avoid the interference caused by the noise of waves breaking on the shore, the rattle of pebbles, &c. The com- parative trial made between a pair of liorns on the summit of the South Foreland cliff and another pair L'OO feet below, close to the sea-surface, proved with scarcely an exception that the higher horns were superior to the lower ones. From this it would appear advisable, where possible, to place the signal high above the sea, but there are positions on our 64 EUROPEAN LIGHT-HOUSE SYSTEMS. coasts where fog-signals are necessary, and yefc where uo considerable elevation could be obtained, notably Dunge- ness, Orfordness, &c. For such positions, therefore, a large and powerful siren would be very suitable as being able to overcome the noises of the sea-shore. For river-banks, light- vessels, and other places undisturbed by interJ'eriug noises, a smaller instrument of the same description, or a trumpet, would prove serviceable, and the gun would be a fit signal lor such places as are of some elevation clear above the sea, without adjacent outlying rocks, and which vessels may ap- proach 'close to.' It is not intended in the above sugges- tions to lay down any system which shall be invariably fol- lowed in the allocation of fog-signals, but, having regard to the performances of the instruments referred to as shown in the report, the foregoing observations may be regarded as indicating to some extent how the respective merits of the instruments may be most usefully applied. " While upon the subject of fog-signal sites allusion may be made to the caution conveyed in the report that in select- ing the position for a fog-signal the possible influence of sound-shadow must be taken into account. This is a point to which reference was made in the report of your committee to America, it being therein recorded that in the experi- ments carried out at Portland Bay, United States.* the effect of a sound-shadow was distinctly experienced, and your committee stated in their report that ' in selecting the site for a fog-signal care must be taken that no outlying point or cliff shall interfere with the arc of sound.' It is satisfac- tory to find the conclusion of that committee on this point entirely borne out by the investigations of another. " Another important conclusion to be drawn from this report iu regard to the question of sites is that no signal should be required to mark dangers extending seaward more than a mile or a mile and a quarter. The minimum effect- ive range of a signal being 2J miles, vessels approaching such dangers and coming into the sound-range would have room to maneuver and be able to keep at a safe distance. This is, of course, taking the minimum range of the signals, as stated in the report, but it is more than probable, as has been stated previously, that in foggy weather, the sound- range being extended farther than the minimum limit re- ferred to, a larger range may be allowed. "Another important consideration has to beborueiumind, viz, the direction in which sound should be projected. As *Tho exporiincuta referred to bave been carried on from tiuic to time lor somo years, raider tlic direction of Professor Henry. — E. EUROPEAN LIGHT-HOUSE SYSTEMS. 65 tlio sound of a signal is ascertained to be most effective in tbe line of its axis, it follows that the instrument should be capable of such adjustment that its strongest sound may be projected directly against the opposing wind. " It is to be observed that on another point these experi- ments confirm the opinions expressed by your committee to America, for, with regard to the question of distinctions, it is clearly shown that it is not possible to rely upon dis- tinctiveness of note alone, for the mariner would not appre- ciate such a distinction; indeed the siren, horns, and whistles have invariably been spoken of by sailors in the vicinity as " the fog-horns." Between the report of the gun and the sound of the siren or the trumpet there is a perfectly intelligible difference ; but for further purposes of distinction for the latter instruments, variation of the length of the silent interval between each blast offers the most satisfac- tory means. With regard to this point it will be seen that Dr. Tyndall has, with some reservation, expressed an opin- ion which hardly seems to harmonize with the exi)erience of the Elder Brethren. Dr. Tyndall would restrict the silent interval to a length of 30 seconds, and in support of his opinion draws an analogy between the action of the eye and the ear, which does not commend itself to actual nauti- cal experience. The board will probably not be disposed to waive a clear advantage in power and great scope for distinctiveness, in order that the longest interval of silence should not exceed 30 seconds, especially with the knowl- edge that guns fired at intervals of a quarter of an hour . have proved of great service to the mariner hitherto. "A general review of the entire report shows that a con- siderable amount of knowledge has been gained, both as to the influence of the atmosphere in the transmission of sound and to what extent the appliances we possess may be relied on for producing" such sounds as will bo of practical service to the mariner. Wc have learned something of our igno- rance in regard to sound-transmission. We now know that the varying conditions of the atmosphere render no judg- ment infallible, and that conclusions founded on tbe ex- l)erience of to-day, are not trustworthy for estimating the results of the morrow. We know, moreover, that after bringing forward all the aid which science can at present give to guide the mariner in thick weather, there is still a large element of uncertainty and mystifying influence with which he has to combat, and which renders it incumbent ou him to use the greatest caution and prudence in thick S. Ex. 54 5 66 ICUEOPEAN LIOnT-HOUSE SYSTEMS. weather, to regard and make use of the souud-siguals as means for assuring the vessel's position, and not as aids for running at high speed ; and, above all, never to trust so implicitly to sound-signals as to neglect the use of the sea- man's best friend and truest guide, the lead. " The subject of fog-signals has by means of this investi- gation received a great impetus. It may fairly be said that we have taken a considerable step in advance, and it only remains to follow it up. As we go forward our experience will widen, and although it is more than probable that a few years of practical experience aud testing of fog-siguals will materially modify our present views, and improve con- siderably the instruments we have, yet we now know ]u)w to go forward and in what direction to head our efforts. It is to be hoped that before very long our coasts will be guarded by a complete chain of sound-signals, all effective and useful to the mariner. No unnecessary delay need now occur before proceeding to supply the light-ships and the important stations already selected by the board, and when they are all established the lights rendered useless at a quarter of a mile by fog will be superseded by sound-siguals capable of warning the mariner at a distance of three miles. " It is almost iinnecessary to add that in thus giving practical effect to the spirit of the recommendations of this valuable report, the Elder Brethren will have the satisfac- tion of knowing they are acting in the highest interests of humanity and conferring an inestimable boon on the nauti- cal community at large." SOUTH POEELAND. 'Location. The great electric lights at South Foreland, two in num- ber, are three miles east of Dover Pier, on the high chalk-cliffs overlooking the Strait of Dover, from which can be seeu Gris- iici'htoi- focal "*^^ ^^^ other French lights. They are about 1,000 feet apart, ■j>]m<£ the high light 372, the low one 275 feet above the sea, and Ibria a range or lead as a guide to clear the Goodwin Sands, one of the greatest dangers in British waiters. A general i)lan of the establishment is shown in Plate I. EugincJionso. -^ flrc-proof enginc-housc, a plan of which is shown in Plate II, is placed midway between the towers, and con- tains the magneto-electric machines, the engine-room, boiler- room, coal-room, and two repair-shops. Near hj are the dwellings of the engineer who superintends the establish- ment, and those of some of the keepers, there being six at this station. J>wellin*r3, EUEOrEAN LIGHT-HOlTSi; SYSTEMS. C7 The electric current is generated by means of large mag- siaenptooiic- ,,,.,"' •1-1 J. 1 tiit^ niacliiiu's, neto-electric machines, two of which are providetl lor each light, though habitually in clear weather but one machine is used for each. These machines are driven bv means of ^i""."''' "'' <■■- r a 1 1 11 j; t Ij t' belting connected with a steam-engine, a duplicate of which sanw. is kept for use in case of accident or repairs. The boilers, which are of the ordinary locomotive class, are also in du- ])licate. About 56 pounds of coke per hour are consumed Cdki! uswi. during the night; during the day the iires are banked. One of these electric machines is of French manufacture, iriioiiinos .if having been made by the Compagnie V Alliance of Paris. The giish luamuac- others are English-made machines of Professor Holmes's patent, and are considered by the Elder Brethren to be su- perior, though the French appeared to be the simpler in con- struction and is the one shown to visitors in explaining tlie operation of generating the electric current. This operation is fully illustrated in the description, which will be found .DLdrripti.m further on, of the magneto-electric lights at La Here near the mouth of the Seine. It may be well to stase here, however, that each machine iieiicos. is composed of ninety-six helices mounted upon six gun- metal wheels, each having sixteen helices. Between these wheels are placed the magnets, eight in napiets. each division, forty of w^hich are composed of six layers or leaves riveted together, and sixteen (the end ones) similarly constructed but having only three leaves or layers. These magnets, which are mounted in frames, are stationary, while the helices revolve at the rate of four hundred revolutions per minute. The power absorbed by the machine alone, disregarding Pnworrcnmna '■ •' J o o f|„, operating I,l,f friction, is four indicated horse-power, and the actual power muciiiiits. required to work one of the machines, including the friction of engine and shafting, is six indicated horse-power. The power of a magneto-electric machine is according to j, ^,^^ ^^ ^,^^ the gross attractive power of its magnets, each magnet hav- maciiiues. iug a certain lifting or attractive power, (expressed in l)Ounds.) In the p>nchines at South Foreland each of the six- plate magnets -^ill lift 108 pounds, and each three-plate magnet will lift 54 pounds, making the attractive power of the magnets in one machine to be 40 x 108-f 10x54=5,184 pounds. This may be considered as expressing the ]>ower of the machine. The proportion of the lifting power to the actual weight of a magnet is a good indication of its value, and, generally speaking, a magnet which will lift two and one-half times its own weight is a good one. Each six-plate , magnet at South Foreland has a weight of 43J pounds, and \:\\ao of mas G8 EUROPEAN LIGHT-HOUSE SYSTEMS. will lift lOS pounds. Tlie total weight of all the magcets iu one machine is 2,088 pounds, the total attractive power being, as stated, about 5,184 pounds. (nijicaoomiect- Tije macbincs are connected with the electric lamps placed i""iM- in the lenses of the tower by underground cables. f.Jsilr"'" ivndau Themauncrof Operating these machines, the arrangements 1^1 (siiiauauons, gf |^[jg Icuses, lamps, &c., were carefully explained to me by Professor Tyndall, who had kindly accompanied me through the station, and who spared no efforts to make my inspec- tion a thorough and minute one. Carbon points, Each lamp contaius two pieces of carbon, each of which is about 10 inches long by three-eighths of an inch square. These are placed end to end, one above the other, and are kept at the proper distance apart by an automatic apparatus. The current leaps across the small space separating the ' carbons,' and a series of sparks is formed, but so rapidly that the eye cannot separate them, and a most brilliant light is produced. By the automatic apparatus the carbon pencils are moved toward each other as fast as they are consumed, and the only danger of irregularity of the lights, t .!''^^)feJence™S '^ *-^® machiues and cables are in good order, arises from !'",'-" ,'"""'='^ the presence of foreign matter in the carbons. I was told la Lln) carbors. ^ " by the keepers that the carbons in use give them trouble in this particular, the lights being sometimes extinguished. This is only for an instant, however, as all that is neces- sary to relight them is to bring the carbons in contact, after which they are replaced in their i)roper positions. foAnam.g?ngthe '^^^ arrangements for bringing the electric light to the focus lifi.t. Qf ^jjg leyg^ and for feeding the carbons as fast as they are consumed, are simple and ingenious, and the duties of the keepers, beyond watching for the occurrence of imperfec- tions in the carbons, are very light. These carbons are made from coke-dust; their rate of consumption is 34 inches per night for each light, at a cost of one penny per inch, exclusive of waste and breakage. i,rasc3. Tiie lenses in use at South Foreland are of abont the same size as ordinary third-order lenses, (39 inches interior diameter,) and were especially designed for the electric light and this locality by Chance Brothers & Co., of Bu-- mingham. i' •imiuition''"'" '^^^ ^^^ °^ illumination required being but little more -rriiizit.g the than 180°, the rear light is ingeniously utilized to reen- ! ar .IK 1 . force the other by means of totally reflecting prisms, and it was observed that a much greater development was given to the catadioptric prisms below the central belt than can be done in the use of the large burners of the oil-light. EUROPEAN LIGHT- HO USE SYSTEMS. 6d Both lights are fixed, and illumine somewhafc more than Dcsoriptiou t.r half the horizon. In both the portion of light which -would tus."''' '''''""•'" otherwise be wasted landward is led round by subsidiary apparatus to intensify the illuminated arc; but the low light presented the peculiarity that it was desired to light the sea brightly from the horizon to 300 yards from the base of the tower, and as the height of the local plane is 290 feet above the sea, this requires that a portion of the light should dip below the horizontal plane no less than 17° 23' 32", while the major portion should go to the sea-horizon. This requirement was met in the following manner: The light Mam appar.i- from both the top and bottom systems of reflecting prisms was directed wholly to the horizon, while the central refracting portion of the cupola was specially arranged to give the required dip. The latter consists of sixteen re- fracting segments, eight above and eight below the focal plane, there being no central refracting belt as is usually the case. These refracting segments are so arranged that the intensity of the light viewed from the point distant 300 yards, or from the horizon, is sensibly the same ; also, that no portion of the sea shall depend for its illumination on one prism only, as otherwise that point might be placed in total darkness, owing to a lantern -bar or other obstacle intercepting the light. The arrangement adopted for using the light which would suiisiainry nj- otherwise be wasted toward the land is symmetrical about p"''"'"''- the middle line of the apparatus, each half consisting of a portion of a holophote, and of a frame of six vertical prisms. Tlie former condenses the light of the spark into a beam of horizontal parallel rays, which pass to the side of the appa- ratus and are there distributed over half the illuminated arc by the vertical prisms. The rays emerging from these prisms do not pass through a single focus as in lights pre- viously constructed on the azimuthal condensing plan, but each i)rism has a special focus so situated that the light is equally distributed over the arc illuminated. Probably the l>lan of a common focus was adopted in some earlier cases as simpler for calculation, and also in order to facilitate the examination of the apparatus for adjustment, but the exam- ination can be conducted with equal accuracy with special foci, and no trouble should be spared to render such an ap- paratus as perfect as possible. The outer prism of the set is of a special and difficult construction, required because the arc it has to illumine is situated at so great an angle from the direction of the rays it receives. Prisms of a sim- ilar construction had been previously suggested by Mr. 70 EUROPEAN LIGHT-HOUSE SYSTEMS. Thomas Stevenson, engineer of the Scottish lights, and have been used by Mr. James Chance iu several other instances. In cases like the South Foreland, many plans for attaining the end in view suggested themselves. It niight be pro- posed that some arrangement similar to the subsidiary one at Souter Point (which will be described further on) should be used. Such an arrangement would be unsuitable in the case of South Foreland, for various reasons, among which may be mentioned that the light would pass through three optical agents instead of two. At Souter Point, the light being revolving, the only feasible plan was to tajje the spare light downward through the pedestal. Again, the central cupola might have been continued entirely round the spark and the spare light from the land-side of the cupola reflected seaward by large vertical prisms. This plan was rejected on account of its being unnecessarily expensive, and for other reasons. The advantages of these and other plans were considered by Mr. Chance before he adopted the ar- rangement shown on the drawing. jioiUrator- To supply any contingency necessitating its use a "mod- c™J'.if acci(knt. erator" oil-lamp is placed under the electric lamp and can be quickly substituted for it. This lens is shown in eleva- tion and plan iu Plate III, in which a and a' show the elec- tric lamp in position and withdrawn for removing the car- bon pencils ; h b, the carbon pencils ; c c, the electric wires ; d, the bed-plate ; c, the burner of the oil-lamp ; /, the tele- scopic supply and overflow pipes for the oil ; g, the oil-lamp ; h, elevation of one of the half-holophotes ; h' h% the two half- holophotes in plan ; i i, i' i', vertical condensing prisms. In substituting tlie oil for the electric light, the bed-plate d is removed and the oil-burner e is run up to the focus by i'oHi>r of ckc- means of a rack and pinion. The power of the uncondensed '''■^ '" ' beam from each of the electric lights at South Foreland, i. e. of the naked light without the condensation of the rays produced by the lenses, is equal to the combined light of 2,000 candles, while the corresponding power of the four- wick sea-coast light-house oil-light is 328 candles. Estimat- ing the power of the condensed beam from the South Fore- laud lenses as ninety times the power of the naked light, (which is tlie result of Mr. Chance's calculation of the con- deusing-power of the South Forelaud lenses,) we have for tlie power of the beams from each of the electric lights at South Foreland, 180,000 candles ! '/, ,rviiiini,^i,t I was sliown the method of lighting the electric lamp, ji.iiMiomUovcr^j^j^ in the evcuiug observcd the two lights from Dover Pier. While the upper light was decidedly the superior, tlie lower SOUTH FORELAND LIGHTHOUSES. ELECTRIC LIGHTS. PLATE IJI. DETAILS OF LANTERN AND LEINS SCALE. jz f If J t a 4- .f Jfu^iry h \i I ' 1 ' ' I -t— THE GRAPHIC C0.PHOT0-LITH.39 441 MRK PlACE.N.r. EUROPEAN LIGHT-HOUSE SYSTEMS. 71 ■waxing and waning very perceptibly, which was caused, as Mr. Douglass iufortned me, by some imperfection in the ma- cliiuery, both of tliem surpassed anything I had ever seen, and I could not convince myself that they were three miles otf. Even at this distance, the shadows of objects on the pier were very distinct. Tlie towers supporting these lights are not high, (their site being an elevated one,) and they are attached to keep- ers' dwellings. The buildings are all constructed in the iiuiuuiigs. most substantial manner, and each dwelling is sufficient for the accommodation of two keepers and their families, with room for the supernumeraries who are kept at the station for instruction. The steam-engineer (the principal official of iiMciiines mrm- the establishment) and the principal light-keepers are com- enjrinm:i- iuMi petent to manage the engine and magneto-electric machines, er"'"''' '"' '' and they attend to this duty in turn. No laborers or fire- men are employed. The dwellings at this station, as at all the stations I visited on the English coast, were kept ex- tremely neat. Eooms for accommodation of any visiting Kcmma n.r ar- officer of the Trinity House are fitted up in the dwelling '^'i:'''''v ^^a^o attached to the engine-house, and everything is provided for his comfort, even to a full set of table-furniture. Attached to the central station (the engine-house) are the stmeroDms. different store-rooms for the supplies, which include lubri- cating and colza oils, the latter for use in the lenses in case of failure of the electric light or of other accident ; but I believe it has rarely if ever been needed. Some of the oil- butts are of tin, the others of galvanized sheet-iron. oii-butts. The colza (rapeseed) oil is of a pale sherry-color, very Coiza-oii. c'.car and limpid, with a strong and peculiar vegetable odor. In all the houses the steps and stairs, as well as the paving of all the halls and corridors, were of stone, rubbed once a week with Bath-stone, which produces a color like that given by a wash of hydraulic cement. In the towers, and also at the engine-house, speaking- tubes are arranged to communicate from one to the other, ^ s i> c a ic i n g - and for the purpose of calling relief. I found such tiibesat all the stations I visited. Each keeper's watch is four hours. Both watch-rooms and lanterns at South Foreland are watciiicMmM considerably larger and more commodious than our own. "ize of. At each dwelling is an earth-closet, placed in an out- ijanii-oiosi'M. building, in which, instead of earth, the ashes produced at the station are used, and I was informed that the use of earth-closets at light-stations is universal, and gives entire satisfaction. 72 EUROPEAN LIGHT-HOUSE SYSTEMS. Fire, moans for Meaus foF extinguishing accidental fires are provided by fxtiiigiiisbiug. ^jig engine whicli drives the magneto-electric machines. The pumps are connected by pipes to each of tlie towers and dwellings, the water being drawn through the chalk, from a well at a depth of 200 feet, during high tide in the Strai' of Dover, when the water baclvs up into the w^ll. Eeser voirs are provided for use at low water. niotonroiogicai Two kecpcrs are designated for each tower, who, in addi oi.stnatious. ^.^^ ^^ ^jj^jj, qi-ijpj, duties, make daily observations with the barometer and with wet and dry bulb thermometers, keep- ing memoranda for the use of some department of the gov- TLc keepers, crnmeut. The two principals, who are assistants to the en- gineer, I found to be very intelligent men who seemed thoroughly to understand the magneto-electric machines, and who gave me a very accurate account of their opera- tion. One of them was by trade a watch-maker, and the other a stone-mason. The latter told me, T\ith evident pride, that he had laid all the stone at the Bishop Eock, near the Scilly Islands, one of the most exposed stations in the English service, and had been for some years the prin- cipal keeper of that light, a position he was obliged to re- sign, the close confinement affecting his health. Each ot these men had been more than fifteen years in the service. cost«f mainte- ^^^'^ aniiual cost of maintenance of a single electric English Miioe of iifiut. ligijt jg about £800, (or $i,000,) about double that of a first- order single oil-light station, while the light produced by the former is between six and seven times that of the most powerful lens with the four-wick Douglass oil-burner. Cost of onbsii- The approximate cost of substituting at a double-light iisbt'''npimra*tnt Station, the magueto-electriclights as used at South Foreland ic, lor oil. £^j. ^jjg oil-lights commonly used is as follows: Building works £7, 3G0 $3G, 800 Lantern and dioptric apparatus 3, 088 15, 440 Electric-apparatus 5, 35G 2G, 780 Miscellaneous 050 3,250 Total £1G, 454 882, 270 I am indebted for my detailed description of the excel- lent optical apparatus at South Foreland to the manufac- turers, Messrs. Chance, Brothers & Co., of Birmingham. THE KOMAN PHAROS IN DOVER CASTLE. ^. ., ,, Throug-h the kindness of Colonel CoUinson, of the Roval Visit to Dover » ' '• Oastic. Engineers, I had an opportunity ot visituig the castle at Dover, and of attending a review of the three regiments of Kent County militia, and of the garrison of three regi- EUEOPEAN LIGHT-HOUSE SYSTEMS. 73 mcnts of regular troops. Colonel Collinson showed uio many objects of great interest — the grand old castle, from wbicb were distinctly visible the coasts of France, the tow- ers of tbecatbedral of Boulogne, and the light-honse at Calais, on the other side of the Channel ; the rooms occupied by Charles 1 and by Queen Elizabeth ; the church of Saint Mary, Within the Castle, founded A. D. 101,* and the modern exte- rior forts ; but nothing was more interesting to me, consid- ering the nature of my mission to Europe, than the old pharos within the castle walls, the present condition of which is reijresented in Fig. 1. FiR. 1. Roman pharos in Dover Castle. The antiquity of this light-house, which has not proba- bly been used as such since the Conquest, no doubt ex- ceeds that of any light-house in Great Britain, and it is supposed to have been built in the reign of the Empeior Claudius, about A. D. 44.* Upou it burned for many centuries those great fires of wood and coal formerly maintained on several towers still standing on the coasts of Great Britain. These earliest guides to mariners at length gave way to reflectors; they, in their turn, being replaced in the year 1819 by that great dhtb of inv™- triumph of scientific skill, the Fresuel lens. system. ° The pharos, like its sister lighthouse, the Tour d'Ordre constrnotion > i at Boulogne, is built of brick, in color and shape like those*''" '''"""" iu the Koman structures found elsewhere in Great Britain ; Description of they are of a light-red color, about 14 inches long, and not* " """''" '"'''■ more than an inch and a half thick. This latter dimension * Hasted's History of Kent. 74- EUEOPEAN LIGHT-HOUSE SYSTEMS. is but little more thau the tbickness of tbe joints, wbieb are filled with a mortar composed of lime and finely-powdered Eoman brick. The preservation of this famous relic of the Eomans iu England is doubtless due to the fact that some centuries ago the tower was turned into a belfry for the church of Saint Mary, and was surrounded by walls of stone. These are now nearly destroyed by time, and the old Eoman ■work is again exposed. While the Trinity House steam yacht Vestal, iu which I was to take my first cruise among tbe English lights, was fitting out for her annual voyage to the northeast coast of England, I made frequent visits to the Trinity House, Visits to Trin- whcre I was always cordially welcomed, and thus I acquired .ty uousc. uiueh information regarding the English lighthouse sys- tem. KindDOBSTc- I rcccivcd much kindness in many ways from Sir Ered- rojved from Sir , r^.. /.-»» . , , . ].io(icricu Ar-erick Arrow, and on the 21st of Jjlay accompanied bim to a dinner at the Mansion House, to which, through bis good Dinner .it tbe ofilcGS, I had the honor to be invited by the Lord Mayor and Loi(iiiayoi3. Lf,(]y ^|;,Yoress, by whom it was given iu honor of there- turn of the Master of Trinity House, the Duke of Edin- burgh. About three hundred guests were present, and it was a highly enjoyable and interesting occasion. A.itnowi e!c M gsaujHjjuui^ EUROPEAN LIGHT-HOUSE SYSTEMS. 77 as desired iu thick and foggy weather, being in this regard similai' in effect to tlie electric and gas lights, although it is not possible to make the iiroportionate increase so great with oil-light as with those just mentioned. These lamps are of different orders. Among those I saw six-wiuk 1.™!.. at Blackwall was the six-wick lamp for mineral or colza oil, (in which mineral oil was to be used,) designed to be placed in one of the towers at Haisborough, on the east coast of England, for experimental comparison with the gas-light, which will receive mention when I come to describe that station. This lamp is called by Mr. Douglass the " lamp of single Descrip.tion. and double power," from its capacity for increasing or diminishing the light to suit the state of the atmosphere. For example, in the case of the six-wick burner, shown in Plate IV, the ordinary fair-weather light is produced by the liame from the outer three wicks only, but, as the weather becomes thick or foggy, the inner three may be successively lighted, increasing the power of the flame from 342 to -722 L-andles — more than double its fair-weather power. These lamps burn either animal, vegetable, or mineral oil. The burner of one for six wicks is shown in Plate IV, in which figures A and B are elevations showing the ad- justment for burning mineral and colza oils respectively, and figure C is a section of the latter ; a is the chimney- holder; J) i the chimney; c the exterior deflector; d the outer wick-case ; e the inner cases ; / the central air-space ; ff the interior deflector ; A' and A" plan and section of in- terior deflector for mineral oil ; B' and B" the same for colza- oil ; D the central button, and E an enlarged view of the burner-tips. In burning mineral oil the wicks are raised about one- usc of mineral Oil. sixteenth of an inch above the tips of the burners, and the exterior deflector is kept in the position shown at A in Plate IV. In burning colza the wicks are raised about five-six- uso of coiza. teenths of an inch above the tips of the burners. The oil overflows as in our lamps, and the exterior deflector is placed as shown at B, Plate IV. Aboutoue and one-fourth inches below the topsof the wick- cases are small holes, kept closed by caoutchouc valves when colza is used, but when mineral oil is burned the holes arc opened and the oil is maintained at that height. Both the exterior and interior deflectors are readily re- fl,So"r"' "^ *'*' moved for the purpose of trimming the wicks. The " buttons" and " tips " are the same for all sizes of^°«<'°''""i"i"- 78 EUROPEAN LIGHT-HOUSW SYSTEMS. lamps, their number correspondiog to the order of the lamp, i. e., the "tip" and "button" of a one-wick lamp is appli- cable to the inner wick-case of a two, three, four, five, or six wick lamp, and a tip of any speciiied number will fit the corresponding wick-case of any order of lamp. Zone of maxi- Mr. Louglass states that a notable feature in the flames mumm ensi y. ^^ ^^^ improved lamp is the increased power of the beam in the direction of the sea-horizon over that from an old one of the same initial power, such increase being due to the narrow zone of maximum intensity found in the flame of the new burner, and which is fully utilized for the longest range by the refracting portions of dioptric apparatus, in the old flames the zone of maximum intensity does exist, but the difference in power between it and the portions of the flame of minimum intensity is not great. Adoption of This levcl of maximum intensity, shown at h h in Plate mumint'eMTty^'l'V, is HOW bciug adoptcd by the Trinity House for the sea- horizon focus of the refractors of dioptric apparatus and its height above the tips of the burners in the several lamps is as follows : Millimeters, Height above Burner of one wick 13 I,t"rncr "^ ""'Burner of two wicks 14 Burner of three wicks 15 Burner of four wicks 10 Burner of five wicks 17.5 Burner of six wicks ; 19 Gaintoiightat With thcse adjustments of the foci some light is neces- tho zono of max- , n- n n ■• -,• , • . , - imam intensity, sariiy cut off irom the lower catadioptric prisms by the " exterior deflector," but the increase of light from the re- fractor is very great, it having been found that the power of the light sent to the sea-horizon or maximum range is from 25 to 30 per cent, more than can be obtained from one of the old flames ; that is to say, by taking two flames, one old and one new, of the same total initial candle-iwwer as measured by the photometer, the beam of maximum in- tensity in the direction of the sea-horizon from a dioptric apparatus with the new flame in focus will be 25 to 30 per cent, greater than with the old flame. Gas-bnrner. I was showu a ncw kind of gas-burner, an invention of Mr. Douglass. The top is perforated with a circle of very small holes, and this is combined with a perforated button similar to that used for the oil-lamp for light-houses. Out- side is placed the adjustable jacket or cone, and the ad- justable chimney is also used. EUROPEAN MGItT-nOUSE SYSTEMS. 79 Tbe liglit from this Fiff. 2. JFpcalM \fZane Douglass Gas-burner. giis-buruer, -which is shown in Fig. 2, was not, in the experiments at Blackwall, equal to that from either colza or mineral oil, on account of the inferior quality of the gas at that place, but I was told that it -was a marked improvement over the com- mon gas-burner. Mr. Douglass told me thatthe power Actu.ipowercf of this Argand gas-burner when burn- e^^ ''"raei-. ing London gas of sixteen candles is about the same as that of the Argand oil-burner, viz, twenty-three candles, and the consumption of gas is about 30 per cent, less than the best burner before used in England. Thebuttousforthe gas-burner when ^ , „ , , , Buttons TfhcTi made oi brass last but a little while. """'« f*" bmsB ™, , , , soon destroyed. 'Ihey have been made of platinum, but this is expensive, and when I last heard from Mr. Douglass he was ex- perimenting with buttons made of lava, which promised good results. He states that there isnodifaculty in producing a gas-burner of the size of „ , , . . . Gafl-bnriicr the tne six-wick Oil-lamp, or even larger, ^'^oofasix-wici; , T . . . ^ o ? lamp easily pro- on the same principle. One of flveduced. rings of flame has been tried, and the illuminating power is precisely the same as with the small burners 'pro rata of gas consumed. The following extract from a letter Lav.i proponed. of recent date, written me by Mr. Douglass, may prove of Extract from importance to us in the future, and 1 here place it on record : a*" ilccn™.v?pTt? " I have just found that a patent has been taken out by ™'^' ^"^ """"' Mr. Silber (the patentee of a miueral-oil burner) for a gas- burner nearly identical with mj' own, but, fortunately, the date of the patent is nearly a month after I reported to the Trinity House the results of experiments made with burners I had made for some new light-houses. It is probably important that you know this, as it is not unlikely that a patent has been taken out for the burner in America. I will send you a copy of the paper as soon as it is published." As I have before remarked, the light-house establishments inoroaNc of . powerof lifrblaiid of Europe have greatly increased the i)ower oi their lights decrease ut tx- peD&es. so EUROPEAN LIGHT-HOUSE SYSTEMS. llcport of itr. Douglass. •with a concurrent decrease of expense, changes which have been produced by the introduction of mineral-oil and the improvements in burners. / I can best illustrate this important subject by quoting one of the earliest reports in regard to this matter made by Mr. Douglass to the Trinity House, dated 30th of March, 1871, which I find in a " Eeturn to an Order of the House of Commons dated 26th of June, 1870, for a copy of ' Corre- spondence between the general light-house authorities and the Board of Trade, relative to proposals to substitute min- eral oils for colza oil in light-houses.'" " Teinitt House, March 30, 1871. " Eeferring to the various and lengthened experiments which have been made at this House for the purpose of de- termining the suitability of paraffine and petroleum oils for the illumination of light-houses, and the most efiScientlamp for consuming these mineral oils, I now beg to submit the following report : Samples of oils " For the purpose of ascertaining the relative merits of parafSne and petroleum oils, a sample of the best burning l)arafflne was obtained from Messrs. Young & Co., and sam- ples of the best burning petroleum-oil were obtained from two respectable manufacturers of that article. The sauiples were as follows, viz : obtained. C o ni p a rativo table. Specific gravitj'. Flashing- poiut. Net price per gallon. Messrs. Tonng & Co.'s parafflne-oil XiiniUatl Petroleum Company's petro- leum-oil. Carless, Capel & Co.'s petroleam-oil .fill .ffiiO .796 136° 130° 116° U. ed. Exact price not stated ; said to be aJjout 2«. 2s. llcsult of trial in ordinary lamp. Colza used. Fivat c X pe r i mollis. "It was found that the three samples, when consumed in an ordinary single-wick paraffiue lamp, gave nearly the same photogenic results; and, being fairly equal as to safety, the parafiflne of Messrs. Young appeared, on the score of economy, to be the most desirable material for the purpose ; it was therefore decided to carry out all farther experiments with this oil. " The colza-oil used in the experiment was taken from the corporation's stock at Blackwall ; it had a specific gravity of .915, and was of excellent quality for illuminating pur- poses. • "The first experiments were made by consuming the oil in the ordinary Trinity House Argand siugle-wick, and EUROPEAN LIGIIT-IIOUSE SYSTEMS. 81 lirst-order four- wick lamps for colza-oil. Ko altex-ation of the lamps was found to be necessary to effect this, but the best result was found to be obtained when the surface of the oil ill the wick-case was lowei'cd somewhat below the level of the tip of the burners. A good, bright, steady flame was maintained in each lamp, and the following are the results: " In recording these results, thephotometric value of each light is expressed in English units or standard sperm can- dles consuming 120 grains per hour. The value of colza-oil vuiucof ooUa. is the contract- pries for this article for the current year, (3s. M. [S3 centsj per gallon,) and the value of parafQne is the contract-price of Messrs. Young for the current year, (Is. "'^'"'• 6d. [37^ cents] per gallon:) ^4rgand burner — Parajjlne and colza oils. Value of par- JUnminating power of the light Cunsiiinptiou of oil per burner per hour Consumption of oil per unit of light per hour. . Cost of li*rht per burner per iiour Cost of light per unit per hour Lamp consuming parafiinc. 8. 4 units .0130 gallou .001-33 gallon.... .ISOd .02M Lamp consuming colza-oil. 13. 9 units. . 0113 gallon. . 0D083 gallon. . 4G0d. . Q33d. ResultwitlithO' Argand burner. First-order four-tolck liurncr — Faroffine and colza oil. TUuminatinjr poller of light Con.sumpticn of oil per burner per liour Consump'ion of oil perunit of light per hour Coat of light per burner per hour Cost of light i)er unit per hoar Lamp cnnnumin^ paraiiino. 209.7 units.. . 20760 sall.>a. . 00099 gallon . 3.7:)ti .018d Lamp consuming colza-oil. 209. units. . 253-^4 gallon. . 00090 gallon. 10. 33d. .038d. . Eoault with four wickburuer. " In these experiments the lamps were kept burning for six hours without any trimming of the wicks; the illumi- nating power of the lights was determined every hour by a 15 u 11 sen's photometer, and the powers given are a mean of those powers. "Tiie first lamp improved was the single-wick or Ar- ijnpiovcmcnt gaud : the alterations eiiected to this lamp were as follows, viz : The tips of the wickcase were closed so as to fit more ciosely to the wick, and beveled for the purpose of admit- ting the ascending currents of air freely to the lower part of the flame ; a perforated button was introduced at the center of the burner ; the wick-case was lengthened for the purpose of economizing the consumption of wick, and an alteration was made in the form of the glass chimney. The results of a six hours' trial Avith this improved burner, S. Ex. 54 G g2 EUEOPEAN LIGHT-HOUSE SYSTEMS. whiclihas uow been ia use at the Milford leading-li^lits for the last three months with good practical results, are as follows : Improved Argand burner. Result with im- proved Argand burner. Illuminating power of tlie ligbt Consumption of oil per burner per hour Consumption of oil per unit of light per hour . . . Cost of ligbt per burner per hour Cost of light per unit per hour Lamp consum- ing paraffino. 20. 6 nnits. . 0109 gallon. . 00053 gallon. . WM. . OO'Jd. Lamp consum- ing colza-oil. 13. 9 units. .0115 gallon. . 00083 gallon. .46ld. . 