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 |f The Pennsylvania State College 
 
 Bulletin 
 
 of the 
 
 Department of 
 Chemistry 
 
 Calcium Carbide 
 
 and 
 
 Acetylene 
 
 By 
 
 GEORGE GILBERT POND, Ph. D. 
 
 Professor of Chemistry 
 
 1909 
 
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 NO. 23233 
 
THE PENNSYLVANIA STATE COLLEGE 
 
 BULLETIN 
 
 OF THE 
 
 DEPARTMENT OF CHEMISTRY 
 
 TP 767.P79™*"'**'^"*'*i' 
 
 Calcium carbid* and acetylene, 
 
 3 1924 004 961 094 « 
 
 CALCIUM CARBIDE 
 
 AND 
 
 ACETYLENE 
 
 Revised Edition 
 
 BY 
 
 GEORGE GILBERT POND, PH. D 
 
 PROFESSOR OF CHEMISTRY 
 
 1909 
 
Cornell University 
 Library 
 
 The original of tiiis book is in 
 tine Cornell University Library. 
 
 There are no known copyright restrictions in 
 the United States on the use of the text. 
 
 http://www.archive.org/details/cu31924004961094 
 
TABLE OF CONTENTS 
 
 PAGE. 
 
 Introduction 7 
 
 Discovery of Carbide of Calcium and Acetylene 13 
 
 Literature 15 
 
 The Carbides in General 16 
 
 Calcium Carbide in Particular 16 
 
 The Manufacture of Carbide 19 
 
 What Is a Gas ? 20 
 
 General Properties of Acetylene 23 
 
 Specific Properties of Acetylene: 28 
 
 Acetylene an Endotherraic Compound 28 
 
 Physiological Effect of Acetylene 29 
 
 ExplosibiHty of Acetylene 30 
 
 Combustion and Illuminating Power 31 
 
 Danger 34 
 
 Impurities of Acetylene 37 
 
 Cool Generation 41 
 
 Types of Generators 43 
 
 Supply of Carbide 48 
 
 Transportation and Storage of Carbide 49-56 
 
 Transportation of Carbide on Passenger Vessels 50 
 
 Insurance Regulations 51 
 
 Rules for Installation and use of Acetylene Generators 51 
 
 Permit for Use of Acetylene 67 
 
 Permit for Storage of Carbide 68 
 
 Permitted Machines 69 
 
 Acetylene Illumination a Measure of Safety 73 
 
 Resolution Favorable to Acetylene Passed by Insurance 
 
 Engineers 75 
 
 Cost of Acetylene Illumination 76 
 
 Burners 7^ 
 
 Freezing 79 
 
 Disposition of Residuum 80 
 
 3 
 
PAGE. 
 
 Purification 8i 
 
 Municipal Lighting 82 
 
 Acetylene Table Lamps 84 
 
 Other Portable Devices 84 
 
 Cooking by Acetylene 85^ 
 
 Dissolved Acetylene 85 
 
 Acetylene for Lighthouses, Buoys and Signals 88 
 
 Railroad Uses of Acetylene 89 
 
 The Oxy-Acetylene Blowpipe , 90 
 
 Welding with Acetylene. , 91 
 
 Acetylene for Motive Power 92 
 
 Acetylene Light and Plant Growth 93 
 
 Dry Process Acetylene 94 
 
 Calcium Cyanamid 95 
 
 Universality of Acetylene 97 
 
 Bibliography 100 
 
 Index to Periodical Literature loi 
 
 The Acetylene Press 119 
 
PRFFACE. 
 
 The original Bulletin, of which this is a second and revised 
 edition, was issued in 1900, when the industry was quite in its 
 infancy, by the Pennsylvania Department of Agriculture, and 
 known as Bulletin No. 57, entitled "The Application of Acetylene 
 to Country Homes." In the years since it was published the 
 acetylene industry has made such tremendous strides in all civilized 
 countries of the globe that the former publication has become 
 entirely antiquated. 
 
 So many and such urgent requests have come to the author, at 
 various times and from all sorts of sources, for a new and revised 
 edition of the Bulletin, as to amount to a practical demand upon his 
 attention, and the present work, which aims to be prepared in the 
 same intelligible and untechnical style as the former one, possibly 
 requires no other explanation of its existence. 
 
 It has been thought best to issue this edition as a bulletin of 
 the Department of Chemistry of The Pennsylvania State College, 
 and to give it a more comprehensive title. 
 
 The author claims for it only the same fair consideration of all 
 interests involved as was aimed at in the earlier work, and bespeaks 
 for it the same kindly reception. 
 
 State College, Pa., January i, 1909. 
 
CALCIUM CARBIDE AND ACETYLENE. 
 
 INTRODUCTION. 
 
 An old writer, I do not recall what one, relates that after sunset 
 Nineveh was illuminated, in its streets and palaces, by lights so 
 brilliant that it was difficult to distinguish night from day. In such 
 an account it is doubtless necessary to make ample allowance for 
 exaggeration, yet the fact remains that we have lost all hope of 
 ever knowing by what kind of light Nineveh and Babylon were 
 illuminated. Still, recent discoveries permit us at least to hope 
 that in our towns lighted by acetylene, this artificial sunlight, as we 
 are wont to call it, night shall be no more regretted than day. 
 
 For a moment it would be well to glance at the past and review 
 the years as they have advanced. The Greeks and Romans lighted 
 their cities in primitive fashion with torches which were mere pieces 
 of resinous wood, or with metallic tubes containing tow soaked in 
 pitch or resin, or with candles made of tallow, resin or wax. Later 
 c^me lamps, vessels made of burnt clay or of metal, filled with oil 
 and provided with a wick. The many specimens of lamps which 
 ancient Rome has bequeathed to us present a great variety, often of 
 marvelously graceful forms. The artistic merit of the antique 
 Roman or Grecian lamp is well known, but, naturally enough, neither 
 the beauty nor the richness of the vessel could prevent the flame 
 from being smoky and dim. There were also candelabra, supporting 
 several lamps or flames, as well as lanterns, the walls of which were 
 of translucent horn or of bladder, and in later days of glass, and 
 until comparatively recent times our ancestors possessed no other 
 means of illumination. 
 
 Under these conditions, one can readily understand that it was 
 difficult to light city streets at night. Imperial Rome was indeed illu- 
 minated on the occasion of certain important festivals. In France, 
 the royal ordinances, which required the inhabitants to maintain a 
 certain number of lamps in each quarter, remained a dead letter till 
 the middle of the seventeenth century. Louis XIV. delighted in 
 
 7 
 
adorning his capital ; he provided, therefore, for the security of its 
 streets, which were tortuous and notoriously beset with criminals. 
 By letters patent dated August 26, 1662, the King ordered the 
 establishment of movable lights to be placed at the disposal of the 
 public. Torch bearers and lantern carriers were stationed every 
 eight hundred paces, in all quarters of the city, and let themselves 
 to each comer, accompanying him a quarter of an hour for the 
 consideration of a few coppers. 
 
 Only a few years later a progressive lieutenant of police com- 
 ' pelled the citizens to maintain lanterns during the winter, in each 
 quarter, and thus organized a definite system of lighting. A decree 
 of Parliament, May 23, 1671, fixed the commencement of the season 
 at October 20, and the end at May 31. The seventeenth century 
 saw, before its close, six thousand five hundred lanterns, consuming 
 each night in the streets of Paris, sixteen hundred and twenty-five 
 pounds of candles. Strangers never tired of expressing their ad- 
 miration of the novel illumination. Dr. Lister, a famous English 
 traveler, writes his impressions, upon his return from Paris in 1688, 
 as follows : 
 
 "The streets are lighted all winter, as much when the moon is 
 visible as during the rest of the month. I remark upon it especially, 
 because of the stupid custom which prevails in London of extin- 
 guishing the lanterns during half of the month as if the moon must 
 surely be brilliant enough to light the streets, and as if it were 
 impossible for the sky to be clouded in winter. These lanterns are 
 suspended right over the middle of the streets, twenty feet high 
 and a score of paces apart. They are furnished with glass about 
 two feet square and have covers of sheet iron. The cord wh^ch 
 suspends them is fastened, under lock and key, to the wall of a 
 neighboring house. In the lanterns are candles sufficient to last 
 till after midnight." 
 
 Perfection was far from reached, but in those times people knew 
 how to be contented with little. Illumination, public and private, 
 made no notable advancement before 1764. At this time a man of 
 great intelligence and energy was made chief of police in Paris. 
 He offered a reward to that inventor who should perfect the illu- 
 mination of the streets. At his suggestion the Academy of Science 
 offered the extraordinary prize of two thousand pounds to the 
 writer who should treat in the most approved manner the subject, 
 "The Best Means of Lighting at Night the Streets of a Great City, 
 Combining Brilliancy, Easy Accomplishment and Economy." La- 
 voisier presented a memoir and received a gold medal, but the model 
 adopted was that of another who invented an oil street lamp. The 
 apparatus was so remarkable that a prominent statesman of that 
 
 8 
 
time wrote to the King, "The light which it gives precludes the 
 thought of any one ever finding anything better." However, some- 
 thing better was found, and in 1821 the Argand chimney was 
 adapted to the street lamp, and increased, to a remarkable degree, 
 the intensity of the flame. Argand was a Genevese chemist, a pupil 
 of the famous Swiss naturalist Saussure. He had completed his 
 university studies in physics and chemistry, and had presented to 
 the Academy a number of remarkable addresses when he invented 
 his lamp with a double current of air, first made in England in 
 1782. The Argand lamp, however perfect it may have been, had 
 one fault ; the level of the oil could not be maintained rigidly con- 
 stant. A clockmaker, Carqel, solved this problem by attaching to 
 the lower part of the Argand lamp a little force pump driven by 
 clockwork, the office of which was to raise to the wick the oil con- 
 tained in the lower receptacle. This new lamp acquired for a short 
 time a just notoriety ; it was called the Carcel lamp ; science adopted 
 the name, and the Carcel became the recognized unit of light. From 
 the Carcel lamp to the Moderator was but a step. Franchot in- 
 vented the latter by simplifying earlier forms, substituting a spiral 
 spring for the clockwork, and thus came into use a style of lamp 
 employed up to the present day. 
 
 During this perfecting of illumination by oil, the candle industry 
 was suffering a transformation. Many investigators had attempted, 
 with little success, to employ the fatty acids in illumination. Mean- 
 time the revolution of 1830 was declared. De Milly, a courtier of 
 Charles X., seeing his career suddenly broken off, sought a for- 
 tune in this industry, and devoted himself to investigation, which 
 resulted in the greatly improved stearine candle so popular today. 
 
 Meantime public lighting had commenced to develop in a new 
 direction. Krueger succeeded, in 1786, in extracting from coal a 
 quantity of gas, sufficient to light the Jesuit College of Stony Hurst 
 in Lancashire, but as this impure gas yielded only a smoky flame, 
 his experiments were discontinued. The same year the chemical 
 laboratory of the University of Wiirzburg in Germany was lighted 
 with the gas obtained by the dry distillation of bones. 
 
 In 1791, Le Bon, a young French engineer, discovered that the 
 gas liberated from calcined wood was ignitible and yielded a bril- 
 liant flame. With indefatigable energy he pushed the development 
 of his discovery, and in 1802 accomplished the successful illumina- 
 tion of his house with this gas. But history gives to William Mur- 
 doch, the Englishman, the honor of being the true inventor of gas 
 lighting, since he in 1792 lighted his workshop in Cornwall with 
 gas obtained from soft coal. Ten years later Murdoch had estab- 
 lished quite extensive gas works near Birmingham, the factory in 
 
 9 
 
which James Watt had constructed his steam engines being one of 
 the buildings to be thus ilhiminated, but it was not till 1812 that 
 gas lighting was adopted to any considerable extent in London. A 
 German named Winsor, who had kept himself acquainted with the 
 results of Le Bon and Murdoch, succeeded in breaking down the 
 powerful prejudice which existed in England against the innova- 
 tion, lighted the Lyceum Theater with gas in 1803, and in 1810 
 founded the first gas company in London. From England, Winsor 
 went to France, where Louis XVIIL gave him every facility for 
 exploiting the novel method of illumination. In the face of all 
 sorts of prejudice the industry made steady advances, and the year 
 1820 saw its introduction to all the larger continental cities. 
 
 Oil gas has had a considerable career, and is used to enrich 
 other gases or is burned by itself; it is made by injecting crude oil 
 into hot cylinders or retorts, called the "cracking" process, because 
 the heavy oils of shale or tar origin are thus broken up, or cracked, 
 into light gases. 
 
 Water gas, made by the action of steam on red-hot coal, though 
 itself non-luminous, is rendered suitable for illumination by im- 
 pregnating it with gases derived from oil, a process familiarly 
 known as carburetting. This gas has had an immense effect upon 
 the gas industry of the world, especially in our own country, wher^ 
 either alone, or accompanying the coal gas manufacture, it is known 
 in every large city of the land. 
 
 Petroleum, introduced into the markets of the world within the 
 last half century, replaced to a large extent the other oils which 
 had been employed in the earlier forms of lamps, but did not revo- 
 lutionize the methods of producing light. 
 
 Dr. von Welsbach, an Austrian chemist, has outstripped all com- 
 petitors in solving the problem of securing the most light from 
 little gas. The Welsbach or incandescent mantle is prepared by 
 saturating a cotton fabric with a solution of the rare earths, thoria 
 and ceria. After drying, the vegetable matter is burned away, 
 leaving a fragile skeleton of the oxides, which are rendered incan- 
 descent in a non-luminous flame. Placed over a Bunsen flame this 
 mantle produces a brilliant light whereby the candle power of coal 
 gas is increased more than three-fold. In this invention, gas com- 
 panies possess a most powerful weapon which they are today wield- 
 ing with great effect in the struggle against electricity. 
 
 Electric illumination, whose history is familiar to all of us, has 
 given gas illumination a real competition, though its cost has pre- 
 vented the destruction of the gas industry. 
 
 And now acetylene, a name so long known only to those who 
 frequented the laboratories of science, but to-day on everybody's 
 
 10 
 
lips, has spread over all civilized parts of the globe, and the u^e of 
 this illuminant has made as much progress in a dozen years as its 
 predecessor, coal gas, made in the first half century of its history.* 
 
 "Note. — Portions of this introduction have been translated and adapted 
 from Capelle 's 1 'Edairage 1 1 'Ac£tyl£ne, 
 
 11 
 
DISCOVERY OF CARBIDE OF CALCIUM AND ACETY- 
 LENE. 
 
 As early as 1836 Edmund Davy, an English chemist, observed 
 that a by-product which he had secured incidentally to the produc- 
 tion of metallic potassium, was capable of decomposing water with 
 the evolution of a gas which contained acetylene. In 1862 Woehler, 
 the most famous chemist of his day, announced the discovery of 
 the preparation of acetylene from calcium carbide, which he had 
 made by heating to a very high temperature a mixture of charcoal 
 with some alloy of zinc and calcium. The product could decom- 
 pose water, like Davy's compound, and yield a gas containing acety- 
 lene. Thus the phenomenon which had been observed but not un- 
 derstood by Davy was explained and published by Woehler, and to 
 him belongs the honor of the discovery of calcium carbide and of 
 acetylene. Woehler further pointed out that the new gas burns with 
 a brilliant but very smoky flame, and announced several other char- 
 acteristics, though it remained for Berthelot, in the same year, to 
 very exhaustively study and describe these new compounds. 
 
 Then for nearly thirty years these two substances seem to have 
 been practically forgotten. During all this time acetylene was pro- 
 curable only by the tedious methods which the early discoverers 
 had used, with the result that even its name was known only to 
 students of science, and it is perfectly safe to say that up to 1892 
 few even of the professional chemists of the world ever saw an 
 acetylene flame, much less dreamed of it as a commercial possibility. 
 
 But with the development of the modern electric furnace, whose ^ 
 high temperature places in the hands of the investigator a means 
 of bringing about chemical changes never before known, the laws 
 which govern its formation could no longer remain undiscovered. 
 It was through the instrumentality of the electric furnace that the 
 possibility of calcium carbide as a commercial product was revealed 
 to Thomas L. Willson, an electrical engineer at Spray, in North 
 Carolina, In May of the above year this gentleman was conducting 
 experiments, with a view to the preparation of metallic calcium, for 
 which purpose he employed an improved Heroult electric furnace 
 
 13 
 
with a current of two thousand amperes and thirty-six volts, oper- 
 ating upon a mixture ef lime and coal tar. He secured a melted 
 mass of dark color, which on cooling became solid and brittle. 
 Willson is said to have discarded this product, as it was clearly not 
 the material for which he was searching — metallic calcium. It was 
 thrown into a neighboring stream, when to the astonishment of 
 those who saw it, there was suddenly liberated a great quantity of 
 gas which, on being kindled, burned with the now familiar, btight 
 but smoky flame, and gave off quantities of soot which showed that 
 it was not hydrogen, which would be liberated from metallic cal- 
 cium and water, but a rich hydrocarbon gas. The smelt was re- 
 peated, the product submitted to analysis, which demonstrated that 
 the solid substance contained calcium carbide, and the gas, acety- 
 lene. Subsequently, on the i6th of September, 1892, a specimen 
 was sent to Lord Kelvin, in Glasgow, with a letter which has since 
 become a famous document in scientific history, since it secures to 
 Willson the honor of being the first to prepare calcium carbide on 
 a scale large enough to promise commercial results. 
 
 Thus, calcium carbide is no new thing, since it has been known 
 for the greater part of a century, but the possibility of its manufac- 
 ture in quantity dates only from these experiments at Spray, in 1892. 
 
 To be sure, the French chemist Moissan and others were occu- 
 pying themselves with similar investigations during the same time, 
 and Moissan in particular has communicated to the world the re- 
 sults of a thorough study of this and other carbides. True it is, 
 that there has been a legitimate controversy between the supporters 
 of the French savant and the friends of the American experimenter, 
 with regard to the right of priority of discovery, with the result, 
 after the question has been thoroughly investigated, that scientific 
 men do not fail to agree that to Willson belongs the honor. The 
 German government has acknowledged it in a most substantial way, 
 by annulling the German patents first granted to Bullier. Thus, 
 through the incidental study of a by-product, and as the result of a 
 chance accident, was the industrial possibility of calcium carbide 
 discovered and made known to the world. To-day calcium carbide 
 and acetylene are familiar terms upon the lips of all the people of 
 every civilized country of the globe. Experiments were continued 
 during the years 1892-93, which demonstrated the practicability of 
 acetylene as a means of illumination and led to the establishment 
 of the Willson Aluminium Company at Spray in the spring of 1895, 
 when the first factory in the world for the manufacture of calcium 
 carbide was installed. 
 
 14 
 
LITERATURE 
 
 Previous to the last few years, the literature of our subject would 
 naturally not be looked for outside of the most remote scientific 
 prints, those journals which are made for the scientific classes only 
 and read by them alone. But within a dozen years there has sprung 
 up a voluminous popular and semi-popular literature on this sub- 
 ject. For those who devote particular attention to acetylene, there 
 are special acetylene periodicals; two are regularly published in 
 Germany, two in France, one in England and one in the United 
 States, all journals of respectable size, responsible editorship and 
 regular issue. Of our own American Acetylene Journal the writer 
 can do no better than quote the following editorial comment, which 
 recently appeared in the London Gas World : "The Acetylene Jour- 
 nal (published at 324 Dearborn Street, Chicago, 111., U. S. A.) is 
 far and away the most interesting of the acetylene periodicals that 
 reach us from time to time. The October issue, recently to hand, 
 is highly creditable to the publishers, both as to matter and manner. 
 Good accounts are given in it of the progress of the acetylene in- 
 dustry in the States and in other parts of the world." Its genial 
 and efficient editor and publisher, Mr. Elias A. Long, is always 
 keenly alert to the best interests of his beloved profession, and no 
 monthly journal, of from thirty-two to forty-eight pages, at fifty 
 cents per annum, could possibly furnish more readable news and 
 sound information on any semi-technical subject. 
 
 Moreover, volumes have been written, monographs and trade 
 annuals issued, lectures delivered and published, while innumerable 
 articles in the general press, as well as in the popular magazines, and 
 consular reports, have spread the knowledge of acetylene and calcium 
 carbide to the remotest corners of the globe. 
 
 Further, the patent literature of all countries has accumulated 
 bulky volumes, first on the manufacture of carbide and secondly on 
 the development of generators. Acetylene machines have presented 
 to amateur inventors an attractive field, both because of the obvious 
 usefulness of these generators, and because of the readiness with 
 which new ideas as to the feeding of carbide and water, one to the 
 other, can be devised. Thousands of people from all walks of life 
 have planned new forms, and patents have been applied for in great 
 numbers in all civilized countries. 
 
 For a further view of acetylene literature, the reader is referred 
 to the bibliography of this subject, which appears at the end of this 
 pamphlet. 
 
 15 
 
THE CARBIDES IN GENERAL. 
 
 By a carbide, those who familiarize themselves with the concise 
 language of science understand nothing more nor less than a com- 
 pound or substance composed of charcoal and a metal. But these 
 two parts are so blended into each other, chemically combined, that 
 the characteristics of both are entirely lost in the properties, of the 
 product. The carbonates are an entirely different class of com- 
 pounds, containing oxygen in addition to carbon and a metal, pos- 
 sessed of entirely different physical and chemical properties, and are 
 in no way to be confounded with the carbides. Limestone and 
 dolomite are natural illustrations of carbonates. 
 
 So far as we know, there may be carbides of all the metals, and 
 many of these are known. Thus potassium carbide and sodium car- 
 bide have been studied and the results published ; we can read, if we 
 wish, about the carbides of barium and of aluminium, of magnesium, 
 copper, silver, etc. Carbides of iron, or iron carbides, play an im- 
 portant role in the metallurgy of iron and steel, but the two car- 
 bides -which are of leading commercial importance are those of 
 silicon and of calcium. The former constitutes carborundum, a 
 most useful and highly valued abrasive material, while the latter is 
 of importance for only a few valuable properties which it possesses 
 in itself, but chiefly because from it can easily be made the valuable 
 illuminant acetylene. The carbides, as a class, are solid substances, 
 not easily melted, uninflammable, hard, unattractive in appearance 
 (carborundum is an exception to this), and about two and a half 
 times as heavy as water. They possess in common no valuable 
 property except that when brought into contact with water, certain of 
 them, but not all, have the power of entering into chemical combi- 
 nation with the water, after the manner in which lime slakes with 
 water, but with copious liberation of bubbles of gas. Of those which 
 do this the one of greatest practical importance, and the cheapest, is 
 the carbide of calcium, or we may use interchangeably at pleasure, 
 with equal propriety, the slightly different name, calcium carbide. 
 
 Carbides do not exist in nature at the surface of the earth, though 
 their existence in the earth's interior may possibly have been a mat- 
 ter of great geological importance, giving origin, as some think, to 
 the natural supplies of petroleum, and to natural gas. 
 
 CALCIUM CARBIDE IN PARTICULAR. 
 
 This compound and its peculiarities should here be described in 
 considerable detail. Deferring the method of its preparation to a 
 later section, it may here be mentioned that calcium carbide is a 
 
 16 
 
hard, opaque, crystaline substance known to the chemist as Ca Cj, 
 which, not to be alarmed at the suggestion of a chemical formula, is 
 merely a shorthand expression for one unit of mass of calcium, the 
 metal which exists in lime, combined with two mass units of carbon, 
 the element of which charcoal is composed. Calcium carbide is 
 therefore nothing more nor less than a compound which contains 
 calcium and carbon only. The calcium in it is about sixty-two and 
 a half per cent, and the carbon is thirty-seven and a half per cent, 
 of the weight of the carbide. We all know that the common ore of 
 iron, which is so familiar, is composed of iron and oxygen, and yet 
 the compound is far diflferent from the iron which it contains and 
 which we know can be smelted out of it, also very different from 
 oxygen, the air which we breathe all the time ; we are quite accus- 
 tomed to realize that the iron is there in the red ore, and the oxygen 
 is there too, though in a substance having properties quite different 
 from either. It should therefore be no difficult matter for us to 
 understand that calcium, a metal, and carbon, a substance like coal, 
 are both contained in this material, calcium carbide, though the com- 
 pound is so different from either constituent. 
 
 Calcium carbide is generally of a dark brown or black color, 
 sometimes described as dark gray, and sometimes as a bluish black, 
 and often possessing a reddish tinge. If broken while hot, the frac- 
 ture exhibits considerable iridescence. It is brittle and is more or 
 less crystalline in structure. Its specific gravity is 2.22 to 2.26; it 
 endures heating to redness without melting or suffering other change, 
 though it softens and fuses under electric heat; it will not burn, 
 except when highly heated in oxygen ; it looks like a mass of stone. 
 A cubic foot of the crushed material weighs one hundred and thirty- 
 six pounds and in weight, color and many physical characteristics it 
 is frequently compared with granite. 
 
 Calcium carbide may be preserved any length of time if kept 
 sealed from air, but the ordinary moisture of the atmosphere gradu- 
 ally slakes it and it becomes changed on long standing into slaked 
 lime, not essentially different from other air-slaked lime. This 
 slaking power gives it a name, which is sometimes heard, Acetylene 
 Lime. It always possesses a penetrating odor, which, however, is 
 not due to the carbide itself, but to the fact that it is constantly af- 
 fected by moisture, yielding minute quantities of acetylene, which 
 accounts for the odor rather than the carbide itself. It is not af- 
 fected by solvents, such as carbon bisulphide, petroleum, chloroform, 
 ethjer or benzol, but if allowed to come into contact with water, or 
 any mixture containing water, an immediate and vigorous decom- 
 position takes place, evolving liberal quantities of gas; it is un- 
 affected by shock, concussion or age. 
 