033(i. " The above exporimeuts with this lamp, as now improved, show the comparative cost of light produced by colza-oil and. parafiine to be as 33 to 9, 11 to 3, or 55 to 15. (See tables.) Improvement "Thecxperimentswith the Argand bumcr, which had bceu in four-wick ^ ° burner. go successful, were followed by similar experiments with the first-order or four- wick burner. The alterations effected to this burner were as follows, viz : The tips of the wick-cases were closed so as to fit closely to the cotton wicks, and wwe beveled in the same manner as the Argand lamp, for the purpose of admitting the ascending currents of air freely to the lower part of each ring of flame ; and the -wick-cases were considerably lengthened for the purpose of economiz- ing the consumption of cotton-wick. Glass chimneys of various forms were tried, but no better result has been ob- tained than with the chimney usually used with the four- wick burner for consuming colza-oil. After a series of trials it was found that the best i^hotogenic result was obtained with the surface of the oil in the wick-case three iuches below the tips of the burner ; it was therefore necessary to keep the oil uniformly at this level during the burning of the lamp, which was done by placing at a short distance from and level with the burner one of the flow-regulating cisterns formerly used for light-house lamps, which receives from an upper reservoir a supply of oil, and maiiitains the supply to the burner at the required level by a self-acting ball-cock. I have devised another and, in ray opinion, a more perfect arrangement for regulating the flow of oil in these lamps, which has been tried with perfect success. i Oil-regulator. " I ^^" to Submit herewith drawings of the improved Ar- gand and first-order four-wick lamps, on the latter of which is the self-acting regulator. This regulator consists of a stand-pipe placed at the side of the burner ; the top of this pipe, which is open, is at the level at v.'hich the oil is in- tended to flow in the wick-cases ; a portion of the supply of oil from a reservoir placed above the level of the burner, or EUROPEAX LIGHT-HOUSE SYSTEMS. 83 from the cylinder of n pressure lamp, flows up the stand- pipe and overflows at the top, descending by anothor pipe surrounding the stand-pipe to a 'cistern below the burner. A glass thicable is screwed on to the top of the regulator, through which the state of the flow can be observed. The r.ecessarj' adjustments of supply are made from time to time by the ordinary regulating-valve placed in the supply-pipe below the buruer. The tops of tlie inner and outer tubes of the stand-pipe are rendered telescopic by a piece of pipe litted to and sliding on theai externally; by means of these sliding pieces the flow of the lamp can be altered at any time so as immediately to adapt it for burning any descrip- tions of hydrocarbon. As the invention appears to me to be of importance for regulating the flow of all lamps used for burning mineral oils, I have had it provisionally pro- tected. "As it is found to be necessary in burning parafQne that its level in the wick-cnse be considerably below the top of the burner, it may reasonably be expected that the tips of the burners will be destroyed by the heat of the flame much sooner than with burners consuming colza-oil, where the latter is constantly overflowing the burners and keeping them cool. 1 have provided lor this increased destruction of burners by fitting each with removable tips, as shown on KcmovaUi' tips. the accompanying drawings. With this arrangement, and by keeping a supply of spare tips at each station, the tips of the burners may be renewed at any moment by the light- keeper in charge, thereby avoiding the necessity for return- ing the burner to the workshops for repairs. " The following are the mean results of several six-hour experiments . Improved first-order four-wicJc burner. TlliiTninating power of Jiglit CoDSUiiiptiou of oil per burner per hour ConsnniTJtioii of oil per unit of ligUt per hour. Cost of liglit per hour per burner Coat of lijiht per unit per hour Lamp consuining parafiiuc. SSOunit? . :J3-J40 gallon .U00d:!(;allou.... ■J.U'd .Olid Lamp consuming culza.oil. KesnlfKitli iv|. proved lonr-wicii lamp. 2Gn nuit.i. . 938J4 colloii. . OUdOO gallon. 9. did. . 033i;. " The above experiments with this lamp, asnow improved, cost of coUa ^^ show the comparative cost of light produced by colza-oil™'" and i)arafiine when consumed in a first-order burner to be as 38 to ID. From these results it will bo observed that the superiority in illuminating power of the paraflino over the 84 EUEOPEAN LIGHT-nOUSE SYSTEMS. colza oil is umcli greater when consumed in tbe Argand burner tban when consumed in tbe large tbnr-wic'.v burner ; consequently tbe contrast between the co.st of light pro- duced by tbe two oils is greater when the oils are consumed in the Argaud burner than when consumed in tbe four- wick burner. .^ " Further experiments were made for ascertaining the relative illuminating power of the paraliine and colza lamps during tbe time required at a light-house on the longest winter night. Each lamp was kept burning for sixteen hoiirs without any trimmiDgof the wicks, and the following are the photometric results of several experiments : mrnovED akoaxd UUEXEI ■ LaPr.OVED FIKST-OnDEE FOUR-WICK DJJBSEU. Hoars. B o B si S i Hoars. o i 'o O 1 Unitx. 20.0 20.0 20.6 20.fi 20.4 20.4 20.0 20.0 in.fi m.o 10.2 10.0 18.7 IS.G 18.5 18.5 Units. 13.9 13.9 13.9 ]:!. 9 13. C 13.3 12.7 12.7 12.7 12.7 12.7 12.3 12.1 12.0 11.9 11.8 • 1 Vnitii. 2t0 274 2fO 2': 6 278 278 274 277 271 200 203 277 207 20fi 230 2.-I0 Unitn. 2 2 3 4 203 201 240 a 4 5 5 249 £4 J 2i3 C 7 7 3 8 . 240 ::. 10 9 _ 10 2.i0 11 n 2.'{"* 12 la 13 233 2J4 2:<0 200 14 14 15 tr, 10 10 Mean 10.7 12.8 271 Dcdnctions. " From these results it is apparent that the paraffine lamps will burn throughout the longest winter night in this couu try without any trimming of the wicks, and give during ^H.istamciiiuten. this tlmc a light of nearly uniform photometric value. At the end of sixteen hours the illiimiuating power of the Argand lamp, burning paraffine, was only 10 per cent, less, and in tbe four-wick lamp only 10.7 per cent, less, than at the commencement of the trials, while the iliuminating power of the lamps burning colza-oil gradually decreased soon after the commencement of tbe trials, and at the end of sixteen hours the illuminating power was reduced 15.1 per cent, in the Argand burner, and '2d.G per cent, in tliu Ibur-wick burner. "At the termination of these trials the wicks of tbe i)ar- affine lamps were not much fatigued : the tips were charred Stait* ol wii-ks. EUROPEAN LIOriT-lIOUSE SYSTEMS. 85 only one-eightb of an iucU in depth, aud to all appearances the lamp was lit for burning many hours longer. The wicks of the colza-lamp were much distressed; they were charred live-sixteenths of an inch in depth, and evidently nearly worn out; trimming would have been absolutely necessary if bnrned for three or four hours longer. " In conclusion, it may be generally stated as the result of the lengthened experiments which have been made at this Douse with parafttno as an illuminant for light-houses — " 1st. The cost of light is 72.7 per cent, less when produced companiive by the Argand or single-wiclc lamp, and G0.5 per cent, less tchen produced in the first-order or four-icich lamp, than colza- oil. " 2d. The lan}ps hurning paraffine will give a light of more ramfiinc li;.-.;! uniform illuminating power throughout the night, icithout trim- ming, than the lamps burning the colza-oil. "3d. 1 he lamps burning paraffine are more readily ignited ; var^.rcm- bnvi^ they burn icith greater certainty, and require less attention than lamps burning colza-oil. "4th. The lamps burning paraffine maybe arranged for ieci(:>s,' , t increasing the power of the light when the state of the weather ''""''' ^'"'""" requires it, as is now done with the electric light and coal-gas. »' 5th. Paraffine can be stored and used at lighthouses icith Pmarinr i! ■.-. > safety, provided that ordinary care is used. Baietj."^^ ' " I am, &c., "JAS. N. DOUGLASS." The tables given iu the foregoing report showed — 1st. That light for light with a first-order lamp, the cost (;„„rm(M r.vsr- of the paraffine was about one-half that of the colza light. °'"^'"' '"'"''• 2d. lAght for light icith the fourth-order lamp, the cost of ^,„^^ ,,.),!, paraffine teas about one-fourth that of colza. [^^^ i- 1"-" ■• ■' ' ■ These results were confirmed by a comparison of the fig- ures in the following table of results obtained by Dr. Mac- ^co;i«™aiin:; , -; adam, scientific adviser of the board of commissioners of northern (Scottish) lights, Mr. Douglass, engineer of the Trinity House, and Professor Tyndall, scientific adviser of the Trinity House, by quite separate and distinct experi- ments. 86 EUEOPEAN LIGHT-HOUSE SYSTEMS. Comparative stalement of experiments for tcsfivg the values of colza andpar- affine aa illmninanlajor Ught-hounea. First-order LAsn- : lUnminatiDf^ power of ligbt expressed in Btaudanl candles, consuiuiiig 120 jjrains per hour Percentafru of iucreaso of li^iht in favor ofparaliina Consumption of oil by tho lamp during one hour in impcii.il gallons Consumption of oil ptr canulo per hour in imperial galloDH Cost rdo(:ect- 3(1. Au outer "cone," (exterior deflector,) by which a secoud current of air is thrown into tho llame at its most advantageous zone. rent."" '''''■'^"'■' 4th. A space between the c.me and the chimney, by which a third or outer air-current is produced. EUEOPEAN LIGHT-HOUSE SYSTEMS. 87 This air-current is injected iuto the flame above that ad- mitted by the " exterior deflector," and is for the purpose of increasing combustion. A portion of this current being drawn np along the surface of the chimney, prevents the heat from melting or otherwise injuring the glass, in which a milkiness resulting from disintegration sufficient to im- pair the light, is found to be produced by long-contiaued heat. Another result produced by this current is that the base ciiimncy ue p t of the chimney is kept at a degree of temperature sufii-"°"'' ciently low to admit the removal of the chimney with the naked hand, rendering the use of tongs unnecessary. 5th. An adjustable gallery by which thechimney is raised Adjustable gai and lowered at will, it being found that the height of the'^"^^' shoulder of the chimney has a marked effect upon the flame. Gth. Very soft and compressible wicks j^dopted for this softwict. lamp only after many repeated experiments. Bach of these inventions, some of which were original .,'^''">'°-''^;9" "' with Mr. Douglass, and some had previously been in use, is considered of importance, but a combination of the whole is essential to produce the remarkable results given iu the following table deduced from the most recent experiments of Mr. Douglass and kindly sent me by him since my re- " turn to this country : Comparative sialements aliou:ing the mean illumhiaiing 2)0wer and consumption Comparative of oil loilh llw old and improced light-house burners of the Corporaliou o/mcuts" with ''ll'r! 'I'tinity House. Douglasa'a bum- Olil concentric bnrners con- Improved concentric burners con- Giuuiug colza. suming colza. Number of wiclts: i^iU power 4 3 2 1 6 5 4 ■ 3 2 1 Halt power . .. 3 3 2 3 1 Mean diameter of outer wick, (in incbee) 3.3-2 2.49 1.C3 .82 .1.00 4.10 3.32 2.49 1.03 .82 11 lum iuatio g powerofiiameiii standard sporm 1' a u (1 1 H , (w uuits.) coiisum- i:iS 1:20 grains per hour: Pull ]mwer 2C9 , 107 53 13.9 342 314 223 328 178 •308 14G H2 51 23 llQil po^\'t'r , , . Coiisiinilttinu per lii'.rm-v perbuur ill lluid-omiccs. IJJti) ATuericau ^7i;•.c-lIaUo^: Ptdl power 39.77 23.09 7. 73 1.77 70. 24 30. 12 51. ?1 22.08 32.12 17.43 20.17 14.10 7.87 4.80 2.20 iiaii powui ■ - - Cousuniption per imitporliourin fluid-ounces .148 .13S .134 .12S .106 .101 .008 .097 .093 .096 Jlean Ijeiclit of flami?. (iuinches;. 3.75 2.5 2.0 1.5 5.5 5.0 .4.5 3.2 2.8 2.3 Increased illumi- iiatio^' power of iiuprovert burn- 21. 93 •24. 55 41.38 63.47 or, pel oi. u u Savinjxinoii witb tew buruer i'or oar. h unit of Tin-lit' TtAT* roni. 33.77 29.86 28,57 34.81 llgQt, Jllil UL/llli - - - 8S EUROPEAN LIGHT-HOUSE SYSTEMS. Consumption of An inspection of the above table shows the consumption toiza. ^^ colzaoil in the new burner to be very nearly one-tenth of Unit nse.1. an ouncc for each unit of light, that unit being the lijiht from a standard sperm-candle consuming 120 grains per hour, and Mr. Douglass informs me that the improved Power of liaiit burners have raised the power of light produced from eolzalo r'wVun'ereqnSsuch a dcgrcc that Ihis oil is now practically equal in illu- u,;x.en'.i-o"' "'^"minatiug power and consumption to the best mineral-oil found in Great Britain, the latter having a specific gravity ranging from .810 to .820, flashing above 130° Fahrenheit ,,"™cotarSiiand^ distilling between 212° and 572° Fahrenheit, so that coltfione"'''' "^the difference between mineral and colza oil for light-house illumination is principally one of economy. In England the Cost of colza, cost of colza-oil is about 2s. 9(7. (68 cents) per imperial gal- of mineral-oil. lou, that of miucral-oil of the quality above stated being Is. Id. (39 cents) per imperial gallon, so that in that country, for all orders of light-house lamps, the cost of maintaining mineral-oil sea-coast lights is about one-half that of maintaining colza-oil li{)kts. sobsutnfion of For this reason, as well as because mineral-oil lamps are Tuuuiiil lor colza , ,, .ii-ij.! i ■ j.- ,.;i. much more cleanly, more easily lighted, and require no trim- ming during the night, thus making their efficiency less de- pendent on the watchfulness of keepers, the English are rapidly substituting mineral oil lamps in their light-houses for those for colza formerly used. Price ofiard-oii. In the United States the average price of our illuminaut, lard oil, of ■which we annually use about 100,000 gallons, is costotmiuerai-89 ccnts per gallon; the cost of mineral-oil of the quality required by the British and French contract-speciflcations is about 35 cents per gallon. The following table gives the comparative values in stand- ard candles of the new English Douglass and the American light-house lamps : cIL Xumber of Tvicks Enplisli lamps, valno in candles American lamps, value in can'lles Percentage in favor of English lamps. 4 333 2J0 50 3 2oa i:« 56 1 5U An examination of the foregoing tables and the facts just stated shows : 1st. That by the adoption of the triple current of air btirn- ers of the English and Fretich into light-houses, ice should gain more than 50 per cent, in tliepoicer of our lights. 2d. By the adoption of American mineral-oil instead of the lard-oil now used in our lighthouses, loe should save $54,(i00 per annum in cost of oil. EUROPEAN LIGIIT-nOUSE SYSTEMS. 89 This is on the supposition that the American refiners will pro- duce, if stimulated by the use of the former by the Government, an article equal to that used in Europe for lighthouse illu- mination. od. If it should be found that such American oils can- not be obtained, precisely the same excellent quality of mineral- oil f Scotch J as is used in the lighthouses of France and Great Britain can be imported at a cost, including freight.* not exceed- ing 3G cents per gallon, and the saving in this case icould not be less than $53,000 per annum in cost of oil. Since my return from Europe tbe Trinity House lias kindly sent to tbe Light- House Board several imjiroved four-wick burners, for both colza and mineral oil ; interior deflectors for cutting off one, two, or three wicks ; one Argand lamp, complete, for burning colza or mineral oil; and one Argand gas-burner, as well as a supply of wicks, chimneys, &c., for use with the lamps and burners sent. In regard to the purchase of njineral-oil, I give below spcciiiontions some extracts from the specifications which the Trinity House '"'' "'""™'-""- furnishes to bidders : "1. The mineral-oil required to be supplied under this con- Quniity. tract is to be of the best possible quality, tiie greatest care is to be taken in its preparation, and it must be as free as possible from oil of vitriol. " 2. If the oil be petroleum, it must have a specific gravity spenf.c' sr-.ivity not less than .785, nor greater than .790, at 00° Fahrenheit ; " i"-"""""'- its flashing-point not lower than 125° to l,'3Co Fahrenteit, and it shall distill between 212^ and i.S2° Fahrenheit. "3. If the oil he, paraffinc, it must have a specific gravitj' oiiwiaffinc. not less than .810 nor greater than .820 at 00° Fahrenheit ; flashing above 130° Fahrenheit, and distilling between 212° and 572° Fahrenheit. " '1. A sample of five gallons of each of the oils proposed to .s.inii.ks be supplied is to accompany the tender ; such sample will be tested by burning to ascertain its action on the wick, and t mlniJies. rivo-gallo:. caua. EUROPEAN LIGHT-HOUSE SYSTEMS. 1 a guotl ouc. Lnm p-cUini on the inside by the workmen at the depot. They nic in size and construction admirably designed for trans- port. Three of them can be easily carried by two men, and they stow in the supply-vessels and boats with litrio loss of snace. They are also strong and durable. I thinic of oil in tuesojj; a better i)hiu for delivering oil to light-nouses than onrs of shipping it in barrels on the eastern coast and m square tin cans to the Pacific coast light-houses. Especial attention is paid to the testing of lamp-chim- neys, which are distributed to the light-houses from Black- wall depot. A gauge, 6, of metal is fastened to a frame, a, (see Fig. 4.) in which the chimney is placed, and its accuracy Pi„_ 4. of sbape and thickness is deter- mined by turning it around its axis. Those which do not fit the gauge closely are rejected. The machine shop is well fitted up with machinery, including lathes, drilling and screw -cutting ma- chines, and all kinds of work, ex- cepting heavy forging and casting of iron, are done here; even the II ixianufacture of the furniture used |\ in the ligbt-house towers and keep- MacUine-sbop. i^l TiHii I oi'u for lij,'!il-shi;i. Lamps (riinnied u'ltlioutlowoling l.mtcrn. Among great varieties of work I saw constructing in the smitli- ery a lantern ior a light-ship, made entirely ofiron, the sash-bars being Chimney-gange. of malle.ablc cast iron. This lantern was not intended to be lowered to the deck for Iriuiming the lamps, as is usual, but was designed to re- main in its place on the mast, which is to be of hollow steel about two feet in diameter. Small doors open from the hol- low of the mast on to the deck, and also into the lantern when placed in position, an inside ladder affording a means of communication with the lantern at all times. There is about 20 inches space between the sides of the lantern and the reflectors, to enable the keepers to trim the lamps, and an outside foot-rail is provided to enable them to clean the exterior of the lantern-glass. QiioBtinn of Whether so heavy a.mast and lantern cau be carried on Khiptocarry'mastl'glit-ships in all weathers is yet a matter of experiment, and lauterii. EUROPEAN LlGHT-ilOUSE SYSTEMS. 9 J but there can be no doubt that i'aeility of trimming without lowering- the lantern is much to be desired. There was also constructing a set of machinery for a f«8'- ^ijil'ir^;'^'^" '""■ bell, the driving-weights of which were square and furnished witli rollers on the sides to avoid iriction against the boxes. Above the buoy-sbed is a convenient photometric gallery • n.ntomctiic ibr testing lamps, oils, and lenses. It is about 80 by iL>s^''">- feet, the interior is painted black, and the sky-lights are so arranged that all daylight can be excluded. At Blackwall is always kept a light ship for relief in case r.cii o i n^iit- of accident to any of the numerous light-ships on the coast ^ "''' near the Thames, and this is also the place of repair not only for these vessels but for the steam-tenders. Trinity House ceased some years ago to build iron light- imn lisht-sinps ships, on account of their fouling so rapidly and the conse- 1:['„";™'""^'' '"''- qnent necessity of bringing them into port once in two years, while the wooden light-ships require to bebroughtin but once in seven years. Further reasons for giving up the use of iron light-ships are that they are cold and damp, and w-hen run into, sustain much more danger than the wooden vessels. The approximate cost of a light-ship, either of iron or cost of liwiit- wood, including everything, is, in England, £5,500, or about ^'^'''' 8127,500. The size of English ligbt-ships is about the same as our size, own, although the latter have much greater beam and depth of hold, and are more rounded at the sides, which probably enables tbem to ride easier and with less shock to the catop- tric apparatus and the lantern. Those placed in exposed situations arc usually held by Moorings. single mushroom-anchors, weighing two tons, and each light-ship has 210 fathoms of l}-inch cable. The Seven Stones lightship, olF Land's End, is anchored Anchors of tiic ill 42 fathoms of water and has 315 fathoms of cable attached to her mushroom. In addition to these moorings every light-ship has on AiiditionMi board spare anchors and cables in readiness to be let go at """"'"'"• a moment's notice in case the vessel should drag her anchor, but such an occurrence has not happened for several years. The chain-cables used by all the vessels of the Trinity cimin-cabic^: —^ i-,i . mi • iTii' reqniremom.s n f Ilouse are made with great care. The requirements and the contract!). mode of testing are as follows : All the cables, mooring-chains, rigging and crane chains, Qii.t1 ity of ... . chain.s. and articles appertaining thereto, excepting the stay-pmn and steel pins, are manufactured from flue tibrous iron of ap- proved quality, and must bear a tensile strain of not less than 94 EUROPrAN LIOnT-HOUSE SYSTEMS. 23 tons per square inch of origiual area, -with a contraction atfracture of not less than 45 percent, of the original aie;i. Qnaiity of stay- j^iiQ cast iron in stay-pins is of the best tough gray nieti.l, ^"'^' and mustbearacompressivestrain of not less than 52 touspiT square inch of original area, with a reduction in length of not less than 10 per cent. steel pins. The Steel pins for retaining the joining shackle-bolt are of the best and toughest raanu(acture, and must bear n tensile strain of not less than 35 tons per square inch of origiual area, with a contraction at fracture of not less than 45 per cent, of original area. wcrkiEflnship. All cablcs, luooriugchains, rigging and crane-chains, and articles appertaining thereto, are required to be of the best possible workmanship. They are proved at a provingina- chiue, licensed by the Board of Trade, at fhe expense of the contractor, and the proving is carried out in the presence of the engineer or other designated ofiicer. Proofstrains The chains are subjected to the following proof-strains, chains. "^ '" ^ viz : Opeu-liiilc cable and niooring-chains, and close-link rigging and crane chains are proved to 8.47 tons per square inch of each side of the link, or 4GG pounds per circular one-eighth inch of the diameter of the iron, and stud-cbains are proved to 11.40 tons per square inch of each side of the link, or C30 pounds per circular inch of the diameter of the iron. Any links which may appear to be defective are cut out and replaced, and the chain re-proved at the expense of the manufacturer. If more than three links are found to be defective in any length after proving, such length is con- sidered liable to rejection. All forelock-shackles, connect- ing-shackles, and spare swivels, are proved to the same strain as the chain with which they are intended to be used. Further testa. lu addition to the above proof, and for the purpose of ascertaining the exact quality of the iron and welding, the engineer selects, as he may think fit, from any lengths of each of the sizes of chain ordered, three test-pieces, four feet long of each size. The.se pieces are cut out of the chains, and, together with a shackle of each size, also selected by the engineer, are stamped with a Trinity House stamp, and are sent by the contractor to such public testing-works as may be designated by tlio Trinity House, to be tested and reported on by the engineer of the Trinity House, at the contractors expense. The quality of the iron i;; ascertained by testing the iron in one link cut off cacli of the pieces of chain, also the iron in each of the shackles. The remainder of each of the four-foot lengths of chain is then tested to ascertain the quality of the weld ing, when the ultimate breaking-stress must not be loss EUROPEAN LlGHT-noUSE SYSTEMS. 95 tban IC tons per square inch of (!ac;h side of the link, or SSO pounds per circular one-eighth inch of the diameter of the iron. In the event of these tests proving satisfactorj-, the lengths of chain from which the test-pieces were taken are to be made good by the contractor, and the lengths re- proved at his expense. In the event of any portion of the material or welding, when tested, proviug inferior in quality to that specified, the chains and shackles are rejected, and the above tests are repeated at the expense of the con- tractor on other pieces of chains and f hackles selected by the engineer in the same manner from other chains and shackles manufactured by the contractor, and submitted for approval. At the depot are a great many buoys of all kinds, most of them of timber, but I believe none ^re now made of that material. Some of thedifferent kinds are the "nun,"' "caii re- versed," "can," "egg-bottom," "convex bottom," "flat bot- tom," "hollow bottom," "spherical," and "conical." The English can-buoy corresponds in shape to our nun-buoy, except that the larger end is in tlie air. The cylindrical buoys used by the English are much like our can-buoy, and are said to satisfy all conditions required. An English nun-buoy is conical at both ends and is used to mark wrecks. An English flat-bottom buoy is, as are some of the others, water-ballasted, i. e., they have a cross diaphragm at a proper distance from the bottom, and the water is allowed to flow in and out of the lower compart- ment thus made through eight holes an inch in diameter, placed at equal distance around its sides. The water can- not be discharged unless the buoy is careened for some time, and it is therefore as completely ballasted as if the water had no means of exit. When those buoys are required for deep water where the weight of the mooring-chain is sufiBcient for ballast, water- ballast is not used, and the holes are plugged with hard wood. With the increased buoyancy thus obtained the same line of flotation as in shoal water is approximately attained. This is a matter of importance, preserving, as it does, a uniformity of appearance in each class of buoys, irrespective of the depth of water in which they are moored. The buoys said to be the best for strong tideways are the can, cylindrical, and flat bottom; for exposed channels and coasts the egg-bottom is used. Another which is used with satisfactory results is a pat- ent hollow-bottomed one, called " Herbert's " buoy. Buoys. Names. Cau-buoy. Cylindricu'u Nun. Flat-lKittom Tvater-baliasiiii;:. When Tjnoys nvo reqnireil lar deep water. Best bnoys fr: stnni£; tulcTv:i>'- lor cliauuels Herbert's l)'.n»y, theory cf. 96 EUEOPEAN LIGHT-HOUSE SYSTEMS. The theory of the action of this buoy is that the air con- fined in the hottom forms an elastic spring upon -which the buoy rebounds in gentle and easy motions, causing but mod- erate friction to the uiooring-chain, little or no pull upon the sinker, and a corresponding relief from agitation or fric- tion to the globe and staff above. Size of buoys. I was especially struck with the great size of some of the buoys which I saw at Blackwall and at other places, many of them being 20 feet in length. iinnriPg ofEn- Thc English ordinarily moor their buoys by a single chain p '•- ' ""^^^ gmj sinker or mushroom, but in some instances double moor- ings are used. The chains of light-ships, after three years' service as such, are converted into buoy-chains. The pro- l)ortiou of chain used in mooring buoys is generally three times the depth of -water. ,''' siiiftiiigbuoya. Small buoys are shifted twice ayea-r, but the buoys above 8 feet remain at their stations lor two or three years and are painted at their anchorage periodically. wvpVi™buov- '^^'^ following is the system observed in buoying cban- 1112 English wa- jjglg . HM-rt. siiii-s of ciiaii- The side of the channel is to be considered starboard or port with reference to the entrance to any port from sea- ward. Eutranco to. The eutrauces of channels or turning-points are marked by conical buoys with or without staff and globe or triangle, cage, &c. Singled-colored can-buoys, either black or red, mark the starboard side, and buoys of the same shape and color, either checkered or vertically striped with -white, mark the port side ; further distinctions are given when required, by the use ot conical buoys -with or without staff and globe, or cage, globes being on the starboard and cages on the port hand. Mi.iiUogrouiia. Where a middle ground exists in a channel each end of it is marked by a buoy of the color in use in that channel, but with annular bands of white and with or -without staff' and diamond or triangle, as may be desirable ; in case of its be- ing of such extent as to require intermediate buoys, they are colored as if on the sides of a channel. When required, the outer buoy is marked by a staff' and diamond, and the inner one by a staff and triangle. ■wiTciis. '\Vrecks are marked by green nun-buoys. iiuiks. Each buoy is plainly marked with a running number and thc name of the locality tchere it hclongs. The white stripes or checkers of buoys are about 20 per cent, less in size than the black and red, it being found that EUEOPEAX LIGHT-HOUSE SYSTEMS. 97 the characteristic distinctions of the buoys are better ob- served at a distance by this inequality. Bell-buoys, of which there are many in use, are constructed Beiibuoya. of iron, and have four hammers or clappers, each hung by a Y, which prevents jamming and obviates the use of guides. They cost about £200 ($1,000) each. At Blackball the buoys are kept under a commodious Buoy-shea. buoy-shed, ■with convenient arrangements of rails, &c., for moving them. The sinkers are square and of iron. The prices of iron buoys most recently obtained are as follows : Prices of buoys. Eight-foot drum-buoy, price £32 10s., ($162.50.) Eight-foot spherical buoy, price £145, ($725.) Eight-foot water-ballasting buoy, price £82 10s., ($412.50.) Thirteen-foot water-ballasting buoy, price £198 Cs. 8d., (8991.CG.) Bell-buoy, price £224 12s., ($1,123.) At the depot are two towers, each having a fixed lens of ^Tower s^ in^ the second order, and in them are tested, under the direction made, of Professor Tyndall or Mr. Douglass, the different lamps, lenses, and oils, the effect of fog, &c. The principal point of observation is Greenwich, distant about two miles. There are several light-house depots on the coast of En- j^^^jf''*^''™,^^ gland, at Yarmouth, Coquet Island, and other places, but ™''»"'fi^"si-''-»i Blackwall is the principal depot for manufacture, supply, and repair. The immediate agents through which the authority of ^^SupPiintemi- Trinity House is exercised are called superintendents, and House nistricis. each has some special duties assigned him, either the sole care of the service in some specified part of the coast or the charge of some special branch, such as the supply and store ^^^^^^^^ ^^^^^^^ houses at Blackwall. The tenders are under their orders. onicTs o? supe • ,, . 1 J » iiiiendeuts. They wear a uniform on all occasions when on duty. Light-keepers are appointed by the corporation. The Keepers. rules'requirc that applicants shall be between the ages of 19 and 28. They must produce certificates of character and physical ability, and (from a schoolmaster) of abihty to read, write, and perform simple operations of arithmetic. <, ^ j„^^„„,„„^. As vacancies occur successful applicants are taken on pro- rios. batiou, i. e., are appointed supernumerary light-keepers. They are then sent to the depot at Blackwall and placed instruction t* under the orders of the superintendent there. They are j;™?^^';^,,^,'!,^;.'^;;: carefully trained in the use and care of lamps and all light-"'"'"'---") house apparatus, including meteorological instruments; the keeping of the light-house journal and accounts, and the "■eneral management of affairs at a light-house. 98 EUROPEAN LIGHT-HOUSE SYSTEMS. Certificates A Certificate of the lowest grade is given for competency ^"^"^ in their duties. A second course of instruction includes the use of tools in carpentry and plumbing, that he may be able to effect ordinary repairs ; also the management and general knowl- edge of the steam-engine. A third course includes instruction in the management of the magneto-electric machine and lamp. A fourth course includes the use and management of fog- horn apparatus. Separate certificates are given for each course. Number of su There are always eight of these candidates for light-keepers iSkwai?"°lndat Blackwall, and two at South Foreland, the latter for in- sonth Foreland. g^.J,^g^.J(JJJ j^ jjjg ^jauagement of electric lights, and to the " great care exercised in their selection, and the thorough- ness with which they are instructed before they enter upon their duties as keepers, is to be attributed the excellent condition of the lights, towers, dwellings, and grounds that I observed at every station which I afterward visited. supernumera- Supernumeraries are supplied with uniforms, and are iL'dpaid"'^"™"^ paid at the rate of £45 ($225) per annum ; but on obtaining the four certificates and giving satisfactory proofs of steadi- ness and sobriety, they become entitled to an assistant keeper's pay. The rates of pay axe as follows : Grade of keeper. Principals -who have served as sucli above 10 years, if insured Principals wbo bave served as such above 10 years, if uninsured Principals above 5 and under 10 years, if insured Principals above 5 and under 10 years, if uninsured Principals under 5 years, if insured Principals under 5 years, if uninsured Assistant keepers who have served as such above 10 years, if insured.. Assistant keepers who bave served as such above 10 years, il' uninsured Assistant keepers above 5 and under 10 years, if insured Assistant keepers above 5 and under 10 years, if uninsured Assistant keepers under 5 years, if insured Assistant keepers under years, if uninsured a £ s. 72 70 10 63 C6 10 65 64 10 53 .00 10 56 54 10 54 52 10 £. .1 3 3 (I S 3 3 (I 3 (I Tvrcpcrs '*^i011Cli. pen. "When no longer able to do service, keepers are pensioned, the pension computed on an estimated allowance of £18, in addition to the above scale. Term of service Keepers and assistants at rock and screw-pile statioii.s inewpiio sta- remain on shore, in rotation, one month each. The regulations in regard to the care of lamps and prem- ises and keeping watch are much the same as our own, but where mineral-oil added is used, the following instructions are EUROPEAN LIGHT-HOUSE SYSTEMS. 99 "The oil is to be placed in the metallic cisterus provided careofmiu.nd- for the purpose; and these are to be kept perfectly closed ""■ by means of the cover and tops with which they are pro- vided. In drawing oil from the cisterns it is to be drawn into a proper can, provided with iin oil-tight screwed cover and au air-tight screwed cap to the spout. After charging the lamps the cau is to be returned to the store with the covers, spour, and top screwed tight. All oil required for the service of the establishment is to be taken from the store during day-light, and keepers are not, under any circumstances, to enter the oil-rooni with a lighted lamp or candle." IRON LIGHT-nOUSES OFF THE JIOUTH OF THE THAMES. After leaving Blackwall we proceeded down the Thames crujse in n-.o in the Trinity House steam-yacht Vestal on a cruise of inspection of the lights on the east coast of England, during which we visited nearly all of them between the Thames and the Scottish border. On this journey it was my good fortune to accompany Admiral Gollinsou, G. B., and Cap- tain Weller, of the lildcr Brethren, and 1 shall long remember the great kindness and attention of which I was the recip- ient from both of these gentlemen. We passed the Mucking light-house, situated in the Miickiii:^iith;- Thames, below Gravesend, and the Mapliu Saud light-house, ,, ', ir.lplin S:;;i ; ou the mouth of that river. Both of these are screw-pile >is'"-''ousc;. structures ; the latter was, I believe, the second of that kind jj i^t^oMc ^1 ■ in the world, having been lighted in 1841, and was one of ???"'' ^'^'''T'i:'" the earliest applications of that useful invention of Mitchell, of which we have many examples, there being more than Number ( fifU' light-houses built on that i)Ia.n in the United States, brases lu "n,,' It may be mentioned here that the first screw-pile light- First 8crew^i,ii. house was built at the mouth of the river Wyre, on the "^'''"'"""*'' '"'"'• northwest coast of England, two or three years before the light-house on the Maplin Sand. The screws were three i'eet in diameter, the piles five inches; and above the ground, instead of iron, as at Maplin, wooden columns were used. This light-house was destroyed in 1870. siroye.f " '' " The Maplin Sand light-house, a view of which is sliown Descnpiion , i in Plate V, is a hexagonal structure, with one central a»d,*i^J5;^^iJ„\,'j.j,'^-" '■ eight exterior piles. The piles were driven vertically, but phos. above the water-line they bend toward the center and in- cline in a pyramidal form to the lantern-fioor. The screws screws. are four feet in diameter, the piles five inches, and they support cast-iron columns 12 inches in diameter. The col- columns. 100 EUROPEAN LIGHT-HOUSE SYSTEMS. umns are very stronjrly braced, and the stiuctnre bad an appearance of great strength. Gm.iicet ligbt- We stopped at tbe Gnnlleet ligbtbousp, situated on a ''""''°' sand of that name, north of the mouth of the Thames, and thirtj--oue miles from the Nore light-ship. It is exposed to the full force of the North Sea. riles. There are one central and six exterior piles supporting columns of about 12 inches in diameter, strongly braced. Sdckots. The sockets for the columns are not cast in one with the sockets for the braces, but the latter are bolted against the face of the piles by tap-bolts. F„rm of the Qniike Maplin Sand light-house, the piles were not driven Rtructaro. .^-grtically, and are inclined from the bottom to the top in the form of a pyramid. The piles, braces, and sockets are of a very massive character, and give an appearance of great durability and of the strength which the site demands. Keepers' iiwi 11- rpjjg duelling for the keepers (below the lantern-floor) is ' ' but one story in height, and is smaller and less convenient than in similar structures in the United States. The sides and roof are made of corrugated iron with wrought-iron Adiiuionaiaugie-plates. Below the floor of the dwelling additional .s!„ico tunii8b,,a. ^^^^^ .^ furnished by placing a store-room in an inverted pyramid, to which access is had by a ladder from the gallery. Tlie dwelling is divided into a living room, (also used as a ncnson for thn kitcheu,) a bed-room, and an oil-room. It was stated that SrJ"vu6turr°'tbe sea rarely rises to the bottom of the house, and the ob- ject of the peculiar form given was to allow the wiud and spray to be warded ofi' without imparting shocks to the structure. I should judge the device to be one of question- able utility, and that but little more expense would have beeu incurred by raising the building a few feet higher and placing another full story for the accommodation of the keepers. Keepers. There are two keepers, one less than we would have in the United States, and it will be observed throughout this report that the British lights are maintained by a less num- ber of keepers for each than for the same order of light in our service. Catoptric .ip- The lantcrii, which is large and commodious, contains a p.n^ns . jj j,g^,Qj^,jyg catoptric apparatus composed of fifteen reflectors and Argand burners in sets of five, i)laced on a frame of i'.d liKht.iiow three sides, and this being a red light, panes of red glass, in i,j,iu;i-.-.i. fijuues hung on hinges, were placed in front of each reflector. This structure seems admirably adapted to the locality, and rcpkicinK "iiKiH- 1 should think the question of replacing by similar struc- piie'ugiit-boubra^tures souie of the great number of light-ships which mark Plate Y MAPJLIN SAND LIGHT-HOUSE. EUROPEAN LIGHT-HOUSE SYSTEMS. 101 the channels through the shoals ohstructing navigation on the east coast of England, would have attracted attention, and there are probably some special reasons why it has not been done. While the first cost of a screw-pile light-house in an ex- comparaine posed locality is greater than that of a light-ship, the cost pifo^ipiit-Jmus.