 17 
 
Carbide Is a safe substance to store or transport under proper 
 conditions. Transportation lines accord it the same classification 
 rates as various other forms of hardware. It cannot explode, take 
 fire, or otherwise do harm, being similar to lime in this respect also. 
 Since even the slow action of the moisture ordinarily present in the 
 air will in time render carbide entirely useless, it becomes absolute y 
 necessary, in order to securely preserve it, to pack it in perfectly 
 tight, closely sealed containers, generally drums or cans. C^ranted 
 protection from water, no substance can be safer or less likely to 
 cause trouble when stored or conveyed from place to place. Lime 
 becomes very hot when acted upon by water; so also does carbide, 
 and the only essential difference is that carbide, when it slakes with 
 water, yields a combustible gas. But this is the very fact which 
 makes it interesting and valuable. Carbide decomposes with water 
 in accordance with the following chemical equation : 
 
 CaCj 
 
 + 
 
 2H2O 
 
 = Ca(OH)2 
 
 + 
 
 C2H2 
 
 Carbide 
 
 and 
 
 water 
 
 yield slaked lime 
 
 and 
 
 acetylene. 
 
 An easy calculation shows that sixty-four unit-weights of car- 
 bide require thirty-six of water, producing also seventy-four unit- 
 weights of slaked lime and twenty-six of gas. But as gas is more 
 conveniently and commonly measured than weighed, a better state- 
 ment of the same fact would be : A pound of absolutely pure car- 
 ,bide yields five and one-half cubic feet of acetylene. Yet absolute 
 chemical purity is not a practical commercial possibility, and it is 
 natural to suppose that commercial products of different manufac- 
 turers will vary in purity. Calcium carbide is no exception. Special 
 reasons for this will be observed later, buf in practice good carbide 
 may generally be expected to produce never less than four and a 
 half cubic feet, measured at ordinary temperature, and rarely more 
 than five and one-fourth cubic feet per pound of carbide; it may 
 ordinarily be calculated at five. It is important to remember that 
 the exact proportional weights of water and carbide must always 
 enter into combination, i. e., sixty-four of actual carbide to thirty- 
 four of water, be it ounces, pounds or tons ; also that the same pro- 
 portional weight of acetylene must always result. Any apparent, 
 exception can only be due to impure carbide, loss of gas, or failure 
 to secure complete consumption of material. • 
 
 The evo'lved gas does not take fire of itself but is easily lighted. 
 Let anyone take a tumbler of water and drop into it a piece of car- 
 bide, the size of a pea, then let him light the bubbles of gas as they 
 rise to the surface. In no way is it easier to secure a practical 
 knowledge of the characteristic properties of this wonderful stone 
 
 18 
 
The gas burns with a bright Hght, not brilliant, for it needs control 
 to bring out this property, and much smoke. In fact, soot in solid 
 flakes may be seen floating through the air when the experiment is 
 performed in this rough way. While carbide, as stated above, is not 
 inflammable, nor possessed of any explosive property, such as is 
 sometimes erroneously attributed to it, it might, by finding access to 
 water in a closed vessel, create such a pressure as to burst the vessel, 
 and it is not impossible that the heat generated might cause an igni- 
 tion of the gas with resultant disaster. But any such condition as 
 water and carbide gaining access to each other in a confined space is 
 most improbable, could only occur by intention, and may be dis- 
 missed from the list of possible accidents. 
 
 When water is sprinkled or sprayed upon carbide, in not exces- 
 sive quantities, the resultant slaked lime is left in a perfectly dry and 
 dusty condition, occupying considerably more space than the original 
 carbide. When more than enough water is employed, the residuum 
 will, of course, be wet, either pasty or thinner if large excess of 
 water is employed. 
 
 THE MANUFACTURE OF CARBIDE. 
 
 In the manufacture of carbide it is well to remember that the 
 materials employed are among the most refractory ones which we 
 know. Lime is so infusible that it is frequently employed for the ma- 
 terial of crucibles in which the highest melting metals are fused, and 
 for the pencils in the so-called calcium light, because it is capable 
 of withstanding extremely high temperatures. Carbon is the ma- 
 terial employed in the manufacture of arc lights and other electrical 
 appliances as well, partly for the same reason. Yet in the manufac- 
 ture of carbide these two most refractory substances must be forced 
 into combination with each other. 
 
 It is the excessively high temperature attainable in the modern 
 electric furnace, five to seven thousand degrees Fahrenheit, which 
 alone accomplishes the combination of these elements to form cal- 
 cium carbide, and it is not necessary to attribute it to the action of 
 any electric force or process. The electric "arc" being formed in 
 the furnace, a thoroughly incorporated mixture of ground coke and 
 lime in Vight proportion is introduced. The change which takes 
 place is: 
 
 CaO + 3 C = Ca C, -t^ CO. 
 
 Quick lime and coke yield calcium carbide and carbon monoxide. 
 
 which means that fifty-six pounds of lime and thirty-six of coke 
 
 19 
 
make sixty-four pounds of carbide and liberate twenty-eight of 
 carbon monoxide, a gas which escapes or is burned at the mouth of 
 the furnace. Thus for each pound of carbide made, is consunied 
 a pound and a half or more of a mixture which is something like 
 seven-twelfths lime with five-twelfths coke. Granted pure material, 
 there is formed an ingot of very pure carbide, surrounded by a 
 crust of less pure product because partially unconverted. In break- 
 ing up, packing and shipping the carbide, this poorer crust is re- 
 jected. At first impure materials were employed for the manufac- 
 ture of calcium carbide, but this resulted in an inferior grade of 
 carbide, which in turn yielded an impure gas, so that at the present 
 time it is everywhere recognized as essential that only first-class 
 materials should be used. It is customary to employ lime which is 
 ninety-nine per cent, pure, and coke of low ash. Both must contain 
 as little sulphur and phosphorus as possible. 
 
 The Union Carbide Company, of New York and Chicago, is at 
 present practically the sole manufacturer of calcium carbide in the 
 United States, and more will be said of their manufacture and the 
 distribution of their product in a later section. 
 
 Of impurities in carbide, and consequently in acetylene, discus- 
 sion will be found under a special topic. 
 
 WHAT IS A GAS? 
 
 For a proper understanding of acetylene, though no more neces- 
 sary than for an intelligent conception of many of the incidental 
 materials which influence our every-day life, one ought to possess a 
 clean-cut conception as to the meaning of the word gas. In prac- 
 tice many ordinary substances are capable of assuming, under dif- 
 ferent conditions of temperature, etc., three different physical forms. 
 
 Water is the most familiar and universal illustration. We use 
 it in its solid form as hard, transparent ice, which everybody knows. 
 When heated it melts, and exists as the abundant liquid which is so 
 common everywhere. Heated still further, above two hundred and 
 twelve degrees Fahrenheit, it boils and becomes converted into in- 
 visible steam, which, though a greatly attenuated form of matter, is 
 still the same substance as the ice or the water from which it was 
 produced. When we reverse the changes and cool the substance we 
 find that at two hundred and twelve (boiling point or liquefying 
 point) steam becomes water, and at a still lower temperature, thirty- 
 two degrees Fahrenheit (melting point or freezing point), it solidifies 
 again into ice. 
 
 Now water is only one of a thousand substances which undergo 
 
just such changes, though each separate substance usually possesses 
 its own characteristic melting point and boiling point. Thus, below 
 its melting point, every substance is a solid; from its melting point 
 to its boiling point it is a liquid ; above its boiling point it is a gas. 
 It is with this latter form of matter that we now have chiefly to do. 
 Aside from steam, other familiar gases are air, hydrogen, illuminat- 
 ing gas, etc., but most of these are mixtures of two or more indi- 
 vidual gaseous substances. Thus air is a mixture of oxygen and 
 nitrogen ; illuminating gas is a very complex mixture of numerous 
 gases, etc. All gases tend to diffuse with each other when oppor- 
 tunity allows, and all tend to occupy all available space. Gases are 
 extremely attenuated as shown by the fact that a cubic inch of 
 water makes a cubic foot of steam. The minute particles which 
 compose a gas must therefore be much farther apart than in liquids 
 or solids. Physicists believe that these minute particles of matter, 
 or molecules, are in constant motion, and possessed of attractive 
 power which holds them firmly together so long as they are in the 
 solid form ; that heat accelerates their motion until presently the 
 molecules move rapidly enough to overcome the attractive force to 
 such an extent that the solid becomes liquid; that in the liquid 
 form the molecules still stick together, so to speak, to such an ex- 
 tent that the substance flows, seeks its lowest level, etc., whereas, 
 when further heat increases their motion still more, the molecules 
 fly away from each other and the gaseous condition is produced. 
 
 Steam, air and almost all gases are colorless and invisible; an 
 incandescent lamp bulb from which the air has been exhausted looks 
 just the same as if it were filled with air. But notwithstanding that 
 they are hidden from our vision, air and steam and acetylene are just 
 as real as any other kinds of matter with which we have to do. No 
 one will deny the reality of the material which fills a distended auto- 
 mobile tire, nor of that which operates within the cylinder of a loco- 
 motive. Manifestly, however, the gaseous state is one of extreme 
 expansion and gaseous volumes consist mainly of intermolecular 
 space; in fact, it would not be a misstatement to say that a cubic 
 foot of acetylene consists of much more than 'niney-nine per cent, of 
 unoccupied space, and far less than one per cent, of space totally 
 filled with matter. This leads to the most characteristic property of 
 gases, which distinguishes them from liquids and solids, namely, 
 their almost perfect elasticity. Owing to this property, gases can be 
 condensed by pressure, and the volume yields exactly in proportion 
 to the pressure exerted upon them. Press twice as hard upon any 
 quantity of gas as you did before and you halve its volume ; reduce 
 the pressure to a half and you double the volume. Sufficient pres- 
 sure compels most gases to assume the liquid condition. 
 
 21 
 
In like manner, all gases expand when heated and contract when 
 cooled, these changes also taking place under a precise and simple 
 law, so that it may properly be stated that the volume of a gas is 
 directly proportional to its absolute temperature. 
 
 It follows from the above facts, since gases are perfectly elastic 
 bodies, whereas liquids are almost entirely devoid of elasticity, that 
 though a cubic foot of water is a fairly definite quantity, being 
 always one thousand ounces at ordinary temperature and varying 
 only a few per cent, in weight from thirty-two to two hundred and 
 twelve degrees, nevertheless a cubic foot of acetylene, or any other 
 gas, is not in any sense a definite quantity, unless it be expressly 
 stated at what temperature and pressure the gas is to be measured. 
 
 Gases vary greatly in weight, according to their composition. 
 Hydrogen, the lightest, is one-fourteenth as heavy as air; steam 
 weighs five-eighths as much as air. Many are lighter and many 
 are heavier; a balloon to float in air must necessarily be inflated 
 with a lighter gas. 
 
 Many gases are inflammable; many are not. Those which are 
 capable of burning do so with varying amounts and colors of flame, 
 which may or may not be smoky, and with the production of greater 
 or less quantities of heat and light. No two gases are alike in these 
 respects, but every individual gas behaves always in the same way, 
 and every gas which can be burned at all requires its definite quan- 
 tity of oxygen to maintain its combustion. This oxygen is common- 
 ly derived from the air and without it no gas or other fuel what- 
 ever can be burned. If the gas burns quietly and slowly, as in an 
 ordinary burner, the oxygen is regularly supplied from the sur- 
 rounding atmosphere and the process continues without interruption 
 or violence. But if a quantity of an inflammable gas is first mixed, 
 intentionally or by accident, with a sufficient volume of air to accom- 
 plish its combustion, and then ignited, an' explosion results, because 
 the total quantity burns in a moment, and suddenly demands and 
 occupies so much space that objects in the neighborhood are com- 
 pelled to give way. 
 
 An explosive mixture of gases is therefore such a mixture of a 
 combustible gas, with air or oxygen, as contains at the outset the 
 right proportions of the two to satisfy each other. 
 
 The products of combustion, since no matter is ever annihilated, 
 and since combustion merely produces new forms, must also be 
 reckoned with. These are usually gaseous also and many possess 
 objectionable or even poisonous character, according to circum- 
 stances. The coal miner fears not only the dreaded fire-damp, which 
 by mixing with air and becoming ignited may demonstrate the ter- 
 rific violence of its explosive character, but he has reason also to 
 shun the deadly after-damp, which may so vitiate the atmosohi 
 
 22 —^'^ 
 
that he may escape the explosion only to fall a victim to the stifling 
 action of the gases which follow in its wake. 
 
 GENERAL PROPERTIES OF ACETYLENE. 
 
 Acetylene, whether prepared from carbide or in any other way, 
 is known to the chemist as C^ Hj, meaning that it has the constant 
 composition of twenty-four parts by weight of carbon and two of 
 hydrogen, or ninety-two and three-tenths per cent, carbon and seven 
 and seven-tenths per cent, hydrogen. Being composed of these two 
 elements only, it belongs to the class of compounds known as hydro- 
 carbons, represented in nature by natural gas, petroleum, etc. All 
 hydrocarbons are combustible, forming as products of combustion, 
 carbon dioxide and water. There are hundreds of hydrocarbons 
 known, of greater, or less importance, and more or less thoroughly 
 studied, and there are many thousands of compounds containing 
 carbon united with elements other than hydrogen, but among them 
 all there is no gas containing a higher percentage weight of carbon 
 than acetylene. It is, therefore, proper to look upon acetylene as 
 essentially gaseous carbon. Carbon, known in so many forms as a 
 fuel for combustion, with a view either to producing heat or furnish- 
 ing light, a constituent of all fuels from whatever source and wher- 
 ever employed, is in no place to be had more closely approaching the 
 condition of pure carbon in the gaseous state than in acetylene. Pure 
 carbon, one hundred per cent., as well as in the various commercial 
 forms, anthracite, coke, charcoal, etc., does not even melt under such 
 heat as can be attained, much less pass into the form of vapor or gas. 
 Hence it is interesting to note that acetylene, containing only seven 
 and seven-tenths per cent, of material other than carbon, is the 
 nearest approach to gaseous carbon at common temperatures with 
 which we are acquainted. 
 
 Acetylene is a colorless and tasteless gas, possessed of a peculiarly 
 penetrating and persistent odor. In describing the gas as it is 
 most frequently known, this characteristic odor should not be ig- 
 nored. Its presence in the air to the extent of only one part in ten 
 thousand is distinctly perceptible. It should be observed, however, 
 that in burning properly at the jet there is absolutely no odor per- 
 ceptible, and if an odor of acetylene is detected about an apparatus 
 in operation, it is certainly because of the leakage of the gas, through 
 faulty piping, an open cock, or otherwise. 
 
 Acetylene dissolves in water to a considerable extent. This is 
 usually stated as thirteen volumes of acetylene in twelve volumes of 
 water. This statement is for ordinary temperature, approximately 
 
 23 
 
correct, and it is near enough for practical purposes to state that a 
 gallon of water may dissolve a gallon of gas. It is more soluble m 
 certain other liquids such as ether, alcohol, petroleum, turpentme, 
 and especially in acetone; we shall have occasion to refer to this last 
 solvent in a later chapter. Since it is most frequently generated m 
 contact with water which, by the very nature of the circumstance, 
 contains more or less lime, its exact solubility in such water, at dif- 
 ferent temperatures, is of interest here. The following figures show 
 the solubility of acetylene in clear saturated lime water, and in milk 
 of lime containing ten parts by weight of quicklime in one hundred 
 parts of water, the figures representing the number of volumes of 
 acetylene dissolved in one hundred volumes of the fluid : 
 
 Degrees Fahrenheit. Lime water. Milk of lime. 
 32 146.2 152.6 
 
 41 : 138.5 
 
 68 122.8 134.8 
 
 112 43.9 62.6 
 
 194 6.2 9.2 
 
 The full measure of the solvent power of water and other liquids 
 for acetylene is not reached unless the gas and the liquid are given 
 ample opportunity to come into free contact with each other. Thus 
 if the gas be kept within a receptacle over water which is at rest, the 
 surface layer of water to a slight depth becomes saturated with the 
 gas, protects the lower layers of water from becoming so, and the 
 further penetration of the gas into the water is retarded or even 
 stopped. But if the water is agitated in any way with the gas, or the 
 gas allowed to bubble up through the water, the water easily takes 
 up its full allowance of gas, and under such circumstances the with- 
 drawal of a quart of water involves also the removal of the_ con- 
 tained quart of gas. This idea of the solubility of a gaseous sub- 
 stance in water is a peculiarly difficult conception to grasp, but if we 
 may just accept it as a fact, and consider it parallel with the solution 
 of salt or sugar in water, we shall be on the right track in this re- 
 spect. Acetylene is lighter than air in the proportion of ninety-one 
 to one hundred; its specific gravity is therefore said to be 0.91. 
 A balloon filled with it will consequently float in air. Yet it is much 
 heavier than coal gas, whose average specific gravity is 0.43, or 
 natural gas, 0.56. 
 
 Acetylene burns in the air with a brilliant but smoky flame. 
 When its illuminating power is properly brought out, as it may be 
 by the use of a suitable burner, it yields a light of greater brilliancy 
 than that furnished by any other gas. 
 
All hydrocarbons burn in air with production of carbon dioxide 
 and water, but the quantity of combustion products, compared with 
 the volume of gas burned, varies with the character of the hydro- 
 carbon used. 
 
 The combustion equation. 
 
 2C,H, 
 
 + 
 
 50, = 
 
 4 CO, 
 
 + 
 
 2H,0 
 
 Acetylene 
 
 and 
 
 oxygen yield 
 
 carbon dioxide 
 
 and 
 
 water. 
 
 means that two volumes of acetylene burned require five volumes of 
 oxygen and yield four volumes of carbon dioxide and two of water 
 vapor. Better stated, one cubic foot of gas burned deprives the sur- 
 rounding air of two and one-half cubic feet of oxygen, throwing 
 into it two cubic feet of carbon dioxide and one of water vapor. 
 Here, of course, is meant the complete combustion as it takes place 
 in a perfect burner, and space will not be consumed in considering 
 imperfect or retarded or partial combustions which are possible, but 
 are aside from the line of importance. 
 
 All gases which burn in air will, when mixed with air previous 
 to ignition, produce more or less violent explosions, if fired. Com- 
 mon illuminating gas, issuing quietly from the jet where it has been 
 lighted, burns regularly and safely with no suggestion of explosion. 
 But allow the gas to become mixed with air as by accidental leakage 
 into a cellar or closet or other confined and unventilated place, then 
 bring about its ignition by applying a flame as when a match is 
 lighted in the vicinity, or when one goes into the dangerous place 
 with a lighted lamp or candle, and an explosion is sure to result 
 which is more violent as the mixture more nearly approaches the 
 proportions necessary for combustion. This is a perfectly general 
 fact, as true of one combustible gas or vapor as another. Creative 
 Power endowed all ignitible gases with this property, and it is as sure 
 to be true as water is to flow, be it in the coal mine, at the gas works, 
 along a leaky city main or in the bowl of an overheated oil lamp. 
 
 Of course, acetylene is no exception. From the statements just 
 presented it is easily calculated that one measure of acetylene and 
 twelve and a half of air are required for complete combustion ; this 
 is therefore the proportion for the most perfect explosion, i. e., 
 mixtures of acetylene and air which contain about seven and one- 
 half per cent, of the gas are expected to explode with the most ter- 
 rific violence. But let it not be supposed that a seven and a half per 
 cent, mixture is the only one which can explode with violence ; all 
 mixtures from three per cent, to thirty per cent, of acetylene in air 
 are capable of exploding with greater or less force, according to 
 
 conditions, if ignited. 
 
 25 
 
It may not be out of prace here to note that a great deal of undi- 
 gested misinformation has been given to the pubUc with regard to 
 this point. Errors may have crept into the statements regarding the 
 explosive limits of acetylene air mixtures, and been copied from place 
 to place. The author of this paper, in its former edition, gave these 
 limits very differently, but he desires now to record his view that it 
 is not possible to secure an explosion, in any true sense, by present- 
 ing a flame to a mixture which contains more than thirty per cent, 
 of acetylene. Numerous experiments have been made in his labora- 
 tory, by competent chemists under his eye, and at no time has an ex- 
 plosion been secured, though bare flame ignition was attempted in a 
 great variety of ways, when the acetylene was present in larger pro- 
 portion than that mentioned. He thinks it therefore a proper correc- 
 tion to make on the data which have often been published before. 
 
 The ignition point of acetylene, is lower than that of coal gas, 
 being about nine hundred degrees Fahrenheit, as against eleven 
 hundred degrees. This is easily exhibited by allowing the gas from 
 an acetylene burner to blow on to a cigar burning in the usual way 
 without flame, when the gas will be ignited. Common illuminating 
 gas cannot be lighted in this way 
 
 Under comparatively light pressure, twenty-six atmospheres, at 
 thirty-two degrees Fahrenheit, or about forty atmospheres at ordi- 
 nary temperature, a measure of compression easily reached with 
 modern pumping appliances, acetylene gas becomes a liquid. This 
 liquid is said to be the lightest liquid known, being only four-tenths 
 as heavy as water. It is possessed also of an expansibility greater 
 than that of any other known liquid. Acetylene may further be had 
 in a solid form, resembling snow, and this is called acetylene snow, 
 bearing as it does to liquid acetylene and gaseous acetylene the same 
 relation that ordinary snow bears to water and steam respectively. 
 
 Acetylene in the gaseous form, at ordinary pressure, is not ex- 
 plosive in any sense except as referred to above, when mixtures of 
 the gas with air become ignited. So important is the correct under- 
 standing of the exact facts in the matter that, even at the expense 
 of some repetition, it should be clearly understood that acetylene, not 
 compressed, cannot be exploded, detonated or otherwise set off in 
 any manner whatever that could warrant its being called explosive. 
 A lighted candle plunged into it will be extinguished, setting fire to 
 it, of course, where it comes in contact with air, for air is necessary 
 for its combustion; but no combustion or explosion can take place 
 in the midst of a body of the gas. Even a fulminate cap exploded 
 in the gas will not propagate a wave of explosion to any perceptible 
 extent whatever, nor will an electric spark in an atmosphere of the 
 
 26 
 
gas cause any injurious or dangerous result whatever, except such 
 as would result from lighting any other gas in the same manner. 
 
 But the liquefied gas, liquid acetylene, is quite another matter. 
 Under certain conditions, not necessary here to analyze, liquid 
 acetylene can be exploded, aiid for that reason liquid acetylene may 
 be set down as a dangerous substance. Even this preparation, when 
 our knowledge of it becomes more perfect, may perhaps be so con- 
 trolled as to render its restricted employment safe, but for the 
 present a wise rule is to allow no liquid acetylene to be handled under 
 circumstances where its explosion might do harm. In fact, it would 
 be wise to go still further and avoid the use of acetylene under any 
 pressure which might by any possibility approach that which is 
 necessary to liquefy the gas. The liquefying pressure has been men- 
 tioned as twenty-six atmospheres at thirty-two degrees Fahrenheit; 
 this means nearly four hundred pounds per square inch at freezing 
 temperature and about seven hundred pounds at seventy degrees. 
 This pressure increases with temperature up to ninety-eight degrees 
 Fahrenheit, which is its critical temperature, above which point no 
 pressure will suffice to hold acetylene in a liquid state. 
 
 No one could, by any reasonable possibility, accidentally liquefy 
 any acetylene, and so the safeguard is a perfectly easy one to apply, 
 and in all appliances in which acetylene is prepared and used by the 
 public, the likelihood of creating a dangerous compression is 
 reduced to nothing. 
 
 It is still further true that acetylene, at some pressures, greater 
 than normal, but not approaching that necessary to liquefy, has under 
 most favorable conditions been found to explode ; but it may be said 
 with perfect confidence that this gas has been studied a very great 
 deal and its properties are as well known as could be wished, yet 
 under no circumstances has anyone ever secured an explosion in it, 
 if subjected to less than one atmosphere of pressure. And as the 
 limit of one atmosphere, fifteen pounds to the square inch, is a per- 
 fectly easy one to observe, and as in the usual domestic apparatus 
 there should never be a pressure of more than a few ounces, the 
 conditions of safety along this line need by no means be overreached. 
 
 There are, it is true, applications of acetylene of a very important 
 character where the gas requires to be used under pressure, but these 
 do not pertain to the ordinary household use of acetylene as an 
 illuminant, and wherever they are applied abundiant precautions may 
 be taken to render them safe. In fact, these applications do not ex- 
 tend in any measure to the uses which the general public makes of 
 acetylene, and when they are practiced it need be only by trained 
 specialists and skilled workmen who thoroughly understand the con- 
 ditions under which they work. More will-be said about these appli- 
 
 27 
 
cations under such topics as Dissolved Acetylene, Oxy-Acetylene 
 Blowpipe, etc. 
 