-H of maintenance as well as of repairs is much less ; and be- "°'' '>siit-siniis. sides, the danger which sometimes occurs of light-ships being dragged from their stations and leading vessels into the very dangers from which they are intended to warn them, is avoided. These considerations have induced us to replace our light-ships by screw-pile light-houses except in the case of shifting shoals like those off the island of Nantucket. ORFOEDNESS. We did not visit these light houses, but as viewed from seaward they are substantial structures. Seen in one, in either direction, they guide clear of certain dangers ; and liihrLonws ^^1 besides this, they mark out, by means of red sectors of light, Orfordncss. other dangers. This was the first instance I saw of what " ^'"^ •='""" the Elder Brethren call " red cuts," which I shall fully de- scribe when I come to treat of the lights at Souter Point and Coquet Island. We ran from the white into the red light, and the line of division was quite distinct. YAUMOUTH. On the 12th of June we arrived at Yarmouth, where there r)eiint at Var- moutb. is an extensive supply and buoy depot on the river Yare. ^ .,^. It consists of a very fine buoy store-house, a store-house for chain-cables, a cooper-shop for wooden buoys, smith and paint shops, a store-house for oil, slips for the repair of light- ships, and quarters for the superintendent, foremen, and clerks. There is also a fire-proof store-house for the sigral- rockets used on the lightships. The buoy store-house is well built of masonry, paved wiili ,^^r.noT etorc- wooden blocks, and traversed by a railway. A trussed traveling-crane, of excellent construction, supported on girders resting on piers projecting from the side-walls, gives great facility for moving the buoys; large sliding-doors open toward the river, and on the wharf is placed a ten-ton crane for hoisting the buoys into the steam-yacht. Beacon, ^^^^^ ^^^^^-^ which, with its steam-launch or ijinnace, is constantly en- gaged in the service of the district under the superintend- ence of Mr. Emerson. 102 EUEOPEAN LIGHT-HOUSE SYSTEMS. Bv.o.vB repaired. At this (Icpot are painted and repaired the buoys for tlie neighboring coast and channels, and a large nnmber are kept in store for relief and to supply losses. AViinckn iiiioTs The wooden buoys (not spar-buoys ; of these I believe the liciualit 1" eacb , . year. Eugllsh havc noue) are brought in once a year for painting, Iron lino ysijut the iron buoys are painted without being unshackled )):llIlle(L lit Hiuin'iu^s. JIarkiug buoys. their ...-pot from their moorings, and are but rarely changed. The of buoys are marked with their numbers and names; these last being the names of the spits, channels, &c., which they are intended to point out. A practice very different from our own is that of painting these numbers and names on heavy canvas strips of two thicknesses, which are fastened to the buoys by means of bolts and niits, or by lashings. These strips arc frequently changed, (without lifting the buoys,) as it is considered of great importance that the names and numbers of the buoys shall always be plain and distinct. Metiiodnj deter- There arc a great many buoys and several light-shins fimi liRbt - Biiips m View irom the high lookout-tower above the dwelling of i:iview from the . -, , -, -nr -r-t i --i-i are in the Superintendent, and Mr. Emerson has contrived a simple and ingenious mode of detecting if any of them have been driven from their positions. A large telescope, (shown in Eig, spider-liues, is movable on a vertical axis, c, fixed upon a platform on which are marked cross-lines c «, c a, c a, and the names of the buoysand light- ships, which indicate the precise direc- tion in which they should be found by meansof a pointer, c h, attached to che pedestal of the telescope; thus tbe slightest drifting from their proper positions is at once discovered. 5,) provided with Fig. 5. Bnoy-fiuiler. In regard to buoys, I should mention that the buoy-list of the English differs in several respects from our own. There is noted in regard to each buoy its name, size, descrip- tion, (kind,) color, material, weight of sinker, fathoms of chain, depth of water, when first laid, and date of last removal. The following is an example : EUROPEAN LIGHT-HOUSE SYSTEMS. 103 riri s-z! •= c- £g THCO Qf^ ■^-B "S — ••S 0£ O o OtziOO » •SJUAOTaOJI a ■^"■j-mrt in •prei ^siT J ssggs •(Baiioi 'joj *i O t^ «) ift M< -Bii JO iHdscr 2 ,»" "" .2 Sooowo •nreqo 1 o u *Soo**«'* s ■jgjiniS i 3 3 'C o O C g O O *J K •2 S r^ 0) ■^ti o-d C 5 "^ Is t^a?; e3 ss S^ f^t ■3 -3 .a dog hfejn ajiii! - 1 H) Ki4A o:i3 1 ^ i la d to o ■- fig 104 EUEOPEAN LIGHT-HOUSE SYSTEMS. A spare light-ship is kept at Yarmouth depot, and I saw one repairing in the dock. The bottom was exposed, and ■was provided with bilge-pieces or " bilge-keels" to prevent rolling, as shown in Fig. C. Fig. c. Bilge-keels for Liglit-sbips. 1 was informed that this was the common practice in the English service. nAISBOEOTJGH. PoBition. There are two first-order sea-coast fixed lights at Hais- borough, in the county of Norfolk, the northern or high light being 140 feet, the southern or low light 94 feet, above the sea. They are about a mile apart and form a range or lead for vessels passing through Haisborough Gat. Competitive At the time of my visit to this station there had been in uongrnesf^our- progrcss for some months an important competitive trial wick 01 lamp, ^g^j^gg^ g^ Douglass four-wick lamp in the low tower and a gas-lamp, patented by IMr. Wigham, of Dublin, in the high tower. The apparatus for the latter was manufactured by Edmundson & Co., engineers, of London and Dublin. Gas in nee in The Commissioners of Irish lights have introduced the ' use of gas into several of their light-houses, as we were in- formed by Professor Tyndall when he was in the United States last year, and in the remarks which he made at a gf session of the Philosophical Society of Washington, he mentioned the great " flexibility " of this kind of light when used for light-house illumination. I will treat more particularly of this invention of Mr. Wigham when I describe the Irish lights that I visited with him, but I will state here that I found the lamp to consist of a horizontal circular disk (hollow) about one foot in diameter, supported upon a stand and into which the tubes Irish houses. lifiht- Flexihility giis-ljght. Lamp. EUROPEAN LIGHT-HOUSE SYSTEMS. lOf) supplying the burners, in sets or frames, were connected by joints made tiglit by means of quictsilvcr. Tlie lamii is designed to burn 28 jets in clear weather. ATraiisomi-.it They are arranged in concentric rings, the diameter of ° the inner row being about the same as that of the outer burner of the ordinary four-wick lamp, i. e., four inches. In case the atmosphere becomes hazy, an additional exte- incrcnsc of rior row of 20 jets is placed in two frames of 180° each,"""' "'" ^'^ "' each frame being supported by a short supply-tube set into a cup containing a quicksilver joint. During this operation the lights from the 28 jets forming the nucleus are turned low, and when the cocks are re- opened the flame from these lights the exterior row. As required by increasing density of fogs or thick weather, additional rows of jets are successively placed in each case, increasing the number by 20, so that from 28, the number in the nucleus, the various powers are 48, CS, 88, and 108 jets, the latter being used only in very thick weather or dense fog. There is no chimney surrounding the flame, but above it, chimncy o. at a distance of about 12 inches, is suspended a chimney of "''''^•■'• mica, into which the flame is carried by the draught through the cowl of the lantern. The mica chimneys vary in diam- eter, and are changed to accord with the number of jets used. The entire operation of changing from one set of jets to Time occiiiiio.v the next higher or lower, or from the lowest to the highest, j.^onl'alit!" ''"''' or the reverse, and also changing the mica chimneys, occu- pies but a few seconds, not more time, I should think, than the trimming of a four-wick lamp. The diameter of the flames corresponding to the different Din,incter3 if powers of the lamp are respectively SJ-, 5i, 7J-, 9^, and 10-J inches for the 28, 48, G8, 88, and 108 jets. It will therefore be observed that a great part of the larger flames is neces- sarily exfocal, increasing the divergence of the light, and the increase of intensity when seen at any point within the arc of visibility is no doubt due to the great tldclness of the flame. The heat inside the lantern, when the larger flames are ue.it prod.ui a turned on, is very great, but I was told that it was not suf- aLics." '"°""' ficient to injure the lenticular apparatus nor to seriously annoy the keepers. As in the electric light at South Foreland, an oil-lamp is oii-iamp ..n , JlilDCl ill ClISC til always at hand in the watch-room, and in case of accident accident to the gas-lamp, it can be removed and the former lighted iu less than two minutes. I did not learn that occasion for 106 EUROPEAN LIGHT-HOUSE SYSTEMS. its use had yet occurred, and I sboulrt think it even less likely to occur here than in the case of the electric light. Coal used. In the gas-house near the tower common Newcastle coals are used for heating the five retorts, and cannel-coal yields the supply of gas. Gtis. iiow con- The gas issuing from the retorts is, after being caused to Mi'vei's. pass through water, conducted through several layers of slaked lime contained in flat boxes, thence through a sys- tem of pipes, depositing the tar-product eti route, and finally is carried into the receivers (of 4,900 cubic feet capacity) from which the light-house lamps ard supplied. Meters. Separate meters are used for registering the quantities of gas consumed in the dwellings and in the light-house, and ifiphtiy con- each amount is reported monthly to the Trinity House. The sumption gas. (.oQgmjjpjjoQ ^f g^.g jn the 4S-jet burner, in a night of 7J hours, was 830 feet, or 2.3 feet per burner per hour. Consumption lu the mouths of April and May preceding my visit the iiay^Ss. "" consumption of gas in the tower had been 21,980 and 20,450 feet respectively. Xnmbor of There are t WO keepers at cach light-house at Haisborough, '"'^"'" (that being the rule for all English sea-coast lights, except Lai.orer em- Tock-stations,) aud iu addition to them is employed a laborer i>"'je . irom the neighboring village, to make the gas, but his attendance at the station is only required every other day. He is paid a weekly salary of fifteen shillings;, (about $3.75.) luci saved by A large saving in fuel is effected by consuming the tar nsooi tar. ^vhich is produced in the manufacture of the gas. A general plan of the buildings at the light-house is shown in Plate VI. Plan of tower. The tower is built of brick and stuccoed ; it and the dwell- ings, out-buildings, and walls surrounding the premises are kept scrupulously clean and neat. stairs. The interior of the tower is cylindrical ; the stairs, like those in the towers at South Foreland, are circular, and apparently self-supporting, one end only being built into the wall, as in our Treasury at Washington, and iu several other buildings I have seen in America. This method of stair-building I found to be universal in Europe, iii private Comparison of as well as public buildings. I think our most recent towers i;"n;'i)Km to^- With coulcal interior and iron stairs winding around the interior of the cone, superior to any I saw iu Europe. European towers are, however, superior to any constructed by us until within a few years, on account of the greater amount of light and .the airiness of towers with a free and open interior. u Ui 3 O z H X o x^ — J !«. xS o 3 O DC O a EUROPEAN LIGHT-HOUSE SYSTEMS. 107 The practice abroad is, in most cases, to make the interior ■wall cylindrical and the exterior one conical, leaving an un- necessarily large air-space between the two near the base, while in our latest towers, such as those at Bodie's Island, Saint Augustine, and others, a small air-space sufiBciently large for the purpose intended is left between the walls, (both ot which are conical,) and the space gained by this mode of construction is thrown into the interior. The amount of masonry in our present system is the same Masonry in oia as in the former, and is calculated to resist by its weight tbeMmef^''"""' the overturning effect of the severest gales. At Haisborough the oil-cellars are placed below the floor o"" of the towers, the cisterns or cans, each holding about 100 gallons, being, arranged around the walls. There are no arrangements for pumping the oil to the top of the towers, and it is carried by the keepers by hand. The fllling-room McnsniTs io below the lantern is provided with brass measures of differ- al]mption"'/mT' ent sizes, from a gallon downward, and every morning the keeper notes the consumption of oil the previous night, and makes monthly returns of the amounts to the Trinity House. These measuring-vessels, the brass-work of the lamp, and \„^ni"imf'Z"v- the hand-rails of the stairs, are always neatly burnished. ^""^' The English lanterns in all the recent light-houses have ba?s""™"' ""''" diagonal sash-bars, as it is considered that the upright bars obstruct a large portion of the light in certain directions. I will more fully treat of the latest lanterns which 1 saw, and particularly of the advantages of the diagonal sash-bars, when I come to describe the light house at Holyhead. The glass for the lanterns at Haisborough is half an inch oiass lor lan- thick, the panes are lozenge-shaped, and the surfaces are *""^' curved to conform to the diameter of the lantern. Xo special means are used to prevent large sea-fowl from breaking the lantern-glass, and 1 was told that the necessity of such means does not exist in England as it does with us, particularly on our southern coast. In the lantern-floor there is provided a basin, covered Bnsin in i^m- when not in use, into Avhich is led rain-water from the rooC*^'""''"'"' for use in washing the interior of the lantern. The air, which supports the combustion of the lamp, is E^nss c,r .lir. not let directly through the sides of the lantern, as in onr service, bnt is admitted below and passes through the grat- ing which forms the lantern-floor. The object in this is to ;;ive the air a uniform temperature, and great importance is attached to this in the English service. (See Plate VII.) The windows of the tower are arranged without admit- siPtiiod of ven- ting the rain, according to an excellent plan which is shown *''*"""• 108 EUROPEAN LIGHT-HOUSE SYSTEMS. ami li;;ii(niiii:- idtls. rinisr-stsff^. in Plate VIII, in ■which it will be observed that the upper sash is hinged at «, and ss'ings, as shown by the dotted arc. To the lower part of the sash is fastened a rod, b, which Ijasses through a sleeve, c, which is movable about an axis, and through which a set screw passes by which the window can be fastened at any desired angle. One only of the lower sashes opens, as is shown in the plate. Cost of cimng- The cost of changing from oil to gas at Haisborough was i'miSr "" '"about £1,700. (88,500,) the gas-holder and other parts of the apparatus being designed to serve both lights. Painting the In the English service the towers and dwellings are gen- vTriodSiy. *''" erally painted white (to make them serve better as day- marks) once in four years, by painters permanently em- ])loyed by the Trinity House, and who for this purpose visit the stations in rotation. The lantern, watch-room, &c., are painted by the keepers once a year. The hand-rails, when of iron, are painted with bronze paint, and when they are of brass, which is often the case, they are kept neatly burnished. At the summit of the lanterns are always placed wind- vanes and lightning-rods. Flng-staffs are provided at each station, placed cither on tlic tower or in the grounds surrounding it. The Trinity- House ilag is displayed whenever the tenders are seen ai> ))ioaching; also on Sundays and holidays. I observed that a neat pavement of i)ebbles, about 15 inches wide, was laid at the foot of each wall, to iirotect the soil from the wash Irom the wall in rainy weather. In regard to the dwellings, each keeper is furnished with a living room, three bed-rooms, a scullery, wash-room, a place lor coals, and a garden. (ho There are at Haisborough, as at all other light-stations ill the English service, certain books furnished by the Trinity House in which are kept the records of the stations. Among them I observed an Order-Book, in which any oflicer of the corporation enters the orders or directions given by him to the keeper while on his visit to the station. It is his duty to observe whether previous orders of himself or others have been properly executed. Another book is called the Visitors' Book, and in it are recorded the names and professions of tlie persons visiting the station. Libraries. Small libraries are provided at each station for the use of the keepers and their families. They always include a Bible and Prayer-book, and are otherwise composed of books suitable for persons of their class. It o m R f n nihheil kcfpers. Books Btatioii. 1ST ORDER ENGLISH LIGHTHOUSE. UPPER PART OF TOWER. PLATE VII. 2 3 « J 6 7 S f TO Jf Jf 13 » J^ T^.ftf. THE GRAPHIC C0.PHOT0-UTH.39A41 PARK PLACE.H.Y. EUROPEAN LIGHT-HOUSE SYSTEMS. 10!) These libraries are interchanged between the stations on tlie annual visits of the supply-vessels. 3Ietlicine-chests also are furnished to each station. MeiiuiuecLcsta. I did not observe any room set apart especi.illy for a work- No worit-iooms shop as at our large stations, though keepers are furnished uons."^ with necessary tools, and their education at Blackwall in mechanical operations would, with the general intelligence possessed by the keepers, make this provision more useful even than in our own service. A certain amount of standing furniture is provided in rumitore. each dwelling. It includes iron bedsteads, chairs, tables, a desk, &c. When a keeper is removed from one station to another (either to a better one as a reward of merit, or to an inferior one as a punishment) his family is transported at public expense. The keepers at Haisborough, as at all the other stations unifonn imra ■which 1 visited, wore the neat uniform of the Corporation of ^ "'' '"' Trinity House. From Haisborough we steamed out to the liTewarp light- ,. observation of D 1 o lights at uight. shii), (to be noticed farther on,) and returned after dark to observe from the sea the comparative intensities of the gas and oil lights. The gas-light is in the northern light-house, the oil-light in the southern, on a point of land nearer the sea, at an ele- vation 4G feet below the former, the respective heights of local planes being, as before stated, 140 and 94 feet above the sea. The lower tower is lighted by one of Douglass's four-wick lamps. The Vestal was stopped at a distance of six and a half miles from the lights, an in my journeys around the English and Irish coasts, and they are, no doubt, much more useful in attracting the at- tention of the mariner than light-ships with fixed lights. We passed the Cockle at night, and I had a good oppor- Daboiitruni;v t . ,, , .r .- 1 , ■ -1 /• ^i en board ih" tunitv of seeing the light. It lies about six miles from the Ne-n-ari) hcav i ,f .._L, i-Ti.L-1 11 from tbo Coclili.'. isewarp, and the crew state that in ugh t winds and clear sis miks. weather the Daboll trumpet of the latter can be heard with great distinctness, but that fog " kills " the sound to a great degree. SPURN POINT. Spurn Point is a low sand-spit, projecting into the mouth EangeUghts. of the river Humber. There are two towers at this station, and they form a double range or " lead," the outside one IIG EUROPEAN LIGHT-HOUSE SYSTEMS. being effected by the eclipse of the inner light by the outer tower. 2;umbor of Thc number of stations ou the east coast of England tSEnsfish'coastl with two towcrs, many of them with flrst-order lights, form- ing ranges or leads, is noticeable, and is accounted for by the intricacies of the channels between the sands and shoals off the coast, and their distance from the laud. cnnstructioDof The high or main liffht-tower was built in 177G by John li''li tower o o t- Smeaton, the builder of the Eddystone light-house, and is as unliiie the graceful light-house towers of the present day as can well be imagined. The rooms are very large. The lower story only is arched over, and Is used for an oil-room, while the upper rooms serve for the families of the keepers, aud^ one is used as a c bap el for chapel for the keepers, coast-guardsmen, and fishermen who kcepera. '^ i v o live at the Pomt. ^"^«- The lens is of the fiirst order, and a* part of the arc of illhmination is covered by white light, while certain dangers jieii cut. are marked by a red sector. The red glass in this light covers the required arc of the lens, and is fastened to its Irame, but in order to sharpen the " cuts " between the red and white light, narrow strips of red glass are placed in the lantern opposite the edges of the red glass outside the lens, as is shown in Fig. 7, in which a a ais the shade of red lied cut at Spurn Point. glass of the entire height of the lens ; h h vertical strips of red glass for the purpose of intensifying the." red cut ;" c the lamp, ■« the sector of red light. Eritu'i', ■■ 'ligb": '^^'^ following, copied from the British lighthouse list, will ijouseiist. - suggest the purpose of this mode of covering by red light any desired area, and of marking by the cuts between the EUROPEAN LIGHT-HOUSE SYSTEMS. 117 red and white lights any line upon the sea within the circle of illumination : " Spurn Point. — A sector of red light is thrown from the high light-liouse bearing from N. W. by N., {cutting tico cables ^. E. of the Sand Hayle buoy,) round northerly to S. E. by E. § E., on tchich bearing it loill cut one cable north of Grimsby Pier. In other directions the light is white." The oil in use at this station when I visited it was colza, Coiza-ou u-ci. but I believe it is the intention to change this and all the Mineral to ii-.- other lamps in the service of the corporation of Trinity ^">"*'*"""'- House for the use of mineral-oil. The lantern was a fine one of gun-metal, the sash-bars Lantom. being diagonal. The diameter is 14 feet. The service-room was fitted up with closets and shelves, serTioc-room. and the articles for daily use are neatly stowed away in boxes marked "Cleaning-cloths," "Skins," "Powder and brushes," " Cotton wicks," " Polishing-powder for brass and copper," &c. The lens is supported by the lantern-floor, which is carried Lens. upon eight double iron brackets, and the interior of the watch-room is finished in corrugated iron. The station, comprising the lower dwelling, &c., is sur- "Waii rounded by a high wall similar to that at the Longstone, (mentioned farther on,) but for a different purpose, viz, to keep out the drifting sand. The lower light-bouse is a comparatively new structure, Lower iis;:t- and was built in shoal water inside the main tower, as a sub- stitute for the tower which Smeaton built outside the high light which was some years ago undermined and destroyed by the sea. The apparatus in this tower is of the fourth order. Apparatus. PLiMBOROUGH HEAD. This part of the Yorkshire coast is high and bold, rescm- Appearauco oi bling the coast of California. I was interested, not onlv in the inspection of the fine oia tovrcr in "■,,,, , . ■ llvlnlmgfioal.'^t;:l new tower on this remarkable headland, but in seeing near atautUns. by a well-preserved example (built in 1G74) of one of those great coal-burning light-towers whose use preceded the invention of either of the systems of illumination now in use; from this tower was witnessed the naval battle between the Serapis and the Bon Homme Eichard, which was fought off this headland on the 23d of September, 1799. tllC Btutioil. jM-niiJul 218 EUEOPEAN LIGHT-HOUSE SYSTEMS. neisbt of focal The focal plane of the new tower is 214 feet above the sea, '''''""■ and 87 feet above its base. The tower is surmounted by a oHeiT"'^"'''"' first-order revolving lens, showing, alternately, one red and two white flashes. Qnaiuyofiena. ^ij^jg jens, made by Chance, Brothers & Co., of Birming- ham, is a fine piece of workmanship, and the Trinity House officers state that all of the optical ap[)aratus furnished by this firm give great satisfaction. Ar^as of red The area of each of the red panels, is to the area of each aiiawLitoiiaDois.^^ the whitc panels of the lens, as 21 to 9, thereby pro- ducing an equalization of the distances at which the flashes can be seen. Lamp. The lamp was one of the latest, combining all of Dong- lass's improvements, and burned mineral-oil, though it is suited also for burning colza. The lantern is of the same character as that at Hais-- borough, which I have described, and there were no points of special interest at this station that were not mentioned iu connection with that light, except that on the edge of the ^ idg-gnn sta- ^^^^ there is a fog-gun station, in charge of a special set of keepers, (two,) who have dwellings and gardens separate from those at the light-station. ivs-snn, iiow The gun, an 18-pounder, is in a small masonry building having an emhrasure on the sea-side; it is fired at intervals of fifteen minutes iu foggy weather, the charges being three pounds. About one thousand rounds arc fired annually, and they are kept in ready-filled cartridges in barrels in the magazine. The gunners have no other duties. wniTBY. These two first-order lights are on the coast of Yorkshire, and, like the Ilaisborough lights, form a range or head which clears a dangerous rock. The towers are about 250 yards apart. A red cut shown Irom the northern tower covers certain other dangers to be avoided by vessels. Fasfonins for The modc of fastening the red panes, so that they can be easily removed for cleaning the lens, is very simple, as -will be seen in Fig. 8, consisting of a turning-plate, which, when shut, rests on a slight projection. La=ip-Kuara. Another simple contrivance in use was a movable metal- lic guard, which is slipped over the burner before the wick is trimmed, so as to catch the cuttings. (See Fig. 9.) The stairs leading from the watch-room to the lantern were noticeable, the step, newel-post, and ornamental bracket being cast in one piece. Towers. Ited cut ri-il paues. EUEOPEAN LIGHT-HOUSE SYSTEMS. 119 The smoke-pipe leading from tbe watch-room stove was Smokepipe. of brass neatlj' burnished. The dwellings for the keepers (each light having two) .^^f »'''' "i^^"- were placed on opposite sides of each tower, and the rule is general that each keeper has a dwelling quite separate and detached from any other. Fig. 8. i |l^ 'ill J, if ' Fastening for red panes. The dwellings at "Whitby — and this is also the rule — are only one story in height. There was nothing noticeable in regard to the lenses, except the large amount of rear light {i. e. through an arc of 180°) not utilized, and I was informed that formerly the ^^f^^^'^^^ ''g; land side of the lens was occupied by a metallic reflector, throwingthereav liglit to seaward. which, reflecting the heat as well as the light from the flame, caused the wick to burn so much more freely on the rear side than on the other as seriously to impair the light. Fig. 9. Lamp-guard. Totally reflecting glass prisms, such as are now used in light-houses, would not produce this effect, but they hare not as yet been supplied. I learned at Whitby that one of the light-keepers has f^is- ^^^'"^^^l ^'^^ covered in his experience that dipping the lamp-chimneys in ^f™'[f^«J° "' a hot solution of soda will prevent them from breaking even when exposed to the strongest flames. 120 EUROPEAN LIGHT-HOUSE SYSTEMS. Tomi of \vhit- Not far from the light-Louse is the town of Whitby, inter- \nii.sofAi)boyesting on account of the ruin of the once handsome Abbey of oi saiut Hilda. Saint Hilda, (founded A. D. C57,) the extensive commerce in jet, mined from the cliffs near by, and as being the poit from -which Captain Cook sailed in his Toyage of discovery. SOTJTEE POINT- The great electric light at Souter Point, which I visited on our return voyage from the north, and a general view of which is given in Fig. 10, is three miles below the mouth of the river Tyne, and I reached it by carriage from South Shields, after a hurried inspection of Sir William Armstrong's o T- d n a n c e- great ordnance-works at Is ewcastle, with Admiral CoUinson, ilm'^Am^stroEg!' to whom I am indebted for the permission which he had thoughtfully obtained from Sir William before leaving London. Fig. 10. View of Sonter Point Light-house. Manufactories Qq ijQth banks of tho rivcr, from the mouth to ISTew Castle and enect oi ' bmokeUierefroni, and beyoud, there is an immense number of manufactories of all kinds, and their smoke hangs over the river like a cloud. ob8oT?ed*"b''y When the wind is from the westward this smoke is driven emoke. oygr ^lie sea-approachcs to the river, obscuring, much to the annoyance of the great number of vessels of all classes contin- ually entering or leaving the river, not only the pier-lights at its mouth, but the sea-coast light at Souter Point which indicates the general position of the harbor. SOUTER POINT LIGHTHOUSE. ELECTRIC LIGHT. PLATE IX. ^^ .„ ,i m iiiii , i ii tn ii a i i m ii i i i i M i i i iiii iiin ii i l"20'ZA>ru^r f uiU WfSt nf {fr^P n>vi'c}i 122 EUROPEAN LIGHT-HOUSE SYSTEMS. quences of any error in designing or executing the optical apparatus, are evQn more serious and far more apparent than when a larger source of light is used. Accidents to re- It is a fact important to be noted that at this station, as volvin^r appara- . , _, t. , tu3 provided for. at all othcrs lu the English service, the contingency of ac- cident to the clock-work carrying the revolving lens is pro- vided for. A crank for turning it by hand can be attached, and a dial placed before the keeper indicates the velocity of revolution, so that he has no difficulty in preserving the proper intervals between the flashes. TTtiiizing the A part of the light thrown to the rear (toward the land) ° ' is taken up by an annular refracting lens surrounded by ca- tadioptric prisms, the whole being about 15 inches in diam- eter and forming a holophote of the sixth order, and the rays after passing, being formed into a cylindrical beam of paral- lel rays, impinge against a set of totally reflecting straight prisms, which in turn cast them at right angles, in a beam of parallel rays, down through a vertical wooden tube, pass- ing through a circular aperture in the floor, upon another set of totally reflecting prisms in the room below, and they again, turn the rays at right angles and out through a large Da n K r s plate-glass window upon some dangers southward of the point, which are called " The Mill Eock," " Ilendon Eock," and " The White Stones." (See Plate IX, which is a chart showing Souter Point and its vicinity.) The window through which this borrowed light passes is divided vertically into two parts, the one on the western or land-side being red and the other white ; the line of divis- Hedcut. ion being produced over the sea gives a "red cut," the utihty of which will "be understood from the following sail- ing-directions, taken from the British light- house list : Sailing direc- " SouTEE PoiNT. — Tlw main light IS elcotric and flashes every minute. A fixed lights also electric, is slioicn 21 feet helow the flashing light, and shows ichite between the hearings of N. hy W. and N. ^ JS., and red between N. J U. and A^. by E. I E. When the fixed white light is seen, vessels icill be in line of Mill Bock and Cape Garr Point, and ichen it changes to red, in that of Whitburn Stile, Ilendon Rode, and Wliitc StonesP Plate X. Plate X shows a plan of the lower light-room and details of the window through which the " red cut " is made, a in the plan showing the position of the lower refracting i)risms. piatuxi. The engine-room, a plan of which is shown in Plate XI, with its accessories, (including fuel-rooms for the storing of coke, of which about 100 tons are used annually,) and the dwellings of the keepers form a large quadrangle, (see Plates lluiis. ■VMOQNIM JO N0I103S ■NVTdaoJinvOS SOUTER POINT LIGHTHOUSE. ELECTRIC LIGHT. PLATE XI. PLAN or MACHINE-ROOM. K:,-'e—= SCALE. rjn^t. THE GRAPHIC CO. PHOTO -UTH. 39*41 WRK PLACE.H.Y. EUROPEAN LIGHT-HOUSE SYSTEMS. 123 XII and XIII,) the former being on the land-side, while, piatcaxiiaiui toward the east or seaward, is the tower, which is detached from the rest of the establishment, except that communica- tion is had by a covered way one story high. The machinery for generating the electric current is simi- iiacbuiery. lar to that at South Foreland. Two rotary magneto-electricmachines of Professor Holmes' Magnpto-eUc- patent are driven by two 3 horse-power engines which can engine, be worked up to horse-power each. Each machine consists of eight radial frames, to each of con.strnctionof which are attached 3G magnets, making 288 in all, and the *•"""'"'''''"="• poles arc alternately pointed toward and from the axis of the machine. A shaft driven by the engine, revolves a series of cylinders The magnets. composed of helices of wire, past the magnets, which pro- duce the alternately positive and negative currents. These currents are collected by the wires i)assing up the tower to C"^renta pn.- the electric lamp within the lens. The number of revolutions made by each machine per xnmberofn-v- minute is 400, and as 16 sparks are produced by each mag- Sto TnY''c™s'.'.- uet at each revolution, the number of sparks at the carbon svaTi's""" points of the lamp is 0,400 per minute, when one machine only is in operation, as is the case in fair weather, and 12,800 per minute when both machines are at work. These sparks are formed so rapidlj' that the eye does not separate them, and the result is a continuous beam of light, so dazzling, that the eye of a person within the lantern cannot rest upon it for an instant, without intense pain. To insulate the shaft of the machine which conducts the insulation of shaft. electric current to the wires, it is encased in ebony-wood journals, and where the wires pass through the wall of the engine-room, there is a coupling-box so arranged that, bj^ a single motion, they can be connected or disconnected, and the current from one machine or two can be turned on to the lamp at pleasure. The electric lamp, as at South Foreland, consists mainly Electric lami). of two carbon points, each about ten inches long by one- half an inch square in section, placed end to end in a ver- tical position, and the automatic machines called regulators, feed the points toward each other as fast as they are con- sumed, which is at the rate of one inch per hour each. An oil-lamp is placed under the electric lamp, and is oiiiampfornse always filled and ready to be substituted in case of accident denT" "' "''"' to the latter, or to the machinery ; but I did not learn that a necessity for its use had ever arisen. 124 EUROPEAN LIGHT-HOUSE SYSTEMS Plate XIV and Fig. 11 illustrate tlie disposition of tlie different parts of the lenticular apparatus at Souter Point. lu the former a is the focus ; a' the electric lamp ; a" a" the carbon pencils ; h the holophote ; c the upper totally reflecting prisms ; d d the fixed dioptric apparatus ; e e the revolving frame of flash-panels; // revolving gearing; p the removable bed-plate ; h the burner of the oil-lamp ; i telescopic tubes for the supply of oil and the overflow, for use if the oil-lamp should be substituted at any time for the electric lamp ; I the oil-reservoir; »n m the oil-supply pipe ; n cylindrical shaft for transmission of the beam of reflected light to the lower liplit-room ; o the lower reflecting prisms ; p p the window of the lower light-room ; g a gallery used when cleaning the sash of the window. Fig. 11. Plan of lens and lantern, Souter Point. In the figure a is the focus ; h the holophote ; c c the upper reflecting prisms ; d d d the fixed dioptric apparatus ; e e e the flash-panels. The dotted circle under c c shows in plan the shaft for transmitting the beam of reflected light to the lower light-room. The tower at Souter Point, shown in Plate XV, is built like most of the towers I saw in England, being a shell of brick-work into which the steps are let at the outer end only, and with landings at the windows. (A 3 O I O o Ij j 1-2 z^ o o 0.3 IE" U I- 3 O V) Z < < K U Z u o ^ '3 ■s I r. 4: "^^ ■5 SOUTER POINT LIGHTHOUSE. ELECTRIC LIGHT. PLATE XIII. GROUND PLAN (I. /ftA'prr/tu ■•*' -^ irnit^tffon / . /i. I I. /-*0/ V */' t'S . h.k.Pftiitt'iey. IJ.Coal. ui.TU. Wooat. ji.fi.Yfif'iJ/jf. lKO.£f Durlston Head, and aboitt a r.UROPEAN LIGIir-UOUSr. SYSTEMS. 135 imhle S. of outer part of Bridge Reef. Its northern limit, hear- ing E. 8. E., passes tico cables south of JJolphin Banlc, and the S. W. huoy of the Shingles. '■^The ray of white light between the bearings of 8. W. by W. and 8. W. by 17. J W. clears Warden ledge."" We did not visit this ligbt, but as we passed it early in tbe morning it shone brilliantly and gave us a good illus- tration of the system of pointing out dangers by "red cuts." THE BILL OF POETLAND. We passed in view of these two fine light-houses on the coast of Dorsetshire without stopping. They were built in 171G, and in 1788 the coal-fires which . Date of b«iia- burued on their summits were extinguished and oil first came into use. They are about five hundred yards apart, and form a range or lead between the Race and Shambles. THE STAET. The Start light-house is a bold headland on the coast of Devonshire, and wheu I visited it there were extensive EeiMirs. renovations going on, including the placing of one of the latest first-order lanterns, of Mr. Douglass's design — 13 feet inside diameter — iu lieu of the old one. The light is revolving, and the difficulty of making this, ciianTP <.f i.d. change without extinguishing the light was overcome by the tiDsmsbin,' tL« use of a ship's revolving catoptric apparatus of the same interval, building the new lantern up around it. This lantern has diagonal bars of steel formed of two. Diagonal sasi!- bars. thicknesses of J inch each, so the bar, when finished, is 3 inches by 1 inch. The glass (J inch thick) is not set iu a rebate, but the setting of the lozenge-shaped panes abut against each other outside the bars, and the joints are covered by strips of brass fastened by screw-bolts, through the glass and into the steel burs. The cost of these lanterns is about £1,700, (68,500.) costof iam«:.. There is a lower light-room, from which a single reflector r-o^ei' I'si-:- throws a fixed light over a danger called " The Skerries." There is a fog-bell at this statiou, weighing thirty-five ros-ij«^ii- hundred pounds, and struck on the inside by machinery. It strikes five hours without winding up the weights, an opera- tion requiring fifteen minutes, during which the striking is interrupted. 136 EUEOPEAN LIGHT-HOUSE SYSTEMS. Eesembinnceto The resemblance of Start Point to Point Bonita, at the ^"'"'^™"^''^'"- entrance of the Golden Gate of San Francisco, is remark- able. THE EDDYSTONE. View of tho Oa.lhe morning of the 26th of June -we came in sight of towei. ^{,g light-house which, more than any other extant, is known throughout the world as a splendid proof of the ability of man to overcome the force of the sea — the famous Eddy- stone, which lies off the coast of Devonshire. swciioftbesca There was a heavy swell from the Atlantic, and as the preventsianding. yggjai ncarcd the light-house we were disappointed to see the waves running high up the tower, and the keepers' signal from the gallery at its summit that a landing was impracti- cable; but I was much gratified .at having even such an opportunity of seeing this historical work. Appearance. Neither in height nor in appearance is it the equal of either of the modern light-houses The Wolf or The Long- ships, off Land's End, which I afterward visited, jet I could not but feel a thrill of admiration as I gazed at this grand old tower which has so successfully battled with the sea for one hundred and fifteen years. Date of iraiki- The first light-housc on the Eddystone was commenced in hmise'on tiie'^'a- 1G96, finished in 1G98, and was destroyed in a terrible storm ' J"'"""- ju 1703. Kot a vestige of the building remained, and neither its keepers nor Ilenry "Winstanley,' its builder, who had wished to be in his light-honse "in the greatest storm that ever blew under the face of heaven," were heard of after- ward. Date of build- The sccoud light-house was built by John Rudyerd. It ing secoud. ^,^^ lighted in 1709, and destroyed by fire in 1755. Date of bniid- The buildcr of the present light-house was John Smeat^n, oni ^ " ''™™ who commenced the work in 175G, and finished it in 1759, Account of Of the construction he has given a most interesting nar- rative, or, as he styles it in the dedication to his King, " a plain account of a plain and simple building that has never- theless heen acknowledged to he in itself curious, difficult, and useful," which clearly exhibits the industry, perseverance, and genius of one of the most remarkable of men. His plan was entirely different from those of his predecessors, he having conceived the idea that a light-house in a posi- tion like this, in order to withstand the sea, must depend upon its weight. Method of join- He therefore built it of stone, dovetailing the joints, as shown in Plate XXI, so that no stone can be moved with- out displacing the others, and his work has furnished a model upon which all rock light-houses built from Smeaton's buildin: ing tbo stones. Plate lYlll. THE EDDYSTOJNE JLIGHT-HOUSE. EUROPEAN LIGHT-HOUSE SYSTEMS. 