 Though not exploded by application of high heat, acetylene is 
 injured by such treatment. More properly speaking, it is partly con- 
 verted, by high heat, into other compounds, thus lessening the actual 
 quantity of the gas, wasting it, and polluting the rest by the intro- 
 duction of substances which do not belong there. Among such com- 
 pounds into which acetylene, C2 Hj, may be partially converted by 
 heat are benzol, C^ H^, and styrolene, Cg Hg. These and others of 
 their like remain in part with the gas, causing it to burn with a per- 
 . sistent smoky flame, which cannot be corrected, and producing car- 
 bonization of burners, and in part deposit a solid tarry residue at 
 the point where the heating takes place. In cases where the gas is 
 generated without avoiding undue rise of temperature objectionable 
 results as above are certain to be secured. 
 
 Compounds of acetylene with copper and silver have long been 
 known and they are violently explosive substances. They are easily 
 made in the laboratory if one takes the trouble to make the experi- 
 ment, and it has been supposed that the copper compound might be 
 formed by action of the gas on copper or brass containers, pipes, 
 parts of apparatus, fixtures, etc. But careful investigations, during 
 which acetylene has been allowed long contact with copper and brass, 
 under more varied and trying conditions than would ever be likely 
 to exist in practice, have been repeatedly and laboriously carried out, 
 and the idea that such conditions can result in the accidental forma- 
 tion of dangerous substances has been entirely set aside as disproved. 
 
 SPECIFIC PROPERTIES OF ACETYLENE. 
 
 Acetylene an Endothermic Compound. A great deal has been 
 said by those who feel that they can afford to use scientific terms, 
 about acetylene being an endothermic substance. This bugbear may 
 as well be disposed of once for all, and we shall find that the name 
 is a great deal worse than the condition which it describes, as regards 
 acetylene at least. There are certain compounds during the forma- 
 tion of which heat has been absorbed, instead of evolved as is the 
 usual rule. Such compounds are scientifically described as endo- 
 thermic, and some of them, because of their power of developing 
 much heat when they decompose, are very explosive substances. 
 Acetylene is endothermic, and if pressure be exerted upon it, forcing 
 its particles nearer together, and compelling it to occupy less than 
 its accustomed normal amount of space, it develops the character of 
 an explosive. The only trouble with the use of the word resides in 
 
 28 
 
the danger of the inaccurate assumption that an endothermic sub- 
 stance is of necessity also an explosive one. Acetjlene at ordinary 
 pressure is not an explosive, and it does not become so, as stated 
 above, until at least one atmosphere of pressure, and probably two, 
 in addition to normal, have been added; these are conditions which 
 never occur in connection with a domestic generator. 
 
 Physiological Effect of Acetylene. Statements have been made 
 to the effect that acetylene is poisonous. These statements are in a 
 general way untrue, though it could not properly be stated that they 
 are wholly without foundation. Reliable investigators, Berthelot, 
 Rosemann, Grehant, and others, whose conclusions are not to be 
 questioned, have independently of each other carried on researches 
 not necessary to detail here but easily referred to when desirable, 
 looking to the establishment of accurate information on this point, 
 and have shown that while it is slightly poisonous, it is less so than 
 coal gas and vastly less poisonous than water gas. 
 
 There is a gas called carbon monoxide, well known to exert a 
 most deleterious action on the blood whenever it is inhaled ; this gas 
 is responsible for the poisonous action of furnace and stove gas 
 when, through faulty drafts, household heaters throw out noxious 
 vapors over night and asphyxiate the householders in their beds. It 
 is the deadly gas which sometimes overcomes persons who breathe 
 the fumes of charcoal burning in confined rooms. It issues from blast 
 furnaces, from kilns of various sorts, and workmen about metallurg- 
 ical operations know full well that it is to be avoided. It is insidious 
 and one never knows he is breathing it till the poisonous symptoms 
 commence, for it is without odor, devoid of taste and color, and it 
 kills! A prominent authority states on this topic, "It is certainly 
 fatal to breathe air containing one per cent, of carbon monoxide, and 
 it is said that so little as one-twentieth of one per cent, may prove 
 fatal." The writer does not wish to decry the use of water gas in 
 our American towns ; on the contrary, he believes that sufficient safe- 
 guards are usually exercised against the dangers and that our city 
 gas supplies, as a rule, call for no serious criticism on this score, 
 although city gas in America runs as high as twenty per cent, of 
 carbon monoxide, and in some localities accidental deaths from in- 
 haling coal gas are of too frequent occurrence. 
 
 When we reflect that "blowing out the gas" is a foolhardy act 
 that everybody knows to be dangerous, and that every great daily 
 paper has frequent occasion to report cases of burners left open with 
 suicidal intent, is there not great satisfaction in the knowledge on the 
 part of a consumer of acetylene that, with equal lighting power, he 
 is using an illuminant so free from deleterious quality that leaving a 
 jet open in a living room for a week involves no peril to human life? 
 
 29 
 
Nor does it involve undue enthusiasm for acetylene if its adherents 
 proclaim that this quality brings it virtually into the class of life 
 savers ! For, just in so far as it replaces poisonous illuminants, it is 
 a direct means of averting death. 
 
 In one of Grehant's experiments upon dogs a mixture of twenty 
 per cent, of acetylene with air inhaled for thirty-five minutes did not 
 seem to trouble the animal. A dog breathing a similar mixture of 
 illuminating gas containing only one per cent, carbon monoxide 
 quickly showed convulsive movements and died after ten minutes. 
 The way in which carbon monoxide, the poisonous constituent of 
 coal gas and water gas acts, is by combining with the hsemaglobin of 
 the blood, producing death by asphyxiation, whereas reliable investi- 
 gation has proved that such acetylene as enters the system under 
 similar circumstances is freely given off again without injury. 
 
 Acetylene is irrespirable, so indeed is nitrogen or hydrogen, but 
 it is not to be claimed that it is toxic in its action on animal life in 
 any such sense as carbon monoxide is. A long time of inhalation 
 and large quantities of acetylene are necessary to bring about symp- 
 toms of illness in animals. 
 
 Explosibility of Acetylene. It has. already been stated that there 
 are. two ways in which an explosion can be secured with the aid of 
 acetylene : First, when mixed with air and ignited ; secondly, when, 
 under abnormal pressures, it is set off by concussion. It is important 
 that these two conditions should now be examined a little more 
 closely. 
 
 1. Mixtures with Air. It has been observed under a previous 
 topic that all mixtures from three per cent, to twenty-five or thirty 
 per cent, of the gas with air explode when kindled. This is the force 
 which is relied upon for the actuating power in gas engines, and 
 acetylene should meet a broad application in this direction. 
 
 In the early days of acetylene lighting it had been suggested to 
 mix the gas with air previous to conducting it to the burner, the ob- 
 ject being to secure a smokeless flame. But in view of the dangerous 
 character of such a mixture, and in view also of some accidents 
 which occurred, this method was given up after the invention of 
 burners, which accomplished the same purpose by effecting a mix- 
 ture with air right at the point of combustion. 
 
 2. Explosions of Acetylene under Pressure. In the first years 
 of the acetylene industry one of the fondest hopes of its promoters 
 was that the transportation, storage and sale of the product con- 
 densed into liquid form might become an assured success. Some 
 four hundred cubic feet of gas are required to make one cubic foot 
 of liquefied acetylene, and when the pressure is released the whole 
 
 30 
 
quantity of the gas is again secured. The scheme was an ideal one. 
 Houses, steamboats, streets or railway cars were to be lighted by 
 gas drawn with the aid of a reducing pressure valve from a cylinder 
 of condensed acetylene kept at any convenient point and connected 
 by a pipe to the usual distributing system. But explosion after ex- 
 plosion occurred, many of them serious and disastrous, in which the 
 cause was always traced back to the use of liquid acetylene. Many 
 and thorough investigations were made with the result that liquefied 
 acetylene was shown to be a highly dangerous substance. Whether 
 the time will come, as the enthusiasts fully believed, when liquid 
 acetylene can be made and employed with safety, when it shall be 
 known how to so prepare and handle this product as to eliminate 
 the danger in'its use, cannot now be said. At present liquid acetyl- 
 ene must be classed as a very hazardous material. Insurance com- 
 panies very rightly refuse to have anything to do with it. Com- 
 mercially there would be no gain, inasmuch as carbide itself is a 
 more condensed form for shipping and storing the gas than is the 
 liquid condition. A cubic foot of crushed carbide represents be- 
 tween five and six hundred feet of gas ; a cubic foot of liquid acetyl- 
 ene represents only four hundred feet. Fortunately, also, we now 
 have a good and sufficient substitute, which will be described in the 
 chapter on "Dissolved Acetylene." 
 
 Combustion and Illuminating Power of Acetylene. Controlled 
 by a suitable burner, the flame of acetylene is absolutely white and 
 of intense brilliancy. In quality it is the nearest approach to day- 
 light that we know. Its spectrum closely resembles that of sunlight 
 and consequently all colors appear the same as by daylight instead 
 of being distorted as by gas light, candle, oil or electric light. This 
 property renders it very desirable for ordinary domestic purposes, 
 and also adapts it admirably to photographic uses, to matching 
 colors and accomplishing other work at night which is impossible 
 with other illuminants, to forcing plant growth, and many similar 
 purposes. 
 
 Light for light, acetylene illumination causes much less eleva- 
 tion of temperature in the atmosphere of rooms than do other forms 
 of lighting with gas or oil ; it therefore possesses a distinct advan- 
 tage in this respect, and while it may be misleading to state that 
 acetylene burns with a cool flame, it is correct to say that an acetyl- 
 ene burner produces much less heat than a flat flame coal gas 
 burner which emits the same quantity of light. 
 
 Acetylene also pollutes the air less than coal gas, and we may 
 calculate the accuracy of this statement somewhat as follows: 
 
 Recalling the combustion formula of acetylene: 
 
 31 
 
2CH, + 50, = 4C0, + 2H,0 
 
 Acetylene and oxygen yield carbon dioxide and water. 
 
 it was pointed out that one meaning to be derived therefrom is that 
 when one cubic foot of acetylene is burned, it takes from the air 
 around the flame two and one-half feet of oxygen and throws out 
 two feet of carbon dioxide gas. Both of these operations vitiate 
 the air in an enclosed room, just as does the burning of any other 
 fuel or the breathing of persons or animals. In the open air, or in 
 pferfectly ventilated apartments, this might be ignored, but under 
 usually prevailing conditions, the injury to the atmosphere is by 
 no means insignificant. One foot of coal gas of average compo- 
 sition requires one foot of oxygen and throws out three-fourths of 
 a foot of carbon dioxide ; but since only one-half of a foot of acety- 
 lene will ordinarily be burned when five feet of illuminating gas 
 would be consumed, it is necessary, for the comparison, to multiply 
 these last results by ten, and it will be seen that light for light a 
 burner consumes — 
 
 Acetylene, 2J/2 feet oxygen, yielding 2 feet carbon dioxide. 
 
 Coal gas, 10 feet oxygen, yielding 7J/^ feet carbon dioxide. 
 
 Or, acetylene in producing the same candle power, impoverishes 
 the air one-fourth as much, and pollutes it also one-fourth as rnuch 
 as illuminating gas. The calculations of Professor Lewes and 
 other authorities are still more favorable to acetylene than are these 
 figures. 
 
 "As an illuminant acetylene surpasses in lighting power and 
 economy all other illuminants known; when burned at the rate of 
 five cubic feet per hour it produces light equal to two hundred and 
 fifty candles, whereas, the best illuminating gas made from coal, 
 or water gas, rarely exceeds twenty-two candles for each five feet 
 burned per hour. Your Philadelphia city gas is rated at from nine- 
 teen to twenty candles. Acetylene will, therefore, produce twelve 
 and a half times more light if the same quantity be consumed, or one 
 thousand cubic feet of acetylene gas will give you the equivalent in 
 lighting power of twelve thousand five hundred cubic feet of your 
 city gas; it has, therefore, twelve and a half times the value." 
 These were the words of Willson and Suckert, quoted from their 
 paper before the Franklin Institute, March 17, 1895, and though 
 that was one of the earliest recorded statements from persons who 
 can be regarded as authoritative, later research has not had occa- 
 sion to greatly modify their figure. The relative light value of 
 acetylene and illuminating gas is variously stated, often in exag- 
 gerated terms, especially in the expressions of those whose chief 
 motive is to sell a machine. But thirteen is a frequent figure now 
 
 32 
 
used by gcx>d authorities, and the writer considers that, for a con- 
 servative and safe figure on which to base any calculations that 
 this paper may call for, one cannot do better than use the ratio set 
 down by the authorities just mentioned, namely, that foot for foot, 
 acetylene has twelve and a half times the illuminating power of city 
 gas. In all such comparisons it is well to remember that acetylene 
 is a compound, a single or individual substance, of invariable com- 
 position the world around, wherever it may exist or be prepared, 
 except for occasional or accidental admixture of other material, 
 whereas coal gas is not a compound, but a mixture, of variable pro- 
 portions, different for every different gas works, though of course 
 possessing an average composition which can be used as a basis of 
 calculation, while the product of individual plants may differ 
 materially from such average. 
 
 The comparison of the illuminating power of our gas with that 
 of other well known compounds, as made by Lewes, is as follows, 
 all based on five cubic feet per hour of consumption : 
 
 1. Methane, 5.2 candles. 4. Ethylene, 70.0 candles. 
 
 2. Ethane, 35.7 candles. 5. Butylene, 123.0 candles. 
 
 3. Propane, 56.7 candles. 6. Acetylene, 240.0 candles. 
 
 This table is of interest because substances (i) to (5) are all con- 
 stituents of coal gas, in varying proportions. But coal gas, as regards 
 its luminous constituents, consists chiefly of methane, mixed with but 
 little of the other gases in the above table, which possess a higher 
 illuminating effect, and mixed at the same time with large per- 
 centages of gaseous matter possessing no luminosity whatever. 
 Hence the low average lighting power of coal gas which for Phila- 
 delphia city gas was placed, above, at nineteen to twenty candles 
 for five feet per hour. With the modern improved burners for 
 acetylene, the best half-foot burners should develop twenty-five 
 candle power as against the five-foot coal gas burner developing 
 twenty candles. Thus the ratio of twelve and one-half to one is 
 maintained. And though this may be variously stated by interested 
 parties, now high, now low, it is safe to accept, as an entirely 
 unprejudiced basis of calculation, that the highest effects which can 
 be produced from acetylene and coal gas respectively, without the 
 aid of artificial air supply other than that created by the flames 
 themselves, are as twelve and one-half to one. 
 
 33 
 
DANGER. 
 
 The possible danger to arise from the use of any commodity, 
 whether a foodstuff, an illuminant or any other article of necessity 
 or convenience, should be thoroughly known before any steps are 
 taken. 
 
 It seems to the writer that all the dangers in the use of acetylene 
 must classify under one of the following heads : 
 
 (a) Danger which may arise from the poisonous action of 
 acetylene in case it should escape through leaks or open burners 
 into jthe air. 
 
 (b) Danger which may arise from breathing air vitiated by the 
 combustion of acetylene in it. 
 
 (c) Danger which may arise from explosion. 
 
 (d) Danger which may arise from fire. 
 
 A few years ago, when the commercial production of carbide 
 was a novelty, most exaggerated accounts of its dangerous char- 
 acter were published in the newspapers and passed from mouth to 
 mouth. Now, every child knows that carbide is a perfectly safe 
 commodity, requiring only to be kept tightly closed and away from 
 water. Transportation companies make no more objection to accept- 
 ing a drum of carbide for shipment than they do to a keg of nails. 
 
 A fire in a carbide storage warehouse at Chattanooga, starting 
 from an overturned lantern, destroyed various other material stored 
 on the same floor and practically burned down the building, but did 
 no damage whatever to the stock of carbide. Again, during the 
 tremendous floods at Kansas City in 1903, a warehouse containing 
 between thirty and forty tons of carbide was completely submerged 
 and in the midst of the swiftest current for eight days. After the 
 water had receded, the carbide was recovered, practically without 
 loss. 
 
 Calcium carbide may now be shipped, on passenger vessels, to 
 any part of the world, and all restrictions upon such shipments 
 which formerly existed before its properties were fully understood 
 have been rescinded. 
 
 In like manner, whether fortunately or unfortunately, about 
 everyone who has heard of acetylene has heard also of its supposed 
 dangerous character. Some would have it dangerously poisonous, 
 others dangerously explosive. No doubt there were some impuri- 
 ties in the earlier specimens of carbide which were placed upon the 
 market, and these caused impurities in the gas, which, whether toxic 
 or otherwise, dangerous in any way or not, modified the character 
 of the first few thousand feet of acetylene used. But, to-day when 
 we may be entirely confident of the commercial purity of our carbide 
 
 34 ' 
 
this question is not serious. The impurities of acetylene will be 
 discussed in a later topic, and now that the first outbursts of the 
 alarmists have long since died away, we may impartially, seriously 
 and quite thoroughly analyze and inquire into all the possible sources 
 of danger. Let us consider them in the order above suggested. 
 
 (a) Danger from Toxic Action. It has been shown that acety- 
 lene is far less poisonous than the usual illuminating gas sold in 
 our cities. While it might occur to a wag to observe here that it 
 matters little what becomes of the man who intentionally, or other- 
 wise, "blows out the gas," it is still to be said that far less gas can 
 pass through an ordinary acetylene burner, one-half foot, than would 
 pass through an ordinary coal gas burner, five-foot size, assuming 
 that both are accidentally left fully turned on and gas escaping at 
 full head. So that if the "patient" should quietly breathe the 
 resultant polluted air, allowing, for the sake of argument, that the 
 two gases are of equally poisonous character, which is not true, it 
 would take him ten times as long to get a troublesome dose of 
 acetylene as of coal gas. But it is highly improbable that he would 
 quietly breathe the gas long enough to do any harm whatever. 
 Acetylene makes its presence known by its peculiar but persistent 
 odor, which in most cases would be a sufficient safeguard. Again, 
 its eflfects are irritant and annoying rather than somnific, a second 
 important circumstance favoring the probability of the acetylene 
 leak being discovered and stopped. Further, no case of asphyxiation 
 by acetylene has ever been recorded. Asphyxiation, in the sense in 
 which we know it, as resulting from the respiration of coal gas 
 and stove gas, is entirely unknown to the character of acetylene. 
 
 (b) Danger from Vitiated Air. The combustion of all oils or 
 gases used for illumination, and the respiration of all animals impov- 
 erish and pollute the air in an unventilated space, rendering it 
 "close." It has been shown that it is an inherent property of 
 acetylene to offend less in this direction, light for light, than any 
 other illuminating gas. Since the results of burning acetylene are 
 exactly the same in character as when petroleum or coal gas or water 
 gas is used, namely, robbing the air of oxygen, and charging it 
 more or less with carbon dioxide, and since exactly the same 
 charges may fairly be made against oil or coal gas as against 
 acetylene, and to a greater degree, it would be manifestly unfair to 
 acetylene to dwell longer on so remote a possibility of danger. 
 
 (c) Danger from Explosion. In case of uncondensed acety- 
 lene, or any other combustible gas whatever, two things are necessary 
 for explosion : 
 
 1. Admixture with air. 
 
 2. Ignition of the mixture. 
 
 35 
 
The gas must first escape itito and mix with the air, and then be 
 ignited or kindled. In no other way can explosion result. Suppose 
 through ignorance or carelessness a gas jet is blown out or left 
 open. As, just now stated, half a foot will pass in an hour. Sup- 
 pose it to be a foot. A room ten feet square and eight feet high, 
 scarcely more than a good sized closet, is certainly small enough to 
 make a fair illustration. Granted that this room is perfectly gas- 
 tight, a highly improbable condition in itself, but let it be supposed. 
 In just twenty-four hours enough gas will be admitted to charge the 
 air of the room to the lowest explosive limit of three per cent. Still 
 this mixture must find a way to become kindled ^before an explosion 
 can possibly ensue. And from what was just stated of the irritating, 
 rather than somnific effect of this gas, it is highly improbable that a 
 person would continue to remain in a closed room long enough for 
 danger to arise from the gas escaping out of an open burner. 
 Acetylene can, however, never escape without revealing its presence 
 by reason of its penetrating odor, which is indeed a blessing in 
 disguise in such cases. In the event of cracks, defective joints, etc., 
 it is further true that far less acetylene would escape in a given time 
 than would be the case with coal gas, because of its greater specific 
 gravity. Distressing in truth are the accounts of accidents caused 
 by the ignition of gaseous mixtures resulting from defective coal gas 
 pipes, but the man who searches for a gas leak with a lighted candle, 
 or lamp is of the same type as the man who "did not know it was 
 loaded." There is no remedy for this inherent difficulty, hence no 
 way to remove the danger except by rigidly adhering to the rule 
 that no light shall be taken where any combustible gas can, by any 
 possibility and to any extent, be mixed with air. 
 
 Open flames should on no account be used in the vicinity of 
 acetylene generators or gas holders ; neither should a lighted cigar. 
 This is a real danger, the writer makes no attempt to conceal or 
 mitigate it ; but it is a danger of which acetylene partakes, together 
 with every other illuminating gas or oil whatever, share and share 
 alike. It is further true that explosions of the character under 
 consideration can scarcely 'ensue except from gross inattention, 
 ignorance or carelessness, and relatively they are no more numerous 
 than those arising from coal gas. 
 
 Everything considered, though prejudiced against it at the outset, 
 and absolutely and purely disinterested at present, after much careful 
 study and feeling the responsibility of being called upon to furnish 
 an unbiased opinion in this matter, the writer believes that the use 
 of acetylene for the illumination of rural homes, provided it is gen- 
 crated from good carbide in a first class apparatus, and all reason- 
 able regulations followed, is no more fraught with danger at the 
 , 36 
 
present day than any available method of illumination by gas, or 
 electricity, and less so than the usual employment of petroleum. 
 
 (d) Danger from Fire. Acetylene will indeed burn, else these 
 pages had never been written. So does kerosene and so does 
 illuminating gas. When, in England, a century ago, the promoters 
 of coal gas, after many and protracted conventions, finally secured 
 the permission to light the Houses of Parliament, the authoritative 
 document contained the condition that pipes conveying the gas 
 "shall be placed upon brackets at least eighteen inches from the 
 wall." And later, in Philadelphia, in the early thirties, the people 
 presented a "Remonstrance Against Lighting with Gas," which con- 
 tained the following wisdom : "We consider it a most inexpedient, 
 offensive and dangerous mode of lighting. We consider gas to be 
 an article as ignitible as gunpowder, and usually as fatal in its 
 results." 
 
 We shall hardly care to go backwards a hundred years and seek 
 a ridiculous objection to acetylene. We shall rather look to all 
 precautions against faulty machines and leaky piping, and not expect 
 fuel to refuse to burn when we kindle it. Care is needed in all 
 things, but some require more than others. In petroleum lighted 
 homes one of the commonest accidents is caused by children over- 
 turning oil lamps. How frequently may we read of such a catas- 
 trophe in the daily press ! Acetylene, now used in a million homes, 
 has never, in this way at least, been responsible for the cieath of a 
 child, a fact which leads to warm praise for acetylene in the home. 
 
 While this general subject will be before us again, in the chapter 
 on insurance regulations, it will not be out of place to remark here 
 that insurance experts have long since officially admitted that acety- 
 lene has proved itself less hazardous in proportion than other forms 
 of artificial illumination in common use, such as gasoline, kerosene, 
 electricity and candles. 
 
 IMPURITIES IN ACETYLENE. 
 
 With regard to impurities in acetylene, it may first be remarked 
 that such impurities owe their origin, almost exclusively, to impuri- 
 ties in the carbide from which it is derived. Impurities in carbide 
 therefore claim the first consideration. These may be grouped in 
 two classes : 
 
 (a) Those which exert no action on water, and 
 
 (b) Those which, reacting with water, throw off some gaseous 
 products of the reaction, which remain with the acetylene, rendering 
 the latter impure. 
 
 The first class, consisting of such substances as carbon (coke not 
 
 37 
 
changed in the furnace), silica (sand), and a few others, since they 
 can with water produce nothing which is added to the resultant gas, 
 are harmless except in so far as they increase the quantity of the 
 residue, and so may be dismissed. 
 
 The second class, which may impart to the gas small quantities 
 of impurities, harmless or otherwise, should be looked into. Some 
 years ago, when the carbide industry was altogether new, and when 
 the attempt was made to put carbide on the market at something 
 approaching the ridiculously low figure which was first predicted 
 for it, cheap materials were employed, and a poor result secured. 
 It was quite naturally supposed that the cheapest lime and the most 
 worthless coal would answer the purpose. The result was that 
 some very poor carbide was sold and some correspondingly impure 
 acetylene was made. It was soon found that this would not do, 
 the practice was corrected, and at present a specimen of carbide 
 made by responsible manufacturers is rarely found, in this country 
 at least, which can be said to be seriously impure. 
 
 Present practice does, and future practice must, insist on purity 
 of material. Good metallurgical coke, the analysis of whose ash 
 shows only the merest traces- of sulphur and phosphorus, is easily 
 obtainable. This with a reasonably pure lime yields carbide of great 
 purity, and there should be no other made. In fact, the quality of 
 carbide has greatly improved and it is reasonable to suppose that it 
 will, in the future, maintain its present high standard. Absolutely 
 chemically pure carbide is an industrial impossibility, but the product 
 which is known as "commercially pure" is an entirely satisfactory 
 article. But even as the best available carbide contains some quan- 
 tities of impurity, it is well to see what results may occur in the 
 quality of the acetylene. 
 
 Phosphorus and sulphur, mostly but not wholly dissipated by 
 the heat of the furnace, appear to a slight extent in the acetylene in 
 the form of minute quantities of phosphoretted hydrogen, PH3, 
 and sulphuretted hydrogen, Hj S. There may also be some small 
 quantities of ammonia, NH3, and traces of hydrogen; silicon hydride, 
 and possibly one or two others of little significance. 
 
 An analysis of the crude acetylene evolved from commercial 
 carbide in a carbide feed machine resulted as follows : 
 
 Acetylene 99.36 per cent. 
 
 Oxygen 00.08 per cent. 
 
 Nitrogen 00.11 per cent. 
 
 Hydrogen 00.06 per cent. 
 
 Sulphuretted hydrogen 00.17 per cent. 
 
 Phosphoretted hydrogen 00.04 per cent 
 
 38 
 
Ammonia oo.io per cent. 
 
 Silicon hydride 00.03 P^J" cent. 
 
 Carbon monoxide 00.01 per cent. 
 
 Methane 00.04 per cent. 
 
 Total 100.00 per cent. 
 
 This is a recent analysis, and while analyses vary somewhat, it is 
 a typical one. Of the impurities considered, hydrogen and methane 
 are harmless and may be dismissed. Oxygen and nitrogen in such 
 small quantities are also of no consequence. They result from 
 unavoidable admission of small quantities of air. Carbon monoxide 
 has already been discussed and a trace can be found in most samples 
 of acetylene, but its quantity is so exceedingly small as to be entirely 
 negligible. Phosphoretted hydrogen and silicon hydride are self- 
 inflammable and hence would kindle the gas, on exposure to air, 
 if either could be present in considerable quantity. This is not so 
 serious a property as might at first seem, for no kindling could occur 
 until the gas escapes into the air, and such ignition, if it ever 
 occurred, could scarcely do harm. Such a thing as kindling the 
 gas within the generator, or while in the pipes, is an impossibility, 
 except in the case of air mixtures which have been discussed earlier 
 in this paper. But the total quantity of these impurities is so very 
 small that the possibility of their ever effecting the ignition of 
 acetylene is an extremely remote one. The instances in which it has 
 ever been claimed that this may have taken place are so few and 
 rest on such slight evidence, that the writer does not believe them at 
 all. Experiments have conclusively shown that the quantity of 
 either one of these necessary to ignite a body of acetylene gas 
 allowed to flow into the air under most favorable conditions, is so 
 great as never to be realized, in the writer's opinion, in the practical 
 use of any carbide likely to be found in the market. 
 
 Phosphoretted hydrogen is exceedingly poisonous and most 
 deleterious if inhaled. But when we consider that a small percent- 
 age of acetylene in air is sufficient to render the air wholly irrespir- 
 able, and that only a few hundredths of a per cent, of the poisonous 
 gas could be present in the acetylene at the most, the possible 
 quantities which a person could take into his lungs in this manner 
 are so small that the writer believes that a case of poisoning by this 
 means could not be brought about, even if the attempt were inten- 
 tionally made. Certainly no such accident has ever been reported. 
 
 Aside from what has been mentioned, no further damage to 
 persons or property would arise from the impurities in acetylene 
 even if quantities of it were to escape constantly into the living 
 
 39 
 
Apartments of our homes. The ammonia and the sulphuretted 
 hydrogen are soluble in water and will to a varying degree be held 
 back in the water of the generator and of the gas holder. The 
 phosphoretted hydrogen is not so and will all enter the pipes unless 
 removed by a purifier. But supposing all three of them, and these 
 are practically the only ones which need to receive any further 
 attention, should pass through the distributing ^stem and arrive 
 at the burner, what will then become of them? Entering the flame 
 where the other gases are burning, they will, for the most part 
 at least, burn also, and the products of their combustion, like the 
 products of combustion of acetylene itself, will be thrown out into 
 the air. Let us see what these are : 
 
 Phosphoretted hydrogen, in burning, produces phosphoric oxide 
 and water vapor. 
 
 Sulphuretted hydrogen produces sulphur dioxide and water 
 vapor. 
 
 Ammonia produces free nitrogen and water vapor. 
 
 Silicon hydride produces silicon dioxide and water vapor. 
 
 Of these products the nitrogen, water vapor, and silicon dioxide 
 may be disregarded as entirely harmless. The sulphur dioxide, 
 remaining for a time in the air, may become converted into sulphuric 
 acid and this may be objectionable to health, and especially dele- 
 terious to book bindings, draperies, etc. Phosphoric oxide is without 
 a question objectionable in the air and may produce poisonous effects 
 of a serious nature if inhaled in considerable quantity. It is there- 
 fore not to be questioned that these impurities in acetylene should 
 be removed from the gas before it arrives at the burner, if they can 
 be present in considerable quantity. Ammonia and hydrogen sul- 
 phide are always present in crude coal gas and are removed in the 
 purifying process to which that commodity is always submitted, yet 
 they may be detected in minute quantity in most city gas supplies. 
 'The question is one of quantity of impurity and whether we can 
 afford to overlook it because of its very small dimensions. 
 
 Purification is discussed in a later topic, but here it may be well 
 to keep before us the fact that the purity of acetylene goes hand in 
 hand with the purity of carbide, and just as prevention is better than 
 cure, so to use only an excellent quality of carbide, thus avoiding 
 impurities, is clearly better than to use a poorer grade, which is sure 
 to result in the formation of these impurities, and then to set about 
 removing them. We are fortunate in the fact that carbide of 
 American manufacture is now so pure that the harmful ingredients 
 never cause any trouble. Enough has been said of impurities 
 arising from carbide, but a word may perhaps be added on the results 
 of overheating- 
 
 40 
 
In the generation of acetylene enormous chemical affinity is 
 displayed between the calcium in the carbide and the oxygen in 
 the water, and as in all such chemical changes, a great quantity of 
 heat is evolved. According to the method of bringing the water 
 and the carbide together, this heat may be localized so as to be 
 harmful, or so distributed as to cause no harm. In the experiment 
 of dropping a fragment of carbide into a tumbler of water, the heat 
 of the reaction is so absorbed by the relatively large body of water 
 that overheating does not occur at any point. But reverse these 
 conditions by allowing water, in limited quantity, drop by drop, to 
 fall on to a lump of carbide and you bring about the overheating of 
 the resultant gas, its conversion to some extent into oily matters, a 
 process known to the chemist as polymerization, and even into a tar. 
 Samples of carbide which have thus been treated in an experi- 
 mental way have come out of the experiment smeared with a yellow, 
 dirty, tarry mass, which shows evidence at once of overheating in 
 the gas making process, resultant loss of acetylene, and consequently 
 oily matters formed which may cause trouble when the gas laden 
 with them comes along to the burners, causing the latter to clog and 
 refuse to properly operate. These products of overheating are 
 therefore of such a nature as to call for discussion, although they 
 are not impurities in the ordinary sense. They do not pollute the 
 air nor endanger health in any way, but as they cause inconvenience 
 and trouble with the burners, they must not be ignored. Since too 
 great heat, and this alone, causes their formation, the rational 
 remedy is to prevent their production by avoiding high heat at the 
 moment of generation. The remedy is prevention. The means of 
 prevention is cool generation. 
 
 There is in acetylene another foreign substance, not exactly an 
 impurity, which is often present in small quantities, and may be 
 mechanically carried along from the generator to the distributing 
 system unless arrested. This substance is lime dust or carbide dust. 
 It is easily held back by a simple sifting or filtering arrangement, and 
 the form most frequently used is a filter consisting merely of felt. 
 Every machine should be provided with such a dust arrester or filter, 
 sometimes called a purifier, though its only office is to arrest dust. 
 
 COOL GENERATION. 
 
 It is essential to emphasize the matter of cool generation as one 
 of the utmost importance in acetylene manufacture. The function 
 of the generator is in principle a simple one. It has to provide for 
 the bringing together of the water and the carbide, wash the gas, 
 filter it as above, purify it if need be, store it to such extent as may 
 
 41 
 
be necessary, and deliver it to the pipes for distribution. The more 
 nearly the generator conforms to the simple experiment of dropping 
 a little carbide into a large volume of water, the more efficiently will 
 the heat be distributed and the more perfectly will "cool generation" 
 be accomplished. The other extreme is where a little water is 
 allowed to drip upon an excess of carbide, as in the second experi- 
 ment ; heat is localized instead of distributed, becoming excessive at 
 the point of most rapid generation. Fortunately for the acetylene 
 consumer of the present day, generators which offend most in these 
 particulars have been practically driven out of the market, and the 
 faulty machines of ten years ago are no longer doing business. 
 American generator manufacturers have been so well educated 
 along this line that it is hardly necessary in a work of this sort to 
 longer dwell upon this simple precaution. But since so much trouble 
 came to some of the first generators on this account, it may be well 
 to recall that without care in this direction, and should any manu- 
 facturer relax his vigilance so that the opposite of cool generation 
 is secured, in just the same proportion will gas once formed be used 
 up in making the heat products, benzol, styrolene, anthracene, etc. ; 
 a lower yield than the correct one will be secured from the carbide ; 
 lower candle power will also result, and the tarry products cause 
 carbonization of the burners, resulting in their becoming choked 
 and smoky, three items of great wastefulness, to say nothing of 
 annoyance and inconvenience. ^ 
 
 Foremost among the requir|Bients for a perfect, modern gen- 
 erator is, therefore, the one which demands that heat shall be avoided 
 as much as possible. Excessive overheating is detected by the 
 appearance of the lime left after the gas generation. If the residuum 
 is discolored yellow or brown, serious overheating has taken place, 
 for this lime sludge should be essentially white. Tarry deposits in 
 the residue indicate a still greater degree of overheating. 
 
 The author learns, by way of one of the German acetylene jour- 
 nals, that an attempt has been made in that country this year to 
 enforce a regulation requiring that the temperature in an acetylene 
 generator shall not exceed two hundred and twelve degrees Fahren- 
 heit. Such a regulation would be entirely too rigid, for while the 
 temperature in the gas containing parts of no good generator ever 
 reaches that point, unless frightfully overworked, nevertheless the 
 momentary temperature of some pieces of carbide, at the instant of 
 reaction, many often exceed two hundred and twelve degrees 
 Fahrenheit, but such strictly local temperatures are quickly quenched 
 by excess of water which must be present. A temperature, even 
 considerably above two hundred and twelve degrees Fahrenheit, 
 may occur within the carbide of any generator; it' is inherent in the 
 
 42 
 
nature of the reaction, but the remedy is found in abundance of 
 water to serve as a prompt and efficient equalizer. 
 
 The German incident is worthy of mention here for two reasons. 
 First, it points out that thinking acetylenists have an eye to the sub- 
 ject of this chapter, cool generation, and, secondly, it leads to the 
 reason for a most important regulation in the primer of acetylene 
 which has now become universal and which demands a gallon of 
 water to every pound of carbide. 
 
 Some earlier generators used only water enough to liberate the 
 gas, and discharged their residuum as a dry ash. The way of these 
 transgressors was hard and we know them no more. 
 
 It is well to remember still further, in this connection, that the 
 most prolific cause of overheating is to overwork the generator. 
 If a generator is calculated for ten burners and is called upon to 
 make gas for twenty, the result is sure to be excessive heat 
 production. 
 
 TYPES OF GENERATORS. 
 
 There are two general methods of bringing water and carbide 
 together for the purpose of generating gas, viz., "carbide to water," 
 and "water to carbide." 
 
 Generators are therefore most frequently designated as carbide- 
 feed and water-feed, respectively. 
 
 Inasmuch as it is far easier to fegulate the flow of liquids, by 
 means of valves and other mechanisms in common use, and uni- 
 versally well-known, than to similarly control the distribution of 
 solid materials, it was very natural that the earlier contrivances were 
 so made as to maintain a properly controlled flow of water, by jets, 
 sprinklers or otherwise, on to quantities of carbide contained in suit- 
 able vessels. Later, because of the very obvious fact that the most 
 rational plan is to drop carbide, in suitable quantities, into a large 
 excess of water, mechanisms in some variety were developed to feed 
 the solid into the liquid. As the years have advanced all the eccen- 
 tric and miscellaneous modifications have practically vanished and 
 only the fittest of both types have survived. 
 
 I. Water-feed Machines. The modem water-to-carbide gen- 
 erator usually consists of two parts, the generator proper and the 
 gas holder. Carbide is charged into what is known as the divided 
 pan, a tray divided into segments or compartments containing about 
 two pounds in each compartment and so arranged that the water 
 first attacks the carbide in compartment i, exhausts and thoroughly 
 floods it, then overflows into compartment 2, where it finds a fresh 
 supply of carbide. This being exhausted and thoroughly flooded, 
 
 43 
 
the water may then*'pass to 3, and so on till all the cells are flooded 
 in rotation, when the advancing water passes from the last com- 
 partment into cell I of another precisely similar pan below, and the 
 process is repeated, the pains being always surrounded by cold water. 
 
 This type of generator is especially adapted to localities where 
 running water is not available and where it is not possible or con- 
 venient to connect with ample drainage pipes for removal of sludge 
 and for flushing. 
 
 These generators also have the advantage of using large sizes 
 of carbide ; the refuse is carried away in the pans and water brought 
 to the machine in buckets. 
 
 2. Carbide-feed Machioes. The modern carbide-to-water gen- 
 erators also consist of two parts, the generator proper and the gas- 
 holder or bell. The generator in all these machines contains a 
 hopper of some sort which receives the carbide, fitted with a 
 mechanism to control it and admit of its dropping into the water 
 below at the right times and in small, regulated quantities. Such 
 mechanisms are of two kinds; one depends upon releasing the 
 carbide by some sort of a yalve whereby it may drop, directly or 
 indirectly, into the water below (gravity feed) ; the other depends 
 on pushing the carbide off a plate or some similar device, usually 
 by means of clock work (forced feed). Whether an apparatus is 
 based on one or the other of these principles, the carbide being sus- 
 tained in a receptacle above the water, it is imperative that its move^ 
 ment must be so safeguarded that it is impossible for the machine 
 to drop its charge uncontrolled, into the water, either by accident or 
 by intent. The feeding device, of whichever type it may be, is 
 obviously the most critical and vital part of a carbide feed 
 mechanism. On it depends uninterrupted and perfect lighting 
 service as well as safety and economy in operation. It should be 
 positive, strong and simple ; must not get out of order ; must respond 
 promptly to every demand made upon it and never feed either too 
 much or too little carbide into the generating chamber. While it 
 must release carbide whenever carbide is called for, it must with 
 equal reliability prevent the feeding of carbide at all times when it 
 is not called for. Since moisture acts on carbide in such a way as 
 to render it in time more or less sticky and less easily responsive to 
 mechanical movements, especially after a charged generator has 
 been standing for some time inactive, it follows that the feeding 
 device must also be, so far as possible, self-cleaning. 
 
 Carbide feed generators usually require a special size of carbide 
 "Nut," i}4x}i or "Quarter," ^xVi^ being in commonest use. 
 
 In either water-to-carbide or carbide-to-water generators, the 
 gas-holder, or bell, performs an important function, that of regw- 
 
 U 
 
lating the feed ; it must do this with positiveness and precision. The 
 fall of the bell, indicating as it does, approaching exhaustion of ga? 
 supply, releases the mechanism, whatever it may be, which starts the 
 feeding; the accumulated gas raises the bell, and the rising bell 
 must arrest the feed. In a nicely adjusted generator, the rise and 
 fall of the bell is very slight, a slow feeding and consequently slow 
 generation of gas assuring cool generation and steady pressure. 
 
 Of whatever type, every generator must have sufficient holder ca- 
 pacity to provide for all generation in excess of use at any time, in- 
 cluding what is called "after generation," which is the amount of gas 
 generated after the lights are turned off, but before gas evolution can 
 entirely cease. This is usually accomplished by the well known bell 
 gas-holder as just described; there are other devices to accomplish 
 the same purpose, but the bell is so common as to be almost univer- 
 sally present in the machines available in this country. Water-feed 
 generators are usually equipped with greater bell capacity than 
 carbide-feed, because in this type of apparatus more surface of 
 carbide is exposed to moist air, hence a greater amount of after 
 generation occurs. 
 
 Acetylene generators are thus seen to be automatic, that is, aside 
 from periodical care in cleaning and recharging, they are designed 
 to need no attention. They provide for the automatic evolution of 
 gas as fast as gas is drawn at the burners, and to cut off the libera- 
 tion of gas, also automatically, so soon as practicable after consump- 
 tion ceases. Large installations, such as for village lighting, exten- 
 sive factories, etc., are properly so constructed as to call for frequent 
 attention during the time when the gas generation takes place, and 
 large holders are used to maintain a supply ; but small plants, such as 
 are employed for household use, ought to demand no attention other 
 than that of occasional charging and removing of residue, in other 
 words, must automatically supply water to carbide, or carbide to 
 water, as the case may be, during the time in which gas is being 
 used. It would, of course, be possible to generate at certain inter- 
 vals when the time of an attendant could be given to this duty, sup- 
 plying carbide by hand to the water, and storing enough gas to last 
 for a day or two. But this method demands unnecessarily large 
 gasometers, which are bulky, expensive and difficult to place, hence 
 this method is nowhere in vogue for small installations, the automatic 
 machines being everywhere preferred. 
 
 Of whatever type it may be, a good generator, such as can be 
 recommended for household use, must be possessed of certain quali- 
 ties which will be conceded by all : 
 
 ( I ) It must allow no possibility of the existence of an explosive 
 mixture in anv of its parts at any time. It is not enough to argue 
 
 45 
 
that a mixture, even if it exists, cannot be exploded unless kindled. 
 It is necessary to demand that a dangerous mixture can at no time 
 be formed even if the machine is tampered with by an ignorant 
 person. The perfect machine must be so constructed that it shall be 
 impossible at any time under any circumstances to blow it up. It 
 must be "fool-proof." 
 
 (2) It must ensure cool generation. Since this is a relative 
 term, all machines being heated somewhat during the generation of 
 gas, this amounts to saying that a machine must heat but little. A 
 pound of carbide decomposed by water develops the same amount of 
 heat under all circumstances, but that heat can be allowed to increase 
 locally to a high point, or it can be equalized by water so that no 
 part of the material becomes heated enough to do damage. 
 
 (3) It must be well constructed. A good generator does not 
 need, perhaps, to be "built like a watch," but it should be solid, sub- 
 stantial, of good material. No light weight, half-price metal, likely 
 to rust through and cause leakage and resultant gas mixtures, should 
 be tolerated. It should be built of the best material adapted to the 
 purpose. It should be built for service, to last and not simply to sell ; 
 anything short of this is to be avoided as unsafe and unreliable. 
 
 (4) It must be simple. The more complicated the machine the 
 sooner it will get out of order. Understand your generator. Know 
 what is inside of it and beware of an apparatus, however attractive 
 its exterior, whose interior is filled with pipes and tubes, valves and 
 diaphragms, whose functions you do not perfectly understand. If 
 a complicated mechanism is employed to perform what seems to 
 you a simple duty, rely upon your own common sense and look 
 further till you find a perfectly simple but strong mechanism to 
 perform the work of automatically making gas. There are plenty 
 of them and you can afford to meet the price of the machine which 
 is least likely to call for repair next season. 
 
 (5) It should create no considerable pressure in any of its parts. 
 More than a pound of pressure at any point may be a source of 
 danger ; more than a few ounces is wholly unnecessary, and not to 
 be tolerated. 
 
 (6) It should be capable of being cleaned and recharged and 
 receiving all other necessary attention without loss of gas, both for 
 economy's sake, and more particularly to avoid filling the house with 
 a disagreeable odor. There is no need of any perceptible odor 
 about the machine, or in the house, and the better machines success- 
 fully guard against this nuisance. 
 
 (7) It should require little attention. All machines have to be 
 emptied and recharged periodically; but the more this process is 
 simplified and the more quickly this can be accomplished the better. 
 
 46 
 
(8) It should be provided with a suitable indicator to designate 
 how low the charge is in order that the refilling may be done in good 
 season. A generator which can by any reasonable possibility leave 
 the household, without warning, plunged in darkness, is not to be 
 tolerated. 
 
 (9) It should completely use up the carbide, generating the 
 maximum amount of gas. 
 
 As to the selection of type of generator, there are good gener- 
 ators of both types, and under Ipcal conditions it should be always 
 an easy matter to select the most suitable one. The famous Moissan, 
 French savant and chemist, wrote as long ago as December, 1896, 
 as follows: 
 
 "The ideal apparatus, which I think does not yet exist, consists 
 in a gas holder containing- an excess of water into which a fragment 
 of carbide of known weight falls automatically at the desired 
 moment. The weight of this carbide should be such that it will fill 
 the gas holder with gas without producing an excess. Moreover, 
 this carbide should not fall till the moment when the gas holder is 
 nearly empty." 
 
 And Professor Lewes, English chemist and illuminating gas 
 authority, wrote early in 1898: 
 
 "The generators of the carbide-to-water type are undoubtedly 
 the best, as, with the water kept in excess, it is impossible for the 
 temperature to rise above the boiling point of water, and under all 
 conditions this class of generators yields the purest gas, as the 
 acetylene, having to bubble through the lime water, formed in the 
 generator, is washed free from most of its impurities." Also, still 
 referring to generators of the same class, "With a properly arranged 
 tank the temperature never exceeds the air temperature by more 
 than a few degrees. Under these conditions, the absence of poly- 
 merization and the washing of the nascent and finely divided bubbles 
 of gas by the lime water, in the generator, yields acetylene of a 
 degree of purity unapproached in any other form of apparatus." 
 
 In following the development of generators in this country from 
 the earliest types to the end of 1908, the writer thinks that the ideals 
 of Moissan have been more than attained in the modern carbide 
 feed generators of the present day, and that the best water-feed 
 machines which are now to be had cover all the points of rational 
 generation so perfectly that, in places where this type is more 
 perfectly adjusted to the surroundings and conveniences, there need 
 be no hesitation in using them. 
 
 47 
 
SUPPLY OF CARBIDE. 
 
 The Union Carbide Company, of Chicago and New York, oper- 
 ating under patents, manufactures and distributes the supply of 
 calcium carbide for the entire United States and its dependencies. 
 Plants for the production of calcium carbide have been established 
 for several years at Niagara Falls, N. Y., and Sault Ste. Marie, 
 Mich. 
 
 The extraordinary advance in the consumption of carbide has 
 made necessary, repeated and, in the aggregate, enormous additions 
 to the productive capacity of the company. For several years, 
 however, the supply has been, and for the future will be, adequate 
 to mefet all domestic demands. 
 
 The Union Carbide Company, by a system of established ware- 
 houses in some fifty cities, selected with direct reference to the 
 convenience of the consumer, has enabled the user of calcium carbide 
 to secure his supply almost immediately, no matter where he may be 
 located. This system of local warehouses is being as rapidly 
 extended as necessity requires and has proved of great satisfaction 
 and advantage to the small purchaser. 
 
 For several years after this company commenced operations its 
 plan was to sell calcium carbide in car-lots to various dealers through- 
 out the country, many of whom were agents for, or manufacturers 
 of, acetylene generators. Under this plan, the price of calcium car- 
 bide to the consumer was materially higher than at present, in 
 order to allow a margin of profit to the dealer, and the cost of car- 
 bide varied all over the country, depending to a great extent upon 
 freight rates. 
 
 It was soon seen that the best interests of the consumer would 
 be served by the establishment of a uniform price, which could only 
 be accomplished by the prepayment of freight to warehouses located 
 in the near vicinity of the consumer, and thus cutting out completely 
 all profits between the manufacturer and the purchaser. This 
 change of method of distribution has resulted, in the last few years, 
 in reductions in the price of calcium carbide of as much as twenty- 
 five dollars per ton in some localities. The United States possesses, 
 therefore, a distinct advantage in this arrangement of the business, 
 and as a strictly uniform carbide of the highest grade is produced, 
 the user of acetylene is thereby enabled to assure himself as to the 
 quality of every pound of calcium carbide which he purchases. 
 
 There are in operation elsewhere throughout the world numerous 
 small plants manufacturing calcium carbide, but in foreign countries 
 the warehouse system is rendered impossible, transportation charges 
 from the manufacturer to the consumer are at local and often 
 
 48 
 
extravagant rates, and confusion as to quality creates a difficulty 
 unknown in the United States. 
 
 The price of carbide in the United States is established on the 
 basis of all freight prepaid to the local warehouse, thus avoiding 
 the long haul and the very much higher expense attached to the 
 method of distribution in foreign countries. Thus, while the price 
 at the works in Europe approximates the price at the warehouse in 
 the United States, the freight to the point of delivery must be added 
 when comparisons are made. The prevailing price of calcium 
 carbide in foreign countries is somewhat higher, and the quality of 
 the carbide considerably lower than in the United States. 
 
 The carbide industry has decidedly outgrown its infancy, and is 
 now a highly organized, scientific business conducted on the broadest 
 of sound principles. 
 
 TRANSPORTATION AND STORAGE OF CARBIDE. 
 