137 time to the present have been constructed, except as regards some of the details, wbicli have been modified in some de- gree by their respective engineers. The science of illumination, as applied to the Eddvstone, ninmiiiatiug- T i- L ..7 pQ-vver first used. was far behind the science of construction, and while Smeatou sprang at once from the prejudice of his time to a full conception of the true principles which should govern the construction of a work of this character, it remained lighted for many years as at first, by '■Hicentyfoiir candles burning at once, five ichereof weighed tico pounds.''* Keflectors were not introdTiced until early in the present Keflectorsuaeu. century, and in 1815 these in turn gave way to a second- order Fresnel lens, (fixed,) the beam from which, with its rresnei lens. Douglass burner, is equal to 4,050 candles. This was the first catadioptric apparatus ever constructed. SAINT ANTHONY. This is an old station on the coast of Cornwall, standing Position, on a rugged promontory projecting into the bay which leads into the harbor of Falmouth. The tower is square, and contains the dwelling for the Tower. principal keeper and his family, the assistant occupying a cottage connected with the tower by a covered way. The apparatus is catoptric, and is composed of eight re- Apparatus. Hectors, one on each face of the revolving frame. There is a bell, struck by machinery, but quite unlike the Fos-beii. others we had seen, and, indeed, there appears to be no uniformity in the bell-machinery of the English service, as many being struck by the hammer on the inner as on the outer side. A single reflector is placed in the living-room of the prin- cipal keeper, and shows through a square window a fixed white light to guide clear of some dangerous rocks, called "The Manacles." PLYMOUTH. This light-house, which corresponds to the general char- acter of "rock" light-houses, is placed on the end of the fine breakwater which protects the harbor of Plymouth, and is one of the most elaborate pieces of stone-work I have ever seen. The material of which it is built is a beau- tiful granite from Penrhyn, in Wales, and on the interior *''""' the immense expense of the construction is shown by the exquisite finish, almost polish, of the surfaces. The floors. Beauty of fln- (;ei!ings, partitions, and walls are all of granite, and no lin- ing of any kind is used. * Smeatou's Narrative of the building of the Eddystone Light-house. Low light. Material of 138 rjJKOPEAJT LIGHT-HOUSE SYSTEMS. StreuKth of (rhe Btructurt-. Arranjrem e u t of ruoius. of the lislit. This tower is exposed to the hearj^ seas which roll over the breakwater, and for a distance of 10 I'eet from the bot- tom it is a solid mass of masonry. Its entrance is througli a heavy gun-metal door, sliding upon rollers at top and bottom. The lower floor contains the srore-iooms; the second floor the oil-rooms; the third floor the kitchen and living-rooms; the fourth the bed-room, and the fifth the service-room. All the doors and window-frames are of gun-metal. ciiirncteristics A Small Segment of a fifth-order dioptric apparatus in the watch-room throws a beam of leading white light through a small window upon a buoy and the fairway, the beam being limited by placing in front of the lens a me- tallic case in which there is a narrow slit about 2J inches wide. •'' The main light shows ichite within the anchorage and red to sfaward. The red light is i)roducedby surrounding the lamp, (one of the second order,) except for the small arc covering the anchorage, with a red cylindrical glass about 9 inches in diameter. iiotiioii n'o):t- To more sharply define the "cut" between the red and y ''" o o DC V) z o I- o u CO UJ > cc 8 O u / "/"NVV^" fe\ 11 1^ ^ us < ° EUEOPEAN LIGHT-HOUSE SYSTEMS. 143 of tbe red and the wbite sectors in the ratio of 21 to fl nntins of aicxs or r (1 ami w uit,e nearly ; aud this rule was followed at Tbe Wolf, so that its sectors. beams of red and white light have tbe same value. The lantern is of the cylindrical helically framed kind, i'aato">- and upon the lantern-gallery is placed a fog-bell, struck by ^"s""-'" means of machinery placed within the pedestal of tbe lens. There is but little wood used in the construction of tbe ounmetaiua-ii interior of the light-house, and all of the doors, the window- ir!ime8r&"' frames, and storm -shatters are of gun-metal. I was told that bronze was habitually used for window-frames and sash-bars at rock-stations, and oak for those of shore-stations. The windows of the watch-room are arranged, as shown watiii-room in Plate VlII, for admitting air to support combustion in the lamp, by means of a valve in the upper part, the current passing over the heads of tbe keepers aud through the grating which forms the lantern-floor. As at other stations, I observed that the floor of the ex- Floor or lan- ' tcrn-gallerv. terior lantern-gallery, unlike ours, is made of stone with raised joints, i. e., the surfaces for about one-half an inch on each side of the radial joints do not partake of tbe inclina- tion of the general surface, but are quite level. There are four keepers belonging to the station, and three xnmbcr of of them are constantly in tlie tower, while the fourth is on shore with his family. The stated term of service on duty on the rock is one Termofservice month, but it sometimes happens that eight weeks or more^'^'^"™™'"'^"'' elapse before a sea can be found sufliciently quiet to make a landing practicable. As before stated, the rock upon which tbe light-bouse stands is submerged at high water, aud tbe winch, mast, and boom of tbe derrick used for landing the keepers, visitors, and provisions are, when not in use, laid into deep troughs or recesses in the stone and strongly fastened down to protect them from tbe sea. It was a comparatively calm day when I went to The MothoiiofLma- Wolf, and I was fortunate in being able to land upon the ;."jV°''"" *'"' rock ; but it is an undertaking attended with a good deal of danger, and many trials and much delay were experienced before we were successful. Tbe landing-boat, which is weU adapted for the purpose, LaucUug-boat. is built diagonally of two thicknesses of elm-plank, without timbers or floor, aud is provided in the bow with a landing- deck and stake. This deck and the forward part of the gunwale are cov- ered with rough rope-matting to prevent slipping in jumj)- ing into or from the boat, which is warped in by means of a 144 EUROPEAN LIG-HT-UOUSE SYSTEMS. line made fast to a buoy asteru and two lines from the bows, the latter of which are managed by the men on the rock. The person who is to land is provided with a cork lile- belt, and stands on the landing-deck forward, holding tho stout mast or stake with both hands, and when the proper instant arrives, of which he is warned by the coxswain, who watches the waves and manages the line astern, he seizes the rope which is lowered from the end of the derrick-boom, places one foot in the loop at the end, and is quickly hauled up by the men at the winch on the rock. Dangy' attend. Lauding by the mode I have described is comparatively ingian mgs. ^^^^^ ^^^ ^^ often impracticable, and sometimes when the keepers are relieved they are pulled ilirough the surf into the boat when it cannot get near enough to the rock to per- mit of their being dropped into it. This light-house is one of the most striking examples of rock light-house engineering for which Smeaton's Eddystone has furnished the model. Moro of this There are now several of this type in the various countries iwulei,''L ireatof the globc, but Great Britain possesses more than any Britain tlian else- , , wliere. Other. Notable in- In the United States we have notably two ; one built by uSitod states. ° General Alexander, of the United States Engineers, on Minot's Ledge, off the coast of Massachusetts, where the rock is exposed to the full force of the Atlantic, and is only uncovered at extreme low water ; the other i)roposed by General Kaynolds and built by General Poe, both of the United States Engineers, and the latter now a member of the Light-House Board, on Spectacle Eeef, in Lake Huron, the site of which is 10 feet below the surface. Spectacle Eeef, The latter, howcver, was quite a different problem from difficulties met in ,. , ,. .,-,,,, , , . .,, , , buiuung. any of the others in that the structure was to withstand the immense fields of moving ice by which it is assailed in the spring. I regret that I could not visit the other rock light-houses of England, or the Skerry vore and Bell Eock, the latter of which have given so enviable a reputation to the Stevensons. the distinguished family of Scottish light-house engineers. THE EUKDLESTONE BELL-BUOY. The bell-buoy which marks the Rundlestone, off the point of Land's End, is 10 feet in diameter at the water-line, moored Moorings. with 45 fathoms of li-inch chain and a 30-cwt. sinker, wliicii is backed with 30 fathoms of li-iuch chain, and a second sinker of the same weight. eukop.i:an light-house systems. 145 The bell weighs 3 cwt. This is a water-ballast buoy, and is sbowu in Fig. 15, in which a is the outer water-tight compartment ; b, the inner water-tight compartment ; d. d, the India-rubber springs. Fig. 15. Mini Eandlestone Bell-buov. THE SEVEN STONES LIGHT-SHIP. Ago. Masts and ap- paratus. This vessel, which marks the dangerous shoal of rocks in- position, dicuted by its name, lies about twenty miles to the westward of L:ind's End, or about midway between it and Saint Agnes (ycilly Islands) light, in what is probably one of the most exposed positions in the world for a light-ship. It is one of the latest constructions, and has been on the station about two years. It has two masts, besides the mast for a jigger or miz- zen, which is stepped on the taffrail. The former carry two lixed catoptric lights, 28 and 20 feet above the sea. A fog-trumpet, of Professor Holmes's patent, shown in rofr-trumpct. Plate XXII, is operated by a hot-air engine, the cylinder of which is 2-4 inches in diameter. The engine is placed between-decks, amidships, and the horn between the masts on deck, I should think the utility of the signal much impaired by Lepstuof tim.^ the length of time required to generate sufficient pressure erate'^stcam ^^i;"- to operate it, which I was informed is an hour and three- 'hc'signai.' ' quarters. This is a serious objection in anj- fog-signal, since the fires are ordinarily not started till the fog comes on, and in the S. Ex. 54 10 3'^n j; in n a ml lioni, positiou ol". 14G EUROPEAN LIGIIT-IIOUSE SYSTEMS. long interval before tlie warning is given serions accit]c'i:ts are liable to occur. "Ueaters'oscd For our signals operated by steam, we frequently provide Sigul"""" '""" " heaters," by which, with a very small expenditure of lucl, the water in the boiler is kept hot, so that when the signal is required, a quick fire v.-ill raise the pressure to the required point in a few minutes. ro-born ran The fog-sigiial on the Seven Stones can be operated by ilLi^""'*'' ^^ hand, by means of a pair of air-pumps on deck, in case of accident to the hot-air engine, or when waiting for the re- quired pressure, but it is extremely hard work for the sea- men, and I fancy the signal may not be satisfactorily sounded at such times, siguaignn Therc is also a signal-gun on deck which is fired when a te\a iJ^o™seeu" vcssel is secu Standing into danger. d'a1"Re"° '"*" The measurement of the Seven Stones is ISS tons. It amrm™rto"3°"is moorcd in 41 fathoms of water by 200 fathoms of 1^;- inch chain to a mushroom anchor Meighing 40 cwt. Three hundred and fifteen fathoms of chain can be run out when necessary. Qj.^^ This lightship carries a crew of fifteen men besides the master and mate; one of the latter and tive of the seamen Tjnifoi-ms o f ^^'*^ coustautly ou shore with their families. Thej' are all «"■"■ uniformed, and the name of the vessel is marked upon their hats and shirts. This rule applies to the crews of all the light-ships of England, and to those of the yachts or tenders belonging to the Trinity House. THE LONGSniPS. Ti-ocation. The Lougships is the name of some rocks about a mile and a quarter to the westward of Land's End, ou the largest of which is the new first-order light-house of that name, which, at the time of my visit, was on the point of comple- tion. Koush seas As at The Wolf, the sea is generally rough at The Loug- iiievaknt. ships, and when we approached it on our return from the Seven Stones light-ship to Penzance, we found it impossible to land. The following day, however, we made another attempt, and were successiul. The rock on which the tower is built is conical in form, and rises about GO feet above the sea : and the tower, wliicli is precisely like that at The \Yolf, is placed on a ledge in front, about 20 feet above the sea. The rock in the rear was being blasted down to the level of the top of the solid part of the tower, at which is the door or entrauce. Form of rock. HOLMES'S FOG-HORN APPARATUS, plate XXII. a Mctntf-fkimps. i. fbch betureenBantir/iempn. cAhs. Vesse/. d. Chrh irtiireen.Eni.. Trinity House, which takes place on Trinity Monday, at House. which were present His Royal Highness the Princeof Wales, the Czarowitch {eldest son of the Czar) of Russia, the Dukes of Argyll and Richmond, and others of the nobility, the Queen's Ministers, and other distinguished personages. His Royal Highness the Duke of Edinburgh, Master of the Trinity House, presided, and during the evening I had the distinguished honor of being presented by him to His Royal Highness the Prince of Wales. They both kindly referred, as the former had done before (as I have men- tioned) at the dinner of the Lord Mayor, to the satisfaction which Sir Frederick Arrow and Captain Webb, of the Elder Brethren, had expressed in regard to their visit to the United States and inspection of some of our light-houses. Before proceeding to Ireland and Scotland I visited the Continent, but I will here continue my account of the British lights in the order in which I visited them after my return. HOLYHEAD. Leaving Loudon by train on the 14th of August, I arrived at Holyhead, on the Island of Anglesea, the following day, where I met, by appointment, Mr. Douglass, the engineer of Trinity House, and had the pleasure of inspecting with him the Trinity House light-stations on the island. The great breakwater for the protection of the harbor of JircaUviater lo refuge at Holyhead, together with the light-house at its uor ot reiugu. ' outer end, had just been completed ; the latter, although quite finished, was not to be lighted until a few days later, when there was to be a grand demonstration to celebrate the completion of the harbor works, at which the Prince of Wales and several members of the government were to be present. The light-house, which was built from designs Ligiit-iionsc. approved by the Trinity House, by Mr. Hawkshaw, the dis- tinguished engineer in charge of the breakwater, at the ex- pense of the fund appropriated for the latter, is a handsome tower of granite surmounted by a flashing lens of the third ^^„,^ order, made by Chance Brothers. Outside the parapet of the tower is placed a fog-bell, rung by machinery, which, Pog-beii. together with the usual revolving machinery, is contained within the pedestal of the lens. The latter revolves upon conical wheels, the outer bearing-surfaces of which iire flat^^Fia,t wiicou iind rot beveled as in the French system and our own. iusmacUiuci;.. 150 EUROPEAN LIGHT-HOUSE SYSTEMS. Mr. Douglass stated that wheels of the latter kind wear into the rail rough channels, which increase the friction and interfere with the regularity of motion, which is essential in wiisi.is.f the revolving machinery of light-houses. The lamp, a " mod- "■"i'- erator" of Chance's manufacture, is like our own, except thivt the weights are hung underneath the cylinder or reser- voir, and are connected with the plunger by means of exte- rior rods. Tlie plain pulleys and rods formerly used for revolving and fog-bell machinery have been replaced by chain-wheels and chains which are much more durable and reliable. Fig. 16. I,;lnii) of siu;:l3 ami ilimblo pow- Lamp of Single and Double Power. The burner, shown in Fig. IG, contains all the recent im- provements, one of which gives to the lamp its name of the EUROPEAN LIGIIT-IIOUSE SYSTEMS. 1">1 " lamp of single and double power." In the figure a a is the Expian.ition ot focal plane; &&,tbe level of the mineral-oil; cc, the overflow- holes, eight in number, aud three-sixteenths of an inch in (liartieter; d, the iuterior, and e the exterior deflector. The adjustable chimney, the perforated button, aud the conical tips to the burners are also shown. Between the exterior deflector or jacket, and the chimney, there is an air-space, open at the bottom, through which a draught of cold air passes and keeps the base of the chimney so cool that it can be removed by the naked hand, as I found by experiment, without the use of the tongs usually required. These burners have three wicks, the exterior I'g, the middle 1£-, and the interior § of an inch in diameter. Dy a simple movement the inner wick ciin be loweretl into the burner and extinguished, or raised and lighted. This and the change of the perforated buttons retjuire but p,™,'r i.r :i'- au instant, and the result is, that the flame and the amounti"';i".',',',',',s;',,,,|,'.i,','j of oil consumed can be exactly adjusted to the quantity ot''^^''' light required. In fair weather only the outer and middle wicks arc burned, but when fog or thick weather comes on, the \iqv- forated button is changed, and the inner wick is raised antl lighted. This is of great importance in the economy of light-house j.>oii.,ni.v,ini.> illumination, and tlie Ecglish have been, as far as 1 am '•"""^'■ iuvarc, the fiist to attempt to vary the power of oil-lights; a result which has been effected, as I have before stated, iu both the gas and the electric lights. riiotometric experiments have shown that the flame of Pi„v,.r of tin the outer two wicks is equal to 146 candles, and the lighting'""'""'""''*'''"'"- of the small iuterior wick raises the power to 20S candles, showing that, though the inner wick has but 19 percent, of the total burning- surface, it yields 30 percent, of the entire amount of light, an amount very much in excess of its power when burning alone; but it must be considered that the circumstances of combustion are much more favorable when the wick burns inside the larger flames. The lantern at Holyhead is of the latest kind. The sash- l,,,,,,.,,, v.-\va bars run diagonally from top to bottom, and the panes of ;{i,^.f":;;,V'';!j:\J;; glass are of a lozenge shape, cast in cylindrical form, cor- '^""'^ -'"^'*- responding to the diameter of the lantern. With regard to the diagonal sash-bars, Mr. Douglass stated that Faraday, the predecessor of Professor Tyndall in the ofBce of scientific adviser of Trinity House, found that the vertical bars, oi.sm.ctio., of which -(^-ere at one time used, obstructed at least 48 perijffM; ''.v ve.tici cent, of the light in certain directions, whereas with diag- 152 EUROPEAN LIGHT HOUSE SYSTEMS. oiial bars the shadow was lost at a distance of less than ji hundred feet. In discussing this matter Faraday consid- ered that the rays of light issuing from the lens in any di rection, form at the exterior surface, a beam, a vertical sec- tion of which is a column of light of the height of the lens; that with diagonal bars the beam from this column of ligbt intersects them in points, the sh.adow of which, the beam being broader than the sash-bars, is terminated not far out- side the lantern, while with vertical bars the best part of the beam is partially obstructed, and a vertical shadow is thrown upon the sea. Extract from The foUowlug cxtract from a report by Professor Tyudall Tlndaii"*^ ^"'^' of experiments with gas and oil burners at Howth Baily light-house, Dublin Bay, confirms this view : " I did not, however, think it safe to limit myself to this particular point of observation, and to meet my wishes, Cap- tain Eoberts was good enough to engage a steamer, which enabled me to proceed down the river and to pass across it from side to side between the North Wall and the (South Wall, thus varying the points of observation. " It soon became manifest that the oil-flame at Howth Baily varied in intensity with our position, and that the direction of minimum intensity corresponded almost exactly with that in which our observations had been made ou the previous evening from the North Wall. " No safe conclusion, therefore, could be drawn from the observations made on the evening of the 7th, for it was manifest that some cause existed which prevented the oil- lamp from displaying its full power in the direction of the North Wall,thus giving the gas a relative superiority, which in reality it did not possess. " It is to be borne in mind that the oil-lamp in these ex- periments was placed in the first-order dioptric apparatus of the light-house, the apparatus being, as usual, surrounded by its glazed lantern. The gas-flame, on the contrary, was placed in a temporary hut at some distance below the lan- tern. A refracting-panel, similar in all respects to those of the dioptric apparatus, was placed at the proper distance in front of the. gas-flame, and to make the conditions alike, tho upper and lower reflecting-prisms of the apparatus were shut off. It was, therefore, the lights transmitted through the two lenticular belts that were compared together. " In company with Captain Roberts, I again visited Howth Baily on Wednesday, tbo, 9th. " We were preceded by Captain Hawes and Mr. Wi;;- EUROPEAN LIGHT-HOUSE SYSTEMS. 153 haul, who were instructed to examine witli all caro whether any obstruction was offered by the lantern to the passage of the light toward our station on the North Wall. "Jit teas soon found tliat one of the vertical sashes of the lantern icas directly interposed between the light and our point of observation, and that to this obstruction the enormous appar- ent superiority of the gas flame over the oil, manifested on the evening of the 7th, teas to be ascribed. ' '• Since my return to London, Captain Robert?, at my re- (juest, placed the gas-flame in the dioptric apparatus and the oil-flame in the hut below. From the North Wall the oil-flame was the brightest, thus affording additional evi- dence, if any were needed, as to the influence of the obstruc- tion offered by,the sash of the lantern." M. Quinette de Eochemont, engineer des Pants et Chaussees, rep^t "o^f m "^X who is charged with the supervision of the French lights r^ochemont. north of the Lower Seine, in his " Note sur les Phares Mec- triques de la Bcce," referring to experimental comparisons between the electric lights at La Ildve- and the oil-lights at llonfleur, Fatouville, and Ver, remarks as follows : " The observations at Fatouville show an anomaly, but this is easily explained, as it was in consequence of one of the uprights of the lantern of the northern (oil) lighthouse being placed in the direction of Honfleur, and thus obscur- ing a considerable part of the light Irom the apparatus." This matter is still further illustrated by Fig. 17, in Ensiish nn.i which a section of the beam is shown, partialK' eclipsed in tums. one case by a vertical sash-bar of the lantern a, constructed on the American and French plan, and in the other crossed by the diagonal sea-bars of an English lantern, b, the width of the beams being drawn the same in both cases. In 1873, the engineer of our seventh light-house ilis-^com^piaintK trict reported to me that grave complaints were made of»^'^ey|W'»'^'(^'^<^ the light at Key West, it having been reported by mariners by^^bioiKi sa.^b- to have been extinguished on several occasions. On investigation it was found that such large shadows were cast by the great sash-bars of the old-fashioned lantern of the light-house that vessels were sometimes in shadow for a long time, and to this cause, and not to the want of vigilance on the part of the keeper, were the above reports due. This old lantern has since been replaced by oueof the new model, in which the width of the sash-bars is very much less than in the old. Ihave been thus particular in referringtothesubjectofob- Error of ii.n struction by vertical sash-bars in light-house lanterns, since of usinsvertiiai. ... T 1 , 1 1 1 baned UuLurn.''. in our service verticulbarred lanterns have always been 154 EUROPEAN LIGHT-HOUSE SYSTEMS. used, and I believe it to be a rerj' serious error into which we have been led by an improper consideration of the matter. cyiiDaricaiian- Mr. Douglass Stated that he had found by experiment '■■''ibl;u piate?°°' that cylindrical lantern-glass is C8 per cent, stronger than plate-glass, an important consideration to us, particularly with regard to our southern coast, where our lantern-glass, Lar.tcm-Eiass ai^;]jQugii onc-half an inch in thickness, is frequently broken broken by sea- => ,,, ,,.-,,i -^ji, luwi. by sea-fowl, which, blinded by the light, fly against the lan- tern, damaging not only that, but the lenticular apparatus, to such a degree that we have been obliged to cover the entire face of lanterns with netting, necessarily of such strength and size of wire as to impair the value of the light. Fig. 17. Lovr parapet nsod on English t(j « crs. Veiitilalioii. American and English Lanterns. With further reference to the English lantern, I will remark that the substitution of the low parapet in i)lace of the high one used by the French and ourselves does not seem to me to be-an improvement. The former necessitates the use of a step- ladder when cleaning the lenticular apparatus, and the door for reaching the outer gallery is necessarily low and incon- venient. The English provision for egress of heated air and smoke is not as good as our own, and the arrangement for turning the cowl with the wind I should think liable to become obstructed by soot and dust. I have the same opinion with regard to the manner of providing fresh air to support combustion in the lamp. The English admit this EUEOPEAN LIGirr-IIOUSE STSTEMS. 155 into the watch-room and theiico through the gratiug of the hiuteru-floor. (See Plates YII aud VIII.) It is true that the tops of the ventilating windows iu the watc't-room are above tlie heads of keepers on watch, but iu our cold latitudes this would be quite inadmissible, and in uo case do I i)erceive the English mode to be in any -way superior to ours of admitting the exterior air directly into the lower part of the lantern. The excess of 2 feet in the diameter of their lanterns, supoiinisizcof Inntciii n.sed by over our own I think unnecessary, as we have ibund 12 feet the nnsrUsii imt ' of Kiifiicicut au- to be quite sufhcient, anording abundance of space between vantaco to com- 11 111, .-. -^ i-.i peiiaale for tho the lens and the lantern-sides. On our eastern coast, with tonseqnent iu- .,,.,, ., f r> J? J. 1 T cipasert cost of our necessarily high towers, the expense or 2 leet £ddi- towws. tional to the diameter of lanterns and towers is much greater thau in England, where the towers are ordinarily on elevated sites, requiring but small elevations of the lights. KOETH STACK. This fog-signal station is about four miles south of Uoly- Fisf. IH. Wiiid-guartl. head Harbor, on the east side of Saint George's Channel. The IfiG EUROPEAN LIGHT-noUSE SYSTEMS. FoRsisnai. siguals, which are in charge of two keepers, whose sole duty is to attend to them, are a pair of 18-pounder guns, placed in a masonry building and fired through embrasures, in thick and foggy weather, at intervals of fifteen minutes, the charges being three pounds of powder. As most of the steamships and other trade to Liverpool pass quite near this point, and fogs are common, this is a stcnm-whistie most important signal; but I am convinced that the long Ii'lmshMit^ "'* intervals between the discharges make it less valuable than a powerful steam-signal, either a whistle, siren, or DaboU trumpet, would be. It is to be remembered that an increase in the number of discharges would luaterially add to the already heavy es- pense. ^ Wind-guard I observcd on the dwelling of the keeper a wind-guard, which Mr. Douglass stated was designed by Faraday, and is in common use in the light-house service as well as through- out the country. In the most trying positions, such as ^orth Stack, which is under high land rising immediately in the rear, it effectually prevents the annoyance, so frequent in such localities, of the smoke being driven down the chim- ney during high winds. A sketch of this chimney-top is shown in Fig. 18. SOUTH STACK. This light-house, at the extreme westerly point of Holy- head, the extremity of the Island of Auglesea, is about five miles south of the harbor, in a remarkably picturesque lo- cality. From the elevated land in the rear, one descends by a flight of 450 steps to a handsome suspension-bridge thrown over the chasm separating the South Stack from the-lslaud of Anglesea. cbaiacteristics This light is catoptric, revolving, and of the first order, " ' having eleven reflectors on each face. r,,^r.i,c.ii. At this station the fog-bell, weighiug two and one-half tons, is placed with its mouth uppermost. A counterpoise- weight is hung underneath the axle, which is turned by Maiir.or o f machinery placed uudcr covcr. The hammer is Avithiu the ™.m,ih,Kibefog- ^^gj,_ ,j,]jg ^^jg ^^ j.jjg cog-wheel which moves the bell and its counterpoise, passes through a slot in the side of the machine-house, and has a slight vertical motion. Great power is not required for ringing this bell, which has been in use for many years, giving entire satisfaction to mariners. Hate IXIU FOG, OR OCCASIONAL LIGHT AT SOUTH STACK, ST. GEORGE'S CHANNEL. EUROPEAN LIGHT-HOUSE SYSTEMS. 157 The only fog or " occasional " light for use at light-statious .for, or " occa. in tliick weather of which I have any knowledge, is at South Stack. It is well known that while lights iu high towers and on Hisu lights ov considerable elevations of land, can be discerned in clear ^"""^ ^ "°^ weather at the maximum distance, (in our service, as in others, about twenty miles,) an object of the first importance, great elevation of site is a disadvantage in foggy weather, since the fog-clouds frequently maintain themselves at a con- siderable height above the sea, and envelope the light when :t is clear below. At many points in our Pacific States, the coast rises so j^cnacs ^^ wiiere abruptly from the sea that no sites can be found at a suffi-needea iu foggy *^ *' weather. ciently low elevation to avoid this difficulty, even when low towers are erected, and the arrangement I saw at South Stack provides a remedy for the obscuration of light during foggy weather. An inclined plane has been excavated in the rock, and a jig^J"''",,^'' j,"^ tramway laid thereon. The fog-light is contained in a car- I'stt. riage, which in clear weather is kept at the summit of this plane near the main light-house, but during a fog is lowered by means of a windlass to a position where, safe from the waves, it is still as near the sea as possible. The forward part of this movable light-house is glazed, and contains a catoptric apparatus of three reflectors in the same plane, on a levolving frame which has a reciprocal motion through the exact arc to be illuminated, thus giving the characteristics of the main light. A weight for driving the machinery in this case being, ^Si^^g\-^^ mo- is evident, out of question, the motion is produced by means tj^^s^^^^e^ejfjjU"? of a powerful spring. sSf Uffbl"' This ingenious light has been in operation for many years, (I believe since 1832,) and has proved to be of great advan- tage. Captain Moodie, of the Ounard line, with whom I re- turned to America, told me that frequent occasions had been afforded him for testing its value, the light at Holyhead being of the first importance to the immense traffic through Saint George's Channel, where, at some seasons of the year, habitual fogs prevail. Plate XXIII will give an idea of this construction. Before closing my notes in regard to the English light- Acunowiedii- ° , , . .. 1 1- i- mciit of atteii- liouse service, I take pleasure in recording my obngationstions reoeivc.i to Sir Frederick Arrow, the Deputy Master, to the Elder u™? of Trinity Brethren, and to Mr. Douglass, the engineer of the Trinity """"'■ Ilouse, for the attentions and kindnesses of which I was constantly the recipient, from the time I arrived in England 158 EUROPEAN LIGUT-nOUSE SYSTEMS. till my departure for Araerici. Tbere was no facility for acquiringinformation ill regard to the object of my journey, no act of hospitality which could suggest itself, which w.-.s uot i)roffered with that hearty generositj- for which their countrymen are distinguished. Drawings, de- While In Londou I was furnished with drawings, descrij)- rreaved"' f r o m tious, &c., of many of their light-houses and accessories, and Tiiuity House. giQce my returu I have received others which have been of much assistance to me in the preparation of this report, and I am happy to believe that such relations are now estab- lished as will lead in the futui-e to that interchange of infor- mation which is desirable in this most interesting and im- portant service. Although I should have been glad to avail myself of the kind invitation of Admiral Schomberg, Harboi'-Master at Holyhead, to whom I am indebted for polite attentions, to remain to witness the demonstration which was to celebrate the completion of the great breakwater, the limited time at my disposal would not permit, and on my return from South Stack, the last English light-station- that I visited, I em- barked in the Irish mail-steamer for Dublin. IRISn LIGHTS. Letter from Soon after ray arrival in England I received the foUow- ?.r"iigl!™."'°' iag letter from the Commissioners of Irish lights : "lEiSH Lights Office, " Westmoreland Street, Dublin, May 2-t, 1873. " Sir : The Commissioners of Irish lights having been in- formed by the inspector of lights to this department that you propose visiting Ireland shortly, and that yon were de- sirous of availing yourself of such opportunity to inspect one or more of the gas light-house establishments under the management of this Board, I have the pleasure to acquaint, you that the Commissioners will be most happy to afford you every facility to carry out your wishes. " Will you be so kind as to let me know a day or two pre- viously, as to the probable period of your arrival in Ireland t " I have the honor to be, sir, your obedient servant, "W. LEES, ^^ Secretary."' "Major George II. Elliot, " Gorj)S of Engineers, United States Army.'''' I reached Uubliu on the IGth of August, and on my j;r- rival proceeded to the ofiice of the Commissioners, where I was politely received by Mr. Lees, who stated that the Com- EUROPEAN LIGHT-HOUSE SYSTEMS. 15!J tnissioners were at that momeut, according to previous ar- rangemeut, embarkiug for Holyhead to take part in the celebratiou at that place, and wished him to convey to me their regrets that they were unable to meet me, and to in- , ii-spccii"!! c,f „ Iviah gas-lishts, form me that Captain Hawes, the inspector of Irish lights, r'tii oaptiiiu ^ 07 jiawcs ami ilr. (whom I had the pleasure of meeting at South Foreland on wigbam. the Straits of Dover at the commencement of the fog-signal experiments of which I have given an account,) and Mr. Wigham, the inventor of the Irish gas-light for light- houses, would take me to such of their establishments as I should desire to visit. We soon set out by rail for Howth Baily, the northern bead of Dublin Bay, where is a first-order flxed gas-light; after describing this station and that at Wicklow Head, where is a first-order intermittent gas-light, I shall give a general description of the Irish gas-lights for light-houses, derived from information received from Captain Hawes and ]Mr. "Wigham as well as from observations made on my visits to the above-named stations, and to the English gas- light at Haisborough. nOWTH BAILY. This station, (see Plate XXIV,) on a bold promontory at F^^^t "•"''* ' ^ '' ^ ^ where Wlffhara » the outer northern limit of Dublin Bav, is of interest asK^'^-i's''* ^•■■* ^ cstablishud. being the first station at which the Irish gas-light patented by Mr. Wigham was established ; this was in 18G5. An inspection of Plate XXV will show the compactness Littio sp.w roquirecl for j;as- of the gas-works, comprising retort-house, gas-holder, &c. viuiu. Few light-house sites are too limited to contain buildings necessary for the apparatus. The gas-holder at this station contains 800 cubic feet, but is considered too small, a disad- vantage not found in later establishments of this kind. Uniformity of pressure of gas at the burners is obtained itegni.itor t.: by means of a regulator, also ot Mr. Wigham's design; and ityot piessmcui I will here mention that this burner is but one of many curious and ingenious inventions led to by, and necessary for, the proper development of the system. As at Haisborough, I saw here from actual trial that the sniistituti™ . 1 ^ ' on lor fi-as-uiilii ordinary first-order oil-lamp, which is always ready, can bewiieuuoitBs;M,>. substituted for the gas in less than two minutes, and the chansp oi Irish regulations require the keepers, for the purpose of J^^i^',-^,J'^^i'""''' keeping. in practice, to change the gas for the oil light once a month. The chancres of the burners and the mica oxydizers to Mann or of ^ , . . ^ cuangiuj; burn- meet the varying atmospheric conditions, require but aucrs. instant, the change of the burners being accomplished IGO EUROPEAN LIGHT-HOUSE SYSTEMS. simply by setting iuto, or lifting out of, the mercury-cups, the short pieces of supply-pipe to which are attached the serai-cylindrical rings of jets, and by opening or changing the cocks. Diameter of rpjjg large&l bumcr, having a diameter of lOA inches, con- bnnier and pow- o i o - ? V of flame. taius 108 jets, and the immense body of flame carried to the mouth of the mica oxjdizcr (sec Plate 10) is most daz- zling. ^e-'it- The heat, as may be conceived, was very great, but the keeper said it gave him no inconvenience, nor did it injure the lenticular apparatus, thus corroborating the information given me at Haisborough. The lens is in no respect dif- ferent from the ordinary fixed lens of the first order. Kcepera. Employed at this station are two keepers, one apprentice under instruction, and a gas-maker, the latter receiving 2s. 6c?. (G2J cents) a day. Captain Hawes considered the employment of the gas-maker quite unnecessary, the labor at any gas light-house being easily jierformed by two keepers. FosbcU. There is at Howth Baily a fog-bell, operated at present by an Ericsson engine, but for some years a gas-engine was used, which was, I believe, discontinued in consequence of the insufficient size of the gas-holder. snpeiionty of Mr. Wigham, who constructed the works at both Howth Iialit at Howlli ' iJaiiy. Baily and Haisborough, stated that at the former place the light was much the purer and whiter, owing to the burner being supplied under much greater pressure. Captain Hawes is of the opinion that 28 jets are here quite enough in clear weather, while 48 are habitually used at Hais- borough. "WIOKLOW HEAD. This station, on the western side of Saint George's Chan- nel, south of Dublin, we reached partly by rail and x)artly by "jaunting-car," a two-wheeled vehicle, which is the common conveyance of the country. v^^aiTs "I'^t- '^^^'^ gashouse, containing the furnaces and retorts, the woius. " gas-holder, and other buildings, are ingeniously disposed on the face of a high cliii', and occupy but little space, as shown by Plate XXVI. oi' rhTif-ht'tnii '^^^^ ^^ ^ first-order intermittent light, the lens-apparatus i.::ii.)ior 'of ' pro. being that of an ordinary fixed light. The gas is let on and shut oft by an automatic arrangement which allows ten seconds of light and three seconds of darkness. This arrangement does not cat the gas entirely off, and each jft during the three seconds' eclipse shows a tiny blue llaaic, which, while it produces no illumination of the lenticular EUROPEAN LIGHT-HOUSE SYSTEMS. IGl apparatus and can scarcely be detected in the daylight, is still sufficient to light the main body of gas when the supply is turned on. To guard against all danger of total extinguishment of •• By-pass," to the light by gusts of wind through the ventilators or door tiDKuisbment 'or of the lantern, each jet is surrounded by a small pipe called '° '' the " by-pass," the top of which, being at a level with the tip of the jet, is pierced by several minute holes through which gas is supplied from a pipe quite independent of the automatic cutoff ; thus protected, these little jets of flame burn from the moment of lighting at sunset to that of extinguishing at sunrise, and it is impossible even if the " cut-off" or a gust of air should completely extinguish the main flame that the burner should not be lighted at regular intervals of thirteen seconds. The two keepers at Wicklow Head agreed witli those fi'ttrSibie''than'oiT' Howth Baily in saying that the gas gives very much less''?!"'- trouble than the oil light. DESCRIPTION OF WIGHAM'S GAS-APPAEATUS FOE LIGHT-HOUSES. FIXED GAS-LIGHTS. The light is produced by a burner shown in the Plates XXVII and XXVIII. It is capable of producing five differ- pSoinf aiflS' cut degrees of power according to the state of the atmos- i^i,^,''"""'* "' phere, the first power being produced from 28 jets of gas. ^'^^^^ ^°^^^- Each jet consists of a hollow tube with an ordinary fish-tail burner of lava at the top. At the bottom of each tube is placed a small lava cone bored with fine holes, (one on each Eeguiator. side.) the effect of which is to act as a regulator and to allow the gas to enter the air at such a rate of speed as is found most conducive to its combustion in connection with the overhanging oxydator, which is formed of talc,, and which is fitted with terminal pieces to suit the respective sizes or the various powers of the burner. The second power is pro- second power; duced from 4S jets as above, except that some of the orifices in the lower cones are slightly larger than in the smaller burner. The third power is from 68 jets, with slight altera- iiiini power, tions in the orifices of the lower cones and also of the upper jets. The fourth is from 88 jets, and the fifth is from 108 Fourth anc jets as above. The flame of the latter is shown in the frontis- piece. The rings which contain the jets for the several powers, ^jii^™"'^ "'''<' except the first, are removable and replaceable at pleasure. Mercurial cups, each fitted with a ground-in valve, are the S. Ex. 54 11 1C2 EUROPEAN LIGHT-HOUSE SYSTEMS. means employed to facilitate this application. Tbe wl;<)l«> of the gas supplied to the burner passes through a chamber of cast brass, at the bottomof -^'hich there is fixed a nici- curial lute which enables the whole gas-burner to W removed in a moment, and the ordinary oil-lamp used' in TaiochiraiicTB, dioptric apparatus to be substituted for it. The talc chim- Rnd substitution '^ \'^ , , , , t t cf oil-lamp. ncys are also removable, and arrangements are made by which the ordinary oil-lamp condenser can be fixed for the use of the oil-lamp. This arrangement for rapidly substituting the oil-lamp in place of the- gas-burner was instituted when gas was first lighted at Howth Baily light- house, in the year 1865, as a precaution against any acci- dent occurring to the gas-light, but during the time thathas since elapsed (about eight and a half years) no occasion has everarisenforputtingthisprecautionary planinto operation. Lenses nseii. By the use of gas in a fixed-light apparatus of any size there isno occasion to alter the existing lenses, but in some lanterns it may be necessary to provide for additional ven- tilation. It will be seen by the table to be found farther on that the photometric values of the flames of the respective powers of the gas-light are largely superior to any photo- metric results obtained from the oil-lamp, either for paraf- cost of gas- fi" Professor Tyuclall very clearlj^ illustrates the application sin 10:111111 .f of the interiaittent light to revolving leuses iu a report to dJi.'^'''" the Board of Trade dated the 7th of February, 1871. After stating that a gas-burner of 28 jets is almost iden- tical in size and sensibly equal in illuminating power to the Trinity four-wick burner, that it is quite as apijlicable as the latter to a revolving light, and that a saving can be se- cured by a periodic extinction of the gas-flame, he says : "The central octagon figure (see Fig. 19) from which the rays issue is intended to represent the eight-paneled re- volving apparatus. The points of the stars are to be re- garded as the centers of the beams issuing from the respect- ive panels. The blackness of the disk underneath the star is intended to denote the darkness of night, while the circle round the disk rei)resents the horizon. Fig. 19. K o Diagram illustrating revolving intermittent gas-light. "Every part of the horizon receives a flash every second minute, the gas being lighted one minute, during which the lens is moved oneeiglith round, and each j)art receives a flash, then the gas is extinguished one minute, aud so on iu succession. Thus half of the consumption of gas is saved. " Let the star be turned so that the beam A shall point to Di'^nipu. I'lg. 11'. and illuminate the station K on the horizon. The ray B Mould at the same moment illuminate L ; C would illumi- nate M ; D, N ; E, O ; F, P ; G, Q ; while the ray H from the eiglith panel would illuminate E, the eighth station. " Let the star be turned, or in other words let the appa- ratus be supposed to revolve, until A reaches L. During this time B travels from L to M ; C from M to In ; D from N to O ; E from O to P ; F from P to Q ; G from Q to Ft ; and EL from E to K. Thus, through the passage of A from K to L, in other words during the rotation of the apparatus through one-eighth of a revolution, every point on the horizon is once illuminated. 164 EUKOPEAX LIGHT-HOUSE SYSTEMS. "If the flame continue burning, tbe same effect is pro- duced during every succeeding eighth of a revolution. Every point of the horizon is once illuminated. At Rocka- bill the time of a complete revolution is ninety-six seconds; hence, the number of panels being eight, as in the model, each point of the horizon receives flashes ^rhich succeed each other in intervals of twelve seconds. " But suppose at the moment the beam A points toward L the supply of gas to be cut off. and the apparatus per- mitted to revolve in darkness until A reaches M. During this eighth of a revolution no gas is consumed, and no flash is received by any point on the horizon. " When A reaches M let tbe gas be relighted. During the succeeding eighth of a revolution every point of the horizon would be once illuminated as before. It is quite manifest that this process maybe continued indefinitely; the gas being lighted and every point of the horizon once illuminated during every alternate eighth of a revolution. "It is also plain that the intervals of darkness between the flashes instead of being, as they now are, twelve seconds, would be twenty-four seconds. This reasoning, which as far as it goes is of tlie character of a mathematical demon- stration, has, as stated in my report of the Sth of October, been verified by actual observations on the Eockabill light. "There is, as far as I can see, but one drawback to the perfection of this scheme ; and this I will now try to point out with distinctness. Let the beam A point, as at the outset, toward K; at a certain moment we start from K toward L with the gas lighted. According to the new scheme K ought to be in absolute darkness for twenty -four seconds. But just as A reaches L, and before the gas is cut off, a glimmer is seen at K, this glimmer being only twelve sec- onds distant from the preceding flash. The same is true of the other seven points of the horizon faced by the panels the moment before the flame is extinguished. In all the remain- ing sweep of the horizon this secondary glimmer is absent." Professor Tyndall further says in regard to this glimmer that he noticed it in his experiments at Eockabill light- house, but attached no practical importance to it; and that on the isolated points where it is seen it is so masked by the superior brilliancy of the true flash that no mariner could be deceived by it. sniistiiiiiimi „f The same method of substituting an oil-lii-mp for the gas- iiurneiv bumer IS arranged lor intermittent as for fixed lights, the only difference being that if the oil-lamp were used the machine which actuates the cutting oft' of the gas is made THE IRISH GAS LIGHT. 108 JET BURNER. SECTION. PLATE XXVII I i^P 1>. Stop Cock d^JUayadl^ Sapplv Mpf,fJn' /t/nr. ^nplv J^pt'S for tJie //7?'i/er 7J7i/-nc7-6: i.i. Stf.'p C'oc?t^f U.^y ■ in.m.ii?cy ' o.o. /f^^ ' ' '^ ■ 4hiebe9 to 1 Foot. ■^HE GRAPHIC CO.PHOT0-UTH.39A41 PARK PLACE.N.y. EUROPEAN LIGHT-HOUSE SYSTEMS. 105 to open and shut semi-cylindrical shades for eclipsing the oil-lamp for the required period of darkness. As in the case of Howth Baily, no occasion has ever arisen at Wick- low for falling back upon the oil-lamp since gas was lighted at that station, about seven years ago. The advantage of ^^^'^^'iJ'JJlij,,;';* the use of intermittent lights as applied to gas light-houses tent iisin. is obvious, for during the period of darkness the consump- tion of gas is saved, whereas in the case of oil-lights, the flames of which are merely eclipsed by shade, the consump- tion of oil continues during the intervals of darkness as well as during the intervals of light. This peculiarity of gas renders its use for intermittent light still more economi- cal than for fixed lights. All the four/o//-powers of the gas- burner may be intermitted precisely as is the case with the first or ordinary power. By the use of gas in an intermittent-light apparatus there is no occasion to alter the existing lenses. REVOLVING GAS-LIGHTS. The burner used in this case is precisely the same as that Bumcis. in the fixed and intermittent lights. The lenses by which i{ovoh.ii..n uf the flashes are directed to the observer revolve around the ''''"'*'"*" gas-light just as they revolve around the oil-light. Au arrangement similar to that in fixed lights for substituting the oil-lamps for the gas-burner is also established. The remarks as to the superiority of gas oyer oil iu fixed lights apply equally to revolving lights, with this additional advan- tage, that bj' the use of gas-burners which have large diame- ters each flash is of longer duration than in the case of the oil-lamp, and this is stated to have been highly appreciated by mariners. GEOUP-PLASHING GAS-LIGHTS. The burner used in this case is precisely the same as that Bmncr. in fixed lights. The groups of flashes are caused by tlie con- I'Usbes. tinual extinction and re-ignition of the gas-flame. This is accomiilished by similar means to that which causes thu in- termission of a fixed light, except that the machinery whicii causes the lenses to revolve is availed of for actuating the cutting-off gas-valves instead of a special machine being provided for that purpose. By means of this system of group-flashing the same economy may be attained which the use of gas presents in the case of intermittent lights, with this difference, that the economy is always at a fixed ratio, viz, about one-half the consumption of the gas. The lenses are continually revolving and the gas-lightis continually in- termitting. By reducing the speed of the revolutions of the 1G6 EUROPEAN LIGHT-HOUSE SYSTEMS. lenses (wliicli themselves require do alteration for this sys- tem) a group of seven or eight distinct and powerful flashes recurring at regular intervals may be obtained, andtheeffect of this kind of light is said to be exceedingly arresting to the eye of the mariner. TEIFOEM FIXED GAS-LIGHT. ■J bivi- iiuiiieis This light is produced by three burners similar to that "^ "' above described, placed vertically over each other as shown A ir - .iiambprs in Plate XXIX, but the two upper burners are surrounded by i.r upper aiu- ^^,^ air-chambcrs for the supply of pure air to the flame and the carrying off of the foul air from the flame of the burner below. Tubes for the introduction of pure air are placed obliquely in these chambers, and the effectof the arrange- ment is that not only are these three burners of equal power when in a light-house lantern in place of one as in an ordi- iiary case, but the light is much intensified by the manner in which the burners are supplied with heated air. Disciipiioii of In the plate, a is the main supply -pipe, 6, b', h" are the gas- -'""' burners, e, c' are the distributing- pipes, d, d', d" are the mica (thimneys, c, c', e" are the sheet-iron chimneys,/, /' are the outer air-chambers, li, h' are flues leading to the inner iiir-chambers g^ :nximci . tlmes that of the single lamp, but the quantity of light is more than three times as great. We must, however, deduct the light which would be transmitted from the top and bot- tom prisms of the single lamp apparatus, which is valued at about one-third of the whole apparatus, and it may be said that the light of a light-house illuminated by the triform ntitio ,.r iiiii. apparatus is to that of a light-house illuminated by a single jiilcVVII.rtrirm'm lamp aud an ordinary lenticular apparatus as 2 to 1. It i.,T:';l "''' "'"" "^ will be seen by the table of photometric values that the ])ower of the largest size of the gas-burner is stated by Mr. Wigliam to be equal to 2,577 candles. Assuming this to be correct, there is therefore transmitted by means of triform iipparatus three times that amount, viz, light equal to 7,731 candles, and if this is increased more than eighteen times by the agency of the cylindric refractors, as is the case EUROPEAN LIGHT-HOUSE SYSTEMS. 167 where the ordinary oil-burner is used in a first-order fixed lens, the immense power of more than 139,158 candles is transmitted to the observer. This power, great as it is, is of course exceeded by the triform light in revolving ap- paratus. TRIFOEM INTEEMITTENT GAS-LIGHT. The apparatus in this case is precisely similar to that described for intermittent lights with one lamp, except that refracting belts are substituted for top and bottom prisms as described in the case of the triform gas-apparatus for fixed lights. TEIPOEM EEVOLVTNG GAS-LIGHTS. The arrangements of burners, lenses, &c., areuearly similar oAnr ''"^^fn"' to those for fixed lights. The lenses are placed vertically es, &o. (see Fig. 2, Plate XXX) in order to give the most power- ful beam that can be transmitted to the horizon, but in case it were desired that the ordinary flash should recur more frequently than is possible with an apparatus containing only one light, the lenses may be placed eccentrically, as shown in Fig. 3, Plate XXX, and this in a very striking manner attains that object. TEIFOEJM GEOUP-FLASHING LIGHT. The remarks made under the head of group- flashing light for a single lamp apply equally in this case, but the groups of flashes proceed from three lenses in place of one, and are consequently of much greater power. EXPEEIMENTS WITH THE TEIFOEM LIGHT. On the evening of our return from Howth Baily to Dub- lin we proceeded to a point near Kingstown, on the south side of Dublin Bay, distant six miles from the Howth Baily fixed gas-light, to observe some experiments to be made Expoiimciitai with a triform light, (previously placed temporarily, for pur- u^m^nTcii anii ])oses of experiments made under direction of Professor ught."'" °'"' Tyndall, in a small cabin near Howth Baily light,) arrange- ments for which had been made by Captain Hawes and Mr. Wigham while we were at that station. The three Wigham burners, each capable of burning from xrvmsemenu 23 to 108 jets, were placed vertically over each other in the tfiJorm uvb" ''"' foci of three panels of the refracting belt of a first-order lens, as already described, stop-cocks being provided, so that any Manner^of in- of the ringsof either burner could be lighted or extinguished creasing light. 168 EUEOPEAN LIGHT-HOUSE SYSTEMS. at pleasure. The principal keeper at tha station had re- ceived instructions to cover and uncover the catadioptric prisms of the first-order lens in the tower, while the assist- ant was to vary the powers of the triform lights, both act- ing according to a memorandum given to each, a copy of ■which we were provided with. Frogramme of experiments with a triform Ufllit at Howih Haili), Dublin Bay, August 6, 1873. Tower lights. Triform lights. P.M. 9. 30.— 28 .lets ; cover the catadioptric prisms . . 9. 35.-28 jets ; tmcover catadioptric prisms 9. 40. — ^28 jets ; catadioptric prisms nncovered . 9. 45, — ^28 'iets ; catadioptric prisms uncovered . 9. 50. — 28 jets ; catadioptric prisms uncovered . 9. 55. — 108 jets ; catadioptric prisms imcovered 10. 00. — 28 jets ; catadioptric prisms uncovered . 10. 05.— End of e3q)erimeDt8. P.M. 9. 30.— 28 jets J upper belt only. 9. 35.— 28 jetB ; the three bolt*. 9. 40.— 48 jets ; the three belts. 9.45. — 68 jets; the three belts. 9. 50.— 88 jets ; the three belts. 9. 55.-108 jets ; the three belts. 10. 00.-108 jets ; the three belts. Appearance of I'rom our poiut of observation at Kingstown the 28-jet thoughts. light, shown only in the upper belt of the triform arrange- ment, appeared slightly inferior to the 28-jet light in the tower when the catadioptric prisms Avere covered. They should have appeared equal, but the difference is accounted Kcaaon for in- for by the facts that the ventilation of the cabin and the li'shT'burSinl'S old refracting belts used for the experiments were imperfect, ihetrifom''a})pa^'*°d neither the latter nor the glazing of the window were r;itus. gQ clear as in the lantern of the tower-light. When the catadioptric prisms of the tower-light were uncovered and the entire beam from the lens thus coming to our view was compared with the triform lights, changed, . .^ „as shown in the table, from 84 to 324 iets, the superioritv Snpenonty of ' °^^"'''=5. the cost per annum to a first-order seacoast-light, burning gas- habitually 28 jets during the average period of illumination. 172 EUROPEAN LIGHT-HOUSE SYSTEMS. (4,311 hours,) would be $550 ; adding for an extreme case (as West Quoddy Head on the coast of Maine for example) 20 per cent, for additional consumption in foggy and thick weather, we have $600 as the approximate annual cost of the gas ior such light. Cost of annual The annual consumption of oil in our light-houses of the consun.iition of^j.^^. ^^^^^ jg about 700 gallous, amounting at the last aver- age contract-price of 89 cents per gallon to S67C.40. Loss cost for At statious with two towers the cost per thousand feet is Kot.^'fu "Sons considerably less than at single tower-stations, since the cost ttan'wii«o"hcr«of the labor and other items is proportionately less the is but one. greater the quantity manufactured. ILLUMINATION OV BEACONS BY GAS. lieacoufloii ont- Mr. Wigham has devised an arrangement for lighting by ijing rucks. gjjg^ bcacous ou detached rocks which are inaccessible dur- ing heavy weather. Gas for the illumination of such posi- tions cannot ordinarily be carried in submarine pipes, on account of the condensation of moisture within the pipe, the lowest part thus becoming filled with water and the flow of gas beiug consequently obstructed. Pryinp gas Mr. Wigham's plan is to dry the gas by chloride of cal- Scium.'''""''' "^ciuiii, and he proposes to light and practically extinguish the beaoou by means of variations of the pressure of gas in the supply-pipe ; that is to say, a high pressure of gas, say of six inches of water, closes a stop-cock at the beacon and keeps it closed during the day; at the time of lighting, this liressure is decreased to the ordinary working-pressure of, say, three inches of water, and the cock opens. The burner is lighted by means of a little flame supported by a small " bypass," such as preserves the light from extinguishment during eclipses at the Wicklow Head intermittent light heretofore described. The full power of the light can be kept up till sunrise, when the increased pressure of gas closes the cock and extinguishes the beacon. The invention Experiments sufficient for determining the utility of this ';'l'''"""-^"'*'' invention have not yet been made ; but it seems a step in the right direction, and affords another indication of the in- genuity of Mr. Wigham. . oiiinioDsoniio In concluding my remarks on the subject of gas as an }i',i?''ic'onoray o?illiminant for light-houses, I will only say that the Irish (.-iisiights. Board and its officers state most positively that the actual use of gas at five of its sea-coast stations proves it to bo Annnoi saving morc ccouomical thau oil, and specifically, at Howth Baily atHowihUaiiy. ^^^ gaviug is £50 ($250) annually, taking iuto account ail THE IRISH GAS LIGHT. TRIFORM BURNERS. PLATE XXIX j7Ich€S 13 S O 3 O SCALE . The Graphic Cii.PJioto-LiUi.an & 41 ParkPlare.S.Y EUROPEAN LIGHT-HOUSE SYSTEMS. 173 expenses of making gas and the interest on the first cost of apparatus. Professor Tyndall states that the 28 jet burner, the lowest Opinionof rm- jf ., , . ,.,. , .-., fessor Tyiulall as power 01 the gas-lamp, gives a light in no degree inferior to to tho compaia- the first-order four-wick oil-lamp used in light-houses. aud o-iTigbia."" The oil-lamp is susceptible of few variations in regard to variability in regard to power power, (our lamps have none; the Douglass six-wick lamp not possessed by /,.. ' ° „ , oil-lamps, except used by the Trinity House has three, and the power of tnethose of Mr. light can be increased from 324 to 722 candles ;) while thepaltent?^^"^^**" gas-light of the triform system can be carried through many more gradations reckoning from the lowest,* so that a skillful keeper can suit Lis light to any condition of the atmosphere. Assuming the facts to be as stated by Professor Tyndall, Eithcrthefouv- either the four-wick oil-lamp or the Wigham 2S-jet gas-lamp ae-jota'sufficieii't are sufficient in clear weather to send their rays from the fair'weathcr. lanterns of sea-coast towers to the sea-horizon a distance of twenty miles. As has been stated in speaking of Haisborough, no light which has been or ever can be invented can be seen through ji dense fog, which ob3cures even the sun itself. It will be seen, therefore, that the required improvement, impi-ovemeut ' ' ^ ^ to bo desired, tlu^ in sea-coast lights is that of a varying capacity of power p"J'«;'';'''?°"™.'[: that can be suited to all stages of the atmosphere, and the ■weather. Irish gas-light certainly appears to ine to meet this require- ment more fully than any other known, with this additional Additional ad- advantage: during the eclipses of revolving and intermit- omy in flashins tent lights the consumption of the illuminant may be en- ^^^' '® tirely suspended, and when, as is often the case, the total amount of eclipses is six hours or more out of twelve, the economy is evident. Professor Tyndall, in one of his reports to the Board of Trade, thus sums np his conclusions : " The results assure me that with gas as a source of illumi- ^Conclusion of ^ . . Professor Tvu- nation an amount of variableness and consequent distinct- daii. iveness is attainable which is not attainable with any kind of oil. It would, I think, be easy to give to every light- liouse supplied with gas so marked a character that a mariner on nearing the light should know with infallible certainty its name. " As stated in a former report, I look in great part to the llexibility with which gas lends itself to the purposes of a signa l-light lor its future usefulness. " It baa been calculated tbat the actual number of i^ossible gradations is 155, altbougb in practice not more than fifteen would probably bo made. 174 EUROPEAN LIGHT-HOUSE SYSTEMS. " It may be beaten in point of cheapness by the mineral- oil now coming into use, (that is to be proved ;) bat iu point of handiness, distinctiveness, and power of variability lo meet the changes of the weather, it will maintain its supe- riority over all oils." WIGHAM'S GAS-GTJN foe FOG-SIGNAIS. Gas-gunforuse Mr. "Wigham has also invented a gas-gun, to be used as asafog-signaL a fog-signal at stations illuminated by gas; and I had au opportunity of testing it, both at the manufactory in Dub- lin and at Howth Baily light-station. Captain Hawes kindly directed that the gun should be fired during our observation of the triform-light from Kingstown, so that, at a distance of six miles, I could judge of its efficiency as a signal. Construction of The. gun is simply a tube of iron connected with the gas- tho gun. holder by a half-inch pipe ; in fact, in these experiments the guns were nothing more than pieces of ordinary gas or Charge. watcr-pipe of different diameters. The charge of the gun is a mixture of oxygen, coal-gas, and common air, one- fourth of the mixture being common air and the remainder composed of equal volumes of oxygen and ordinary illu- minating gas. Manner of fiu- The propcr quantities of the gases are allowed to flow ingtbegan. fi^Qjn their respcctivc reservoirs into a holder, and the mix- ture is thence transferred to the closed end of the pipe or breech of the "gun," the flow being regulated by a stop- cock. The mixture is lighter than common air, and when it fills the feed-pipe and gun, the latter being lower than the source of supply, it will remain charged or full until fired, which may be done by touching a match to an orifice at any point of the connecting-pipe desired, taking care thfit communication with the holder is closed by the stop- cock. Prodnct of the The product of the explosion is carbonic acid gas and e::p osion. -water, and, as the latter would rapidly fill any part of the feed-pipe which might be lower than the gun, it would probably be a fatal objection to the use of the invention iieasonsfornot which immediately suggests itself, viz, its application as a naf''*to^o*uUyilig fog-signal on outlying rocks difficult to approach or nearly rocks. submerged. The defect is all the more to be regretted, as it is at precisely these points that fog-signals are most needed and the erection of other kinds is impracticable. At Mr. Wigham's extensive works at Dublin the feed- pipe was several hundred feet long. UJ si ^ to ?^ S2£ ACS ~ I- u ■go E5 EUROPEAN LIGHT-HOUSE SYSTEMS. 175 The use of the gun at any gas-light station would be simplicity <, r extremely simple, and the beeper need not go to the gun '^ ^'""■" itself, but could easily fire it from his watch-room at the required intervals. 1 do not know that the experiment has Sn-rgesti™ thi.t even been tried, but it will readily be seen that by using flrwrbV^'Lti'ili the electric spark the service of the gun might be made '''°''^■■^■•"^^• still easier, for a system of clock-work connected with a battery could be easily devised by which an electric circuit could be formed and a spark produced at any desired in- terval, and thus the gun be fired without any attention on the part of the keeper except what might be required to keep the apparatus in order. At Howth Baily the guns were twelve inches in diameter Description of -,„..„, , guns at Howtb and from six to nine feet long. The latter were duplicated, Baiiy. and consisted of two connected pipes, fired simultaneously. Near at hand the reports seemed loud and clear, but when ^^"ar report heard from Kingstown a high wind prevailed over Dublin Bay, and I was disappointed in the results. It is true that the distance was six miles, and a comparison with other signals would have been more satisfactory, but I fancied snpmoiitv of that the 18-pounder fog-signal gun at North Stack, on the p\'n at^ ^"S'r n'l other side of the channel, would have been more distinctly ^'''^''^' heard under the same circumstances. The flash from this gun is said to illuminate fog much iiu, miration better than that from a gunpowder-gun. S™h"*'"' '*'' *""" I have no doubt of the utility of the invention for fog signals at stations illuminated by gas, if the very great expense attending the manufacture of oxygen can be over- come; and, as Professor Tyndall is now charged by the Board of Trade with the conduct of a complete series of ex- periments with the gas-gun, it is to be hoped that the in- ventive genius of Mr. Wigham will overcome all objections to which it may now be subject. In concluding my observations on Irish lights I must ex- press sincere thanks to the commissioners and to Captain Hawes, the very intelligent inspector of lights, as well as to Mr. Lees, the secretary of the board, and to Mr. Wigham, for the pleasure and instruction I derived during my limited sojourn in Ireland. SCOTTISH LIGHTS. From Dublin I proceeded to Belfast by rail ; thence by steamer to Glasgow, and by rail again to Edinburgh. Immediately on my arrival I called at the office of the Com- yi?it to c.ioi. missiouers of Northern Lights, and introduced myself to Mr. ^ortbem lisIus 176 EUROPEAN LIGHT-HOUSE SYSTEMS. Alexander Cunniugham, for many years the secretary of the Commission, who received me with great cordiality, and with whom I had an interesting conversation concerning the Scottish system of light-house administration, and especially in regard to the appointment, payment, and regu- lations affecting the keepers of the northern lights. The iieguiationa. regulations are quite severe, and for any neglect of duty or other misconduct the keeper is peremptorily dismissed or otherwise punished, and a printed circular, advising keepers of the facts in the case, is at once sent to all the stations in the service. The warnings thus received tend greatly to promote the efSciency and good management of the lights. The following extracts from the regulations of the Scot- tish light-house service will give an idea of the great care that is taken to promote the interests of the keepers and to secure efScieut lights. Appointmeniof All light-kecpcrs are appointed by the Board, after an Keepers. examination in reading, writing, and arithmetic, and a pro- bation of three months' instruction at light-houses,-(viz, six weeks in a dioptric or lens light-house, and six weeks in a catoptric or reflector light-house.) i-.Mtrnction oi While on probation the'' expectant" is carefully instructed wpd'is.'^"'"' ^y the principal keeper of the light-house where he is as- signed, cautioued as to the responsibility he is undertaking, and the invariable rule of the board, that if he goes to sleep at his post he cannot be admitted into the service. He is specially instructed in the management of the lamp, cleaning the lenses and mirrors, and in taking apart and readjusting the various machinery. He makes the monthly returns, and keeps the books of the station while there. At the expiration of his term of instruction the principal keeper certifies to his competency, or gives reasons for not doing so. If found competent, he is appointed when a vacancy occurs. The following are the ordinary rates of pay allowed to keepers : Term of service. Under 5 years' service Above 5 and under 10 years' servico. Above 10 years' service Principal keeper. Per annum. £50, (SaSO) £58, ($SflO) £62, (S310) Assistant keeper. Per annum. £44, (IS20)- £46, l$3J0) £48, (iHO) Additional pay is given for rock and other detached sta- tions, in some cases as much as £20 ($100) per year. EUROPEAN LIGHT-HOUSE SYSTEMS. 177 Each keeper has a furnished house, with annual supplies of Dweiung ana coal and oil, and where no land is attached to the station an allowance of £10 ($50) per annum is made. They have also an allowance for washing and for expenses when traveling on public service. They are uniformed at public expense. Three pounds ($15) per annum is retained from the salaries of each and applied toward eiiecting an insurance on their lives. Eetiring pensions are allowed, and gratuities if they are Pensions. constrained to quit the service before being entitled to a pension by reason of injury sustained in the discharge of duty or from other infirmity of mind or body. The ground attached to light-houses is carefully culti- vated and turned to the best account, and the growing crops are transferred' when one keeper relieves another. Light keepers at rock-stations are allowed daily rations, as follows : One pound of butcher-meat. One pound of bread. Two ounces of oatmeal. Two ounces of barley. Two ounces of butter. One quart of beer. Vegetables when procurable. For tea, sugar, salt, and other table necessaries, 4d. per day. The light-houses are arranged in groups, and each group Libraries. is supplied with a moderate amount of current literature and periodicals, which circulate in the group, remaining a specified time at each station, and afterward are bound and Ibrm part of the library of the last station. Each light-house is in turn the last of ics group, so as to give each station its fair share of books. The Weekly Scotsman and the Il- lustrated London News are sent to each light-house. An ordained clergyman of the Church of Scotland is ap pointed to visit annually those remote stations where keep ers and their families cannot attend divine worship. He remains about two weeks at each station conducting divine service and instructing the children at the station in ordi- nary branches of education as well as in their religious duties. It is recommended by the Commissioners that each light- Iceeper or his wife spend some time daily teaching their children after the clergyman leaves, and when he returns the following year he examines the children as to their pro- gress. Medical attendants are also appointed for remote stations, J^^'^''^'*'""^"'^- Attendance clergyman. of S. Ex. 54- -12 178 EUROPEAN LIGHT-HOUSE SYSTEMS. and are allowed a fixed sum per annum, exclusive of the fees paid by the keepers. They are to attend on the keepers, who pay them a fixed fee for each visit. Medicines and medical instructions are furnished each station. Eeport or quai- Kcepcrs are required to report annually the quality of the cSveci. ^'™^* ™ stores received after a trial of them in detail. A special Test of oil. ^jjj^i jg ma^e of the oil for ten nights from December 1 to 10 ; the result of each night's trial is noted on a form prepared for that purpose and finally reported to the Eoard. precantiops Special precRutions are taken with mineral-oil. The tanks mm r - ^^^^ tight-fitting covers, and the oil is tested in the presence of the keepers to ascertain that the flashing-point is not beloAv 120° Fahrenheit. In addition to this the keeper is required to test it before commencing to use out of a new tank, Appointmentof For cach Station a person resident near the light-house is iishtkeepers.*^ appointed an " occasional " light-keeper, and is required to attend the station whenever required by the regular keepers. They are regularly trained, are under the supervision of the commissioners, and are allowed regular rates for each day's attendance at the station. They are obliged to attend the light at least twenty nights i)er annum in order to keep in practice. Boatman for At cach islaud-station a boatman is appointed and paid jsund-atations. gj^j^gj, ^ fixed Salary per annum or a certain rate per trip, and when he has no boat of his own, the Commissioners furnish one. He is obliged to make at least four trips to the light-house every month, and to visit it whenever sig- naled. Sketch of the The " Board of Commissioners for Northern Lights" was Tnus°a'ioners."''°™ established in 1798. Up to that time the Trinity House exercised direct control over the Scottish lights, and it does so now in some small degree. The Commissioners receive no salary. They are all ex-officio members, viz, the Lord- Advocate and Solicitor-General of Scotland, the chief mu- nicipal authority (whether Lord Provost or Senior Bailie) of Edinburgh, Glasgow, Aberdeen, Inverness, Campbell- town, Dundee, Leith, and Greenock, and the sheriffs of the maritime counties of Scotland. The committees of the Board meet twice a mouth, but the entire executive func- tions are exercised by the secretary and engineers. The latter are Messrs. David and Thomas Stevenson, whose published writings on light-houses and their illumi- nation have not only given them a world-wide fame, but have established the reputation of the light-house system EUROPEAN LIGHT-HOUSE SYSTEMS. 179 of Scotland as second to none but that of France, which is acknowledged to be tlie model for all others. Both were unfortunately absent the first morning I called, and I took the opportunity of seeing somewhat of Edin- burgh, which, I think, is justly called the most picturesque city of Europe. As I found I would have sufficient time, I made a quick journey to Stirling Castle, Loch Lomond, Loch Katrine, and the Trossachs. On my return, I had the pleasure of meet- ing Mr. Thomas Stevenson, and had a prolonged and inter- esting conversation with him, gathering much information on subjects connected with the object of my visit. He ^f^^^J*°|,^'^^'^''' showed me a reflector for light-houses, which was made after designs of his grandfather nearly a century ago. The interior reflecting-surface is composed of little facets of mirror-glass set into a paraboloidal form, and it is appar- ently as bright and useful to-day as when it was new, show- ing that such reflectors, which suffer no wearing of the sur- face by polishing, are very durable. In the opinion of Mr. Stevenson the silvered copper reflectors, which depend for their efficiency on the polish given them by the keepers, are really no improvement, they having no advantage over those previously used. Mr. Stevenson has invented a new form for harbor and shins' lights, which he calls the differ- Diircrentini lo. . , „ . ° . tTi- fleeter. ential reflector, m which the vertical sections are parabolic and the horizontal elliptical ; and he showed me a model. None of this kind, however, had been made for service. He also showed me models illustrating the use of dioptric lights in light-ships ; also his holophote, hemispherical diop- tric mirror of total reflection, and holophone or sound re- flector. The latter is shown in Figs. 20 and 21, and Mr. stevonsoi;^ Stevenson kindly promised to send me a model of the ]at-«''°"'i'-''fl<='=""- ter as soon as the mechanics employed by the Board could find time to make it, (I have since learned that it is en route, having been sent according to promise,) so that from it a fog-signal reflector can be made for actual trial in our experiments. In regard to reflectors for fog-signals, Mr. Stevenson con- firmed the opinion entertained by Professor Henry, that if they are of metal they should be covered with plaster or some other substance to prevent vibration ; also, that wooden surfaces would be as efficient reflectors as any others. This would enable us to construct a holophone cheaply and ex- peditiously, if it should be desired to use one in our experi- ments. 180 EDEOPEAN LIGHT-HOUSE SYSTEMS. Apparatus raiige-liglit.s. Mr. Stevenson is the inventor of several important modi- fications in the form of dioptric apparatus for light-hoases, and at the time of my visit, the liTorthern Lights Board oc- cupied a large space in the industrial exhibition at Edin- burgh, having an exceedingly full and interesting display of illuminating-apparatus, and of models of some of Scot- land's famous light-houses, including Skerryvore and the Bell, or Inch Cape Rock. Among other interesting objects for I noticed a fixed azimuthal coudensing-apparatus, designed for "leading," or, as we say, "range" lights, for the river Tay. It collects the rays of the lamp and distributes them equally over an angular space of 45°, and combines for this purpose Ave optical agents, viz, Fresuel's fixed light-apparatus, Ste- venson's condensing prisms, a half holophote, right-angled conoid al prisms, and a hemispherical mirror of totally re- flecting prisms. Fin.. 21. Verticai section of holophonc. Frout elevation of holopboue. Bia.CTnai snsii. There was also on exhibition a model of a light-house ljni-s;m invention " .It Mv.stpvenson. lantern with diagonal sash-bars, the placard of which stated that the first lantern of that description was constructed by Mr. Stevenson in 183(J. iii-4.si,i,'n.iis. Mr. Stevenson remarked, iu regard to fog-signals, that tlie Board have none operated by steam, but that bells are ])laced wherever they are useful. The only instance in Scotland of a steam or hot-air fog-signal is in the river Clyde, and it is maintained by a steamship company ; yet the coasts of Scotland are habitually foggy at some seasons EUROPEAN LIGHT-HOUSE SYSTEMS. 181 of the year, being, I infer, as unfortunate in this respect as our northern Atlantic or our Pacific coasts. Neither have the Scottish Board any light-ships, nor in- . ko ligbtsiiips deed is there any occasion for them, the coast being every-"" where abrupt with no outlying shoals or reefs. Mr. Steven- son gave as his opinion, derived from observations, that re- volving lights should be used as much as practicable for light-ships, for the reason that they have a greater range of visibility than fixed lights. Messrs. Stevenson and Cunningham confirmed the state- Aaoptio.ioTtho meut made to me by Captain Doty in London, viz, that theP^JyJ;',';;^;,.;-,',:!;; mineral-oil lamp invented by the latter had been adopted 5fj,/j;^ ^<"'"'"' by the Scottish Board, subject to the approval of the Board of Trade, andwith the understanding that he should receive as remuneration for his patent the saving effected in one year at each light-house where it might be introduced. At the time of my visit, however, it had been actually intro- duced into but five light-houses, as the Board of Trade hesi- tated at the terms of Doty's offer, which would give him for the use of his patent about £75 ($375) for each first- order light-house, and proportional amounts for smaller lights. The Board of Trade, acting under the advice of Trinity House, directed that the substitution of mineral for colza oil in Scotch light-houses should be deferred until the experiments on the relative values of the Trinity House (Douglass) and the Doty lamps should be completed ; in order, I presume, to avoid paying a royalty to Doty if the Douglass lamp should be found superior or equal to his.