 Carbide, to be properly preserved for storage and shipment, 
 must be packed as soon as made in some sort of hermetically sealed 
 containers to preserve it from the deteriorating action of moisture. 
 When dry, it is a perfectly harmless substance, being solid and 
 incombustible. Its only dangerous attributes can be developed solely 
 by contact with water. Well packed, it is as safe to store or trans- 
 port as other ordinary commodities. If the building in which it is 
 stored should burn, unbroken packages will go through the fire 
 unharmed, so also would loose lumps if packages break, except 
 for the circumstance that considerate firemen usually play plenty 
 of water upon them, compelling them to generate gas, which in turn 
 burns and contributes to the conflagration. But in itself there is 
 nothing about carbide to render it to any extent a hazardous article. 
 Very early in its history certain false impressions were disseminated 
 about carbide, and have by their persistence much handicapped this 
 deserving though youthful aspirant for honors in the field of 
 industry. 
 
 As the London Chemical Trade Journal put it, "All trouble has, 
 we think, undoubtedly arisen through a certain amount of misunder- 
 standing and confusion of ideas. It would seem that the fire insur- 
 ance people have not been quite clear as to the diflFerence in the 
 nature of calcium carbide and acetylene. Knowing that the one 
 generally had something to do with the other, they have evidently 
 thought they were pretty much of a muchness, and made no dis- 
 tinction." But all these things have passed away and the notion 
 
 49 
 
that caicium carbide is a dangerous material for transportation is 1 
 relic of the past. 
 
 Calcium carbide is packed for shipment and delivery in various 
 sized sheet steel drums, containing from fifty to one thousand pounds 
 each; the price includes the cost of the drums, which, being used 
 but once, are not likely to become so battered as to prevent their 
 remaining air-tight. 
 
 Following is a reprint of a circular issued by Department of 
 Commerce and Labor : 
 
 TRANSPORTATION OF CALCIUM CARBIDE ON 
 PASSENGER STEAMERS. 
 
 Department of Commerce and Labor. Steamboat Inspection Service. 
 
 Washington, February 28, 1907. 
 Bureau Circular No. 2. 
 
 To Supervising and Local Inspectors of Steamboats, Owners of 
 Steamboats, and Others Concerned : 
 
 Treasury Decision No. 19507, dated June 18, 1898, in so far as 
 the same prohibits the transportation of carbide of calcium or calcium 
 carbide on passenger steamers, is hereby rescinded, and such trans- 
 portation, from and after the date hereof, is hereby permitted, pro- 
 vided the following requirements are observed: 
 
 Calcium carbide or carbide of calcium may be transported on 
 passenger vessels when the same is contained in steel drums or steel 
 receptacles, the seams of which are lapped and properly riveted or 
 fastened in such manner as will best insure the maximum strength 
 of the joints, and when the said drums or receptacles are fitted with 
 double covers, so that such drums or receptacles shall be watertight 
 and airtight during such transportation. For packages of one hun- 
 dred and ten pdunds or less, such drums or receptacles shall be 
 made of open-hearth steel of not less than No. 26 gauge. For 
 packages of more than one hundred and ten pounds, such drums or 
 receptacles shall be made of open-hearth steel of not less than No. 24 
 gauge: Provided, that said calcium carbide or carbide of calcium 
 may also be transported on passenger vessels in cans containing not 
 more than ten pounds of said calcium carbide or carbide of calcium 
 each, such cans to be constructed and packed as follows : Said cans 
 shall be made of ninety-pound basis tin or terneplate, shall have 
 double and lapped seams, shall have the openings in the tops fitted 
 with tight compression caps, shall be constructed so as to render 
 them watertight and airtight, and shall be packed in substantial 
 
 50 
 
wooden cases with not more than sixty pounds total weight of 
 calcium carbide or carbide of calcium in each of such cases. 
 
 Calcium carbide or carbide of calcium must not under any con- 
 ditions be transported on such vessels in other than such original 
 unopened packages, which must be plainly marked "Calcium car- 
 bide." 
 
 Geo. Uhler, Supervising Inspector-General. 
 
 Approved : Oscar S. Straus, Secretary. 
 
 INSURANCE REGULATIONS. 
 
 It would lead beyond the intended limits of this bulletin to enter 
 upon a discussion of insurance regulations which have- existed in 
 this or other countries, but which are not now in force. Those in 
 operation in this country at the present time, annulling, as of course 
 they do, all previous rules, are alone of interest to us. All insurance 
 regulations affecting carbide and acetylene should be based on the 
 most accurate scientific knowledge of the gas and the method of its 
 production. The National Board of Fire Underwriters have 
 adopted a code of rules and regulations for the construction, installa- 
 tion and use of acetylene machines, and for the storage of calcium 
 carbide, as recommended by its Committee of Consulting Engineers, 
 who have elaborated the matter with scrupulous care. These regu- 
 lations have been amended to June, 1908. They first of all abso- 
 lutely prohibit the use of liquefied acetylene and of gas generated 
 therefrom.. Part i of the code contains rules for the installation 
 of generators, part 2 embraces regulations for the storage of carbide, 
 and part 3 for the construction of generators. Generators are 
 grouped in two classes, A and B. Class A embraces all stationary 
 automatic apparatus, class B stationary non-automatic generators. 
 
 Such parts of the rules as are of particular interest for the 
 purposes of this bulletin will be here given in full : 
 
 PART I. 
 
 RULES FOR THE INSTALLATION AND USE OF 
 ACETYLENE GAS GENERATORS. 
 
 The use of liquid acetylene or gas generated therefrom is abso- 
 lutely prohibited. 
 
 Failure to observe these rules is as liable to endanger life as 
 property. 
 
 51 
 
To secure the largest measure of safety to life and property, tne 
 following rules for the installation of acetylene gas machines must 
 be observed. 
 
 CLASS A. 
 
 Stationary Automatic Apparatus. 
 
 1. Foundations, a. Must, where practicable, be of brick, 
 stone, concrete or iron. If necessarily of wood they shall be extra 
 heavy, located in a dry place and open to the circulation of air. 
 
 The ordinaiy board platform is not satisfactory. Wooden foundations 
 shall be of heavy planking, joists or timbers, arranged so that the air -will 
 circulate around them and so as to form a firm base. 
 
 b. Must be so arranged that the machine will be level and 
 unequal strain will not be placed on the generator or connections. 
 
 2. Location, a. Generators, especially in closely built up 
 districts, should preferably be placed outside of insured buildings, 
 in generator houses constructed and located in compliance with 
 Rule 9. 
 
 b. Generators must be so placed that the operating mechanism 
 will have room for free and full play and can be adjusted without 
 artificial light. They must not be subject to interference by chil- 
 dren or careless persons, and if for this purpose further enclosure is 
 necessary, it must be furnished by means of slatted partitions, per- 
 mitting the free circulation of air. 
 
 c. Generators which from their construction are rendered inop- 
 erative during the process of recharging must be so located that 
 they can be recharged without the aid of artificial light. 
 
 d. Generators must be placed where water will not freeze. - 
 
 3. Escapes or Relief Pipes. Each generator must be provided 
 with an escape or relief pipe of ample size ; no such pipe to be less . 
 than three-quarters inch internal diameter. This pipe shall be sub- 
 stantially installed, without traps, and so that any condensation will 
 drain back to the generator. It must be carried to a suitable point 
 outside the building, and terminate in an approved hood located at 
 least twelve feet above ground and remote from windows. 
 
 The hood must be constructed in such a manner that it cannot be 
 obstructed by rain, snow, ice, insects or birds. 
 
 4. Capacity, a. Must be sufficient to furnish gas continuously 
 for the maximum lighting period to all lights installed. A lighting 
 period of at least five hours shall be provided for in every case. 
 
 b. Generators for conditions of service requiring lighting 
 periods of more than five hours must be of sufficient capacity to 
 
 52 
 
avoid recharging at night. The following ratings will usually be 
 found advisable. 
 
 (1) For dwellings, and where machines are always used intermittently, 
 the generator must have a rated capacity equal to the total number of burn- 
 ers installed. 
 
 (2) For stores, opera houses, theatres, day run factories, and similar 
 service, the generator must have a rated capacity of from thirty to fifty 
 per cent, in excess of the total number of burners installed. 
 
 (3) For saloons and all night or continued service, the generator must 
 have a rated capacity of from one hundred to two hundred per cent, in 
 excess of the total number of burners installed. 
 
 c. A small generator must never be installed to supply a large 
 number of lights, even though it seems probable that only a few 
 lights will be used at a time. An overworked generator adds to the 
 cost of producing acetylene gas. 
 
 5. Carbide Charges. Must be sufficient to furnish gas con- 
 tinuously for the maximum lighting period to all burners installed. 
 In determining charges lump carbide must be estimated as capable 
 of producing four and one-half cubic feet of gas to the pound, com- 
 mercial one-fourth inch carbide four cubic feet of gas to the pound, 
 and burners must be considered as requiring at least twenty-five per 
 cent, more than their rated consumption of gas. 
 
 6. Burners. Burners consuming one-half of a "cubic foot of 
 gas per hour are considered standard in rating generators. Those 
 having a greater or less capacity will decrease or increase the number 
 of burners allowable in proportion. 
 
 Burners usually consume from twenty-five to one hundred per cent, 
 more than their rated consumption of gas depending largely on the working 
 pressure. The so-called %-toot burner when operated at pressures pf from 
 20 to 25 tenths inches water column (2 to 2% inches) is usually used with 
 best economy. 
 
 7. Piping, a. Connections from generators to service pipes 
 must be made with right and left thread nipples or long thread 
 nipples with lock nuts. All forms of unions are prohibited. 
 
 b. Piping must, as far as possible, be arranged so that any 
 moisture will drain back to the generator. If low points occur of 
 necessity in any piping, they must be drained through tees into drip 
 cups permanently closed with screw caps or plugs. No pet-cocks 
 shall be used. 
 
 c. A valve and by-pass connection must be provided from the 
 service-pipe to the blow-off for removing the gas from the holder in 
 case it should be necessary to do so. 
 
 d. The schedule of pipe sizes for piping from generators to 
 burners should conform to that commonly used for ordinary gas, 
 but in no case must the feeders be smaller than three-eights inch. 
 
 53 
 
}i 
 
 2 
 
 3 
 
 3/2 
 
 4 
 
 The following schedule is advocated : 
 
 inch pipe, 26 feet, three burners. 
 
 inch pipe, 30 feet, six burners. 
 
 inch pipe, 50 feet, twenty burners. 
 
 inch pipe, 70 feet, thirty-five burners. 
 
 inch pipe, 100 feet, sixty burners. 
 
 inch pipe, 150 feet, one hundred burners. 
 
 inch pipe, 200 feet, two hundred burners. 
 
 inch pipe, 300 feet, three hundred burners. 
 
 inch pipe, 450 feet, four hundred and fifty burners. 
 
 inch pipe, 500 feet, six hundred burners. 
 
 inch pipe, 600 feet, seven hundred and fifty burners. 
 
 e. Machines of the carbide-feed type must not be fitted with 
 continuous drain connections leading to sewers, but must discharge 
 into suitable open receptacles which may have such connections. 
 
 f . Piping must be thoroughly tested before and after the burn- 
 ers have been installed. It must not show loss in excess of two 
 inches within twelve hours when subjected to a pressure equal to 
 that of fifteen inches of mercury. 
 
 g. Piping and connections must be installed by persons experi- 
 enced in the installation of acetylene apparatus. 
 
 8. Care and Attendance. In the care of generators designed 
 for a lighting period of more than five hours, always clean and 
 re-charge the generating chambers at regular stated intervals regard- 
 less of the number of burners actually used. 
 
 Where generators are not used throughout the entire year, always 
 remove all water and gas and clean thoroughly at the end of the 
 season during which they are in service. 
 
 It is usually necessary to take the bell portion out and invert it so as to 
 allow all gas to escape. This should never be done in the presence of arti- 
 ficial light or fire of any kind. ' 
 
 Always observe a regular time, during daylight hours only, for 
 attending to and charging the apparatus. 
 
 In charging the generating chambers of water-feed machines, 
 clean all residuum carefully from the containers and remove it at 
 once from the building. Separate from the mass any unslacked 
 carbide remaining and return it to the retainers, adding new carbide 
 as required. Be careful never to fill the containers over the specified 
 mark, as it is important to allow for the swelling of the carbide 
 when it comes in contact with water. The proper action and ecoii- 
 omy of the machine are dependent on the arrangement and amount 
 of carbide placed in the generator. Carefully guard against the 
 escape of gas. 
 
 54 
 
Whenever re-charging with carbide always replenish the water 
 supply. 
 
 Never deposit residuum or exhausted material from water-feed 
 machines in sewer pipes or near inflammable material. 
 
 Always keep water tanks and water seals filled with clean water. 
 
 Never test the generator or piping for leaks with a flame, and 
 never apply flame to an outlet from which the burner has been re- 
 moved. 
 
 Ncz'cr use a lighted match, lamp, candle, lantern or any open 
 light near the machine. 
 
 Failure to observe the above cautions is as liable to endanger life 
 as property. 
 
 OUTSIDE GENERATOR HOUSES. 
 
 9. a. Outside generator houses should not be located within 
 five (5) feet of any opening into, nor shall they open toward any ad- 
 jacent building, and must be kept under lock and key. 
 
 b. The dimensions must be no greater than the apparatus re- 
 quires to allow convenient room for recharging and inspection of 
 parts. The floor must be at least twelve (12) inches above grade 
 and the entire structure thoroughly weather-proof. 
 
 c. Generator houses must be thoroughly ventilated, and any 
 artificial heating necessary to prevent freezing shall be done by 
 steam or hot water systems. 
 
 d. Generator houses must not be used for the storage of cal- 
 cium carbide except in accordance with the rules relating to that 
 subject. 
 
 CLASS B. 
 Stationary Non-Automatic Apparatus. 
 
 10. Foundations, a. Must be of brick, stone or concrete. 
 
 b. Must be so arranged that the machine will be level and so 
 that strain will not be brought upon the connections. 
 
 11. Gas Houses, a. Must be constructed entirely of non-com- 
 bustible material and must not be lighted by any system of illumina- 
 tion involving open flames. 
 
 b. Must be heated, where artificial heating is necessary t6 pre- 
 vent freezing, by steam or hot water systems, the heater to be located 
 in a separate building, and no opep flames to be permitted within 
 generator enclosures. 
 
 c. Must be kept closed and locked excepting during daylight 
 houra 
 
 d. Must be provided with a permanent and effective system of 
 ventilation which will be operative at al! times, regardless of the 
 
 periods of operation of the plant. 
 
 65 
 
12. Escape Pipes. Each generator must be provided with a 
 vent pipe of ample size, substantially installed, without traps. It 
 must be carried to a suitable point outside the building and terminate 
 in an approved hood located at least twelve feet above ground and 
 remote from windows. 
 
 The hood must be constructed in such a manner that it cannot 
 be obstructed by rain, snow, ice, insects or' birds. 
 
 13. Care and Maintenance. All charging and cleaning of ap- 
 paratus, generation of gas and execution of repairs must be done 
 during daylight hours only, and generators must not be manipu- 
 lated or in any way tampered with in the presence of artificial light. 
 
 This ■will require gas-holders of a capacity suffieient to supply all lights 
 installed for the majcimum lighting period, without the necessity of generation 
 of gas at night or by artificial light. 
 
 In the operation of generators of the carbide-feed type it is important 
 that only a limited amount of carbide be fed into a given body of water. 
 An allowance of at least one gallon of generating water per pound of carbide 
 must be made in every ease, and when this limit has been reached the generator 
 should be drained and flushed, and clean water introduced. These precautions 
 are necessary to avoid overheating during generation and accumulation of hard 
 deposits of residuum in the generating chamber. ~ 
 
 Part 2. 
 RULES FOR THE STORAGE OF CALCIUM CARBIDE. 
 
 14. Storage of Calcium Carbide, a. Calcium Carbide in quan- 
 tities not to exceed six hundred (600) pounds may be stored, when 
 contained in approved metal packages not to exceed one hundred 
 (100) pounds each, inside insured property, provided that the place 
 of storage be dry, waterproof and well ventilated, and also provided 
 that all but one of the packages in any one building shall be sealed 
 and the seals shall not be broken so long as there is carbide in excess 
 of one ( I ) pound in any other unsealed package in the building. 
 
 b. Calcium Carbide in quantities in excess of six hundred (600) 
 pounds must be stored above ground in detached buildings, used 
 exclusively for the storage of Calcium Carbide, in approved metal 
 packages, and such buildings shall be constructed to be dry, water- 
 proof and well ventilated. 
 
 c. Packages to be approved must be made of metal of suffi- 
 cient strength to insure handling the package without rupture, and 
 be provided with a screwed top or its equivalent. 
 
 They must be constructed so as to be water and air-tight without 
 the use of solder, and conspicuously marked "calcium carbide — 
 
 DANGEROUS IF NOT KEPT DRY." 
 
 Part 3. 
 
 RULES FOR THE CONSTRUCTION OF GENERATORS. 
 
 The following rules are intended to provide only against the 
 
 more hazardous defects usually noted in apparatus of this kind. The 
 
 rules do not cover all details of construction npr the proper propor- 
 
 56 
 
tioning of parts, and devices which comply with these requirements 
 alone are not necessarily suitable for listing as permissible for use. 
 These points are often only developed in the examination required 
 before permission is given for installation. 
 
 CLASS A. 
 
 STATIONARY APPARATUS FOR ISOLATED 
 INSTALLATIONS. 
 
 IS- General Rules — Generators, a. Must be made of iron or 
 steel, and in a manner and of material to insure stability and dura- 
 bility. 
 
 b. Must be automatically regulated and uniform in their action, 
 producing gas only as immediate consumption demands, and so de- 
 signed that gas is generated without producing sufficient heat to 
 cause yellow discoloration of residuum (which will occur at about 
 five hundred degrees Fahrenheit) or abnormal pressure at any stage 
 of .the process when using carbide of any degree of fineness. 
 
 The presence of excessive heat tends to change the chemical character 
 of the gas and may even cause its ignition, while in machines of the carbide- 
 feed type, finely divided carbide will produce excessive pressure unless pro- 
 vision is made to guard against it. 
 
 c. Must be so arranged that during recharging back flow of 
 gas from the gas-holder will be automatically prevented, or so ar- 
 ranged that it will be impossible to charge the apparatus without 
 first closing the supply pipe to the gas-holder, and to the other gen- 
 erating chambers if several are used. 
 
 This is intended to prevent the dangerous escape of gas. 
 
 d. The water or carbide supply to the generating chamber must 
 be so arranged that gas will be generated long enough in advance of 
 the exhaustion of the supply already in the gas-holder to allow the 
 using of all lights without exhausting such supply. 
 
 This provides for the continuous working of the apparatus under all 
 conditions of water feed and carbide charge, and it obviates the extinction 
 of lights through intermittent action of the machine. 
 
 e. No valves or pet-cocks opening into the room from the gas- 
 holding part or parts, the draining of which will allow an escape of 
 gas, are permitted, and condensation from all parts of the apparatus 
 must be automatically removed without the use of valves or me- 
 chanical working parts. 
 
 57 _. 
 
Such valves and pet-cocks are not essential; their presence increases the 
 possibility of leakage. The automatic removal of condensation from the 
 apparatus is egsential to the safe working of the machine. 
 
 U-traps opening into the room from the gas-holding parts must not be 
 used for removal of condensation. All sealed drip connections must be so 
 arranged as to discharge gas to the blow-off when blown out, and the seals 
 must be self -restoring upon relief of abnormal pressure. 
 
 The apparatus must be capable of withstanding fire from outside 
 causes. 
 
 Sheet metal joints must be double seamed or riveted and thor- 
 oughly sweated with solder. Pipes must be attached to sheet 
 metal with lock-nuts or riveted flanges. 
 
 This prohibits the use of wood or of joints relying entirely upon solder. 
 
 g. Gage glasses, the breakage of which would allow the escape 
 of gas must not be used. 
 
 h. The use of mercury seals is prohibited. 
 
 Mercury has been found unreliable as a seal in acetylene apparatus. 
 
 i. Combustible oils must not be used in connection with the 
 apparatus. 
 
 j. The construction must be such that liquid seals shall not 
 become thickened by the deposit of lime or other foreign matter. 
 
 k. The apparatus must be constructed so that accidental siphon- 
 ing of water will be impossible. 
 
 1. Flexible tubing, swing joints, unions, springs, mechanical 
 check valves, chains, pulleys, stuffing boxes and lead or fusible 
 piping must not be used on acetylene apparatus, except where fail- 
 ure of such parts will not vitally affect the working or safety of the 
 machine. 
 
 Floats must not be used excepting in cases where failure will 
 result only in rendering the machine inoperative. 
 
 m. Every machine must be plainly marked with the maximum 
 number of lights it is designed to supply, the amount of carbide 
 necessary for a single charge, the manufacturer's name and the 
 name of the machine. 
 
 i6. Generating Chambers, a. Must be constructed of galvan- 
 ized iron or steel not less than No. 24 U. S. Standard gage in thick- 
 ness for capacities up to and including 20 gallons, not less than No. 
 22 U. S. Standard gage for capacities between 20 and 75 gallons, 
 and not less than No. 20 U. S. Standard gage for capacities in excess 
 of 75 gallons. 
 
 b, Mu5t each be connected with the gas-holder in such a man- 
 
 58 
 
ner that they will, at all times, give open connection either to the 
 gas-holder or to the blow-off pipe to the outer air. 
 
 This prevents dangerous pressure within or the escape of gas from the 
 generating chamber. 
 
 c. Must be so constructed that not more than 5 pounds of car- 
 bide can be acted upon at once, in machines which apply water in 
 small quantities to the carbide. 
 
 This tends to reduce the danger of over-heating and excessive after-gen- 
 eration by providing for division of the carbide charges in machines of this 
 type. 
 
 d. Must be provided with covers having secure fastenings to 
 hold them properly in place, and those relying on a water seal must 
 be submerged in at least twelve inches of water. Water seal cham- 
 bers for covers depending on a water seal must be one and one-half 
 inches wide and fifteen inches deep, excepting those depending upon 
 the filling of the seal chambers for the generation of gas, where nine 
 inches will be sufficient. 
 
 e. Must be so designed that the residuum will not clog or aflfect 
 the working of the machine and can conveniently be h?ndled and 
 removed. 
 
 f. Must be provided with suitable vent connections to the blow- 
 off pipe so that residuum may be removed and the generating water 
 replaced without causing siphoning or introducing air to the gas- 
 holder upon recharging. 
 
 This applies to macliines of the carbide-feed type. 
 
 g. Feed mechanism for machines of the carbide feed type must 
 be so designed that the direct fall of carbide from the carbide holder 
 into the water of the generator is prevented at all positions of the 
 feed mechanisms; or, when actuated by the rise and fall of a gas 
 bell, must be so arranged that the feed valve will not remain open 
 after the landing of the bell, and so that the feed valve remains 
 inoperative as long as the filling opening on the carbide hopper re- 
 mains open. Feed mechanisms must always be far enough above 
 the water level to prevent clogging from the accumulation of damp 
 lime. For this purpose the distance should be not less than 10 
 inches. 
 
 17. Carbide Chambers, a. Must be constructed of galvanized 
 iron or steel not less than No. 24 U. S. Standard gage in thickness 
 for capacities up to and including fifty (50) pounds and not less 
 
 59 
 
than No. 22 U. S. Standard gage for capacities in excess of fifty 
 (50) pounds. 
 
 b. Must have sufficient carbide capacity to supply the full num- 
 ber of burners continuously and automatically during the maximum 
 lighting period. 
 
 This rule removes the necessity of recharging or attending to the machine 
 at Improper hours. Burners almost invariably require more than their 
 rated consumption of gas and carbide is not of staple purity, and there 
 should therefore be an assurance of sufficient quantity to last as long as 
 light is needed. Another important consideration is that in some establish- 
 ments burners are called upon for a much longer period of lighting than in 
 others, requiring a generator of greater gas producing capacity. Machines 
 having several generating chambers must automatically begin generation in 
 each upon exhaustion of the preceding chamber. 
 
 c. Must be arranged so that the carbide holders or charges may 
 be easily and entirely removed in case of necessity. 
 
 18. Gas Holders, a. Must be constructed of galvanized iron 
 or steel not less than No. 24 U. S. Standard gage in thickness for 
 capacities up to and including 20 gallons, not less than No. 22 U. S. 
 Standard gage for capacities between 20 and 75 gallons, and not less 
 than No. 20 U. S. Standard gage for capacities in excess of 75 gal- 
 lons. 
 
 Gas bells, if used, may be two gages lighter than holders. 
 
 Condensation chambers, if placed under holders, to be of same 
 gage as holders. 
 
 b. Must be of sufficient capacity to contain all gas generated 
 after all lights have been extinguished. 
 
 If the holder is too small and blows off frequently after the lights are 
 extinguished there is, a waste of gas. This may suggest improper working 
 of the apparatus and encourage tampering. 
 
 m 
 
 c. Must, when constructed on the gasometer principle, be so 
 arranged that when the gas bell is filled to its maximum with gas 
 at normal pressure, its lip or lower edge will extend at least 9 
 inches below, the inner water level. 
 
 d. Must, when constructed on the gasometer principle, have 
 the dimensions of the tank portion so related to those of the bell 
 that a pressure of at least eleven (11) .inches will be necessary 
 before gas can be forced from the holder. 
 
 e. The bell portion of a gas-holder constructed on the gasome- 
 ter principle must be provided with a substantial guide to its upward 
 movement, preferably in the center of the holder, carrying a stop 
 acting to check the bell one inch above the normal blow-off point. 
 
 This tends to insure the proper action of tbe bell and decreases the 
 liability of escaping gas. 
 