* In this connection I quote, from a parliamentary paper Extracts fro!n in my possession, the following extracts from a report madeMcs-;rs!^'^"st've".- in 1870, before the adoption of mineral-oil in British light- ^""' houses, by the Messrs. Stevenson, engineers of Scottish lights : ''1st. The parafflne-flame produced by the four-wick trie- Fiame pvi, chanical lamp is 2^ inches in height, and of great purity flucf' '^ '""'" and intensity. " 2d. There is no difficulty, or even trouble, in maintain- caieiieceEsar.i ing the flame. " 3d. According to those in charge, the light is, on the whole, more easily attended to than that from colza-oil. " 4;th. The same wicks have been used throughout the wkts. whole thirty days' experiments, and are still quite fit for use. * The Board of Trade have since given Its authority for the substitu- tion of mineral-oil in all of the Scottish light-houses. Buincd. 182 EUROPEAN LIGHT-HOUSE SYSTEMS. Lamp-glass. " oth. The lamp-glass used for the experiments has stood during the mouth without breakage. vcDtiiation. "Cth. The Ordinary Ventilation of the light-room has been found quite sufficient. Absence) from " 7th. 1^0 incouveuience has occurred from smoking of B-.iiokc. ^j^g ^.^j, ^j, gjjjgjj Qf jjjg parafQne. xtiriae in torn- " 8th. No uuduc rise of temperature of the light-room or i^Li-.ituru of the , , , loaui. apparatus has occurred. Temperature of " 9th. The temperature of the paraffine in the cistern of *''""''' lamp did not, after twelve hours' burning, rise above from about 55° to 03°. Fiasbing-point. " 10th. The safc vaporiziug temperature, or that to which Young's paraffine maybe heated without giving inflammable vapor, as tested by us with Mr. Eowat's patent instrument, is about 140°. Quantity con- " Hth. The quantity of parafQne consumed in the first- order light was at the rate of 718 gallons per annum. The consumption of colza-oil is about 800 gallons per annum. Cost, " Taking the cost of colza-oil at 34s. per cwt., (24'. Qd. a gallon, G82 cents,) which was the price in 1869, adopted in our recent reports on illumination by gas, and paraffine at its present price of Is. 4d. (33J cents) per gallon, we find that the cost of maintaining a first-class light with colza and parafSuc will be £110 ($550) and £47 17s. id. ($239.33,^) respectively, thus giving a yearly saving on each first-class light of £62 2s. Sd., ($310.GO§ ;) but if we take the present contract rate of colza of 38s. Gd. per cwt., (3s. Id. per gal- lon, 77 cents,) the saving would amount to £75 9s. id., (8377.33J.) On the supposition of paraffine being used for all the lights under the charge of the commissioners, the Acuaai saving, gaviug, Calculated on the same basis, would amount to about £2,874 ($14,370) per annum, but at the present contract rate of colza the saving would amount to £3,478 15s. Id. (817,393.89^) per annum. * * » * * * # "We have perfect confidence in recommending the use of paraffioe for light-house illumination. Its iutroductiou would require to 'be done gradually; the light-keepers would require to receive some instructions in its use, and a slight alteration would in each case require to be made on the level of the burner with reference to the optical axis of the apparatus, and the marks for testing the adjustment of the lamp to be carefully altered. A full set of directions would also require to be drawn up and furnished to all the stations when the change is made." EUROPEAN LIGHT-HOUSE SYSTEMS. 183 No more conviucing proof of the utility of permaneuce Good results of ill the peculiar service of light-house administration can be fight-house serv- given than the excellent reputation the Scottish lights bear '™" throughout the world for economy and eificiency, and it is well known that the Commissioners are eager to adopt any improvement which tends to the increase of either. JSl'. Cunningham has for many years most ably filled the posi- tion of secretary, and for nearly a hundred years the Ste- venson family has supplied engineers. The time at my disposal was too limited to allow me to visit any of the Scottish light-houses, and I especially re- gretted that I could not accept Mr. Stevenson's invitation to visit Bell-Eock light-house. My thanks are due both to Mr. Thomas Stevenson and Mr. Cunningham for their polite attentions while I was at Edinburgh. THE MANUFACTOEY OF DIOPTEIC APPAEATUS FOE LIGHT- HOUSES OF CHAKCE BEOTHEES AND COMPANY, KEAE BIEanNGHA TV T. On my return to London from Edinburgh I visited the extensive glass-works of Chance Brothers & Company at Spou Lane, near Birmingham, in compliance with an invi- tation which I received from Mr. J. T. Chance soon after arriving in England. This establishment is most extensive, and is mainly devoted to the manufacture of plate-glass, which is sent from here to all parts of the world. A part of the works is, however, devoted exclusively to the manufacture of apparatus for light-houses, a manufac- ture commenced by this firm in 1855, in competition with the lens-makers of Paris, who until that date monopolized this branch of industry. Mr. Chance stated that in establishing this part of their jj^^?^^ °l^^. trade they had lost more than $100,000, but that their rep- 2ojfgo"appfrafus.' utatiou is now established, and they supply not only Great Britain, but many other countries, with lenses, lanterns, lamps, and accessories of all kinds necessary for the service of lights. They have in use a great variety of machines for grinding Machines f or ^ o ./ o o pohshmg prisms. and polishing the prisms, and the establishment appears to be as complete in every particular as any which I saw at Paris. The scientific branch of this industry is in charge of Dr. HopkiDson. Dr. Hopkinson, who is responsible not only for the cor- rectness of the forms of the various parts of every optical apparatus, but for their correct assembling, and he person- ally tests each lens before it leaves the manufactory. Cost of estah- 184 EUROPEAN LIGHT-HOUSE SYSTEMS. Fia shing-iens Among Other works in hand, I saw a revolving lens of the first order for the light-house at Start Point, on the coast of Devonshire, remarkable for having flash-panels that cover arcs of 60°, which is larger than any before attempted, as far as I am informed. Heretofore the arcs of first-order lenses have not extended 45°, and as the amount of light in the flashes is nearly in proportion to the size of the panels, it follows that the power of this lens, when compared with those of similar character heretofore made, is nearlj-^ as 3 to 2. Ked cut to bo -A- red cut showing the position of outlying rocks near pro 5i P s o 'jo;oapaj ^noq^iM. 'siijujtuddc iq^n poxgB q:jL4i.A':(teaajai oooo o o o ooo o oi ^r rn o» "S g ■^ t- « — w c» p r- lo ei -V ^ C3 CS C4 o o ira c « w o I 1 to t^ Ifil-Hi-i o o o o o o cc w o w 030 e^ 1-1 g *«« CJ CO i-« draiJi oq; JO ^^isaajai 'Bni^BJBddB -saoxaq; JO Ja:^^raBICI ■laninq aq:}. jo J9 4.anxt;i(X JO jaiaoiBEp iiBaj^ •B:qoiAi. JO jaqra,n_ti -Mioiomw onf-vci o^cor-M » ^ w t- « nmfr-O'-t ■V WOti-n-i ne4^<- S|ig« 3 .2" §5 o i © o a o +3 1 a •a —No all act bj- th eaary to i 8. To en not inclu ^?|§ o Snfl-S a BSERVA as this dered u us dime 1 e w fc."S 2 2 02 EUROPEAN LIGHT-HOUSE SYSTEMS. llesults p r ■ duoed iu eclipse lights. The xH'eceding table, whicL. clearly shows that the new system notably increases the intensity of fixed lights, shows nothing as to eclipse-lights, for the reason that with the latter the advantages gained are divided between increase of intensity and increase of duration of the luminous appa- ritions, and the figures showing the effect on each of these two j)henomena vary greatly for each order of lights, ac- cording to the number of divisions of the lenticular drum, the rapidity of rotation, and the arrangements for prolong- ing the flashes. Therefore, without unnecessary details, we shall only give the proportional values, constant in each order, of the increase of intensity and of duration which the new lamps give to the flashes of eclipse-lights. Table of increase in eclipse-lights. Order of light. Proportional increase. Intensity. Duration of flashee. First Per cent. 7 26 7G 3;-) Per cent. 22 Second . . . .......-.- .. 22 Third 59 Fourth 58 Fifth" * There are no fifth-order eclipse-lights on the coasts of France. Besides, whether the light is fixed or eclipse, the quantity of light emanating from the apparatus is constant for each order, and it may be concluded from the above figures that, as our sea-coast lights now are, the total intensity of the ir.croaae of in-lumiuous beams scnt to the horizon will be increased nearlv tPDsity l)v use of ^w^j miucrai-iiii. 45 per cent. This, however, does not take into account the very considerable advantage resulting from the fact that flames fed by mineral-oil preserve their brilliancy longer than the others. The percentage would be much higher if the comparison, instead of being made when the lights are iu their first condition, were made after they have been burning for a few hours. The annual saving in oil will amount to 106,076.80 francs, (820,268.59,) about 32 per cent. Thus the advantages of the change are that 45 per cent, more light is sent to the horizon, and 32 per cent, is saved iu the expense of oil. There is, however, one objection to the new mode of illu- mination: it depends on the qualities of a foreign article. This may be adulterated, its price increased more or less 3;pcflpitulation oi' iiiiv.iiita.i;e! tlio cliiin: of EUROPEAN LIGHT-HOUSE SYSTEMS. 203 when its merits, better known, cause a greater demand, or our supplies might bo cut off in case of a maritime -war, a sad calamity which we must at the present day certainly take into account. It is to be observed, however, that the lormation of bog-head is very active, and aside from their own integrity the Scotch company will be more interested to maintain the reputation of their article the more their customers increase; the French manufacturers also will probably be induced by foreign competition, and perhaps by governmental regulations, (which would certainly be justifiable,) to improve the article they manufacture, if not as to luminous intensity, at least as to safety ; wars, more- over, have ceased to be of long duration ; finally, the burners of our mechanical lamps are so arranged that in order to go back to colza, we have only to close the tube regulating the level of mineral-oil. All our mechanical lamps will be re- tained and kept in use ; the burners alone will be altered. There are at present two kinds of burners in use, both of Kimis of bum. 1 • 1 • J 1 !,..-> era in US9 which give the same results; the Doty burner, manufac- tured in Paris by Messrs. Barbier & Fenestre, and another made by Messrs. Henry-Lepaute, called the modified Fres- uel burner. To complete the change now commenced of colza-oil lamps to mineral-oil lamps, and to purchase the various receptacles and implements needed, will not require more than 50,000 francs ($9,500) more. This amount will be saved in less than a year by the new system. THE LENS-MAKERS OF PAKIS. During my limited sojourn at Paris I visited the manufac- mJiutLtorier'' tories of MM. Henry-Lepaute, MM. Sautter, Lemonnier & Co., and MM. Barbier & Fenestre. These three firms were, until the establishment of the works of Chance, Brothers & Co., in England, the exclusive manufacturers of dioptric apparatus, and supplied all countries. They all have exten- sive establishments, and are contractors, not only for lenses, but for light-houses, (particularly small ones of iron,) for dif- ferent European countries. The method of grinding and polishing the prisms and Ifuses is almost identical at the different establishments, all of which keep on hand a large stock of prisms, adapted to different sizes of apparatus, so that orders can be filled !iy them with but little delay. Lenses, lamps, and lanterns v.erc in different stages of manufacture under orders from dillerent countries. 204 EUROPEAN LIGHT-HOUSE SYSTEMS. Estaiiiishment At M. Lepaute's, iu the faubourg Saint Germain, 1 was pLit^'. ^™''y"^^ shown among others a beautiful third-order lens, a dupli- cate of which I afterward saw at the Industrial Exhibition at Vienna. Lens shown. It was for a " fixed light varied by flashes, " 180° being provided with fixed-light apparatus, and the other half divided into eight flash-panels ; the characteristic of the Characteristics, light would therefore be, that between comparatively long periods of fixed light, there would be observed eight short consecutive flashes ; quite a new characteristic and a most distinctive one for a light to be placed within short dis- tances from other varieties of lights. Swedish light- M. Lepaute showed me his designs of a tower and diop- '"''■ trie apparatus for a light-ship the construction of which he was about to commence for Sweden. This design will be readily understood by an inspection of Plate XXXI. Description of I was much interested in modifications of apparatus for ap]>aratiis for i.t-itt-/. lioating lights, floating lights, and am indebted to him for a paper on the subject, from which the following extracts are translated. After describing the ordinary catoptric fixed light, he says : " The arrangement of revolving floating lights is similar to those of fixed floating lights, but the reflectors are 36 cen- timeters in diameter, and but eight in number, the same as the faces of the lantern. The entire system of lam^js and reflectors is supported by a chariot on rollers which has a wheel toothed on the inner side, to which a rotary move- ment is given by a pinion which communicates by means of a stem fixed by collars along the mast, with the clock-work placed between the decks. A special mechanism has been added to the floating light at Dunkerque, so that when the sea is too boisterous it may be hoisted only half-way up the mast and yet be made to revolve. ^.onstrnction of " Por scvcral ycars attempts have been made to construct light"" "*'' "° floating dioptric lights. One method which has been em- ployed, is to suspend on gimbals to an armature sliding along the mast, three harbor-lights {fmx de port) lighting 235° each with its lantern. " There has also been used a system of eight or ten small dioptric apparatus for signal-lights, 15 centimeters in diam- inventionof ii. ^tcr, suspcudcd arouud a mast in a single lantern. In 1848 Usury. Lepaute, q^j, father projected a system of two fixed catadioptric ap- paratus, 60 centimeters in diameter, suspended on gimbals in a single lantern, and each lighted by a two-wick constant- level lamp. The power of this apparatus is very great, and its service very simple. " In 1869 we recommenced our father's studies of an ap- X CO H X O n kr — >' \ ; 11 ,V M ix' s.,^- V "'*' .'- L^ i6l >."!"; ■oo|%\ I • 5 M < t« EUROPEAN LIGHT-HOUSE SYSTEMS. 205 paratus for a floating catadioptric light, illuminating the whole horizon, and lighted by a single two-wick lamp. Our project was appreciated, and in 1873 we were charged witli the construction for Sweden of an apparatus of this Swedish ligiit- kind, placed in the center of an open iron frame-work, which °'''p- takes the place of the mast of the vessel. (See Plate XXXI.) " The engineers, both French and foreign, who have ex- amined this apparatus in course of construction, have expressed to us their good opinion of the result which can be obtained by this new arrangement. " For revolving lights we have proposed to place before Floating re- the reflectors, annular lenses of 15 centimeters focal dig. ^I'i^K "gi>ts tance, which will considerably augment the range of such an apparatus. "Plate XXXII shows a floating eclipse-light, which is ri o a t i n g entirely catadioptric, composed of two annular half-appa- •"'''P'^''^''* ratus suspended on gimbals at the two opposite extremities of the same armature, and each lighted by a two-wick burner. These two apparatus are placed in the same lan- tern. The objection that the intervals between the flashes are unequal on account of the distance of the two half-ap- paratus is of but little importance, as there is not more than a half-second difference during a rotation of four minutes, which, with three lenses in each half-apparatus, l)roduces flashes of twelve seconds' duration. " We have just finished a study of a floating catadioptric Floating cata- light with a single burner placed in a single lantern and ar- ^"p*"" '"«'''• ranged similarly to the floating catadioptric fixed light. " By making floating lights with a single burner we have the advantage of being able to make apparatus of sizes vary- ing from the sixth order, 30 centimeters interior diameter, to the three and a half order, 70 centimeters interior diam- eter. " The power of these apparatus is much greater than that of those hitherto used, and the advantage of having but one lamj) makes the service much easier." M. Lepaute has also on exhibition at his manufactory a Minorai-oii lamp suitable for burning mineral-oil, which was designed '""P"*^ '^'''' by M. Lepaute, Sr., in 1845. The papers in support of his claim to the original inven- tion of a lamp suitable for burning mineral-oil iu light- houses, as well as the reasons for such claim, are fully set forth in an interesting paper on the subject of light-house burners, written at my request by M. Henry-Lepaute fils, and which he has kindly sent me since my return to Amer- ica. A translation of it will be found on page 208. 206 EUEOPEAN LIGHT-HOUSE SYSTEMS i.amp-vaivcs. In the construction of mecbanical lamps at i.his establish- ment, the valves are made of calf-bladder, and it was stated that for this use, this material is superior to any other. i: staiiiiahmcnt Sautter, Leraonnier & Co. have a very extensive establish- monn?er"rco.^^ment near the Champ de Mars, and their shops are largely devoted to the manufacture of metal-work of light-houses. Parapets o f '£\iQ parapets of light-houses and the floors of the galleries or " decks," as we call them, are in Europe, ordinarily ot stone. I saw, however, one making for Eussia, of cast iron, which we have found to be the best material for this pur- pose, in consequence of the leaks at the joints of stone, caused by contraction and expansion due to our extremes of temperature. M. Sautter, who speaks English wit-h fluency, was attached to the Eoyal Commission which reported on the condition of the light-houses of Great Britain in 18G1. He has had Test of appa-ujucij experience in the specialty of testing of prisms and ratus by M. Saut- ^ . ,,. ,., ter. lenses, and I was much interebced and instructed in the ac- count of the means and care which he takes to insure that every dioptric apparatus supplied from his establishment shall be of the highest standard of efficiency. It should be stated in this connection that the other lens-makers also exercise great care in this particular. I observed at this establishment a handsome lantern for an electric light, designed for the Industrial Exhibition at Vienna, (represented by Fig. 24,) in which the diagonal sash-bars are reduced to a minimum thickness, viz, one-half inch. Besides this lantern there was an iron tower for a harbor- rarquharburn- light, of good design and workmausMp. I was shown the " Farquhar " burner, of which Sautter, Lemonnier & Co. are the sole proprietors, and which they claim is superior to all others in that it gives a whiter and higher flame, of greater intensity, caused by the fact that the tubes for the supply of air to the conceutric flames are of such capacity as to produce equal currents to the interior and exterior, so that the draught is the same to all parts. The flame is of dif- ferent shape, not being pointed like those of ordinary lamps. EstabiisbmcDt At the establishment of Barbier & Peuestre, I was shown ienestre. a second-ordcr lens ordered by us for Cape Elizabeth, a second-order lens for Scotland, a third-order lantern (of iron) for Uruguay, to cost 11,500 francs, ($2,300,) and fifth- order lanterns (of bronze) for Venice and for France, cost- ing each 3,200 francs, ($040.) Oil-cans. This firm were also making a large number of oil caus or butts for mineral-oil destined for use iu the French service. REVOLVINC CATADIOPTRIC APPARATUS FOR LIGHT-SHIPS. platexXXII Sust _ Pisjl^ ^■/«Jf ? f ? T THE GRAPHIC C0.PH0T0-LITH.39&41 PAUK PLAOE.N.Y. EUROPEAN LIGHT-HOUSE SYSTEMS. Each of these cans, which are of sheet-iron, contains seventy- five liters, (about20 gallons,) and costs SOfrancs, ($C.) They are hung in iron stands on pivots placed slightly below the middle, and the cocks are at the tops of the cans, the advan- tage claimed being that, as the cocks, except while oil is be- ing drawn, are always in the air, there is no danger of leak- age of this subtile fluid. Fig. 24. 207 Lantern for electric light. Barbier & Fenestre have purchased from Captain Doty DotyburDer. his patent for mineral-oilburners, (see Fig.2,P]ate XXXVI,) except as regards Great Britain and the United States, where he reserves the right, and the French government, with which he has made special arrangement. They state that thej' are making mineral-oil lamps for light-houses in all parts of the world, and that mineral-oil has been adopted in most countries of Europe, as well as in South America and Canada. All thelens-manufocturers were busy in fitting the colza-oil lamps of the French lighthouses for the use of min- eral oil. A variation of one millimeter (Jjof an inch) in the height of the overflow in winter and summer is provided for. The tops of all burners made by French lens-makers arc copper duir.. of copper. I suggested to one of them that we had found " "^ iron to be much more durable, and he concurred in the opin- 208 EUEOPEAN LIGHT-HOUSE SYSTEMS. ion that iron would not submit as readily as copper to the destructive action of the flame. Lanterns and lenses are differently constructed for differ- ent countries, some preferring the diagonal bars, on ac- count of the less obstruction to the light, and others prefer- ring the vertical ones, on account of the greater economy. The difference in cost between the two kinds of lenses was stated to be for the first order about 1,000 francs, ($200.) Lraises suited Lcnscs are made to suit the height above the sea-level at a'bovl'™iie ''s'ea- which the different orders are usually placed, and any ex- "'" ' cess of such height requires special calculations and adjuct- ments. Unless otherwise stated, the height at which a first- order lens is to be placed, is supposed by the makers to be piiotomoter between 150 and 200 feet above the sea. The photometer used by all the lens-makers in Paris is the same as I have described as in use at the Depot des Phares. I was informed , , that most countries use the " mechanical lamp " for the first Lam]).s used for ^ didereotordeisof and sccoud ordcrs of lights, the " moderator" for third and li<;bt3. ' fourth orders, and common (capillary attraction) lamps for the fifth and sixth orders, but that the sixth-order lamp is little used. I found the members of the several firms all to be cour- teous and intelligent gentlemen, and my experience with them at their offtces and manufactories confirmed the high opinion I had previously entertained, and which were de- rived from my correspondence with them and from the ex- cellent quality of the apparatus furnished to us. 1 should state, before concludingmy notes in regard to Paris, that Mr. Washbnrne, the American Minister, was absent at the time of my visit. I am, however, under obligations to Colonel Hoffman, the secretary of legation, for his valu- able assistance. [Translation.] REMARKS ON BUENEES EMPLOYED FOE LIGHT-HOUSE ILLU- MINATION. By Henry-Lepaute Bugthers. In all countries in the world burners with concentric wicks are used in light-house apparatus, the number of wicks varying from one to four, according to the order of the lens. These burners were invented in 1821, on the principle of 1.111 llJrs" '""ith those of Argand, by MM. Augustin Fresnel and Arago. loiitentiiciMcUs. .j,^^ coucentric wicks are separated by air-spaces for supply- ing the oxygen necessary for good combustion. UJ z CD EUROPEAN LIGHT-HOUSE SYSTEMS. 209 The conditions fulfilled by the ordinary Fresnel burners are the following : Order of lens. Number of Tricks. Dimensions of fully devel- oped flames. Luminous in- tensity in Carcel units. Maximum di- ameter. Height taken from the burner. First 4 3 2 2 1 1 MiUimtters. 90 75 45 36 30 27 Millimeters. 100 eo 70 es 45 37 23 15 Third 5 3 Kith 1. C 1.3 Table of ordin- ary Fresnel burn- ers. lu examining this table it will be noticed that third-order apparatus, interior diameter one meter, is lighted by two- wick burners, differing but little from those employed in fourth-order apparatus, the interior diameter of whose op- tical part is but half a meter. In 1845 M. Henry-Lepaute, Sr., who had been a colaborer in the experiments and construction of the apparatus de- signed and calculated by M. Augustin Fresnel, sought to apply to third-order lenses more powerful burners than those then in use. After his own drawings he then had made, by M. Blazy-Jallifier, a two-wick burner of special construc- tion. The two wicks, respectively 54 and 28 millimeters in exterior diameter, were separated by a double air-space, and an air-tube was placed around the larger wick. These air-tubes were elongated and enlarged below, and the chim- ney-holder slipped over the outside. This burner gave an intensity of from four to five Carcel units, and consumed I'OO grams of colza-oil per hour. Some experiments were made in 1845 in the workshops of M. Henry-Lepaute, Sr., and M. Leonor Fresnel, engineer of the corps des ponts et ehaussees and director of the French light-house service, verified the principal results by one of his assistants. These new burners were adopted by the kingdom of the Nether- lands for the light-houses of Brouwersbaven, (1845-1847,) Subeveuingen, (1851,) Eeuesse, and Schiermonikoog. The French government, while recognizing the merits of these baiiiers, did not adopt thcm,notwishingto alter the standard burners invented by Messrs. Fresnel and Arago. For this reason M. Henry-Lepaute continued to make them only when specially ordered. In 1SG8 the question of the use of mineral-oil in light- houses was brought up. Previous experiments had not given very good results. An American, Mr. Doty, i)ro- pcsed a form of burner which succeeded quite well for S. Ex. 54 14 Efforts of M. Henry - Lepaute, sr.,to increase tlie power of burn- ers. Burner of 134.'). Intensity of burner of 1845. Adoption o f burner of 1845 by kinedom of tho Netherlands. Question of tlm use of mineral-oil in light-houscs. Doty burner. 210 EUEOPEAN LIGHT-HOUSE SYSTEMS. Experiments with burcers. Invention of t r u n c atecJ-con© burner, 1809. Comparison TTith tbe Doty burner. Modification of the Fresnel burn- .^?r, 1872. Exterior air- vnibe. Table of modi- fied burners. schist-oils, but its arrangement and dimensions differed from the standard which the light-house administration had not, up to that time, consented to modify. About that period we were making numerous experiments relating to the burning of mineral-oil, and after many attempts we succeeded in constructing a burner with air-tubes enlarged below, and with a tube exterior to the large wick. The arrangement was almost identical with that of the 1845 burner invented by our father, except that the air-space between the wicks was not double. We then experimented with the 1845 burner, feeding it with mineral-oil, and found the combus- tion very satisfactory. In 1869 we invented the truncated-cone burner, preserv- ing exactly the dimensions of the Fresnel burner for lights of all orders. Specimens of these burners Tvere sent in 1869 to the light-house administrations of Sweden, Norway, Denmark, the United States, and Brazil. The French ad- ministration tried our truncated-cone burners, comparing them with the Doty, and found them always equal, and sometimes superior, especially the one-wick burner. Still they charged us to try to modify the Fresnel burner so that with the same general arrangement, it might, by means ot some additions, be used for mineral-oils. The experiments undertaken in 1872 succeeded, and we fixed upon the arrangement of the new modified Fresnel burners of 1873, which are now being substituted for the ordinary Fresnel burners, so that schist-oil may be used in all light-houses of France. The success of these burners is due in a great measure to the addition of an exterior air- tube, as in the 1845 burner ; an arrangement also used by Mr. Doty in his burners. In fine, all schist burners now in use are reproductions of the burner invented in 1845 by M. Henry-Lepaute, Sr., still in actual use in a large number of light-houses in Hol- land. The conditions fixed by the French administration for the dimensions and intensity of the new modified FreS' nel burners are the following : Table of modified hurnefs. =4-1 O Dimensions of the fully developed flame. Order of lens. Maximum diameter. Height taken from the burner. 111 5 4 3 2 1 1 Millimeters, 105 85 65 45 23 25 Millimeters. 110 90 bO 70 45 45 30 14 C.4 Third Kfth *-' ~ > X X X u -J Q. hi > .J D. M U z o u X I- 2 3-1 .'^"'" "'''"' erator lamp is used, an excess of oil cannot be entirely sup- pressed, and there should be a lucans of varying the level in the burner itself. Livei varied in 1" the Doty burner, (see Fig.L', Plate XXXVI,) an ap- tbo uoiy burner, pg^jage for this purpose is attached to the outside of the cistern.* This has the disadvantage of being fragile, and * By Ibe following coiumuiiicatiou, which I bavo recently received from M. Lepaute, it would seem tliat the French government has decided to nse this appendage: '■A modification bus been made in mineral-oil lamp-burners for the purpose of regulating the supply of oil. Tliis modificatiou consists of EUROPEAN LIGHT-JIOUSE SYSTEMS. 213 obscures the light in oue direction. All the systems pro- liosed by us are for the interior of the burner, and have been used wiih success since 1869. In the modified Fresnel burners, (Fig. 1, Plate XXXIV,) scTcw-tubeHys- the oil overflows into a central tube, which can be length- ened by means of short sections (B) screwed on. These are of determinate lengths, and are fixed in place by a wrench, (A, Fig. 1.) When it.is required to burn vegetable or animal oil with an overflow, the tube is stopped by a cap, (C.) A friction- stem carries the disk. These various operations cannot be j)erformed when the burner is lighted, and, besides this disadvantage, the level of the oil can be varied only by a jigjjj.g^ established respectively in 1863 and 18C5, being the first of that kind in the world. I arrived at the lights after dark, and requested the niaitre dephare to show me tlie establishment, saying that I had endeavored to find M. dc Eochemont, but without \m c^f --til 2S Si mt w^ ■IS if?, 4, it; L^^^*- -^-H If i" '•<■ *,^ ■'.'-.■'■'/'? frf^^r* 7'TS'i EUROPEAN LIGHT-HOUSE SYSTEMS. 221 success, showing Lim at the same time the letter addressed to that gentlemau bv M. Arnoiix. He would not, however, Eefuaai of " * ' ^ keeper to aamit lead the letter, aud politely stated that he must refuse to visitors alter dark. show me the lights, as he had positive instructions not to admit any visitors within the station after lighting. He was inexorable to all my arguments, and I was at length obliged to yield, and, while praising him for his strict obedi- ence to orders, could not but regret my unsuccessful journey, and drive of two leagues back to Havre in the rain at mid- night, without seeing the interesting objects of my visit. I mention this circumstance as indicative of the character of the French light-house keepers as far as I saw them. At all the stations I visited I found them to be bright, intelligent, and fond of their profession. The following morning I again proceeded to Cape la Heve, and had the gratification of inspecting what is prob- ably the most extensive light-house station in the world. The towers are very handsome, and are Co feet high, their rocai planes. local plane being 397 feet above the sea. The dwellings, engine and machine rooms, &c., occupy the intervening space, about 300 feet, between the towers. In the engine-room, which is kept with the utmost neat- Boilers, ness, are two boilers, which are a combination of the up- right and horizontal, and of about eight horse-power. In the machine-room are four magneto-electric machines Magneto - eiec- made by the Gompagnie V Alliance of Paris. One machine, *""'"'"' '"'^''' running with a velocity of four hundred revolutions a min- ute, supplies each light ; and in case of fog or thick weather the other machines are added, so that the uncondensed beaui, which in the former case is equal to 200 Carcel-buru- power of nn- ers, (2,000 caudles,) is increased 400 Carcel-burners, or 4,000 caudles. The lanterns which surmounted the towers when oil was Magneto - eii-c- nsed as the illumiuant have been removed, and the magneto- iteS 'irum'^ the electric lights are exhibited from what were the watch- '"''"^'*'™"""'' rooms. Small cylindrical lanterns, about 2^ feet in diameter, Lanterns. formed of glass, cast specially for this purpose, without any sash bars, either vertical or inclined, being projected from the square seaward angles, aud illuminating about 275° of the horizon. Figs. 25 and 26* represent in plan and elevation the electric light-room, which is in two stories, each contahiing an entire set of apparatus. * Kijjiires 23, 26, and 27 have becu takeu from M. Eeynaud's Mimoire eur V£elairage des Cites de France. 222 EUROPEAN LIGHT-HOUSE SYSTEMS. In Fig. 25 A is the lower room ; B, the stairway of the tower; C, steps leading to the upper chamber; D, diiov leading to the outside platform ; K K, iron rails for tlio regulators ; L, the lantern ; O, the illuminating apparatus ; E, the spare regulator; S, the luminous beam of rays emanating from a small lens placed in rear of the focus, and wMch throws upon the wall an image of the light. The Fig. 25. Plan of lantern and watcb -room, La Hfeve. position of this image, with reference to a iixed mark, indi- cates to the keeper whether the light is in the focus of the lens, and is of the greatest assistance to him, as it is impos- sible to look at the light itself without injury to the eye, on account of its dazzling intensity. T T are the conducting EUROPEAN LIGHT-HOUSE SYSTEMS. wires ; U, the switch for changing the direction of the cur- rent ; V, an india-rubber speaking-tube. The arc of visi- bility of the light is represented by the arc m, n, p. In Eig. 26 A A represents the illuminating apparatus; B B, rails for the lamps or regulators ; C C, the conducting- wires ; D D, the switches, and E E, india-rubber speaking-tube. Fig. 26. 223 Section of lautom and Tvatch-room, La Hfeve. In each of the lanterns, two at each tower, is placed a fixed lens three-tenths of a meter in diameter, the size of the sixth order, shown in Fig. 27, and for each lens there is a duplicate electric lamp, so that, in effect there are three reserves in case of accident. It is found by experience, however, as I was informed by the maitre de phare, that a second lamp is only required 224 r.ITROPKAN LIGHT-HOUSE SYSTEMS. \vl ( 11 t.'baiigii)g tlic charcoal pencils, so tbat so many re- st'i VIS of lamps are more than are actually necessary. Fig. 27. Apparatus i ii duplicate. Optical apparatus, La Heve. All the other parts of the appaiatns, inckuliL'g- the en- gines, boilers, and machines, are in duplicate, excepting the cables or wires connecting the magneto-elcctiic machines with the lamps. These, M. EcvEr.iul alterwaid informed me at Paris, it was not thought nccr^sary to duplicate, but I should infer that it would be well to provide in all cases a second wire, from the fact that in observing the lights from the steamer, while crossing the Seine from Honfleur to Havre, I saw that one of them waxed and waned very perceptibly, and on ray questioning Ihe maitre dc pharc in regard to it, he stated that the wire leading to that light wr.s in an imper- '"^"t condition. EUROPEAN LIGHT-HOUSE SYSTEMS. 225 In regard to the carbons, I was told that those used for carboususcdii- fog are much larger than those used in clear weather, in "' order to provide for the rapid consumption when two mag- neto-electric machines supply each of the lights; also that the carbons now obtained in France are much superior to French carbon* the Englif.h, (which were used at La Hfeve during the wariingHs™ with Germany,) and that with the former the impurities (which are said to be the only source of danger to this light) are never so great as to cause its extinguishment, and they are also not subject to the production of that fine black dust which I observed at South Foreland and Souter Point as in a slight degree interfering with the full power of the dioptric apparatus. It will be observed that the only provision at LaHeve, for Provision lo^ the exhibition of an oil-light in case of accident from any cause to the supply of the electric current to the lamp, is an oil-lamp in the small lens used for the electric light, pro- ducing an illumination of but little value for sea-coast lights of their importance. I was informed that at Grisnez, on the Straits of Dover, Light at capB- where the French government has established another elec- ^^'^'''^■ trie light, the old lantern and lens for the use of an oil-lamp have been retained, the electric light is exhibited from the watch-room, as at La Heve, and an oil-lamp is always ready for lighting in the first-order lens in the main lantern. A casualty, such as I have mentioned, requiring the substi- lob» of light bv- tution of an oil-lamp for the electric lamp at Grisnez would """' " °' '""' ' reduce the intensity of the light to G,300 candles, while at La Heve it would be reduced from 50,000 to 260 candles in fair weather, (and from 100,000 to 260 candles in fog,) and probably even less, as the lens used for electric light is not suited in any case for the exhibition of an oil-light. Drawings illustrating the arrangement at Grisnez were kindly furnished me by Chief Engineer Allard, and are re- produced in Plate XLVL K'either the electric light at La Heve, nor those of Souter Point or South Foreland, which I saw in England, are suffi- ciently high to make necessary the plan which I am informed by General Sherman has been adopted at the new electric EieotnoUgiit , , , ..-.. ^ .,,.■■ ■.;r ,.. i i at Port Said, el- light-house at Port Said, at the Mediterranean entrance to cvator in tower. the Suez Canal, that of providing for the tower an elevator or " lift " which is operated by the steam-power used to drive the magneto-electric machines. Up to the present time there have been established nine electric light-houses, viz : S. Ex. 54 15 226 EUEOPEAN LIGHT-HOUSE SYSTEMS. In France, two fixed lights at La Heve, and a revolving light at Grisnez ; In England, afixed light at Dungeness, two fixed lights at South Foreland, and a revolving light at Souter Point; In Egypt, a revolving light at Port Said ; In Eussia, a fixed light at Odessa. The following excellent paper, which I have found in the Annates des Fonts et Chaussees, givesa clear exposition of the electric sea-coast lights at La Hfeve. [Translation.] DESCRIPTION OF THE ELECTEIC LIGHT-HOUSES AT LA h£VE By M. Qdixette de Eochemokt, Engineer des Fonts et Chaussees. Dates of con- The light-houscs of La Hfeve, constructed during the lat- hghi/u°^ ''"^ter part of last century, were lighted for the first time in 1774 ; wood-fires were then used. In 1810, lamps with re- flectors -were introduced, which, iu 1843, were replaced by dioptric apparatus. A final change has been recently effected by the introdtiction of the electric light. The application of the electric light to light-houses had XTrg of d^ctric jiiiea. already been an object of investigation for a long time. Currents produced by electric piles were first tried, but their intensity very rapidly decreased when the apparatus had been in operation for some time ; the expense was consid- erable, and, besides, it appeared rather hazardous to confide to ordinary keepers the care of keeping and regulating the piles. The system based on induction currents gave, on the contrary, very good results, in experiments made at the Cen- tral Light-House Workshops at Paris ; so that iu 18C3 the Tcstof oiectric Minister of Public Works decided that one of the light-houses '•'fLaHo'vo."''"''ofLaHeve should be iUuminated provisionally by electric light as a test. As the experiment confirmed the anticipa- tions, electric illumination was definitively applied to both light-houses toward the end of 1865. Description of ^^® curreuts are produced by magneto-electric machines the apparatus, worked by steam-engiucs, and are carried by con ducting- cables to the regulators, or electric lamps, used to regulate the separatioi! of the carbon points, between which the light is produced. The magneto-electric machines and the en- gines are placed in the center of the keepers' dwelling, in two rooms fitted up for that purpose. (See Plates XXXVII, XXXVIII, and XXXIX.) tric inachiiie*. EUROPEAN LIGIIT-IIOUSi: SYSTEMS. _ The steam-eugines are two in number, and present no pe- steam mp culiarity worthy of notice, as they belong to the couiraon stationary class with Ibcoinotive-boiler of eight horse-power. They ai'e certified as capable of resisting a pressure of 70 pounds to the square inch. But one engine is generally used at a time, as it is sufficient to work two magneto-elec- tric machines. At first it was. thought necessary to keep the second engine with banked fibres in case of accident to the first, but practice has shown that this precaution was needless. The motion is conveyed from the steam-engines to the machines by belts and an intermediate shaft. (Plates XXXVIII and XXXIX.) The magneto-electric machines were furnished by the Al- , iiagn';'." *^ *^ trie miichiii liance Company. They are composed (Plates XL, XLI, and XLII) of a cast-iron frame on which are placed mahogany cross-pieces which serve as supports to seven parallel series of compound magnets, all of which converge toward the central axis of the frame. The magnets of the two outer series are formed of three superposed' plates, curved horse- shoe shape, the others of six plates. They are so arranged that the poles nearest each other, both horizontally and ver- tically, are always of opposite signs. The six-plate magnets are of a power of 145 to 155 pounds, the three-plate, about 75 pounds. Between the seven rows of magnets, there re- volve six bronze disks, (Plate XLIII,Figs. 1 and 2,) mounted on an axis supported by the frame. On each of these disks, sixteen induction-spools are fixed by bronze clamps and screws. (Plate XLTII, Figs. 10 and 15.) Each spool (Plate XLIII, Figs. 10-14) is a tube of soft iron about one-third of an inch thick, IJ inches in exterior diameter, and 3f inches long, slit radially so as to more quickly lose its magnetism. Each tube is wound with eight copper wires one-twenty-fifth of an inch in diameter and about 50 feet long, so that there are about 400 feet of wire wound around the spool. These wires are covered with cotton aud insulated by asphalt dis- solved in spirits of turpentine ; they are wound in the same direction on all the spools. The best method-of placing the spools has been deter- iietiKKi mined by experiment and trial ; a certain number of ex- spools. tremities of wires of the same sign or denomination are brought together, and an equal number of extremities of the opposite sign. All tlie extremities of one sign communicate with the central axis of the machine, all of the other sign with a metallic sleeve fixed on the axis but insulated from it by a plate of India rubber placed concentrically and joined to two other perpendicylar plates. " (Plate XLIII, Figs. 5-8.) 228 ETJEOPEAN LIGHT-HOUSE SYSTEMS. The shaft and sleeve revolve in journal-boxes (Plate XLIII, Figs. 5, 6, 9) insulated from the rest of the frame by plates of vulcanized rubber. From these boxes and the axis start the wires which transmit the currents generated by the ma- chine. iiiiinction-car- luduction-currents are produced whenever the spools touts. either approach or leave the poles of the magnets." Thus there are sixteen changes of direction of the current to each revolution of the cylinder ; and the wires are therefore alter- nately traversed by currents of opposite direction and a series of discontinuous sparks is obtained. The eye, how- ever, perceives no interval, for the number of sparks ex- ceeds 100 per second, since the magneto-electric machines make from 390 to 400 revolutions per minate. Groi.pincof Four magncto-electric machines (Plates XXXVIII, "'" "'"•'"■"^«- XXXIX, XL, XLI, XLII) have been set up. They are grouped two and two, each group connected with one of the lights. Under ordinary circumstances one steam-engine works two machines, one of each group, but during a fog, Avhen it [s wished to increase the intensity of the lights, each group of machines is worked by an engine. For this liurpose the shaft for transmitting the motion is of two l^arts, which are connected or disconnected at pleasure, as either ordinary or double light is wished, (Plate XLII, and Plate XLIII, Figs. 3, 4, and 30.) In the latter case the two machines of the same group are connected. Switches. Accordingas it is wished to use one, the other, or both oi the machines connected with one light-house, it is necessary to change the points of attachment of the conducting- wires. In order to avoid the mistakes which might result, M. Joseph Tan Malderen, superintending engineer of the Alliance Company, has contrived a most ingenious switch, placed in the machine-room, (Plate XLIY, Figs. 1 to 4.) From this switch alone proceeds the cable conducting the electric currents. This cable is composed of three wires, one of which, /3, communicates directly witli the wire b, uniting the axes of one of the groups of mnchiues, while the two others, a and ;-, proceed from buttons at the lower part of the switch. The wires a and c, coming from the journal- boxes of the machines, are brought to two buttons at the upper part of the switch. Oon.mimicniion The commuuication between the wires « or c (Plate XLIV, mmJ.''"" '" Fig. 3) and the wire a, wliich, when a light of ordinary in- tensity is lequired, is always the one which conducts the current to the lights, is through a forked piece of metal, one end of whlcli is attached by a pin to the upper button which EUROPEAN LIMIT-HOUSE SYSTEAIS. 229 corresponds to the macbiue then in operation. On the con- trary, when a ligbt of double intensity is wished, the cur- rents arriving at the upper buttons pass to the wires a and r through two straight rods, (Plate XLIV, Fig. 1,) and do not meet until they reach the interior of the lamp. Thus no displacement of the wires need be feared, as all are permanently attached to the machines or switches, the SAvitch-key being all that it is necessary to touch. Each cable is carried underground to the light-house, thence through the stairway to the lantern. In order to avoid extinctions which might result from ac- Duplicate! . p cidents to tlio regulators, it has been thought necessary to*"'*'"'''*"'"""" have in each light-house two optical apparatus, one above the other, and for each two lamps. These lamps slide on rails fastened to a cast-iron plate, and can thus be moved into exact position. As it was also wished to avoid displacing the conducting second switih. wires in the light-house lanterns, a second switch is used, by which the light can be doubled on either stage at will without moving the wires. (Plate XLIV, Figs. 5 and G.) The wire ;S, coming from the axes of the two machines of the same group, connects directly with the lower cast-iron table, and the communication between the two tables is through one of the uprights of the lantern, also of cast iron. The current passes directly from the table into the lamp to reach the upper carbon point, as will be seen here- after. The wire a communicates with a large copper bolt, A, (Plate XLIY, Figs. 5 and C) by the metallic plate on which the bolt slides. The wire y communicates in the same way with another bolt, B, sliding vertically like the large one, from which, moreover, it is magnetically insulated by an ivory handle. When the bolts are pushed down, the currents arrive by the wires a and ;', pass into the wires «' and /, and go to the lower stage ; on the contrary, if the bolts are pushed up, tbc currents pass into the wires a" and y", and thus reach tbc upper stage. If the ligbt is of ordinary intensity, there is no current in the wire y, and consequently none in the wires -/ and ;-". The currents from the wires a' or a" reach the lamp through a flat metallic spring placed above the cast- iron plate on which the lamp rests. In case of double ligbt the currents from tJie wires y' or y" reach the interior of the lamp by a second spring placed at the side of the first. In this way, when double light is used, only one of the ^^k of sin^-io "" ° 3 ii e t a K c w h <■ II stages of the lantern is lighted. Experience has shown that 10 O o M K U K M O 3 U O -• I- O Devices of JI. KUEOPEAN LIGHT-HOUSE SYSTEMS. 231 the points are a proper distance apart ; the voltaic arc can thus be kept of a constant length. As "we have already stated, the currents enter the regn- course of tho - ' ' . curreiita. later by the base-plate and through either one or two springs placed beneath, as either ordinary or double light is required- lu the former case the current passes from one of the springs into one of two pieces, shown together at T; thence around the two magnets S, through the piece XX, and reaches the oscillating tube and the lower point-holder. In the second case, the other current of the same denomination, conducted by the wires y' or ;'", passes from the second spring into the second piece at Y, and attains the piece V, where it meets the first current, without having passed about the electro- magnets. The current of the contrary sign passes from the base-plate through all the other parts of the lamp to reach the upper point-holder. The parts traversed by currents of contrary signs are insulated from each other by vulcanized rubber and ivory. To assure good working of the lamp, M, Serrin has contrived some devices which we will point out. scn^iL! When the upper rod is raised, the pulley G (on which are wound the chains connecting the ends of the rod) revolves; but, to prevent forcing the clock-work, a ratchet-wheel, G, is placed on the same axis as the first cog-wheel. The two screws H and I, which meet two pieces on the side NO of the parallelogram, limit its motion. By the screw K (Plate XLV, Fig. 1) the upper rod can be raised or lowered to alter the position of the luminous point. In his last lamps M. Serrin has adopted a much better device, by which the luminous point can be placed in exact position by moving both carbons at once, thus prevent- i ng any decrease of light. For this purpose the chains A and i> are run over a little auxiliary pulley which can be moved up or down by a screw and lever so as to raise or lower both points the same distance at the same time. This device is applied to four of the lamps in use at La H6ve. A small gauge, Z, movable around the upper rod, indicates the exact height at which to place the gap between the car- bons; that is to say, the luminous point. By the two screws L and L' the carbon-points can be adjusted exactly opposite each other by moving the upper point in a direction either parallel or perpendicular to the plane of the two rods. Finally, to prevent the point-holders burning when the carbon is consumed they stop at a distance of about 2^ inches from each other, as then the upper rod strikes the base of the lamp and can go no farther. Tatus. 232 EUKOPEAN LIGHT-HOUSE SYSTEMS. Poncauifs reg- Aiiotber regulator, invented by M. Foncaalt and con niiitor. structed by M. Dubosq, has also been tried. It was, bow- ever, not well adapted to be placed on a cast-iron table, and was twice broken witbiu a short time, in consequence of a too great separation of the carbon points.* Its use was then abandoned. Carbon points. The carbou'poiuts used for electric illumination are iDan- ufactured from the residue contained in gas-retorts. They are about 10 inches long and from one-third to one-half au iucb thick, according as they are used for ordinary or double light. Optical appa- The Optical apparatus, Fig. 27, are about one foot in diameter; the catadioptric rings are symmetrical, both above and below, on account of the form of plie points and the luminous center. The luminous rays are sent from the rings tangentially to the surface of the sea. The joints of the rings are placed in a direction parallel to that taken by the rays after their refraction. The luminous center being of very small dimensions, (about two-fifths of an inch by two-fifths to three-fifths of an inch,) the lantern can have no sash-bars, as the occultation of a part of the horizon which they would produce must be avoided. Direr enco ot "^■'^^ divergence of the luminous rays is about C°; about rays and position tijQ same as that of a first-order oil-light. It is indis- point pensable that the luminous point should remain in ex- actly the proper position iu the optical apparatus, as a vertical displacement of one-fifth of an inch would raise or lower the luminous beam 2°. To assure a correct position for the luminous center, there has been attached to the edge of the optical apparatus a small lens, which throws the image of the points on a screen placed at the other end of the service-room. This image should be in such a posi- tion that the gap between the points appears on a line pre- viously traced on the screen. If it does not, the position of the luminous center should be adjusted as has been indi- cated above. The image is magnified 22 diameters. The lights of La Heve illuminate three-fourths of the horizon. The lanterns and service-rooms are at the un- lighted angle. other aids. Oil-lamps with large burners can be placed in the center of the optical apparatus if there should occur an accident preventing the production of electric light ; iu such case one of these burners is placed on each stage of the lantern. M. Dabosq has since placed a r.top-pioce to prevent the too great sepa- ration of the points; the lanip works with more regularity, hut wo have not acaiu nsed it. > s .Ul z I • X <0 u ©-■J y Ob" M S u ^ U £ J o ~f ^ U (C lO O I '^ 3 bl o O-Ju X ■•) z S 1 O EUEOPEAN LIGUT-HOUSE SYSTEMS. 233 Each luminous point Las about the intensity of a fourth- order light ; at a short distance the two lights blend and appear as one. Call-bells with dials connect the engine-room and the cau-iicUs. lighthouse lanterns, so that the engineers and keepers can communicate Y«ith each other. Other bells are placed in tae dwellings of the principal and other keepers. Water for the steam-engines and for domestic use is kept -sv'ater. in cisterns of a total capacity of about 46,000 gallons. It is rain-water collected from the roofs of the buildings and from courts paved -with asphalt, a total surface of about 2,CC0 square yards. It is pumped by the engines into a tank near the engine-room, (Plate XXXVIII.) There is a small workshoiyfio that the engineers can make all current repairs which tfo not require special artisans or implements. In charge of the lights there is a principal keeper, {maitre organization «< dephare,) who has under his orders six assistants, (gardiens,) *'^* service. two of whom are engineers, whose special duty is to attend to the steam-engines; tlie others attend the lamps. The engineers have the title and rank of keepers (gardiens) of the first class, but as their service is much more arduous I ban that of their comrades, an extra compensation is allowed them at the end of the year if tliey have given sat- isfaction. With a view to subordination and harmony of lelations at the lights, it seemed better to give these "em- ployes a relative rank rather than to exclude them from the service by giving them the title of engineers. Since commencing the use of electricity (November 1, ^(.ciiients, ei- ]8G5) several accidents and a few extinctions have occurred, tiuotions. We give below a complete list. March 5, 1866. — The suspension-chain of the upper rod of one of the electric regulators breaks. April 8. — Light out five to six minutes, in consequence of the slipping off of several of the belts. July 12. — The heel-screw of one of the magnets of ma- chine No. 22 becoming loose, rubs against the spools of one series and injures them so that several have to be replaced. As this accident happened at the moment of setting the machine in motion, no extinction resulted. July 21, September 5, September 8, September 12. — The sus- pension-chains of the upper rod of tour regulators break; the damaged lamp being immediately replaced by another, the light was out but a few seconds. October 2. — Four mahogany cross-pieces of machine No. 19 are broken ; four spools are inj ured. The reserve machine 234 EUEOPEAN LIGHT-HOUSE SYSTEMS. being immediately set in motion, tbe light was out bat a .short time. January 11, 1807. — The suspension chain of the lower rod of a regulator breaks. March 9. — Light out 3 minutes, the belt of the engine having slipped off. March 17. — Light out 3 minutes, the fire-grates of the en- gine having fallen. March 25. — Southern light out 7 minutes and 3 minutes. March 29 to 30. — At 10.35 p. m. the southern light out. Being unable to relight it, oil-lamps are placed in the lens- apparatus. At 2.35 a. m., on again trying the electric light, it works. Electric light out about 4 hours. May 25. — At 12.5 a. m. the water-pipe of the engine bursts, the pressure falls; reflectors are lighted at 12.20. The dam- age having been repaired, the electric light is reestablished at 1.5. November 20. — Southern light out 5 minutes, caused by the slipping ofif of the belt of the magneto-electric machine. January 5, 1808. — Southern light out 9 minutes. March 3. — Light out 7 minutes, caused by the belt of the steam-engine having twice slipped ofif. March 19. — Light out 2 minutes. The pin of the fly-wheel becoming loose, it was necessary to tighten it. May 4. — Southern light out 3 minutes, the belt of the magneto-electric machine falling off at the time of firing up the southern engine. October 20. — At the laoinent of lighting, the joint of the steam-gauge of the southern engine bursts. The fires of the northern engine are lighted, but before steam is up the acci- dent is repaired, so that the hopr cf lighting is not delayed. October 30, 1809. — Northern light out 15 minutes, the keei)er having fallen asleep. ni?My^''cxUn'o° ^^ addition to the extinctions mentioned above, which tioas. v^ere the result of accidents, there occur every night a few others of short duration, which cannot be avoided. When the lamps are changed, for instance, the light is out a few seconds ; also, when double light is to be produced after ordinary light, or vice versa, it is necessary to throw in or out of gear the two i)arts of the shaft connecting the two magneto-electric machines of the same group, so the light is out 2 to 3 minutes. Eecapituiatijn. r£Q recapitulate, wc find that in fcair years there have occurred — LIGHTHOUSES OF LA hIiVE. ELECTRIC LIGHTS. plate: xli MAGNETO-CLCCTRIO MACHINE. SIDE ELEVATION. Iiirhtv I^ » If 3 O SCALE. ■ifWr. THE SRAPHIC CO. PHOTO -LITM.39441 P*RK PLACt.NY. EUROIEAN LIGHT-HOUSE SYSTEMS. 235 Three extiuctions of 2 minutes, 3 minutes, and 1 hour duration, caused by accidents to the steam-engine. Five extinctions of from 3 to 7 minutes, caused by, the slipping off of the belts. These extiuctions were the result of the negligence of the keepers. Measures have been taken to prevent similar occurrences. Two accidents to the magneto-electric machines, from which no extinctions of consequence resulted, as the machine in reserve was immediately set iu operation. Six lamps were sent back to Paris in consequence of the breaking of the suspension-chain of one of the carbon holders, but the extinctions caused by these accidents are not worthy of mention. Four extinctions of 3, 7, 9 minutes, and 4 hours' duration, the causes of which we have not been able to determine. One extinction of 35 minutes, resulting from the sleep of a keeper. The extinctions originating from the steam-engines, or the slipping off of belts, offer nothing particularly worthy of notice ; one only exceeded 7 minutes, and was the result of the breaking of the water-pipe ; the others are mainly attributable to the uegligence of the machinists. The accidents which occurred to the magneto-electric ma- causes of acci- chines rendered it necessary for 31. Joseph Van-Malderen,'^f°^fp''j"^''*-'™1;': superintending engineer of the Alliance Companj', to make"'""'^''' a journey to Havre, in order to attend to their reparation. The second of these accidents was probably caused by the falling out of one of the wedges used for keeping the mag- nets in position, and the magnet having nothing to hold it, hit the wheel carrying the spools. The breaking of the suspension-chain of one of the carbon- canscofbreoit- , ape «t Ruspen- liolders (an accident which occurred six times) was caused aioD-oiiaiuoi- the by these chains passing too near other parts irom which tliey should have been separated, and thus becoming heated. M. Serrin has easily succeeded in remedjing these disad- vantages, and they will not again occur. The extinctions of 7, 3, and 9 minutes, occurring to tlie Extinctions i>,v southern light, are due to causes which we have been unable to ascertain ; it is probable that they were the consequences of a lack of vigilance on the part of the keepers. In regard to the extinction of four hours' duration, we are unable to attribute its cause to anything but malice on the part of some one, for the light went out at 10.35 p. m., and it was impossible to relight it, as the currents no longer reached the lantern. Subsequently, however, when we arrived, about 2 o'clock a. m., the light was immediately restored 2oG EUROPEAN LIGHT-HOUSE SYSTEMS. without anything being done to the machines. The t^o eonducting-wires had probably been connected at some point before reaching the lantern, and the circuit being thus closed, the currents no longer reached the lamp. It is proper, however, to state that an open investigation on this subject gave no result. DccieasointiiB The list givcu above will show that accidents happen S!:ut&"^ ° ^" less and less frequently. Such a result might have been foreseen to a certain extent ; still it is well to prove it. As the keepers become better and better acquainted with the management of the apparatus of which they have charge, they become less surprised at incidents "which may occur, and can Immediately apply the proper remedies to a state of things which might become grave if allow€d to continue. Thus, one of the engineers, who has been in the light-houses since the end of 1863, has never had any accidents on his watch, while others serving during the same period have bad only too many. Substitution of In addition to the accidents mentioned above, it was new steam -„ ^ ,, . . _ ««rt engines. found ncccssary, at thebegmningof 1868, to substitute new , steam engines for those which had been in the service since ] 865, and likewise to replace some of the journal boxes of the magneto electric machines. euffidcDt^'°^° "'■ The old steam-engines were furnished by M. Roufiet : they were of five horse-power and certified for a pressure of six atmospheres. This was found insnflScient for the labor they had to perform. From experiments made on their greatest power, in March, 1866, the results, indeed, showed that they were nnable to develop continuously more than six horse-power; that, under these conditions, they gave one hundred revolutions per minute, and the mean pressure in the boiler was five and a half, without ever reaching five and three-quarters atmospheres. Now, to produce a light of normal intensitj', these engines are required to make one hundred revolutions, and the pressure was five and a quar- ter atmospheres. The engines were thus necessarily driven to the limit of their capacity, which could not be otherwise than very injurious, resulting in rapid waste. Already, in 1807, a part of the plates of the fire-box, and the pipes of the southern engine, had to be replaced at an expense of $385.25. Other repairs made on these engines to prevent them from heating cost $234.60. journui-boxes. The magneto-clectric machines are furnished with the self-lubricating journal-boxes of Avisse, but in the insula- ted parts the arbors had the same diameter beyond the jour- nal-boxes; the oil was drawn along by centrifugal force, and EUROPEAN LIGHT-HOUSE SYSTEMS. 237 the Ijearing was not uniformly lubricated. On this account tbo journals did not wear evenly, wbich was remedied by ^'100 .ing the arbor beyond the box. The worn journals had to be re-turncd, and the cushions of the journal-box re- newed. Quite a number of different apparatus are combined to Cauncs of iiie produce the electric hght ; if any are not in proper condi- the light, tiou they affect the light. If there is a lack of pressure in the boiler, the magneto- electric machines run slowly and the light scintillates mark- edly ; instead of a steady light, the eye perceives successive Hashes. The bearings of the central shaft of the machines must be well insulated, as otherwise the light loses in intensity. In the regulators the separation of the carbon points some- times varies; the light decreases until they return to a proper position. This disadvantage has been almost en- tirely obviated by recent modiflcations made by M. Serrin. By suitably regulating the tension of the spiral spring the variations of intensity of the light, as far as depends on the regulator, may be almost entirely prevented. Th€!.principal causes of the irregularity of light originate wantof homi>- iii a want of homogeneity of the carbon points and the dis- Smpoiuta^ '" ])lacement of the voltaic arc. The points, as we have already stated, are made of the carbon deposits of gas-retorts. This is sufficient to explain their want of homogeneity. They should be hard, well jHCSsed, and give a very dry sound when broken ; by their external appearance alone a just estimate of their quality can be formed. The breaking of the points when in use, although rare, will sometimes occur; this necessitates a change of lamp, and therefore au extinction of a few sec- onds ; it is not practicable, in fact, to wait until the carbon l)oints re-approach, as the luminous point would then be displaced. The want of homogeneity of the carbon also causes a displacement of the luminous point. In order to remedy this, M. Serrin contrived the mechanism for simul- taneously lowering and raising the points. The metallic or siliceous grains found in the substance of the carbons also affect the regularity of the light by acting on the voltaic arc. It is proper to state, however, that these oscillations of oacuiation of ,. , , , ^ ' ' . , the lisbt not ,irr- the light are much stronger and more apparent when seen ceptibie at adis- near at hand than when observed at a distance, and that they are no serious disa.'ivantage ; under no circumstances could they be confounded with those of eclipse or scintil- 238 EUROPEAN LlGHT-nOUSE SYSTEMS. latiug lights. These oscillations, moreover, have greatly diniinishecl, and electric lights may henceforth be consid- ered as quite steady. Luminons iu- Experiments made at the central light-house workshop show that the mean intensity of the light produced by a six- disk magneto-electric machine is two hundred burners. This intensity varies within certain limits, and it was found necessary to make a great number of experiments in order to estimate its mean. The luminous center, placed in an optical apparatus of one foot diameter, gives an intensity of about five thousand burners. Expenses of tiio More than four years having elapsed since the definitive. ^^^^ establishment of electric lights at La Hfeve, we are enabled to furnish an exact statement of the annual expenses. The following table shows the expenses, including sala- ries. The items are taken from the light-house journal and from the accounts of the conductor: LJ < _J Q. bJ > .kl X ■ 10 19 O (O £ up Ui o 3 bi O-i I w I- Z o u z X o < o I- < O -I U Q- -I u I o t3z: z o < EUROPEAN LIGHT-HOUSE SYSTEMS. 239 ■ e:3tnoot»c3i- o 0'2'='3 SCO m'^ t o So P40 o o P.CJ tmjl g CO ■<*< ..M" eiotmr-tontS'-' ©• S^ g a'a^ o c o sT; d e p h C5oe»t-aooi-i«oc»r-e*-JOMODvoc»r-r5^'^WMO» o) aj«oi'*waDaoo"!pm«M'eocJt-C4mot-t-t--a«o*(?*' ^l: Cc to if » 240 EUEOPEAIT LIGHT-HOUSE SYSTEMS. Expense for WHter lor Ibo cu- Expense of re- paiia to the ma- cbiuery. Eaiu-water is used for steam-engines, but in Tcry dry years it Las failed; it is then brought from Saiute-Adresse at an expense of about 40 cents per hundred gallons. This will explain the item of expense for water in 1860 and 1868. Before increasing the water-collecting surface, or con- structing another cistern, we wish to ascertain if the saving will justify the expense of construction. The old steam-engines consumed about thirty-four gal- lons of water per hour ; the new average about forty. The repairs to the machinery in 1867 and 1868 were con- siderable on account of the inefficiency of the steam-engines ; there is every reason to hope that this expense will be diminished with the new engines, which are much more powerful; we have consequently reduced^his item in the last column. Other expenses for supplies and repairs in- clude stowage of coal and cleaning of cisterns and of the water-collecting surfaces, washing of linen, and other items of little consequence. In order to obtain an exact state- ment of tlie annual expense incurred for the production of electric light, it would be necessary to add a certain amount to the figures mentioned iu the preceding table for deterio- ration of the apparatus. It is proper, however, to state that there is but little wear to most of the machinery. The regulators, which have been in use for six years, work as well as on the first day, the only wear being to the journal- item nfwarto boxes of the magneto-electric machines. Thus, the wear of I >» taken into »c- . ■ •■ , .1 1 ., , , . . lount. the steam-engines IS almost the only item to take into ac- count. These diminish quite rapidly in value. Table showing nuniber of hours of illumination and duration of the working of tlie engines. Engines working !^£a^ncto-eleoL^ic macbiucs working: - Total boura iUuminatiou.. ( ))-(linary lijibt need Donblc iigbt used 27. 4,888 M. 3,943 23 3,872 10 3,789 53 £2 Ij H. 4,518 4,152 28 4,087 51 3,989 04 98 47 18G8. JOT. 4, 5U9 4,203 47 4, 14a 47 4,129 01 13 4G 1869, IT. 4,496 4,188 00 4,127 16 4,0H7 22 39 54 Average year. Htb. 4,540 4, 200 4, 13.5 4,055 bO Tinip of li^bt- i!t<; anil extin- ixuisbinji'. Since May 1, 1807, the time of lighting is a quarter of an hour after sunset, and the lights are extinguished a quarter of an hour before sunrise ; while formerly they were lighted a quarter of an honr later, and put out a quarter of an hour earlier; so the total annual illumination is iusreascd 182J hours. This increase is taken into consideration in the last column of the i)recediiig table. It occurred in 1808, 1809, and a part of 1867. 1 S ! b/.i Ex. LIGHTHOUSES OF LA HEVL. E.LECTRIC LIGHTS. MAGNETO-ELECTRIC MACHINES. DETAILS. PLATE XLII o ,s Fig'.d Kjff.o. Kill-. 11. ^rrtion flu-o'tJ-VfS. Fie;. 7. Ko'.s. b'eclion ci/. Srrtion rJ.' Re'. 9. ,/ourt(nl aW^ONjtji vf'S'lmH. yig-.is. THE GRAPHIC q0.PH0T0-UTM.39 4*1 MRK PUCt.H.V. EUEOPEAN LIGHT-HOUSE SYSTEMS. _ 241 The steam-engines are fired up about an hour before the time of lighting- It takes nearly three-quarters of an hour to get up steam. The magneto-electric machines are started about ten min- utes before the hour of lighting, so that the currents may be well established. Double light is produced whenever the fog is so dense 3)o"iJie ijsnt that keepers at La Heve cannot see the beacon-lights on the north pier of Havre. Electric light was twice introduced at La Hfeve ; in 1863 Expon se of and 1865. At the first period the superstructure of thetemofifghting. southern light-house was finally modified by substituting for the glass lantern, mounted on a sub-base, a structure of stone-work with the lantern in the angle. / Temporary Jbuiidings were made for the engines, but these were demolished in 1865, at which time the lantern of the northern light-house was also altered, and the engines were placed in the house formerly used as a dwelling by the principal keeper, a small building being added in the rear. Three new dwellings for the keepers were constructed, as well as a cistern, and the water-collecting surface was enlarged. Two sums, one of $6,266.58, the other of $11,676.50, were Expense or expended for these works ; but these do not include the price of the steam-engines, magneto-electric machines, regu- lators, lanterns, cupolas, &c., which were sent from the cen- tral light-house depot. As the details of these expenses have no general interest, we shall not give them. In altering other light-houses the expenses, taking into account the difference of location, would probably be quite different. We shall confine ourselves to giving some details of prices „ " " . -^ Cost of special of special apparatus, as these prices are almost entirely m- apparatus, dependent of the situation of light-houses : The two steam-engines and accessories cost $2,493 42 That is to say, For two engines $2, 161 60 Two Foucault regulators 77 20 Two chimneys 41 56 Two bed-plates for fly-wheel .... 50 82 reed-pipes and mounting of the machinery 156 24 The feed-pump and water-tank cost 388 31 Shaft 378 76 Six belts, about 48 25 Six magneto-electric machines , 9, 339 86 S. Ex. 54 IG 242 EUROPEAN LIGHT-HOUSE SYSTEMS Namely, for — Four machines $9, 264 00 Columns and copper rods for con- ductors 56 56 Two counters 19 30 Four switches, with their accessories $77 07 Two condncting-cahles, about 271 2C Eight regulators, with their accessories 2, 242 OG Namelj^, for — Eight regulators 1, 544 00 Alteration of first regulator in 1865 119 66 Four cast-iron plates, with the springs 308 80 Expenses for experiments al- ^ lowed to M. Serrin* 270 20 Four optical apparatus 1, 389 CO Electric bells 262 50 ijompaiison of From December 25, 1863, when the southern light-house w^ctrio and oil ^^^ lighted for the first time by electricity, to August 31, 1865, the date when the aorthern light-house was still light- ed with oil, it was easy to compare the two modes of pro- ducing light. At that time the magneto-electric machines had but four disks ; the intensity of the luminous point was only 125 burners, and the intensity of the beam sent to the horizon not more than 3,500 burners wheu ordinary light •electric luminous was uscd. The intensity of the oil-lights was 630 burners. Jight. "" "' From information obtained in 1865, it seems that the elec- tric light always was seen before the otlier, even in clear weather.t The light of Barfleur was often seen at the same ^ Kaij're of eiec- time as the electric light of La H6ve. According to state- ip nients of commanders of vessels, this frequently occurs now, while with the oil-lights it was very rarely observed. The electric light appears to have had a considerably greater range. "^Ve shall refrain from giving too great emphasis to a note sent us by a captain of a steamer, who asserts that in one particular instance, under favorable circumstances, he did not lose sight of the electric light until at a distance of forty miles from Havre, after having seen the light of *Two hundred aud t\yelve dollars aud thiity cents was allowed in 1863, and $57.90 in 1865, to M. Serrin as compensation for experiments .and models. We mention these items in order to show the exact price of the regulators; besides, M. Serrin now tells his apparatus at§28U.50, iustead of |193. t Wo have more especially consulted the captains of steamers running toDnnkerque, Morlais, Bordeaux, and the portsof Spain, as they have more opportunities for observing the lights of La H6ve. LIGHTHOUSES OF LA HEVC. ELECTRIC LIGHTS. PLATE XLIV. SWITCHES. TOWtR SWITCH. R^.5. Rg.6. LIj m^"^ □ N i //zV L '\ A T 5|* o o cc I < * _,n7- -:mmmm:^mi;^mm:?'^mm^ Tf -j-=',^ Eg.]. scale:. THE GRAPHIC C0.PMOT0-LITH.39*«l P»RK PLACE.N.r. KUEOrEAN LIGIir-llOUSi: SYSTEMS. L'43 Barfleur for an hour and a half; but we sball call attention to tbe following statements, selected from a great number of others, which confirm the same results : The electric light has generally been visible at a greater stats .-. Uistance taan the other by : ws. 6 to 7 miles according to Captain Fautrel. 4 to 5 miles according to Captain Morisse. 2 — miles according to Captain Leraonnier. 3 — miles according to Captain Eebour. 4 to 6 miles according to captain of the Villedu Havre. 4 — miles according to Captain Duval. 4 to 5 miles according to the pilot, Lecoq. 5 to 6 miles according to the i»ilot, Guerrier. 4 — miles according to the pilot, Mazeras. Some captains corroborate these statements by declar- ing that, at great distances, when the lights were first seen, the electric light seemed a little higher than the other. At some distance there was a notable difference in their bril- liancy; the electric light appearing white and brilliant, the other red and smoky. The effect produced was well de- scribed by the picturesque comparison made by one of the pilots of Havre, (Pilot Savalle:) "There is as much differ- ence between the lights as between a candle and a gas- light." This effect was moreover distinctly visible from the north pier of Havre. The statements agreed still better in regard to the light Li-ht dmirs during foggy -weather. All the captains and pilots con-^""' suited by us declared that during fog there was a great difference in the range, and they all spoke highly of the services rendered them by the electric light ; they assured us emphatically that a large number of vessels had been able to enter the harbor without difiiculty, perceiving the southern light, while formerly they had been obliged to re- main outside, the lights not being visible. Even before per- ceiving the electric light, its presence w^as marked by the illumination of the atmosphere surrounding it, and its range was thus increased, especially in foggy weather. This is an important advantage of the electric light, and may be of great practical utility, as is shown by a letter from Captain Delbeke of the steamer La Flandrc, which we give below, as it well states the facts : " In the nights of the 26th and 27th of February, 1805, 1 , sti^i.ni.i.t .^ t was doubling Cape Antifer at 1 a. ni., three miles out, in eighteen fathoms of water, the point of the cape bearing S. E. i E. The weather was very foggy on shore, but an ex- perienced seaman could make out the point well enough to determine his position. 1 was then eleven miles and a half 244 EUROPEAN LIGHT-HOUSE SYSTEMS Diminisbed dif- ference in range tluriiij; ioii. from the Fecamp light, which was not visible for the fog, and twelve miles from LaHeve lights, toward which I could steer, as I saw, rot the lights themselves, but their reflec- tion. Approaching iu order to make the channel and enter the inner roadstead of Havre, (it was then 3 a. m.,) I clearly saw the electric light and could not see the ordinary light." The difference of range between electric and oil lights diminishes rapidly when the fog thickens. Inspector-Gen- eral Eeynaud, in a report dated May 20, 18G3, estimated the comparative range of a fixed light of the first order illumi- nated by oil or electricity as follows : TaWe of coiii- pamtive range. Eange in kilometers of a first-order fixed light. Eange of the uuit ©flight. /' Oil : inten- Electricity : sity, 630 Intensity, units. 3,500 units. KiJcmeter$. Kilometers. Kilometers. 0.1 0.160 0.177 0.5 0.93 1.06 1 2.08 2.40 2 4.80 5.77 3 8.45 10.2 4 12.9 15.9 5 18.7 23.4 It is seen that even in a slight fog the electric light is but little superior iu range in spite of the great difference of luminous intensity, but it gains in proportion to the clear- ness of the atmosp*here. This result is also shown by the following table, the result of observations made in 18G4 at the light-houses of Honfleur, Fatouville, and Ver:* Tabic of results of comparative observatiens. Places of obser- vation. Distances. Light ob- served. Proportion of visibility in 100 observa- tions. Proportional value of elec- tricity. lloufleur FatouviUe Miles. 9.32 13.30 23. 89 (Oil ( Eleiitricity. \ Oil j Electricity- (Oil \ Electricity. 1.045 1.020 1.24 Li^iit <;bstriict- The observations mede at Fatouville seem anomalous ; naah-uiis. ' *"' but this is easily explained, for one of the uprights of the * This table and the remarks following are talien from the report of M. Eeynaud, inspector-general, and dated March 31, 1800. EUROPEAN LIGHT-HOUSE SYSTEMS, 245 lantern of tbe northern light-house was placed in the direc- tion of the light of Honfleur, thus masking a considerable part of the light emanating from the apparatus. The range of the electric light is, moreover, diminished in foggy weather, on account of its inferior power of penetration. This arises from the different composition of the two lights, and is the more marked as the fog thickens. Experiments made at the central depot have shown, however, that if the electric light has an intensity two and a half times greater than a light of colza-oil, it will penetrate fog as well. As the intensity of the electric lights at La Heve, compared with an oil-light, far surpasses this proportion, -we may be assured that the electric lights will always be superior in range. Since 18G5 six-disk machines have been used. The iuteu- trsrof sixdisu sity has thus been considerably increased, and the relative '"'"' '""'"' range of the lights has always surpassed that shown in the preceding tables. In order to complete the comparison of the two modes of producing light, there are yet a few words to be said as to the expense of each. At La Heve, as we have already shown, the electric lights comparison of cost $3,215.29 annually, deterioration of machinery not in- ""^''^ eluded. For the same period the oil-lights before the altera- tion cost 82,823.88, distributed as follows : * Salaries $820 25 Fuel 77 20 Oil 1,800 58 Sundry supplies 84 53 Keeping apparatus in order 4G 32 The expense is thus greater by $380.41, or about one- seventh ; but this increase of cost is largely repaid by the increase of intensity of the lights. * The electric lights of La Heve have this economical ad-rt„^;,;,i""ij;"J "^ vantage, that, ■while two in number, the expenses are fur from being double what they would be for a single liKhr. A certain number of expenses are, in fact, common to the two, or approximately so, especially salaries, the extra com- liensation and allowance for fuel to the engineers, tlie coal for the engines, &c. This is not the case when oil is used, for then two lights will cost very nearly double what a single one would in the same circumstances. * See M. Eeynand's Memoire sur VEclairage des Cotes de France. 