 60 
 
f. A space of at least three-quarters of an inch must be allowed 
 between the sides of the tank and^the bell. 
 
 g. All water seals must be so arranged that the water level 
 may be readily seen and maintained. 
 
 19. Heater Supply, a. The supply of water to the generator 
 for generating purposes must not be taken from the water seal of 
 any gas-holder constructed on the gasometer principle, unless the 
 feed mechanism is so arranged that the water seals provided for in 
 Rules 20, b, c and d, may be retained under all conditions. 
 
 This provides for the proper level of water in the gas-holder. 
 
 b. In cases where machines of the carbide-feed type are sup- 
 plied with water from city water mains or house pipes, the pipe 
 connection must discharge into the regularly provided filling trap on 
 the generator and not through a separate continuous connection 
 leading into the generating chamber. 
 
 This is to prevent the expulsion of explosive mixtures through the filling 
 trap in refilling. 
 
 20. Reliefs or Safety Blow-offs. a. Must in all cases be pro- 
 vided, and must afford free vent to the outer air for any over- 
 production of gas, and also afford relief in case of abnormal pres- 
 sure in the machine. 
 
 Both the above mentioned vents may be connected with the same escape 
 pipe. 
 
 b. Must be at least J^-inch internal diameter and be pro- 
 vided with suitable means for connecting to the pipe leading outside 
 of the building. 
 
 c. Must be constructed without valves or other mechanical 
 working parts. 
 
 d. Apparatus requiring pressure regulators must be provided 
 with an additional approved safety blow-off attachment located 
 between the pressure regulator and the service pipes and discharg- 
 ing to the outer air. 
 
 This is intended to prevent the possibility of under pressure in the serv- 
 ice pipes due to failure of the pressure regulator. 
 
 21. Pressures, a. The working pressure at the generator 
 
 must not vary more than ten-tenths (one) inch water column under 
 
 all conditions of carbide charge and feed, and between the limits of 
 
 no load and 50 per cent, overload. 
 
 61 
 
b. Apparatus not requiring pressure regulators must be so 
 arranged that the gas pressure cannot exceed sixty-tenths (six) 
 inches water column. 
 
 This requires the use of the pressure relief provided for in Eule No. 
 20a. 
 
 c. Apparatus requiring pressure regulators must be so arranged 
 that the gas pressure cannot exceed three pounds to the square inch. 
 
 The pressure limit of three pounds is taken since that is the pressure 
 corresponding to a water column about six feet high, which is about the limit 
 in point of convenience for water sealed reliefs. 
 
 22. Air Mixtures. Generators must be so arranged as to con- 
 tain the minimum amount of air when first started or recharged, and 
 no device or attachment facilitating or permitting mixture of air 
 with the gas prior to consumption, except at the burners, shall be 
 allowed. 
 
 Owing to the explosive properties of acetylene mixed with air, machines 
 must be so designed that such mixtures are impossible. 
 
 23. Purifiers, a. Must be constructed of galvanized iron or 
 steel not less than No. 24. U. S. Standard gage in thickness. 
 
 b. Where installed, purifiers must conform to the general rules 
 for the construction of other acetylene apparatus and allow the free 
 passage of gas. 
 
 c. Purifiers must contain no carbide for drying purposes. 
 
 d. Purifiers must be located inside of gas-holders, or, where 
 necessarily outside, must have no hand-holes which can be opened 
 without first shutting off the gas supply. 
 
 24. Pressure Regulators, a. Must conform to the rules for 
 the construction of other acetylene apparatus so far as they apply 
 and must not be subject to sticking or clogging. 
 
 b. Must be capable of maintaining a uniform pressure,, not 
 varying more than four-tenths inch vvater column, at any load within 
 their rating. 
 
 c. Must be installed between valves in such a manner as to 
 facilitate inspection and repairs. 
 
 CLASS B. 
 
 Stationary Apparatus for Central Station Service. 
 
 Generators of over 300 lights capacity for central station service 
 are not required to be automatic in operation. Generators of less 
 than 300 lights capacity must be automatic in operation and must 
 comply in every respect with the requirements of Part 3, Class A. 
 
 62 
 
25. General Rules — Generators, a. Must be substantially con- 
 structed of iron or steel and be protected against depreciation by an 
 effective and durable preventive of corrosion. 
 
 Galvanizing is Htrongly recommended as a protection against oxidation, 
 and it may to advantage be reinforced by a thorough coating of asphaltum 
 or similar material. 
 
 b. Must contain no copper or alloy of copper in contact with 
 acetylene, excepting in valve». 
 
 c. Must be so arranged that generation will take place without 
 overheating; temperature in excess of 500° F. to be considered 
 excessive. 
 
 d. Must be provided with means for automatic removal of con- 
 densation from gas passage. 
 
 e. Must be provided with suitable protection against freezing 
 of any water contained in the apparatus. 
 
 No salt or other corrosive chemical is permissible as a protection against 
 freezing. 
 
 f. Must in general comply with the requirements governing the 
 construction of apparatus for isolated installations so far as they 
 are applicable. 
 
 g. Must be so arranged as to insure correct procedure in 
 recharging and cleaning. 
 
 h. Generators of the carbide-feed type must be provided with 
 some form of approved measuring device to enable the attendant to 
 determine when the maximum allowable quantity of carbide has 
 been fed into the generating chamber. 
 
 In the operation of generators of this type an allowance of at 
 least one gallon of clean generating water per pound of carbide 
 should be made, and the generator should be cleaned after slacking 
 of every full charge. Where lump carbide is used the lumps may 
 become embedded in the residuum, if the latter is allowed to accu- 
 mulate at the bottom of the generating chamber, causing overheat- 
 ing from slow and restricted generation, and rendering the mass 
 more liable* to form a hard deposit and bring severe stress upon 
 the walls of the generator by slow expansion. 
 
 26. Generating Chambers, a. Must each be connected with 
 the gas-holder in such a manner that they will, at all times, give 
 open connection either to the gas-holder or to the blow-off pipe into 
 the outer air. 
 
 b. Must be so arranged as to guard against appreciable escape 
 of gas to the room at any time during the introduction of the 
 
 charges. 
 
 63 
 
c. Must be so designed that the residuum will not clog or aflfect 
 " the operation of the machine, and can conveniently be handled and 
 
 removed. 
 
 d. Must be so arranged that during the process of cleaning and 
 recharging, backflow of gas from the gas-holder or other generating 
 chambers will be automatically prevented. 
 
 27. Gas-Holders. a. Must be of sufficient capacity to contain 
 at least 4 cubic feet of gas per J/^-foot burner of the rating. 
 
 This is to provide for the requisite lighting period without the necessity 
 of making gas at night, allowance being made for the enlargement of burn- 
 ers caused by the use of cleaners. 
 
 b. Must 'be provided with suitable guides to direct the move- 
 inent of the bell throughout its entire travel. 
 
 28. Pressure Reliefs. Must in all cases be provided, and 
 must be so arranged as to prevent pressure in excess of 100 tenths 
 (10) inches water column in the mains. 
 
 29. Pressures. Gas-holder must be adjusted to maintain a 
 pressure of approximately 25 tenths (2.5) inches water column in 
 the mains. 
 
 CLASS D. 
 
 Portable Table Lamps. 
 
 30. General Rules — Lamps, a. Must be substantially made 
 )f metal, and the construction must embody no copper, either pure 
 or alloyed, in contact with acetylene. 
 
 b. Must in all parts subject to corrosion be thoroughly pro- 
 tected by an effective and durable preventive of rust. 
 
 c. Must be designed with a view to stability, the assembly 
 being sucli that when completely charged and ready for operation 
 inclination at an angle of 30 degrees with the vertical will not result 
 in upsetting. 
 
 d. Must be fitted with not more than one single or multiple 
 burner, and the total rated gas consumption must not be more than 
 % cubic foot per hour. 
 
 e. Must be automatically regulated and uniform in their action, 
 producing gas only as immediate consumption demands, and be so 
 designed that gas is generated without producing sufficient heat to 
 cause yellow discoloration of the residuum (which will occur at 
 about 500 degrees Fahr.) or abnormal pressure at any stage of the 
 process when using carbide of any degree of fineness. 
 
 f. Must have no mechanical or spring relief valve, and must 
 
 64 
 
be so designed as to prevent automatically the accumulation of 
 excessive pressure when placed in any position or overturned. 
 
 g. No valves or pet-cocks opening into the room from gas- 
 holder parts, the draining of which would allow an escape of gas, 
 are permissible, and condensation from all parts of the apparatus 
 must be automatically disposed of without the use of valves or 
 mechanical working parts. 
 
 h. Gage glasses, the breakage of which would allow escape of 
 gas, must not be used. 
 
 i. The use of mercury seals is prohibited. 
 
 Mercury has been found unreliable as a seal in acetylene apparatus. 
 
 j. Combustible oils must not be used in connection with the 
 apparatus. 
 
 k, Water seals, the breakage of which would allow escape of 
 gas into the room, are prohibited. 
 
 1. Every lamp must be provided with a permanent marking 
 stating plainly the amount of carbide necessary for a single full 
 charge, the manufacturer's name and the name of the lamp. 
 
 31. Generating Chambers, a. Must be so designed that gen- 
 eration will take place under conditions similar to those which 
 obtain in the best generator practice. 
 
 b. Must afford ample room for the residuum without contain- 
 ing unnecessary air spaces. 
 
 c. Must be so designed that the residuum will not clog or affect 
 the working of the device, and be so arranged that the residuum 
 can conveniently be handled and removed. 
 
 32. Carbide Receptacles, a. Must have sufficient carbide ca- 
 pacity to supply continuously the burner for which the lamp is 
 rated during a lighting period of not less than six hours. 
 
 In determining charges the yield of gas from the various grades of carbide 
 must be estimated as follows: 
 
 From the 3% in. x 2 in. grade 4% cubic feet per lb. 
 
 <i "2 " X %" " -1% " " " 
 
 " " 1% " X %" " ••4% " " " 
 
 " " %" X 1-12" " 4 " " 
 
 " " "Electrolite" 4 " " 
 
 These figures are specified in order that a reasonable allowance may be 
 insured for depreciation after the initial opening of the package. 
 
 The gas consumption of burners must be estimated at 50 per cent in 
 excess of the rating. 
 
 b. Must be arranged so that the carbide holders or charges 
 may be easily and entirely removed in case of necessity. 
 
 c. May in no case have capacity for more than two pounds of 
 
 carbide. 
 
 65 
 
33- Water Supply. Must be similar in quantity to the allow- 
 ance made in the best generator practice. 
 
 34. Pressures, a. The working pressure at the burner must 
 not vary more than ten-tenths (one) inch water column under all 
 conditions of carbide charge and feed. 
 
 b. Lamps requiring pressure regulators or reducers must be so 
 constructed as to withstand without injury a pressure equivalent to 
 four times the maximum pressure obtainable in normal operation. 
 
 35. Pressure Regulators, a. Must conform to the rules for 
 the construction of other acetylene apparatus so far as they apply, 
 and must not be subject to sticking or clogging. 
 
 b. Must be capable of maintaining a uniform pressure, not 
 varying more than four-tenths inch water column, at any load within 
 their rating. 
 
 36. Purifiers. Where installed, purifiers must conform to the 
 general rules for the construction of other acetylene apparatus and 
 allow the free passage of gas.- 
 
 37. Means of Control, a. Must be such as to obviate accu- 
 mulation of pressure within the lamp or appreciable discharge of gas 
 after extinction of the light. 
 
 b. Must be so arranged as to necessitate tight closure of the 
 carbide filling opening before the feed can be put into operation. 
 
 Prominent features in the above rules, to which attention is here 
 called, are: 
 
 (i) Use of liquefied acetylene or gas generated therefrom is 
 absolutely prohibited. 
 
 (2) Generators must be well made and of substantial material. 
 
 (3) Generators must effect a regular and complete liberation 
 of gas. 
 
 (4) Machines must accomplish cool generation. 
 
 (5) Safety is as near absolute as possible. 
 
 (6) Air mixtures and undue pressures are eliminated. 
 
 ACETYLENE AND CARBIDE STORAGE FORMS. 
 
 National Board of Fire Underwriters, 135 William Street. 
 
 New York, June 30, 1908. 
 At a meeting of the Executive Committee, held on the 25th inst., 
 the following revised forms were adopted on recommendation of 
 the Committee on Clauses and Forms : 
 
 66 
 
N'ational Board Standard Form No. i2. 
 
 PERMIT FOR THE USE OF ACETYLENE GAS. 
 
 (As Amended June, 1908.) 
 
 In consideration of the following warranties on the part of the 
 assured permission is hereby granted to light the premises described 
 
 m this policy with acetylene gas, using a Acetylene Gas 
 
 Machine manufactured by at 
 
 warranted. 
 
 1. That the charging of the generator and the handling of the 
 calcium carbide shall be by daylight only, and that no artificial light 
 or fire shall be permitted within ten feet of the generator unless 
 separated therefrom by brick or other non-combustible walls. 
 
 2. That no additions to or changes in the installation shall be 
 made without notice to and the written consent of this company 
 endorsed hereon. 
 
 3. That the use of liquid acetylene or gas generated therefrom 
 on the premises described herein, shall be absolutely prohibited. 
 
 4. That in all respects the installation shall be in accordance 
 with the rules of the National Board of Fire Underwriters. 
 
 5. That not more than 100 lbs. of calcium carbide will be per- 
 mitted upon the premises, the same to be kept in water-tight metal 
 cans and to be stored in a dry, waterproof and well ventilated place. 
 
 Attached to and forming a part of Policy No of In- 
 surance Company of 
 
 Agents. 
 
 CAUTIONS. 
 
 1. A regular time, during daylight hours, should be set for at- 
 tending to and charging the apparatus. 
 
 2. In charging generating chambers, clean all residuum care- 
 fully from the containers and remove it at once from the building. 
 Separate the unexhausted carbide, if any remains, from the mass 
 and return it to the container, adding new carbide as required. Be 
 careful never to fill the container over the specified mark, as it is 
 important to allow for the swelling of the carbide when it comes in 
 contact with water. The proper action and economy of the machine 
 are dependent on the arrangement and amount of carbide placed 
 in the generator. Carefully guard against the escape of gas. 
 
 67 
 
3. Whenever recharging with carbide, always replenish the 
 water supply. 
 
 4. Never deposit residuum or exhausted material in the sewer 
 pipes or near inflammable material. 
 
 5. Water tanks and water seals must always be kept filled with 
 clean water.' 
 
 6. Never install more than the equivalent of the number of 
 half- foot burners for which the machine is rated. 
 
 7. Never test the generator or piping for leaks with a flame, 
 and never apply flame to an outlet from which the burner has been 
 removed. 
 
 8. Never use a lighted match, lamp, candle, lantern or any 
 open light near the machine. 
 
 9. See that the entire installation is in accordance with the rules 
 of the National Board of Fire Underwriters, a copy of which may 
 be obtained of your insurance agent, and obtain a written guarantee 
 from the party installing same that these rules are complied with. 
 
 Note. — The failure to observe the above cautions is as liable to 
 endanger life as property. 
 
 National Board Standard Form No. 13. 
 
 PERMIT FOR STORAGE OF CALCIUM CARBIDE CON- 
 TAINED IN APPROVED METAL CANS HOLDING 
 NOT MORE THAN 100 LBS. EACH. 
 
 (As Amended June, 1908.) 
 
 In consideration of the following warranties on the part of the 
 assured, permission is hereby granted to store not exceeding six 
 hundred (600) pounds of calcium carbide on the premises described 
 in this policy. 
 
 warranted. 
 
 , I. That all calcium carbide will be contained in water-tight 
 metal cans having a capacity not exceeding 100 pounds each. 
 
 2. That all such metal cans of calcium carbide will be stored 
 in a dry, waterproof and well ventilated place and not more than 
 one can of calcium carbide shall be opened for use or sale at any 
 one time. 
 
 Attached to and made a part of Policy No of the 
 
 Insurance Company of 
 
 Agents. 
 
 68 
 
PERMITTED MACHINES. 
 
 It is still further to be noted that the Consulting Engineers of 
 the National Board of Fire Underwriters examine and test genera- 
 tors submitted to them, and publish a list, revised from time to 
 time, of machines which they approve. Factory practices used by 
 manufacturers are also inspected from time to time and the manu- 
 facturing concerns are placed under agreement to furnish for sale 
 under the names of permitted machines only such apparatus as are 
 similar in all respects to samples and specifications on file at the 
 Underwriters' Laboratories. The examination is rigid and search- 
 ing, and while it may be that an occasional inferior and unsafe 
 machine may have received the approval of the underwriters, an- 
 swer may be made that the system, nevertheless, now rules out 
 machines which do not comply with the requirements. 
 
 The public has thus been spared the danger which would have 
 arisen from the unrestricted use of a large percentage of machines 
 which failed to pass the inspection. There were also a multitude of 
 others, especially in the early days of the industry, which never 
 reached the inspection board, presumably because the makers of 
 these machines were conscious of their defects. It is still further 
 true that of the numerous different kinds of generators approved 
 by the board, many, probably a majority, perhaps nearly all, failed 
 to receive the official approval on first appearance and only did 
 secure it after making repeated improvements at the suggestion of 
 the board. The work of the underwriters is directed in the line 
 of the common good, and aims at minimizing danger of fire ; they 
 are worthy of full credence when they attest, as they do, that the 
 permitted machines "are safeguarded to as great an extent as it is 
 possible to safeguard appliances of this character." The writer 
 ought not to fail to include in his advice to persons who contem- 
 plate introducing acetylene illumination that they purchase only 
 such machines as continue to bear the approval of the underwriters. 
 There are plenty of such. 
 
 The latest list of such generators as the board will permit to be 
 installed within insured buildings, issued under date of July, 1908, 
 is here given. It is worthy of notice that out of about two hundred 
 and fifty machines which passed the examination during the ten 
 years from 1897 to 1908, inclusive, less than sixty remain on the 
 latest list as now complying with the advanced requirements of the 
 underwriters. 
 
 Attention is also called to the "Cautions" appended at the end of 
 the list. 
 
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4. Whenever recharging with carbide, always replenish the 
 water supply. 
 
 5. Never deposit residuum or exhausted material from water 
 feed machines in sewer pipes or near inflammable material. 
 
 6. Water tanks and water seals must always be kept filled with 
 clean water. 
 
 7. Never install more than the equivalent of the number of 
 half-foot burners for which the machine is rated. 
 
 8. Never test the generator or piping for leaks with a flame, 
 and never apply flame to an outlet from which the burner has been 
 removed. 
 
 9. Never use a lighted match, lamp, candle, lantern or any open 
 light near the machine. 
 
 ID. See that the entire installation is in accordance with the 
 rules of the National Board of Fire Underwriters, a copy of which 
 will be furnished by your insurance agent, and obtain from your 
 contractor a written guarantee that these rules are complied with. 
 
 Note. — Failure to observe the above cautions is as liable to 
 endanger life as property. 
 
 ACETYLENE ILLUMINATION A MEASURE OF SAFETY. 
 
 . It is the business of the fire insurance underwriter to take 
 cognizance, in his conservative way, of every new process, or in- 
 dustry, which affects the fire hazard in any way and to adjust his 
 rulings to changes of condition. If these be in the direction of 
 greater safety, he will encourage them ; if of increased hazard, he 
 will do the reverse. 
 
 No innovation can come much nearer to the heart of the under- 
 writer than a new method of illumination. Candles came into gen- 
 eral use long before the underwriters were organized and, how- 
 ever great the hazard they cause, they are hardly under the juris- 
 diction of the underwriter. Acetylene, on the other hand, a develop- 
 ment of the last dozen years, and now so far advanced that its bril- 
 liant light encircles the globe, and that its use in the United States 
 alone exceeds twenty billion candle power hours per annum, has 
 grown into popular favor under the complete control of the Na- 
 tional Board. The advance of the new illuminant has been per- 
 mitted only after its competent committee of consulting engineers 
 have rigidly held to every detail of requirement, which they, as 
 representatives of the Board, have themselves established. 
 
 Acetylene does cause a certain measure of fire hazard, it is true. 
 Put so also does the man who throws his lighted cigarette into the 
 
 73 
 
waste basket, or the lady of the house who cleans her gloves or her 
 canary bird with gasoline, and so did the servant girl who lighted 
 the fire with benzine, and about whom the local paper unfeelingly 
 remarked that "nothing had benzine of her since!" So likewise do 
 lighting hazards arise from the use of liquid hydrocarbons in any 
 form, of matches and candles, and of electric lighting. But when 
 we recall that acetylene is used in so many homes, largely in country 
 places, that when a million burners are lighted, as occurs every 
 evening, replacing as they do the candle with all its dangers as well 
 as gasoline and kerosene which may be spilled or used to encourage 
 the kitchen fire, can there be any denial of the truth of the assertion 
 that acetylene in such cases diminishes the hazard? 
 
 It seems to us that we may assert with positiveness that the 
 introduction of acetylene does produce a distinctly lower fire risk 
 than existed in the same localities before. If not, wherein lies the 
 danger? Certainly not in the carbide, whose properties we have 
 described fully elsewhere, and whichns transported at the lowest 
 freight rates, long experience with large shipments having con- 
 vinced the transportation companies that it can be handled literally 
 without hazard. It certainly does not reside in the water, the only 
 other substance which is required for the generation of the gas; it 
 is therefore not behind the generator so to speak. Now, to the front 
 of the generator we find only the pipe system, laid in accordance 
 with underwriters' rules, fitted with a minimum of leakage, because 
 this gas being more concentrated than other illuminating gas, every 
 owner looks carefully after his pipes as a measure of the common- 
 est economy. Then come the burners, about which, it has been 
 pointed out that if a full sized burner should by any chance be left 
 open in a sleeping room, and should the occupant fail to be roused 
 by the odor, or be unable to escape from the room, he would die of 
 starvation before the air would become irrespirable. Compare this 
 with the inevitable result of leaving the coal gas burner open in a 
 small sleeping room for a few hours ; and then recall that even if a 
 large leak should occur, from a broken fitting or a disconnected 
 pipe, the ordinary house generator could only deliver the result of 
 a single charge, probably not over a hundred cubic feet, whereas 
 a similar leak in a city supply pipe has behind it the entire ' contents 
 of the city gas holder ! 
 
 Now if the hazard is neither to the front nor to the rear of the 
 generator, we have only the generator itself yet to inspect. The 
 acetylene generator is the only illuminating contrivance which has 
 enjoyed, from its inception, the guidance of the underwriters. The 
 industry has paid the tax and heartily cooperated with the under- 
 writers in their efforts to attain their ideal. Safety devices lock and 
 
 74 
 
interlock the different parts exactly as prescribed by the underwrit- 
 ers. Their trained guidance has determined the thickness of the 
 metal employed, the feeding devices, escape valves, means for pre- 
 venting over-feeding, for stopping the action of the machine should 
 any detail be out of order, etc., etc. Their primary idea has been 
 to produce an ideal machine, so nearly as possible perfect for inside 
 installation, and it may be truthfully said that they have developed 
 a generator which assures a smaller risk than the illuminants it 
 replaces. 
 
 RESOLUTION ON ACETYLENE 
 
 PASSED BY THE NATIONAL BOARD OF ENGINEERS 
 AND REFERRED BY THEM TO THE NATIONAL 
 BOARD COMMITTEE ON LIGHTING, HEATING AND 
 PATENTS, BY WHOM IT WAS SENT TO THE EXEC- 
 UTIVE COMMITTEE OF THE NATIONAL BOARD OF 
 FIRE UNDERWRITERS, WHO, ON JANUARY 30, 1908, 
 MODIFIED THE RULES IN ACCORDANCE WITH THE 
 SUGGESTIONS OF THE ENGINEERS. 
 
 In viewf of the fact that the number of acetylene generators 
 installed inside of buildings has very largely increased in the past 
 few years, while at the same time our records seem to show that 
 the number of fires ascribed to such installations has, if anything, 
 decreased, thus showing that the rules of the National Board cover- 
 ing the construction in installation of acetylene apparatus has ap- 
 parently safeguarded the hazard to a very great extent ; and 
 
 In view of the fact that the introduction of this method of 
 illumination generally replaces some methods which entail an equal 
 if not greater hazard ; and 
 
 In view of the fact that outside installation is frequently imprac; 
 ticable on account of climatic conditions ; 
 
 Therefore, we are of the opinion that the time has arrived when 
 the National Board rule as to outside location may properly be 
 modified so that, while it vvill recommend the outside location as 
 being the ideal location, yet it will permit, under proper restrictions, 
 the location of the generator inside of the insured building, and we 
 therefore recommend that Rule No. 2, Section A, of the National 
 Board rules be amended to read as follows : 
 
 Generators, especially in closely built up districts, should prefer- 
 ably be placed outside of insured buildings in generator houses con- 
 structed and located in compliance with Rule No. g, 
 
 75 
 
COST OF ACETYLENE ILLUMINATION. 
 
 The cost of acetylene illumination is necessarily made up of two 
 elements: (i) the first cost of the generator and its installation, 
 and (2) the current expense for carbide. 
 