24G EUROPEAN LIGHT-HOUSE SYSTEMS. Estimated cosi of electric light. Basing our calculations on tbe experience of 1803 to 1SG5, \re estimate the cost of an electric light of 5,000-burner intensity as follows : Nature of expense. Price. Quantities. Cost. Salaries Allowance for fuel Bonus to engineers Water Coal, per ton of 2,240 pounds Coke, per ton of 2,240 pounds Carbon points Cotton-waste Lubricating-oil Illuminatiug-oil Grease - Hemp, ■\vhite-ltead, &c Towels, mops, &c Various supplies and repairs to ma- chinery $6 18 8 69 23 27 25 71,328.60 15,428 110,200 393. 70 308.56 440. 80 551 y- 88.16 Total. $834 72 77 20 57 90 43 2.T 434 25 156 33 32 43 77 20 67 55 10 04 9 65 11 58 156 52 1,968 60 (■i,s( of order oil-li; l;-|]l. iirst The average cost of a first-order oil-light of C30-burner in- '"■ tensity is $1,494.40,* viz : Three keepers, (two first and one second class) $477 08 Fuel 48 25 Oil 003 04 Sundry supplies 42 27 Keeping apparatus in order 23 10 The electric light would cost about $475 more than the other, and the expense would therefore be increased nearly one-third. A comparison of the cost of the unit of light for oil-consuming and electric lights may easily be made from the preceding, and the figures given by Inspector-General Eeyuaud arc verified. At La Heve, as tbe expense of the electric light amounts to $3,215.34 for 4,135 hours' illuml- . , .. p 4,055x5,000 -1-80x10,000, nation, and a mean intensity of -^ ? — ^^^ ! ' or 5,097 burners, taking into account the time double light ni's'T'i; was produced ; the unit of light sent to the horizon by each $3 215 34 light-housecosts, therefore, 2 x 5 097 x 4 lotj ~ $0.000070. The cost of the unit of light produced by the oil-con- * See JI. Eeyuaud's Mcinoire sur l'£clairage (ics Cotes de France. LIGHTHOUSES OP UA HEVC. CLCCTRIC LIGHTS. PLATE! XLV. ELECTRIC REGULATOR. SCALE. =ilfhat. THtOHAPHICCO PHOTO-LITH. 39*41 MBK PUCtK./. Hecapitulatlon, EUROPEAN LIGHT-HOUSE SYSTEMS. 24'. suming ligUt-lionses before their alteratiou amounts to $2,828.88 . J X (J30 X 3 900 ~ ^0-00057G,* which shows that the unit of light at the light-houses at La Hfeve costs about seven times less than that of oil-consuming lights. If, on the con- trary, we consider a single electric and a single oil-consum- ing light, the unit sent to the horizon would cost for the I'ormer 5 ooo^^^f 135 ' ^'^ $0.0000052, and for the latter, 030 \f 3 9U0 ' *"^ ^0.000608. The difference of cost is therefore somewhat more. Conclusion. — Since the first establishment of the electric light, six years ago, sufficient time has elapsed to give an exact idea of its value for coast illumination. Navigators acknowledge with pleasure the excellent serv- ice which the electriclights render them; the advantages navigators, of the system have been keenly appreciated, the range of the lights is sensibly increased, especially during somewhat foggy weather, thus allowing a great number of vessels to proceed on their course and enter the harbor at night, which they would not have been able to do with the oil-light. The light, which at first was not as steady as could be „, „ wished, acquired a remarkable steadiness, thanks to im- the light, p'rovements in the apparatus and the experience acquired by the keepers. Tlie fears which were entertained, a priori. on account of the delicacy of some of the apparatus, have not been justified in practice. Accidents have been rare, extinctions short and few; two only of the latter during the period of six years being of notable duration; one, of one hour, was tlie consequence of an accident to a steam-en- gine; the other, of four hours, seems to have been mali- ciously caused. Under these circumstances there seems but little reason to be troubled about possible accidents. Still there are some disadvantages inherent in the system Disadvantases. of electric illumination which necessarily limit its applica- tion. A considerable space is required for the steam-en- gines and the magneto-electric machinery, for storing coal, coke, oil, &c., and for collecting and preserving the water for the engines. llnally, the repairs of apparatus in use require special workmen, not usually found in the vicinity of light-houses. * These calculations suppose the electric light in operation 4,135 hours, and the oil-consuming lights 3,900 hours, because under these conditions the expenses were estimated. 24S EUEOPEAN LIGHT-HOUSE SYSTEMS. The keepers usually can attend only to current repairs ; the more important ones have to be done in workshops better appointed than those attached to light-houses. In case of an accident of some importance, the magneto-electric appa- ratus can only be repaired by the Alliance Company. The lamps, under the same circumstances, have to be sent to M. Serrin at Paris. It is true that, as there are several regulators at the light-houses, one of them may be spared, so that the rare accidents ^hich occur to these apparatus never cause but a few seconds' interruption of the light. Proper situn- We therefore think that in a great number of cases, espe- tiou tor electric 7 x- lights. cially in those of lighthouses in the sea, or distant from important centers of population, or not easily accessible, the substitution of electric light for that produced by the combustion of colza-oil would be disadvantageous, or even impossible. But as this substitution offers great advan- tages to navigation, it seems advisable to adopt it for light-houses favorably situated ; that is to say, where there is plenty of space, and they are sufficiently near to cities or easily accessible. The French light-house administration have already established a second one at Grisnez. England, after having first tried the electric light at Dungeness, is about to establish others at South Foreland and Lowestoft. The attention of other governments is also drawn to itbis matter, and it appears probable that the example of England and France will be followed. The change will cause a slight increase in the running expenses, but the difference is not so great as to cause hesi- tation when the increase of intensity and of range is con- sidered. CAPE GRIS-NEZ LIGHTHOUSE. ELECTRIC LIGHT. PLATE XLVI. PLAN AND SECTION, I i SHOWING ARRANGEMtNTS OF LANTERN AND LENSES FOR THE ELECTRIC AND OIL LIGHTS. /„.v,-/g.;„;. j.^- SCALE. THEGRAPH1C C0JHIOT0-LITH.39&41 PARK PUOt.H.Y. rur.oiTAN ] TGiiT-iious;.; evstems. 2-!'J I had no ouportuiiity of visiting any of the ligUt-sbips iv'otos mi iiic belonging to tbe Frencli seiTice. Tlieso iire teu in number, swpsavite.''' one of whicli carries a revolviug red liglit. Most of tbem are on the southwest coast of France. 1 have learned, how- ever, the following particulars in regard to the regulations, A light-ship's crew consists of a captain, mate, boatswain, crcw. (maitre Wequi^age,) and seamen. They are under tbe orders of the engineers or such superintendents as they may be as- signed tp. None can enter this service but regular sailors, ■who have had at least three years' service in the navy, and who know how to read and write. Appointments are made by the prefect on nomination of Appouitmeuts. the engineer-in-chief. The salaries are fixed by the Ministry of Public Works, g^j^^,; ,^ and are subject to a deduction of 3 per cent., -which is ap- plied to the marine-hospital fund. The captain is responsible for the service of the light, and Dutips of ild has, on board ship, all the rights of captain of the merchant- "^p""""- marine. He keeps the log and all the correspondence. In his absence his place is taken by the mate. The boatswain sees that the captain's orders are executed, of tho ijoat- and he is particularly charged with tbe order and cleanii- ^'^'""' ness of tbe vessel. He is not required to assist in the man- uiil labor of cleaning tho vessel, but he directs the details of the work and keeps watch like tbe seamen only in excep- tional cases to be judged of by the engineers. In case of ab- sence his place is supplied by a sailor selected by the cap- tain. Tbe captain and mate have alternately fifteen days of services of cap- service and fifteen days ashore; the sailors pass alternately of crew.''' a month afloat and fifteen days ashore. These leaves arc, on some vessels, reduced one-half during the bad season. While ashore the ofScers and sailors are at tbe disposal u n rt or onii-rs of tbe engineer -in-chief, and cannot quit their places of resi- asho'i?"'^'^' dence without authority. They are obliged to obey any orders that may be given tbem, either to return aboard, to attend to embarkations, or to any of tbe lights or beacons of the department. The captain is responsible for tbe provisions, and keeps the account of them. He may detail a seaman for cook, or decide that all shall take tbeir turn. THE INTERNATIONAL EXHIBITION AT VIENNA, 1873. From Paris I proceeded to Vienna bj' way of Ulm, Augs- burg, and Munich. I intended to have gone via Venice and 250 EUJROPEAN LIGHT-HOUSE SYSTEMS. Trieste, but when I arrived at the foot of the Saiut Gothard Pass, exaggerated accounts of the cholera prevailing at the former place,- deterred me from taking that route. On arriving at Vienna and presenting myself at the lega- tion of the United States, I was received in the most cordial manner by the Hon. Mr. Jay, the American Minister, who proffered every assistance in his power. BniidiDgs. The exhibition buildings were on a grand scale, and it was said the Austrian government had already expended on this exhibition more than 20,000,000 gulden, or more than $10,000,000. Most of the departments, particularly the department of machinery, were well filled ; and the same may be said of the spaces allotted to the different countries, with a few exceptions, which include, I regret to say, that assigned to the United States. From some cause, i)robably our re- moteness from Vienna, the American exhibition was ex- tremely meager. Articles on ex- J ^^s disappolntcd at the small number of articles of hibition pertain- ■*- ^ iiiK to ii?ht- interest pertaining to light-houses and other aids to naviga- gatiM. tion. iind those which were exhibited were mainly sent by tlie French and Austrian governments and the lens-makers of Paris. Display by tiie The " Department of Public Works"' of France had a iiHoTof Public fine display of models and drawings of light-houses in con- nection with an extensive exhibition of views and models of other works of the Corps cles Fonts et Chaussecs. I did not observe anything particularly novel in the construction of the light-houses, but they all showed evidences of the good taste in architecture which characterize all works of the French engineers. Lisiit-boiises The following is a list of the light-houses represented: rciji-csented. '^ ° '■ Pliare de la Palmyre, a wrought-iroa range or leading light-house on a screw-pile foundation. Pliare de Royan, a masonry range or leading light built in alternate courses of stone and brick, the upper portion of the tower being of a peculiar shape, for the purpose, most likely, of serving as a day-mark. Phare des Boches-Douvres, a wrought (plate) iron coast- light, very much like the Pliare de la Nouvclle Caledonie, shown in M. Keynaud's L^£clairage dcs Cotes de France. Phare du Four, a '' rock" light-house. Pliare d^Ar-men, a coast-light of stone masonry — a rock- statioc. Kui.niarino The Corps des Fonts et Cliaussees had also models of sub- marine foundations for harbor light houses built ou shoals SUBMARINE CONCRETE FOUNDATION FOR A HARBOR LIGHTHOUSE. plaTEXLVII THE GRAPHIC CO. PHOTO-UTH. 39*41 PARK PLACE, »r. EUROPEAN LIGHT-HOUSE SYSTEMS. 251 or bars, very much like tliose ■which 'I had designed for our lights in Long Island Sound, Delaware Bay, Chesapeake Bay. and other localities jN'here light-houses are subject to injury from ice. Two methods were represented, in one of which the iron tube or shell is left in place after it is filled with concrete ; the other showed a cylindrical foundation of concrete made by means of a movable mould, which ia turned around an axis, as represented by Plate XLVII. . Several novelties were shown by the lens- manufacturers of Paris. M. Lepaute exhibited a third-order revolving lens, a Lens oxhiiiited duplicate of the one which I have described as exhibited to ^ ' '-^'^^^^"' me at his manufactory at Paris, in which one-half showed a fixed light and the other half was divided into eight con- secutive flash-panels. This would be a striking characteristic in waters where there are already many lights, and where iu placing a new one it becomes necessary to distinguish it, particularly if theflash panels were covered with red screens, which would tend to equalize the range of the fixed light and the flashes. This leus was furnished with a mechanical or pump lamp, with a three-wick burner of the kind recently adopted by the French, which is adapted to the use of either colza or mineral oil, though the latter is designed to be used iu it. The clock- work or)erating the pumps was speciallv do- cioou-wmi,- for ^ CT i 1 r .- revolving; Jeiirt. signed for revolving lights by M. Lepaute, and was remark- able for the small space required for it, viz, not more than six inches in diameter, a great imiirovement for small orders of lights. Sautter, Lemounier & Co. exhibited photographs of the flame from the Parquhar burner, (the patent-right of which is owned by this firm,) and the following lenticular ap- paratus : 1st. A range light ov feu do direction.^ showing alternately , r.iniKo-iiaiit i.-.- red and green. This apparatus was composed of a dioptric nier &' c.>., 'i'.' and catadioptric lens for fixed light, embraciug 150°, a cata- glecia." dioptric reflector ])laced iu the dead angle, and two groups of vertical prisms arranged in front of the apparatus for fixed light, in the space on either side of the axis aud out- side the angle which it is required to light. These elements are so calculated that they concentrate the light from the fixed-light lens aud distribute it as uniformly as possible tlironghout an angle of 45°. Between the fixed-light ap- liaratus and the vertical prisms there is a circular screen, coini)osed of three plates of glass, each embracing 75°. 2ri2 EUROPEAN LIQHT-HOUSE SYSTEMS. r.od and greciiTlie two oiiter plates are red, the middle oue green. TIio frame-work supporting this screen receives au intermittent oscillating movement, so that the light changes rapidly from one color to the other, preserving a constant color for a determinate time. The screen passes through an arc of 75° in four seconds ; then it is at rest for sixteen seconds, and then repeats the motipn in au opposite direction, and again becomes motion- less. This movement brings successively before each part of the apparatus first the red and then the green panes, so as to produce the characteristic required. Picr-iisht by 2d. A inei-Wght, (f anal de jettee.) This light presents a Eaii.eiirui. very Characteristic appearance, and if placed near a town it would never be confounded with ordinary street and house lights. The apparatus is composed of an ordinary fourth-order lens for fixed light, around which revolves a drum composed of vertical plano-cylindric lenses, each of which receives a luminous beam IS^- wide, and concentrates it within 0°, thus diminishing the divergence and augment- indn""flasiLr° ^^S tho intensity in proportion of 1 to 3. This drum reaches to just above the central lens of the apparatus, so that all the upper prisms preserve the appearance of a fixed light of sufficient intensity to be seen at least twelve miles. On account of the interposition and regular revolution of the movable lenses, the light presents a series of dilatations like equidistant pulsations, which gives it a very character- istic appearance. Experiments made to determine the best interval between two pulsations showed that it ought not to be less than a second and a half, for if the flashes were nearer together they might be confounded with the natural scintillation which lights near water have, under certain atmospheric conditions. The lens exhibited was of the fourth order, but fifth and sixth order lenses of the same kind can be easily con- structed. ^■l?s'^^fu^''eleotri3 ^^' "^ ^^^^ ^^^ Scintillating lens for electric light, for the ''»'''• following description of which I am indebted to the courtesy of Messrs. Sautter, Lemonnier & Co.: " In most of the apparatus for electric light hitherto con- structed, the optical part is composed of a cylindrical lens for fixed light 30 centimeters in interior diameter, before which, in flashing lenses, prisms of vertical elements are made to pass. We prefer to increase the diameter of the lens, and that for several reasons. , J!l'^'to^^i'.1lu"- " 1st. In case there should be used a more intense clec- iiioftiu., i.us. ^pjg ]\g\it than the oue produced by the machines now em- ployed, (such a one, foiiiist;iiice, as is giveu by the new ma- EUROPEAN LIGIIT-IIOUSE SYSTEMS. ^iio cLines of Gramme,) it would become necessary for the pres- ervation of the glass that it should be farther removed from the luminous focus. " 2d. Because a hirger apparatus is easier to keep in order. " 3d. Because the larger the apparatus the less the inevi- table variations in the ])osition of the luminous point will afl'ect the direction of the rays emerging from the lens. " The apparatus (shown in Plate XLVIII) is composed of l e u s -appara- a cylindrical lens for fixed light, 75 centimeters in interior diameter, with upper and lower catadioptric zones. The metal supports of the central part are diagonal, so that in no direction does the frame completely obstruct the light. "A polygonal drum, composed of twenty-four vertical plano- cylindric lenses, envelops the apparatus from the top down to just below the central lens, and is made to revolve regularly, by means of clock-work placed in the pedes- tal of the apparatus. Each lens receives a luminous beam 15° wide, and concentrates it within 5°. In the apparatus which was exhibited, the drum makes a complete revolution in 120 seconds, so that the flashes succeed each other every live seconds. The duration of the flash is half the interval between the flashes, and the fixed light of less intensity is constantly visible. The intensity of the former is about eight times as great as the latter. The proportions remain the same whatever may be the intervals between the flashes ; if the interval is increased the absolute duration of the flash is increased in the same proportion. " In oil-lights a remedy is sought for the short duration of the flashes by iucreasing the diameter of the flame. This disadvantage will not exist in electric lights arranged as we have described, the divergence being caused not by the di- ameter of the luminous focus, but by the form of the lens, and existing only in the horizontal plane— that is, without loss of light. " The electric lamp constructed by M. Serrin is placed on a revolving plate, eccentric with regard to the platform of the apparatus. This plate can receive two lamps back to back. It has two rails on which the lamps slide, and which are prolonged on a platform attached to that of the appa- ratus, and jutting out behind. The plate can be held by a spring-catch in two positions diametrically opposite. In the iirst of these positions, one of the lamps is at the focus of the apparatus, and the other in position to be attended to and its carbons changed. In the second position the rever.se takes place. The current passes and the lamp is lighted of itself when placed in position. 254 EUKOPEAN LIOIIT-HOUSE SYSTEMS. " This apparatus should be placed in a lantern havinfj flat steel diagonal sash-bars with an inclination corresiwnd- iug to that of the lens-frame." Iron liRht- Besidcs the optical apparatus exhibited by Messrs. Saut- Louse toTver. ^^^^ Lemouuier & Co., they displayed an iron light-house tower of peculiar construction and excellent workmanship. Translation of The followiog description of it, is translated frpm the description. , ,, Anualcs IndustHelles " of September 28, 1873 : ******* "The tower shown in elevation, (Fig. 1, Plate XLTX,) rests on a foundation formed of eight radiating iron ribs bound together by masonry, and rising about 5 meters above the terrace on which the structure rests. It is composed of a sheet-iron cylinder 12'".50 high, with a winding stairway inside, and strengthened by eight buttresses or ribs of iron. These buttresses take the form of brackets above and sup- port a cast-iron gallery which extends around the lantern. rorm.ition of " The Cylinder or central tower is formed of five sheet- '*"*'"• iron sections O^.OOG thick, each 2"'.50 high and 1°.80 in diameter. The interior of each is occupied by twelve steps of corrugated sheet-iron, the upper part of which forms a landing ; riveted corner-pieces hold them against the outer envelope, and a cylinder O^.iO in diameter supports them at the center. The sections fit into each other and are held together by rivets. Each weighs 1,500 kilograms. The vertical ribs are eacli formed of four pieces, one above the other, and they are bound together by three bands or rigid horizontal crowns placed at equal vertical distances. Crane. " The tower is mounted without exterior scaffolding by means of a gallows-crane supported on the last section jjut in place. It is shown in detail in Tig. 4. It is composed of an upright formed of two T-irons connected by tie-pieces and held at the lower end by a cast-iron pivot. The arm, for.Tiedoftwo flat pieces of iron connected by braces, carries two pulley-blocks and a hook intended to receive a tackle. The fall of this tackle is conducted from the pulley-blocks to the upright axis of the crane. It descends vertically in this axis, traverses the pivot, and a final pulley carries it to a windlass used for hoisting. riaciugtiiofirst " It was first necessary to place the first section on the foundation, an operation which was somewhat difficult, as the space for maneuvering was small. In order to efix}ct. it the crane was used, it being set up on the foundation and supported by guys. Eaised to the required height the solu- tion was brought into place by rotating the crane. This first operation wonld in general practice ofi'er no dilBcnlr.v, Itf^CllOU. EUROPEAN LIGHT-HOUSE SYSTEMS. 255 Tools. and could be done, according to circumstances, by any other means than that we have just described. But -when this section is once placed and solidly bolted to the foundation, the mounting should continue and be finished without the aid of any scaffolding or support taken outside of the tower itself. The mounting comprises, first, the placing of the Mounting. iron tube or the superposition of the sections of which it is composed, and which, as we have said, weigh about 1,500 kilograms each ; second, the ijlacing of the ribs, rings, brackets, galleries forming the frame-work, and the crown- ing of the structure with the lantern and apparatus. These latter pieces are relatively light, and can be raised to place "by means of falls attached to the upper part of the central tube, if the tower is not verj- high the most simple mode of mounting consists in first superposing all the sections, and then fitting the ribs and other pieces of the frame- work. When the tower is high it is prudent to can-y on at the same time the monnting of the tube and the placing of the ribs which strengthen it. "The tools employed are: "The crane above described, with an extra pulley and a windlass on the ground ; "A movable scaffold shown in Fig. 5; " Falls and cordage. " The successive operations are : "Eaising and putting in place the sections; "Bolting the sections together; "Eaising the crane after the placing of each section; "Lowering and raising the movable scaflbld for each section placed; that is to say, once before to raise the crane and i)ut it iu position, and once after to bolt the sec- tions together. • " The placing of the ribs, the rings, the upper gallery, and finally the lantern and illuminating-apparatus. " We have already described the crane and the way it is used to mount the first section. It is used similarly to mount the other sections, with this difference: that instead of placing it on the foundation, it is set, by means of cast- iron supports, on the last section placed. The bolting of the sections is done by means of the movable scaffold at- tached to pulleys suspended from the summit of the tube already mounted. The raising of the crane is shown iu Fig. 3, and is effected as follows : Two ialls are attached to the top of the section and each side of the foot of the crane, to hooks made for the purpose. The support c is unbolted, it is remounted and fixed to the top of the last section; at Operations, llaisiiiK craiK-. t h o 256 EUEOPEAN LIGIIT-nOUSE SYSTEMS. tbe bottom of the same section is placed the guide-support (7, which obliges the crane to ascend vertically. Finally, when it is raised as far as desired, the su^jport of the pivot /is bolted and the operation terminated. Scaffold. "The lowering and raising of the scaffold is done by hand, by men placed on the scaffold itself. The raising of the ribs and all the other parts of the central tube is done by hand with pulleys. The putting of them in place and the bolting or riveting of them is done by means of the movable scaffold. For all these operations six men are quite sufScient, and no greater number was employed at Vienna during the entire mounting. ''The ease and economy of mounting, is not the sole advantage of the system of constructing iron towers adopted by Messrs. Sautter, Lemonnier & Co., and applied by them to towers of all dimensions. Bnt in this article we have only wished to call attention to the interesting fact that an edifice of great height can be rapidly, surely, and inexpen- sively set up by a very few men, and without the aid of scaffolding." LoTiF.arpnratus Barbicr & Fcnestrc had on exhibition the following lens- Lior & reuestre. apparatus : A third-order apparatus iiashingSC" — 30", with hydraulic Funcb lamps. A fourth- order flashing apparatus, with Boty lamps and a new mechanical arrangement. A fifth-order apparatus F. V. F., 2'— 2', ISQo. A sixth-order range-light, with two prisms so arranged as to permit of an accurate adjustment of the direction in which the light is thrown. They had also a Doty four-wick lamp with a clock-work pump. Modpisofswoa- The Swedish exhibition contained two models of iron ° - 0USC8. ]jgljj-.ljQygggpggg,^]j^JQgQyj.gQIj |-Jjg Ji'jQpJQr^ j,ggfg_ luStCad, however, of the socket-joints which we have used, the col- umns are connected together by means of.flanges and bolts. Between the flanges are placed stout wrought-iron disks, having projections to which are fastened the horizontal, radial, and peripheral braces. The lugs or ears to which the tie-rods were made fast were on the upper or lower side of the flanges, as the strain was to be downward or upward; in other words, the flanges took upon themselves the strains upon those lugs. These arrangements, which are shown in Figs. 2S and 20, are, I think, improvements in the modes commonly in use for similar structures. EUROPEAN LiaHT-HOUSE SYSTEMS. ,257 In Fig. 28, A A are two hollow cast-iron columns fas- tened together by bolts through flanges; a, ear to which the tie-rods b are secured; e, large link through which the small link flanges. d is passed; e, wrought-iron plate between Fig. 28. Details of Swedish light-house. Elevation. In Fig. 29, A is the column ; a a, ears for the attachment of the tie-rods ; ///, radial and peripheral struts of rolled iron fastened to wrought-iron plate e e, which is held be- tween the columns as shown in the elevation. Fig. 28. Fig. 29. Details of Swedish light-house. Section. stria S. Ex. 54- In the Austrian part of the exhibition was a " JJTebelhorn," ^ Austrian fog- -17 258 i;UEOPEAN LIGHT-HOUSK SYSTEMS. or fog-trumpet operated by steam ; of this, however, I coukl learn but little except what was contained in the acconut given in the official catalogue, of which the following is a translation : deIcri"tio*'™ "* " '^^^^ apparatus has been constructed at Trieste, after the designs of G. Amadi, engineer, " In foggy weather it is impossible to bring to the notice of mariners the threatening or desired proximity of land, by means of light-houses or light-signals in general. It therefore becomes necessary to carry sound far over the sea by means of vigorous acoustic apparatus, and thus to advise the mariner that he is approaching the coast. Several kinds of apparatus constructed for experimental purposes, and to which were applied the shrill notes of the whistle, could' not, just on account of the high pitch of the sound, answer the purpose, and the sounds were lost at a short distance from the coast. " In this new fog-signal there are deep notes, formed like those of an organ, by means of movable metallic reeds vi- brated by steam, and they are sent out in a given direction through a trumpet or augmentor of sound. This signal has been heard, according to the experiments made, as far as sixteen nautical miles. "In this apparatus, (a similar one is in operation at Trieste,) the notes are formed automatically by means of a steam-engine at given intervals, and the apparatus is turned at the same time on a vertical axis to reach all points of the horizon in a uniform manner." After my return to Paris, I wrote to the Hon. Mr. Jay, and requested him to be good enough to procure, if the Austrian government would be pleased to communicate the information, drawings and descriptions of this fog-trumpet, of a reflector which I had also observed in the Austrian part of the exhibition, and of the Austrian buoys. A few Urawiups sent *^ ty tiio Austrian davs ago I had the great pleasure of receiving from Mr. government. -r,>nr>i-r^ Jay, through the State Department, a package containing the desired drawings and descriptions ; also copies of cor- respondence between himself and the Austrian Minister of Foreign Afi'airs, in regard to my request, and of which the following are copies and translations : Letter of Hon. "THE AMEEIOAN LEGATION AT YiENNA, ^'' ^''^'' " February 23, 1 874. " Dear Major Elliot : In acknowledging your note of January 30, 1 am happy to be able to send you, as I do by this post, through the State Department, a roll which I re- ceived this morning from the Foreign Office. EUKOPEAN LIGHT-H0US1-: SYSTEMS, 250 " I annex a translation of the note of the Count Andriissy and a copy of my reply. " You -^vill see that the Ministry of Commerce is prepared to appreciate the drawings and plans which you had pro- posed to send, and which 5'onr note leads me to expect presently. Should there be any others that you think would be new and interesting to this government and which there is no objection to communicating, I hope you will send them. Ifot only the Foreign OfQce, but all the Ministers here, are so obliging in furnishing promptly and gracefully all infor- mation asked for, and extending facilities to our officers, that I am always glad of an opportunity of reciprocating their courtesies. y "I am, dear sir, faithfully yours, "JOHN JAY. " Major Geoege H. Elliot, " Light-House Board, Washington J' [Translation.] " The undersigned. Minister of the Imperial House and Translation of for Foreign Affairs, is only to-day enabled to place at the dis- tJian^ Minister 'lo posal of Mr. John Jay, Envoy Extraordinary and Minister ^°°■^'''■■^"^• Plenipotentiary of the United States of America, in compli- ance with his esteemed notes of 20th August and 13th De- cember last, the drawings and description transmitted by the Imperial and Eoyal Ministry of Commerce. "a. Of the fog-horn exhibited at Vienna in the year 1S73 ; " b. Of the parabolic reflector of Professor Osnaghi ex- hibited on the same occasion ; " 0. Of the buoys in use upon the Austrian sea-coast. " The Minister of Commerce, to whom the compliance with the wish of the Envoy has afforded especial pleasure, has at the same time requested the undersigned to plead with the Envoy, as excuse for the delay in the transmission of these drawings, the circumstance that the authorities at Trieste who exhibited at the Vienna exhibition the objects in ques- tion were able but recently to obtain a description of the fog-horn. "While the undersigned has the honor to communicate to the Envoy the above fact, he begs further to state that the Minister of Commerce would gratefully acknowledge the courtesy should Major Elliot, in return for this collection, ]ilace the Imperial and Eoyal Government in possession of the promised, drawings of those safety-signals which in the United States are in use and have attained such high per- fection. 2i)0 EUROPEAN LIGHT-HOUSE SYSTEMS. " The undersigued avails himself of this occasion to renew- to the Envoy the assurance of his distinguished considera- tion. " Vienna, February 22, 1874. " For the Minister for Foreign Affairs, " OEOZY." M^jlyto A™: "The undersigned. Envoy Extraordinary and Minister Irian MiniBter. Plenipotentiary of the United States of America, has the honor to acknowledge the receipt this morning of the note of his Excellency the.Count Andr4ssy, Minister of the Impe- rial House and for Foreign Affairs, dated February 22, accom- panied by a sealed roll of drawings and descriptions trans- mitted by the Imperial and Eoyal Minister of Commerce — " a. Of the fog-horn exhibited at Vienna in the year 1873 ; " h. Of the parabolic reflector of Professor Osnaghi, ex- hibited on the same occasion ; " c. Of the bnoys in use upon the Austrian sea-coast ; " These drawings are to-day transmitted to the Depart- ment of State for Major Elliot, of the governmental Light- House Board at Washington, and will probably reach that office in time to be used in the preparation of his forthcom- ing report. " The undersigned begs to add in reference to His Excel- lency's remark, that the Imperial and Eoyal Minister of Commerce would gladly acknowledge the courtesy should Major Elliot, in return for this collection, place the Imperial and Eoyal Government in possession of the promised draw- ings of the fog-signals which in the United States are in use, and which, His Excellency is pleased to say, have attained such high perfection, that the undersigned has received a note from Major EUiot, dated the 30th of January, saying that in a few days a parcel would be dispatched to this lega- tion for the Imperial and Eoyal Ministry. >' The undersigned has the honor to present his thanks to HisExcellency, and, through His Excellency's obliging inter- vention, to the Imperial and Eoyal Minister of Commerce, for the valuable information now afforded upon a subject so interesting and important to the commerce of the United States, and for their courtesy in furnishing the same to this legation immediately upon its transmission by the authori- ties at Trieste. " The undersigned embraces this opportunity to renew to His Excellency the assurance of his distinguished considera- tion. "JOHN JAY. "Febuuaey 23, 1874. " His Excellency the Count ANDRjtssr." K X J u CO z h U D. s D K h u. < H !/) D < w X h EUEOPEAN LIGHT-HOUSE SYSTEMS. 261 Plate L, whicli is copied from the photograpli sent me by Mr. Jay, represents the fog-trumpet as 1 saw it at the exhibition at Vienna, and the following is a translation from the Italian of the description which accompanied it : " Since the introduction of acoustic signals, used in Amadis f o - America as well as in Europe to mark dangerous points on ^"""^* ' the coast in foggy weather, it has become desirable to have a more perfect instrument, an apparatus that can be used not only at light-stations in foggy weather and snow-storms, but also on board of ships, especially on steamers, not only as an alarm but as a signal for correspondence. " This object has been fully accomplished by the inven- tion of Giovanni Amadi, of the Technical Institute of Trieste. His trumpet yas exhibited at the universal exposition at Vienna, and was awarded a medal of merit. " This apparatus, which consists of a trumpet, formerly Description. operated by compressed air, but now directly by steam, is provided with an automatic distributing steam-valve, and ■with a special valve with finger-board (operating keys) so as to produce sounds at will. " The instrument has a most extraordinary power in i)ro- Power. portion to its dimensions and to the pressure of steam re- quired to produce the vibrations ; it can be put up either directly over the boiler or separately, and connected with it by a pipe, and it can be turned to any part of the horizon. " In addition to its use as a fog-signal on shore, it may be applied on board of steamers of whatever steam-power, and is especially advantageous on board of men-of-war. " By means of the finger-board, one is enabled to give long uso of fins, Voik. ]jad observed them, and spoke particularly of the great value of the revolving light at Fire Island, on the outer coast of Long Island, which is the first light ordinarily made by oversea steamerss approaching New York, but he is of the opinion that our aids for using Gedney's Channel into the EUROPEAN LIGHT-HOUSE SYSTEMS. 267 harbor, (which he says cannot now be used in the night- time, particularly in thick weather) are insufficient, and suggests that a light-ship should be moored where the fair- way buoy is, inside the bar ; that the fair-way buoy outside the bar should be replaced by a bell-buoy, and that the present light ship should be moored north-northwest from her present position and into line with the bell-buoy and the light-ship inside the bar. Captain Moodie mentioned the difficulties of entering the Buoyago of harbor of JSTew York in the winter-time when the iron buoys Tort. iu Dover experiments, 42 ou Newarp light-ship, 113 — Holmes, in Dover experiments, 43, 4f> at Souter Point, 125 — — Seven Stones light-ship, 14."> Ti'.skar Eoek, view of, 17 gas-light on, 266 Tyiidall, Professor, his opinion of gas- lights, 10-1, 163,173 sash-bars obscuring light, 152 report on fog-signal expi^riments, 25 UNIFORMS worn iu English light-honse service, 98, 109, 114, 139 Unit of light, photometric, English, 81 French, 187, 196 comparative values of Fronili and English, 187 cost of, in France and the United States, 269 cost of, Tvhen produced by elec- tricity and oil, 246 Utilization of landwiird light, 122, 271 T7"ALVES, lamp, made by Lepante, 206 I Ventilation of English lauterus, 107,143, I 154, 155 Vestal, description of, 131 Vienna Exposition, 249 TTTALES, PPJNCE OF, 149 Walls at Longstone, 130 Spnrn Point, 117 Watch of keepers, 71, 126. Watch-room at Souter Point, 122 Phare de rHOpital, 217 English, size of, 71 painted by keepers, 108 Water at South Foreland, 72 — supplied at La Heve, 233 Washing, allowance for, to Scottish keep- ers, 177 Webb, Captain, 18, 132, 144 Weller, Captain, 99, 131 Westminster clock-tower, lights ou, 75 Wheels of revolving machinery at Holy- head, 150 Whistles, best form of bell, 25 — on steamers as fog-signals, Ki — qualities as fog-signals, 23, 62 Whitby light, description of, 113 Wicks, care taken in jiurchase of, 189 — concentric, separation iu burners, 20'.' — effect of different oils on, 84 — for Frencli mineral-oil lamps, 201 — in six-wick lamp, 151 — tested as to effect of combust imi on. !!0 — used in Douglass burners, r-1 Wigham, Mr., description of liis j;iis-lig!ils, 161-167 — — his apparatus at Haisborough, 104 burner, used at Westminster cloc';- tower, 75 • gas-gun for fog-signal, 174 offer to erect apparatus in United Sttites, 171 (■>C ■;l INDEX. y\r. Wigliam, Ills plau for illuminotiiig boa- ions with gas, 17 AViiid, its effects on sound, 4G, 51, 61 Wind-guard at North Stack, 155 Wind-vanes at English stations, lOS Window-frames at English stations, 143 — at the Wolf, 143 — of low light-room, Souter Point, 122 Wolf Eock light-house, plans of, 19 description cf, 140 Wood, used for sound-reflfctors, 17'.i Wrecks, English system of buoying, U3 YAKMOUTII, buoy-depot at. 101 Young's paraffine used by French govern nient, 197 ZONE of masiuiuni intensity in sis-wick burners, 78