 The first item, cost of generator and its installation, is of neces- 
 sity a variable quantity, and no attempt would better be made here 
 to fix upon a figure. The size of the machine must naturally be 
 adapted to the space which is to be lighted but, in general, it would 
 be well to purchase abundantly large for present needs, as these may 
 become increased and new needs may develop. If the buildings 
 have already been piped for illuminating gas, the old piping and fix- 
 tures will do equally well if not better ; the burners alone will need 
 to be changed. If new piping is required, only about half the size 
 requisite for city gas is usually employed for acetylene, and the cost 
 of this is a matter of local conditions. Nor need the matter of 
 placing a pipe system even in a completed and finely finished resi- 
 dence be regarded as objectionable. With a little care it can be 
 thoroughly concealed beneath the floors and within the walls. 
 
 The present cost of carbide may be stated at seventy dollars 
 per ton, or in small quantities three and three-fourths cents per 
 pound. On the Pacific coast, owing to -high freight rates the price 
 is ninety-five dollars per ton, or five cents per pound. Since a 
 pound of carbide yields, as a conservative estimate, four and a half 
 cubic feet of gas, a safe and reasonably close approximation is made 
 when the cost of acetylene is stated as distinctly less than one cent 
 per cubic foot, aside from the first cost of the installation. And 
 when it is considered that the commonest acetylene- burner in use 
 (one-half foot) consumes only one-tenth as much gas per hour as 
 the usual coal gas burner (five-foot), acetylene is found competing 
 with coal gas at ninety cents per thousand, a lower price for the 
 latter commodity than is often realized. Still further, if the greater 
 illuminating power of acetylene be considered, it may be stated with 
 little likelihood of challenge that, light for light, acetylene is 
 cheaper than coal gas. The writer has seen a large number of let- 
 ters from householders, storekeepers and others using acetylene gas, 
 who declare without reserve that their present light is not only vastly 
 better, but also much cheaper than their former coal oil illumination. 
 Again, as the acetylene flame is usually burned free, without shade 
 or chimney, there may be at once eliminated from all estimates any 
 allowance for expense of broken globes, chimneys, shades or in- 
 candescent mantles, an item of no inconsiderable importance which 
 is often underestimated in making calculations of prospective ex- 
 pense. Another matter of importance is that all the light produced 
 
 76 
 
is utilized without diminution of its intensity by opaque globes, 
 shades or chimneys, for it is to be remembered that even clear glass 
 absorbs a perceptible percentage of light which is never utilized by 
 those who derive their artificial light from flames surrounded by 
 glass or porcelain. 
 
 It is true that many an acetylene trade catalogue presents fig- 
 ures so much more favorable to acetylene than the above that, if 
 credence were accorded them, one could but wonder why acetylene 
 does not at once expel coal gas and electricity from use. The 
 sophistry and bombast of such irresponsible people is to be carefully 
 avoided, lest one be led astray. On the other hand, the devotees of 
 coal gas, the journals which represent the capital invested in that 
 industry, may very likely display calculations at times which would 
 indicate that acetylene must promptly and irrevocably fail. As be- 
 tween the two, the strides with which acetylene has bounded into 
 popularity must serve to direct our judgment, and while the con- 
 tention can hardly be that acetylene is fitted by its nature and its 
 present cost, to compete with coal gas in the cities and towns, the 
 statements given above may be reasonably relied upon as showing 
 the fitness of this illuminant for inexpensive and beautiful lighting 
 of isolated factories, of churches, hotels, schools, institutions, stores, 
 small country villages, and particularly rural homes. And the fig- 
 ures given in this chapter on the expense of acetylene illumination 
 may be treated as reasonably reliable, showing the results of the best 
 experience at the present time, assuming always a well made, safe, 
 reliable generator of responsible manufacture. 
 
 BURNERS. 
 
 It is not practicable to utilize acetylene in the usual burners em- 
 ployed for other gas. The burners must pass less gas and be espe- 
 cially constructed to meet the demands made upon them. Much in- 
 genuity has been expended in producing good acetylene burners, 
 with the result that there are on the market to-day a large number 
 of different types which serve their purpose admirably. 
 
 The first and most serious difficulty was in finding a burner in 
 which acetylene could be consumed without the nuisance of smoking 
 and clogging. This was because the burner of ordinary form be- 
 comes too hot ; the gas polymerizes as was explained under the prop- 
 erties of acetylene ; the condensation products penetrate the material 
 of the burner and, charring, clog the passages with soot. The prob- 
 lem of finding a burner which should not exhibit this objectionable 
 character was solved bv the introduction of burners in which two 
 
 77 
 
small jet& of acetylene are discharged from two different points' in 
 the burner, so directed that they impinge upon each other at a slight 
 distance from the burner, forming a flat flame which stands at a 
 right angle to the plane in which the jets He. These jets also carry 
 air with them, taken in at the burner by the aid of a device which is 
 similar in principle to a Bunsen burner on a small scale. The in- 
 jected air is merely sufficient to bring about a complete and smoke- 
 less combustion, and the flame itself is so remote from the burner that 
 the latter scarcely becomes heated. 
 
 ' In some of the earlier forms of branched burners in whichonetal 
 arms were employed, it was found that even the slight heating to 
 which they are subjected would, in time, warp the tube so that they 
 would cease after a while to work "true," and would begin to smoke 
 when used but a few hundred hours. This was obviated by- a modi- 
 fied construction of the metal burner or by substituting steatite, 
 which is a poor conductor of heat, for the metal in the branching 
 portion, and thus, in different ways, burners are now available which 
 do not either smoke or clog after some thousand hours of use. A 
 burner in a buoy under the inspection of the Canadian Government 
 was recently found in perfect condition, and giving full light, after 
 
 .fifteen months' continuous service without attention. 
 
 More recently burners have been invented which produce the 
 fiat flame without employing a branched construction. It is claimed 
 for such that, having no jets to align, they can not get out of align- 
 ment. This is certainly an advance in burner making if it shall suc- 
 ceed in producing the other necessary qualities of a perfect burner; 
 but, after all, failure of alignment is for the most part a thing of 
 the past, and there are plenty of good burners to-day which fulfill 
 all requirements to an admirable degree, as may be seen by a glance 
 at the advertising pages of the Acetylene Journal. Much inge- 
 nuity has also been expended in the production of satisfactory 
 turn-down burners, and this has not been wholly without success. 
 Burners are made in sizes ranging from one-eighth to one and one- 
 . fourth foot, and should be marked on the pillar. Competition 
 in burner manufacture has been such that this very necessary 
 adjunct to acetylene illumination has been most perfectly cared 
 for, and no improper or inefficient or uneconomical burners can 
 to-day find any sale. The purchaser cannot go far astray in this 
 matter. 
 
 It may be remarked here that the quality of the gas has much to 
 do with the excellent operation of the burner. A gas which has 
 been overheated in the generator in disregard of all precautions 
 concerning cool generation, a matter under the absolute control of 
 any one selecting a generator, will most surely carry with it prod- 
 
 78 
 
ucts other than pure acetylene, which will cause it to behave badly 
 even in the most approved and perfect burners. 
 
 Again, it is false economy to turn down the ordinary form of 
 acetylene burner, as this causes the air injection to refuse to work, 
 brings the flame nearer the burner, heating the latter and thus de- 
 feating the very object of its careful construction and causing it 
 to become clogged by the deposit of solid matter in the minute 
 passages in the burner, which once accomplished is difficult if not 
 impossible to remedy. The flame of all acetylene burners is small, 
 but there is no dark, non-illuminating portion common with other 
 gas. We are likely to underestimate its lighting power because 
 of its small size, which, however, is more than offset by its great in- 
 tensity. All good burners produce a delightfully steady, quiet and 
 agreeable flame, free from flickering. 
 
 If anything can be judged from the discussions in the various 
 journals on the principles underlying the production of light by 
 processes of combustion, we might reasonably conclude that the 
 ways in which acetylene is consumed at the present time by no 
 means exhaust the possibilities of our illuminant. But this is no 
 place for a consideration of the various problems which arise in 
 burner construction, and all of the novelties in acetylene combus- 
 tion will be deferred until another time. 
 
 FREEZING. 
 
 As water is necessarily used to produce acetylene, and as it is 
 also usually eftiployed for seals, as well as for washing the gas and 
 for the operation of the holder, it follows that acetylene generators 
 must be placed where they can not freeze. On the other hand, there 
 should be no fire near such a machine. The proper arrangement is 
 to install a generator in a protected space where the temperature 
 never falls below freezing, or supply the generator room with a 
 small radiator or coil fed with hot water or steam. If installed in 
 a separate generator building, such building may be made practi- 
 cally frost-proof by providing two or three dead air spaces in the 
 walls, giving it double doors and windows, and taking such other 
 precautions as may suggest themselves. No free fire can ever be 
 permitted under any circumstances, but a coil of hot water or steam 
 pipe, when it can be inexpensively provided is an excellent safe- 
 guard. If installed within the building lighted, similar precautions 
 may be properly taken, and whatever the method of securing the 
 result, it is absolutely essential that the generator be so placed that 
 
 no freezing can take place. 
 
 79 
 
DISPOSITION OF RESIDUUM. 
 
 The liquid and semi-liquid residue may be passed into the sewer, 
 provided there is sufficient fall and no scarcity of flushing water, 
 and allowed to accompany the sewage, upon which it can exert no 
 action or influence, other than that of a partial disinfectant. The 
 use of the agitator with which most generators are provided, facili- 
 tates this removal of refuse. But if the drain is too flat, the sludge 
 will settle in a compact mass, which eventually stops the pipe. In 
 many cases, therefore, it is far preferable to allow the sludge to flow 
 through a separate drain with plenty of fall and permit it to accumu- 
 late where it may subsequently be utilized if in sufficient quantity. 
 If care is taken in the construction of a sludge pit, so that the re- 
 siduum will be drained as well as possible, and yet not placed so deep 
 as to be difficult to load it into carts for removal, this material may 
 even become of some pecuniary value. 
 
 The chief uses of the sludge, frequently called acetylene lime, 
 are for mixing mortar, for whitewashing fences, cattle pens, fruit 
 trees, etc., for making paths, and for fertilizing, with some occa- 
 sional application as an insecticide and disinfectant. Mortar made 
 from it is reported to bind quickly and hard ; there is no reason why 
 it should not be at least of equal value with mortar made from or- 
 dinary slaked lime. It may be added that in any of the multi- 
 tudinous uses to which ordinary lime whitewash is applied, a white- 
 wash made from carbide residuum answers equally well. The dis- 
 posal of residuum depends on local conditions; manufacturers of 
 generators usually possess information in the matter which enables 
 them to advise, under specific circumstances, so that no general 
 statement can finally solve the problem. 
 
 In view of the many practical uses to which acetylene lime has 
 been successfully applied, and particularly because of its usefulness 
 as an application to the soil, it may not be out of place to submit 
 the chemical analysis of carbide residuum. The following figures 
 show the analysis of three specimens of residue taken at remote 
 times and places > 
 
 I. II. III. 
 
 Per cent. Per cent. Per cent. 
 
 Sand (silica) 1.24 ilio 0.97 
 
 Carbon (coke or coal) 2.08 3.95 2.14 
 
 Oxide of iron and alumina. ... 3.1 1 2.90 2.30 
 
 Lime 62.50 63.65 66.10 
 
 Water and carbonic acid 31 -07 28.40 28.49 
 
 Total 100.00 100.00 100.00 
 
 80 
 
I. is an analysis of sludge from a German carbide; II. is an 
 analysis by Professor E. H. Jenkins, of New Haven, Conn. ; III. is 
 an analysis made by the writer at The Pennsylvania State College. 
 In order to present an authoritative statement of the fitness of such 
 residues for application to the soil, the above analyses were sub- 
 mitted to Dr. William Frear, Chemist to the Pennsylvania Depart- 
 ment of Agriculture, with a request for a statement, regarding the 
 use of residuum of such character for agricultural purposes. The 
 following response was received: 
 
 State College, Pa., Dec. 28, 1907, 
 Prof. G. G. Pond, State College, Penn. 
 
 Dear Sir: The three analyses submitted by you of residuum from acety- 
 lene machines show it to consist principally of partially carbonated slaked 
 lime. Its composition is very nearly that of the lime slaked in the field for 
 agricultural use. I know of no reason why this acetylene residue is not 
 well fitted for the same agricultural use. On the basis of the analyses 
 submitted, one ton of the residuum would be equivalent to approximately 
 fifty bushels (forty pounds to the bushel) of the slaked lime above men- 
 tioned, or to twenty bushels of the best stone lime (seventy-two pounds 
 to the bushel). Very respectfully, 
 
 (Signed) WILLIAM FBEAR, Chemist. 
 
 PURIFICATION. 
 
 The question of the purification of acetylene has been vigorously 
 agitated at various times, especially in Germany and France. Some 
 excellent suggestions have been made, and various chemical purifiers 
 proposed, some of which are of undoubted merit. 
 
 It should be understood, as has been mentioned before, that the 
 first and most important purification to which acetylene is subjected 
 is the washing which it receives by bubbling through the water as it 
 must do in all forms of generators; then it is always "filtered" 
 through felt, a purifying treatment which has been found invariably 
 necessary in order to remove solid particles or dust which float in 
 the crude gas, chiefly lime dust. 
 
 Purification, therefore, in the sense in which the word is. used in 
 this chapter, means chemical purification, the aim of which is to 
 remove those minute traces of ammonia, sulphureted hydrogen, and 
 particularly phosphorus-containing compounds which escape the 
 washing apparatus. Throughout the discussion we must bear in 
 mind that these impurities can arise only from impurities in the car- 
 bide from which the gas is made, and that American carbide, 
 as it is produced to-day, is of such high grade that the question 
 
 81 
 
of purification is by no means a vital one. The removal of the last 
 traces of accompanying impurities in commercial acetylene is not a 
 necessity, though it may be a thing to be dpsired. Most of the hun- 
 dred and fifty thousand homes lighted by acetylene in this country 
 to-day, employ no method of purification other than the water wash- 
 ing and filtering mentioned above and to which the gas is submitted 
 in every good generator, yet no harm whatever results from this 
 omission. Nearly all of the American manufacturers believe that 
 chemical purification is unnecessary. But if anyone desires to free 
 his gas a little more perfectly, if possible, from the last traces of ac- 
 companying impurity, it can be most easily accomplished by means 
 of readily available purifying apparatus which can be attached to 
 any machine or inserted between the machine and the distributing 
 pipes with little trouble and at trifling cost. Four purifying mix- 
 tures which have been proposed, and used with more or less success, 
 are: 
 
 1. Heratol. A solution of chromic acid or sulphuric acid ab- 
 sorbed in porous earth. 
 
 2. Acagine. A mixture of bleaching powder with fifteen per 
 cent of lead chromate. 
 
 3. Puratylene. A mixture of bleaching powder and hydroxide 
 of lime made very porous, and containing eighteen to twenty per 
 cent, of active chlorine. 
 
 4. Frankoline. A mixture of cuprous and ferric chlorides dis- 
 solved in strong hydrochloric acid absorbed in infusorial earth. 
 
 A discussion of the relative merits of the chemical purifiers would 
 lead too far into the realm of chemistry for the limits of a popular 
 bulletin. The writer still maintains the belief that, so long as the 
 present high quality of American carbide is maintained, purification 
 may just as well be omitted in small installations. 
 
 MUNICIPAL LIGHTING. 
 
 The usefulness of acetylene is not necessarily limited to small in- 
 stallations adapted to single small buildings. Larger establishments 
 such as factories, groups of summer hotels, army posts, schools or 
 colleges, public institutions, etc., particularly when somewhat iso- 
 lated in location so as to be beyond the reach of city gas supplies, 
 may often be very beautifully and economically illuminated with 
 acetylene. Plants of sufificient size to serve for the illumination of 
 villages and small towns, ranging from five hundred to five thousand 
 inhabitants, are becoming more and more numerous every year. 
 There are several hundred such acetylene towns in the United States 
 
 82 
 
and similar progress has been made in Germany, Prance, Austria 
 and other countries. A few towns with central acetylene plants have 
 been reported as giving up this form of illumination after a season 
 of trial and some such have been exploited in the public press, to the 
 detriment of the industry. But such instances have been, almost 
 exclusively places where, by reason of imperfect installations or un- 
 skillful pipe laying, the outfits have been of too cheap an order to 
 survive, and no case has come to the attention of the writer in which 
 a really excellent and well equipped acetylene lighting station has 
 been discarded in favor of any other form of public illumination. 
 Prominent among the features which require to be especially looked 
 after in successful town-lighting are : 
 
 1. Solid and substantially constructed generators of approved 
 type. 
 
 2. Sufficient gas storing equipment so that there need be no 
 question as to abundance of gas on hand. 
 
 3. Perfect pipe fitting so as to minimize leakage. 
 
 Generators for town lighting are in many cases not of the auto- 
 matic type ; that is the generation of gas is not controlled by the sup- 
 ply in the bell as in the small household generator, but they are fed 
 by hand, or better by a small motor so that a slow and steady feed 
 is assured. It is customary to generate enough gas at a time to last 
 at least over a single night and often for several nights. To this end 
 ample storage is desirable, so that the gas may be completely cooled 
 as well as to avoid the possibility of the gas supply failing when 
 lights are burning, and being turned on again while the burners are 
 still open; very perfect pipe laying is essential in order that there 
 shall be no unnecessary leakage since acetylene is a very concentrated 
 illuminant, possessing large candle power in small bulk and hence 
 any considerable loss of gas by leakage means decided reduction in 
 profits. 
 
 Consumers generally express themselves as greatly pleased with 
 the quality of the light, the excellence of the service and the cheap- 
 ness of the illumination. Street lamps and other forms of public 
 illumination are provided as well aa the house-to-house service, and 
 satisfactory meters are on the market, especially adapted to the re- 
 quirements of acetylene. This form of acetylene apparatus is also 
 carefully safeguarded by the underwriters; a central station is 
 erected in a manner similar to that used for coal gas lighting, with 
 this important difference that it is much smaller and .consequently 
 less expensive. All the cumbersome, expensive and care-demanding 
 equipment including retorts, scrubbers, etc., essential for coal gas 
 are entirely unnecessary. A small, compact generating system is 
 
 83 
 
all that is required and gas is produced in precisely the same manner 
 as in a private installation. 
 
 ACETYLENE TABLE LAMPS. 
 
 Our illuminant is unique for its great flexibility of application. 
 We have considered its perfect adaptability to the requirements of 
 a town and its admirable fitness for being selected as the illuminating 
 agent for a house of any dimensions. But we shall fall far short of 
 exhausting this singular flexibility if we do not introduce our 
 readers to the portable lamps which may perhaps have attracted 
 their attention in the underwriters' regulations. 
 
 These admirable contrivances, no less truly than larger domestic 
 equipments, arp easily and cheaply available at the present day. 
 They are little automatic generators in themselves, adjusted to feed a 
 single burner, and may easily be carried from room to room. They 
 are charged by filling the base with about a gallon of water, and 
 placing in the urn a proper quantity of especially prepared carbide, 
 of a size which roughly resembles granulated sugar. They work ad- 
 mirably, furnishing a smooth, unwavering flame. Daily filling is 
 desirable, though not necessary, but it is more easily accomplished, 
 and cleaner work than the daily attention required by an oil lamp 
 of the same " size. The cost of operating the portable lamp is a 
 trifle greater than that of other forms of acetylene lighting, because 
 of the somewhat increased cost of the prepared carbide, known as 
 Electrolite, which is packed expressly for use in these lamps, but 
 one cent per hour is the allowance of cost which the writer estimates 
 will supply his study table with this restful convenience. The port- 
 able acetylene lamp is a distinct advance in civilization'; it is fully 
 as efficent as that grotesque Vesuvian monstrosity, known as the 
 piano lamp, and greatly to be preferred on grounds of care, con- 
 venience and safety. It also possesses the enormous advantage that 
 it contains no inflammable material to spill and cause disastrous 
 conflagration ; it may be overturned while burning, without any like- 
 lihood of harm other than the possible breakage of the fragile parts, 
 or indenting of the metal. 
 
 OTHER PORTABLE DEVICES. 
 
 Nor does the table lamp exhaust the smaller and portable ap- 
 paratus which make use of calcium carbide and acetylene. There 
 are hundreds of thousands of lamps in daily use, employing acety- 
 
 84 
 
lene as a means of illumination for bicycles, carriages, motor cars 
 etc., with which everybody is familiar and which call for no other 
 comment here except to say that acetylene has proved its usefulness 
 for this kind of illumination, in which we may include also vendors' 
 torches, torches for lamp-lighters, searchlights, miners' lamps, which 
 in Germany have become a staple article, and in this country are al- 
 ready selling in great quantities, automobile mail cars and delivery 
 wagons, ploughing, threshing and other farming operations at night, 
 headlights for traction engines and steam shovels for night work, 
 lanterns, apparatus for projection of pictures either on the small or 
 on the large scale, mechanics' torches and so on. 
 
 COOKING BY ACETYLENE. 
 
 A few years ago cooking by means of acetylene was thought to 
 be entirely out of the question, by reason of expense and impractica- 
 bility of securing suitable burners. It is safe to assert today that 
 the burner problem has been very perfectly solved and such a meas- 
 ure of .economy in heat production brought about that cooking by 
 acetylene is both entirely practical and reasonably inexpensive. Ex- 
 cellent blue flame burners are now readily obtainable anywhere, and 
 complete cooking ranges, equipped with a variety of such burners, 
 are to be found ih the stock of every up-to-date dealer. Cookers, 
 hot-plates, chafing dish heaters, in fact stoves of every sort which 
 have long been employed for coal gas are now adapted to acetylene, 
 and are giving satisfaction in thousands of homes. 
 
 Other accessories for the household are instantaneous water 
 heaters, flame spreaders for heating sad irons, radiators for room 
 heating, fire places, and grates. It is literally true, and no longer the 
 dream of the visionary enthusiast that, with the use of acetylene for 
 lighting, cooking and heating, the out-of-town resident is placed 
 in a position to enjoy equal conveniences with the resident of the 
 city, if not even superior ones. 
 
 DISSOLVED ACETYLENE. 
 
 The remarkable application of acetylene, which will be described 
 under this caption, is one which has extended the usefulness of the 
 gas to a very enormous extent and lies at the basis of its extension 
 in so many ways not known before that no discussion of acetylene is 
 complete without a full consideration of dissolved acetylene. We 
 have had occasion to mention, in an earlier chapter, the fnall degree 
 
 85 
 
of solubility in water which acetylene possesses. It is of conse- 
 quence for us to know about it, for the excessive use of water 
 might cause considerable loss of gas. But the solubifity of the gas 
 in water is too limited to be put to any practical use. Its solubility 
 in other liquids is not of more interest to us except in a single liquid 
 which, though familiar to the chemist, is not commonly known to 
 the public as it meets no important uses in. the arts or manufactures. 
 Acetone, one of the products of the distillation of wood, and pre- 
 pared also in other ways for the market, is a limpid, colorless, 
 mobile, fragrant liquid, boiling at one hundred and thirty-three de- 
 grees Fahrenheit, inflammable and burning with a luminous flame, 
 an excellent solvent for many resins and gums. It is four-fifths as 
 heavy as water, is capable of mixing freely with water, alcohol or 
 ether ; it has a peculiar but not disagreeable odor and a biting taste 
 not unlike peppermint; it is much employed in the manufacture of 
 chloroform, iodoform and certain other medicinal preparations. 
 This long known but rather unfamiliar fluid is a peculiarly excellent 
 solvent for acetylene. Acetylene dissolves in it as freely as sugar 
 does in water, and the solubility increases with the pressure applfed. 
 Acetone dissolves twenty-four times its own bulk of the gas at ordi- 
 nary temperature and pressure, and for each additional atmosphere 
 of pressure to which it is subjected a similar quantity will be dis- 
 solved, in other words the quantity dissolved increases directly with 
 increase in pressure. 
 
 Now the compression of acetylene to an extent greater than two 
 atmospheres, and particularly to the liquid condition which is 
 reached at about forty atmospheres, at ordinary room temperature, 
 has been shown to be accompanied with so much danger to endother- 
 mic explosion, that the practice has been given up. But if the gas 
 be forced into this remarkable liquid, acetone, a mixture is secured 
 which seems to be devoid of the dangerous quality of other forms 
 of compressed acetylene, and hence available for safe transportation 
 and use. 
 
 But at the same time that acetone dissolves acetylene, it increases 
 its volume very perceptibly in so doing. When the pressure is re- 
 leased the acetylene escapes, and can be utilized at pleasure, but the 
 acetone reassumes its smaller volume and thus produces a space in 
 which "free" acetylene would of necessity exist, and create a source 
 of danger. Of course this possibility of accident had to be removed 
 before dissolved acetylene could be a commercial success. 
 
 This important problem was solved by first filling the receptacle 
 with some porous solid material which should leave no space what- 
 ever to be subsequently occupied by "free" compressed acetylene. 
 Various absorbent materials were employed for this purpose, chief 
 
among them being asbestos, wood charcoal, infusorial earth, etc., 
 the aim being to secure a material which should possess a porosity of 
 seventy-five to eighty per cent, and at the same time remain inert 
 towards the acetone and acetylene which it is destined to absorb. In 
 practice, the industry has settled upon asbestos, and by careful pack- 
 ing of cylinder or tank, making use of such a system of devices that 
 there can be no possibility of any free space, either when the cylinder 
 is freshly prepared, or by subsequent sagging down of the asbestos, 
 this kind of apparatus has reached a very high degree of perfection. 
 
 Briefly the method of preparing dissolved acetylene is as fol- 
 lows : The gas is generated in the usual way, is carefully washed, 
 purified and dried. Great care is exercised to keep the acetylene 
 as free as possible from impurities, and to exclude so far as possible, 
 all admixture of air. The compressers force the gas into large stor- 
 age tanks or accumulators containing asbestos saturated wtih ace- 
 tone as above described. The pressure is allowed to increase to 
 one hundred and fifty pounds and the storage tanks are connected 
 by means of a system of steel pipes to the cylinders, previously 
 sharged with porous material and acetone, for the final reception of 
 the gas for transportation and use. 
 
 The measure of safety which is claimed for this storage system, 
 as compared with other forms of compressed acetylene, resides in 
 the degree of perfection with which the tanks are so completely 
 filled with the absorbent material that there is no possibility of free, 
 or undissolved, gas anywhere in the system, and secondly upon the 
 fact that the solution of acetylene in acetone is inexplosive even 
 under high pressures. Its freedom from likelihood of accident has 
 been demonstrated to the entire satisfaction of many railroad of- 
 ficials on whose roads the system is employed. 
 
 Since the gas issues from the tanks, whenever released, at a high 
 pressure, it is necessary to employ a pressure regulator to bring the 
 pressure down to the correct extent for practical use. But such 
 apparatus is easily secured, inexpensive and reliable. Dissolved 
 acetylene possesses the advantage of being delivered at the burners 
 cool, dry and at uniform pressure, the minute quantity of acetone 
 vapor which accompanies it possessing no disadvantageous quality. 
 It can be turned on and off at any moment without waste of gas, 
 cannot freeze and the quantity of gas left in the tank is always 
 known by a glance at the gauge. 
 
 The applications of dissolved acetylene are numerous, and in- 
 creasing daily. For ordinary house lighting, it is entirely out of the 
 question ; acetylene can be provided for stationary purposes by gen- 
 erators already described -so much more economically that dissolved 
 acetylene finds no application. But where portability is a requirf-- 
 
 87 
 
ment, as on yachts and excursion barges, for vehicles of all sorts, 
 motor cars, railway coaches, locomotive head-lights, etc., dissolved 
 acetylene finds ready and welcome application. More particularly 
 where accessibility is so difficult that the use of a generator is pro- 
 hibited, as in buoys and lighthouses, some of which can only be ap- 
 proached at long intervals and in favorable weather, there is a de- 
 mand for a form of illuminant which dissolved acetylene is most ad- 
 mirably adapted to fill. 
 
 ACETYLENE FOR LIGHTHOUSES, BUOYS AND SIGNALS. 
 
 The United States Lighthouse Board commenced experimenting 
 with acetylene for beacons and other marine lights as early as 1896. 
 The generators of that day were not highly perfected, and progress 
 was retarded, but within the last five years much has been done in 
 the way of utilizing this illuminant for the maintenance of lights for 
 the guidance of mariners. Some thirty-five generators have been 
 installed in Mobile Harbor and others in the Harbor of Galveston. 
 Some of them have been in continuous service since early in 1902. 
 The saving in cost of maintenance, as compared with the old oil 
 system, is nearly fifty per cent. Other acetylene lights are main- 
 tained oflf Cape Henry, off Point Judith, at Sandy Hook and other 
 points. Most, if not all, of these installations are carbide-feed gen- 
 erators ; some of these receive attention every sixty days ; others are 
 self-sustaining for a much longer time, even up to six months ; and 
 pilots and masters of vessels speak in high terms of the excellence 
 of the lights and particularly their fog-penetrating character. 
 
 The Canadian Government has, since 1901, been maintaining 
 acetylene lights of various kinds in Canadian waters, and such 
 lights are much in favor with the Lighthouse Service officials at 
 Ottawa, who have expended a large percentage of their appropria- 
 tion upon the installation of Willson acetylene buoys, most of which 
 are of the low pressure type. Such a buoy can carry from nine to 
 ten thousand feet of gas, in the form of carbide; can be charged 
 at the opening of navigation and requires no attention, so far as 
 supply is concerned, until navigation closes. There is no artificial 
 illuminant known, except acetylene, which can be left to burn un- 
 attended, and without replenishing the supply of fuel, for anything 
 like so long a period. Such rapid progress has been made by acety- 
 lene in replacing other illuminants in the lighthouse service in various 
 parts of the world, the coast of France, the Isle of Shetland, Scotr 
 land, Alaska, etc., that it is unnecessary to further accumulate data to 
 show that acetylene already occupies an important place as an aid to 
 
 8§ 
 
navigation. It is quite obvious that the very qualities which cause 
 this gas to occupy the advanced position which it does, as a domestic 
 and municipal illuminant, namely efficiency, economy, and small care 
 in operation, are the very ones which influence governmental use of 
 the same light in aiding navigation. 
 
 RAILROAD USES OF ACETYLENE. 
 
 The advantages of acetylene as an illuminant have from the first 
 appealed to the railroad officials of all countries. Aside from the 
 lighting of small stations, its use has been chiefly for two purposes, 
 locomotive headlights and the illumination of coaches. As an en- 
 richer of coal gas and oil gas, acetylene made some advances long 
 ago, but it was not destined to achieve its great ascendency in this 
 way. Portable generators on coaches have also been tried out to a 
 considerable extent, and not largely adopted, but with the advent 
 of dissolved acetylene, the problem seems to be efficiently solved. 
 Dissolved acetylene is now used by hundreds of railroads for loco- 
 motive head-lights, and while it is not possible to secure so high a 
 candle power as electricity, the light is far more efficient and satis- 
 factory, at one-fifth the cost of an electrical arc headlight. Many 
 leading railroads employ it for lighting ordinary coaches, parlor cars, 
 mail cars, diners, suburban trains,' locomotives, railway stations, rail- 
 road yards, signal lights in towers and elsewhere, and it is also em- 
 ployed for trolley cars, both as to interiors and headlights. The ad- 
 vantage of independent headlights for trolley cars is obvious to all, 
 when it is remembered that if the electric current chances to be cut 
 off, as frequently occurs, away goes the headlight as well as the 
 power, leaving car and crew in total darkness ; acetylene headlights 
 are also much cheaper than electrical ones. 
 
 For the operation of a system of this sort, a charging plant, on 
 lines indicated in a previous chapter, is usually erected near the 
 terminal or main railroad yard of the road to be thus equipped. The 
 usual receiver employed on many roads for Pintsch gas contains, 
 under ten atmospheric pressures, two hundred cubic feet of gas ; it 
 measures twenty inches in diameter and one hundred and fourteen 
 in length. A cylinder of the same size, packed with asbestos discs 
 and charged to forty-three per cent, with acetone, contains, at ten 
 atmospheres, two thousand cubic feet of acetylene. This fact, 
 together with the much greater candle power of acetylene, renders 
 it possible to provide a car, at one charge, with gas enough to last 
 for a month or more. Coaches have for some years been charged 
 
 89 
 
at St. Paul for the round trip to the Pacific coast and return, a 
 distance of more than thirty-six hundred miles, each coach being 
 equipped with from twelve to sixteen half-foot burners. 
 
 THE OXY-ACETYLENE BLOWPIPE. 
 
 When any gas whatever burns or undergoes combustioii, in the 
 air, it is merely combining, chemically, with the oxygen of the air. 
 This gas, oxygen, the active portion of our atmosphere, consti- 
 tutes one-fifth of the entire volume of the air, and it is only by 
 means of it that anything burns. Whenever a candle, or an oil 
 lamp, or a jet of illuminating gas is kindled, we see something 
 which we are accustomed to call Mame. This flame is nothing 
 more or less than burning gas. Heat volatilizes, or gasifies, converts 
 into vapor or gas, the material of the candle, or the oil in the wick 
 of the lamp, and approaching currents of air feed the flame with 
 oxygen by which it is sustained. Cut off the air supply and the 
 burning ceases ; increase the air supply and you may accelerate the 
 burning. Use pure oxygen in place of air, thus getting rid of 
 the nitrogen which constitutes the other four-fifths of the air, and 
 you accelerate the flame still more because the oxygen is no longer 
 diluted with four times its bulk of inert and useless material.. 
 Again, if the aim is to secure high heat, pre-heating the gases, as 
 well as mixing them in just the right proportions at the moment of 
 combustion, aids in accomplishing this result, and the greater the 
 amount of fuel we can burn in a limited space and limited time, 
 the more we can localize the heat of the combustion. 
 
 The great energy with which hydrogen combines with oxygen 
 is turned to account for the purpose of producing high tempera- 
 ture by means of the instrument known as the oxy-hydrogen blow- 
 pipe. The separate gases are led in tubes to the burner, where 
 they are mixed and burned to best advantage. This instrument 
 enables us to secure a temperature of forty-five hundred degrees 
 Fahrenheit, and it is employed in various ways. One well known 
 application is in the familiar calcium light, or Drummond light. 
 In this the oxy-hydrogen blowpipe is utilized to raise a piece of 
 lime to the temperature of incandescence when it emits a powerful 
 light, utilized for projections, for signaling at sea, etc. 
 
 Very naturally any combustible gas may replace the hydrogen 
 and in fact coal gas is used much more commonly than hydrogen. 
 When the attempt has been made to utilize acetylene, difficulties 
 have been met regarding the proper adjustment of parts, which 
 
 90 
 
were slow to yield to inventive genius but which have been over- 
 come in the Fouche, the Rodrigue-Ely and Gauthier torches blow- 
 pipe, are oxy-acetylene blowpipes which seem to be very perfect in- 
 struments and which are now applied to a large number of uses. 
 They bring out the much greater calorific intensity of acetylene as 
 compared with hydrogen and secure a temperature, locally, as high 
 as seven thousand degrees Fahrenheit. The flame is easily regu- 
 lated, all metals used in the arts are melted before it, and welding 
 is easily accomplished. No ponderous plant is necessary; acetylene 
 may be used right from the generator, or under pressure, as may 
 be desired; cylinder of dissolved acetylene and of compressed oxy- 
 gen are both commercial articles everywhere available, and hence a 
 complete oxy-acetylene blowpipe outfit is readily portable. 
 
 WELDING WITH ACETYLENE. 
 
 The oxy-acetylene blowpipe affords a most valuable and prac- 
 tical method for welding, which far surpasses the oxy-hydrogen 
 method and rivals electric jvelding. In fact, it can be employed in 
 1 large variety of work where electric welding is out of the question, 
 [t is more easily accomplished, less cumbersome and Jess expensivei 
 It is stated also that it affects the character of the metal less than 
 other forms of welding. A controlling reason why the oxy-hydro- 
 gen blowpipe cannot secure a temperature greater than four thou- 
 sand to forty-five hundred degrees Fahrenheit is because oxygen 
 and hydrogen refuse to unite at temperatures above the dissociation 
 point of water. When acetylene is used the carbon continues to 
 burn and produce heat, while the atmosphere of hydrogen, which 
 is maintained about the weld, takes no part in the combus- 
 tion, but prevents both the metal and the point of the blowpipe 
 from oxidation. The work is not difficult to acquire; an intelli- 
 gent workman promptly develops skill and the process is rapid. 
 While two and a half volumes of oxygen are theoretically needed 
 for the complete combustion of acetylene, it has been found that 
 welding can be satisfactorily accomplished with a proportion of 
 slightly over one and a quarter to one, hence the cost of oxygen is 
 distinctly less than would be calculated. Since acetylene burns in 
 oxygen with a blinding light, the operator may have occasion to pro- 
 tect his eyes with dark glass spectacles, but the heat of the operation, 
 though locally intense, does not interfere with the convenience of 
 the workman, and aside from the necessity of an occasional cooling 
 of the torch in water, the rapidity and apparent ease of the work 
 are not interfered with. In fact, the operation looks exceedingly 
 simple to the casual observer, and the autogenous soldering together 
 into homogeneous metal of considerable masses, or the cutting of 
 
 91 
 
thick slabs of iron goes on before his eyes with marvelous rapidity. 
 
 By reason of the facility with which it can be applied, this 
 form of welding has become quite common abroad, and its use is 
 being greatly extended in this country; it has already revolution- 
 ized some kinds of metal working ; it is applicable in many operations 
 which are totally impossible by the older methods; the portion of 
 metal acted upon is so small that the factors of expansion and 
 contraction are for the most part negligible. Welds are so homo- 
 geneous that when the piece is finished there is often no evidence 
 that a joint has been made. Steel, iron, brass, copper and other 
 metals used in the arts can all be treated with success, and there is 
 authority for the statement that iron can be economically welded up 
 to one-half inch in thickness, while any shaped hole can be cut 
 in steel plates up to a thickness of several inches ; the operator can 
 accomplish feats impossible with the saw. 
 
 Iron or steel can be welded to much greater thickness by the 
 process of "building up," and the writer has been reliably informed 
 that a shaft more than twenty-four inches in diameter has been suc- 
 cessfully welded on a steamship. For repairs in small and inac- 
 cessible rooms, on roofs and at sea, the oxy-acetylene outfit is 
 becoming indispensable. 
 
 It will not be surprising if autogenous welding by this process 
 largely supersedes all other methods, since it possesses such valuable 
 advantages over all rivals in the facts that such welds are effected 
 without any deleterious effect upon the metal, and that it is inex- 
 pensive and portable, entailing no elaborate preparations or heavy 
 initial expenditure in regard to plant and equipment. 
 
 ACETYLENE FOR MOTIVE POWER. 
 An interesting field for a display of inventive genius is the 
 application of acetylene for the generation of motive power. The 
 high temperature of its combustion, affording a much greater 
 explosive power than coal gas or gasoline, and the trifling trouble 
 and expense involved in generating and storing this fuel should work 
 together to render its use in gas engines of great benefit to the 
 mechanical engineer. Suitably contrived engines or motors are 
 a prime requisite and such appliances must come, but for some 
 reason really brilliant progress along this line has been deferred. 
 This is in spite of the fact that the efficiency of the acetylene 
 explosion, as compared with coal gas, is about as three to one. 
 Acetylene will eventually demonstrate its superiority in this line, 
 perhaps is already doing so, but the difficulties seem to be slower of 
 remedy than in the other uses to which acetylene is applied.- The 
 blowpipe was not prompt in making its appearance, but the diffi- 
 
 92 
 
culties were finally overcome, and so they will be, must be, in case 
 of the successful acetylene motor of the future. 
 
 One interesting development in this direction is the alcohol- 
 acetylene motor for vehicles. This invention is, in broad terms, 
 "the process of producing a gas for power purposes which consists 
 in carburetting air with dilute alcohol and then bringing such car- 
 buretted air into contact with calcium carbide." Such dilution of 
 the alcohol is employed as may be determined by experiment to be 
 most advantageous, and when this is sprayed through a layer of 
 carbide, the water is extracted from the dilute alcohol, rendering 
 the latter more efificient as a fuel, and converted into acetylene by 
 reaction with the carbide. The dry gaseous mixture of alcohol 
 vapor and acetylene passes to the explosion chamber and burns far 
 more advantageously than alcohol vapor alone. The qualities of 
 the two substances supplement each other, and the mixture is a fuel 
 of considerable efficiency; it is probable that the inventive genius 
 which is now being applied to this problem will in due time develop 
 its full efficiency. 
 
 ACETYLENE LIGHT AND PLANT GROWTH. 
 
 The light of the acetylene flame is the nearest approach to 
 sunlight with which we are acquainted. It is composed of the 
 same colors and they are present in very similar degrees of intensity. 
 Physicists have shown that if the intensity value of each color in 
 sunlight be placed equal to unity, we have the following comparative 
 
 figures : 
 
 Sunlight. Acetylene Light. 
 
 Red . . . 
 Yellow 
 Green . 
 Blue .. 
 Violet . 
 
 1.03 
 1.02 
 0.71 
 1.46 
 1.07 
 
 The ultra-violet rays are practically absent. This composition 
 of the light rays of acetylene naturally directed the attention of 
 experimenters to its possible use as a plant stimulant. Careful 
 work has been done in studying its effect on plant development at 
 the West Virginia Experiment Station, at Cornell University and 
 elsewhere, but chiefly at Cornell. These experiments are still under 
 way and the results have not been fully published, but the conclusion 
 is certain that acetylene can be used to advantage by the commercial 
 grower in the case of certain plants. It does not possess the 
 
Injurious effect of the naked electric arc and its effect is very similar 
 to that of sunlight. It can therefore be utilized to supplement 
 deficient sunlight, either by utilizing it at night, or as an offset to 
 insufficient sunlight on dull and cloudy days. The forcing house 
 equipped with acetylene is therefore able to overcome unfavorable 
 conditions of deficient daylight. In the main, growth is increased, 
 and the time of flower and fruit diminished ; at the same time there 
 is little or no abnormal development such as has been observed with 
 other' artificial illuminants. Acetylene can thus be used profitably 
 to hasten a crop and prevent the delays caused by inclement weather 
 conditions. 
 
 Some of the specific results which have been made public are 
 worthy of mention here: 
 
 Strawberries showed an increase of twenty-five per cent, over 
 those grown by sunlight alone, and fruit was ripened sixteen days 
 in advance of other plants grown under like conditions of tempera- 
 ture but uninfluenced by acetylene. 
 
 Peas derived very marked benefit, and beans showed a notice- 
 able gain in acetylene as compared with unaided sunlight. Tomatoes 
 ripened more and larger fruit, though considerably later, while 
 r cucumbers exhibited no gain. 
 
 Radishes were grown in three- fourths the usual time ; lettuce 
 and other salad plants were considerably accelerated, and some of 
 them gained in quality as well. 
 
 In general, between ninety and ninety-five per cent, of the plants 
 which have been experimented with responded favorably to the 
 stimulus afforded by acetylene light. 
 
 The results which have been thus far published in this field are 
 only preliminary and there are numerbus problems as yet unsolved. 
 While many facts have been established, many tendencies shown, 
 there is still a large and promising field for further experimentation, 
 and it is to be hoped that the field will be further explored, for 
 there seems to be a grand future for the profitable application of 
 acetylene light to the wants of the market gardener and the 
 commercial florist and horticulturist. 
 
 DRY PROCESS ACETYLENE. 
 
 The so-called Atkins dry process for generating acetylene is a 
 method which has been exploited to some extent in England, but 
 not employed in the United States up to the present time, so far as 
 the writer has been able to learn. The essential feature of the 
 system is that the gas is generated by mixing calcium carbide with 
 
 94 
 
soda crystals instead of with water. Soda crystals, otherwise known 
 as sal soda or washing soda, contain a large amount of water of 
 crystallization, about sixty-three per cent, of their total weight. 
 The attraction of the carbide for water is so great that it extracts 
 it from the soda crystals, and it is with this water, though originally 
 contained in a dry substance, that the carbide reacts and produces 
 acetylene in the usual way. Other substances which contain water 
 of crystallization, such as alum, may be used in lieu of soda crystals, 
 but soda is preferred. The heat accompanying the reaction is said 
 to be very slight, not much above two hundred degrees Fahrenheit, 
 hence distinctly below the polymerizing point of acetylene, which is 
 above five hundred degrees Fahrenheit. The resultant gas is there- 
 fore free from impurities such as are produced by high temperatures, 
 but it is to be doubted whether other impurities are at all affected. 
 The residue is removed as a dry powder and contains all the actual 
 sodium carbonate originally present in the soda crystals. The opera- 
 tion is not automatic and the apparatus is a mechanical one, 
 requiring the service of an attendant and hand or other power to 
 actuate the mixing device, which must be kept in motion whenever 
 the gas is in the process of being generated. 
 
 It seems hardly likely that such a generator will seriously com- 
 pete with the admirable automatic generators of the present day, 
 as it involves a cost of a few cents per pound for all the water which 
 takes part in the decomposition of the carbide, with no offsetting 
 advantage in the salable character of the residuum, increased value 
 of the resultant gas, or otherwise. 
 
 CALCIUM CYANAMID. 
 
 One of the most important facts about calcium carbide is that 
 discovered by two German chemists, Frank and Caro, namely, its 
 property of absorbing nitrogen at a high temperature. Because of 
 the great need of soluble nitrogen compounds for application to 
 the soil as fertilizers for the growing of plants of every sort, every 
 known source of such nitrogen compounds has been drawn upor\ to 
 the fullest extent during recent years. All the agriculturally avail- 
 able nitrogen has hitherto been drawn from only three chief sources : 
 ammonium salts resulting from the by-products of the illuminating 
 gas industry, chiefly sulphate and muriate ; Chilean saltpeter, a sub- 
 stance secured from the rainless district of western South America, 
 and nitrogenous residues from the slaughter house, such as dried 
 blood and tankage. These three sources are drawn upon to their 
 utmost capacity and the price of the nhrogen-containing fertilizers 
 
 95 
 
remains so high that the discovery of a new source of nitrogen 
 available for the purpose is a thing greatly to be desired. The 
 atmosphere of the earth supplies us with never failing quantities of 
 the desired element nitrogen, containing as it does nearly eighty 
 per cent., whether by weight or volume. Unfortunately, however, 
 this great superabundance of nitrogen, within reach of everybody 
 and at no cost, is free or uncombined, and hence incapable of be- 
 ing utilized for the purpose desired. Free nitrogen will not an- 
 swer the requirements of a fertilizer; nature requires that it be in 
 the form of soluble compounds in order to be available. It is not to 
 be wondered at, therefore, that it has been the aim of much expen- 
 sive and laborious investigation, during many years, to find a practi- 
 cal means of compelling nitrogen of the air to enter into unwilling 
 union with some other elements so as to yield soluble nitrogenous 
 compounds in paying quantities. Every field in which there is any 
 promise of ultimate success has been thoroughly explored. The best 
 scientific ability in the world has been lavished upon this problem 
 and no expense has been spared. One process after another has 
 been proposed, tested out, and abandoned as unsuccessful. Finally, 
 within the last six or seven years, the discovery above" referred to 
 has been the subject of earnest, active collaboration on the part of 
 engineers, agriculturists and chemists, with the result that factories 
 are now established and engaged in the production of a new nitro- 
 genous fertilizer made by the fixation of nitrogen along entirely new 
 lines, by the aid of calcium carbide. The fundamental reaction is 
 as follows : 
 
 Ca Cj 
 
 + N, 
 
 = Ca C N, 
 
 + 
 
 c 
 
 Calcium carbide 
 
 and nitrogen 
 
 yield calcium cyanamid 
 
 and 
 
 carbon, 
 
 which means that calcium carbide, heated with nitrogen, under 
 suitable conditions, yields about its own weight of calcium cyanamid, 
 frequently called lime-nitrogen, and a certain amount of carbon. 
 The method of bringing about the reaction is not in the least com- 
 plicated. The carbide is placed in electrical furnaces of especial 
 form, and nitrogen brought into contact by suitable pipes. The 
 nitrogen may be secured from the atmosphere in any known way, 
 and for this purpose have served both the old copper method, 
 whereby metallic copper is oxidized in air until the oxygen is all 
 removed, leaving only the nitrogen, and the more recent Linde 
 process, in which air is first liquefied and then separated by 
 fractional distillation into its two constituents. 
 
 The lime-nitrogen is removed from the furnace, reduced to a 
 fine powder, delivered from the factory in ordinary jute bags, and is 
 
 96 
 
immediately ready for use. It possesses a dark gray color and a 
 slight odor resembling sulphuretted hydrogen ; it is absolutely stable 
 in its constitution, non-hygroscopic and unaffected by exposure to 
 air or moisture. It is sufficiently soluble to answer to the require- 
 ments in that respect, and it is absolutely fireproof, hence produces 
 no insurance hazard. 
 
 The question of its fitness for agricultural purposes has been 
 thoroughly investigated by European agriculturists and chemists, 
 and all results are favorable to its employment. It has now passed 
 beyond the experimental stage and is widely employed in half a 
 dozen different countries, so that its adaptability to many soils, 
 different climates, and a wide variety of crops is assured. There 
 can be no further question as to its fitness for use as a fertilizer, 
 and it ranks in value fully up with Chile saltpeter and ammonium 
 sulphate, in some individual cases surpassing these. 
 
 It is possible to make ammonia from cyanamid, and as there is a 
 large demand for this commodity, both as liquid ammonia for 
 refrigerating machinery and for the production of ammoniacal salts, 
 and as its production from calcium cyanamid seems to be perfected 
 on an industrial scale, a large use of carbide may here be indicated. 
 
 It is possible also to convert cyanamid into the various metallic 
 cyanides, and as there is a considerable market for these, particularly 
 for cyanide of potassium, which finds wide application in the recov- 
 ery of precious metals from low grade ores and tailings, there may 
 be in this direction also a coming market for carbide. 
 
 Cyanamid may also be utilized in the preparation of other 
 products in considerable number, rather too technical in character 
 for enumeration in this paper except one, namely, nitric acid. The 
 nitrogen contained in calcium cyanamid can unquestionably be 
 transformed into nitric acid and commercial nitrates; investigators 
 are engaged in solving this problem at the present time, but we 
 must ^patiently await the careful elaboration of this very promising 
 process before we can expect to see it placed on a commercial basis. 
 
 THE UNIVERSALITY OF ACETYLENE. 
 
 Prometheus, in mythological lore, stole fire from heaven and 
 brought it down to earth for the use of man. The beast of the 
 field had been man's enemy; Prometheus' torch, celestial gift, 
 lighted at the chariot of the sun, enabled man to forge weapons 
 with which to overpower him. Man had had no heat ; with heaven- 
 stolen fire he warmed his dwellings and thenceforth inhabited every 
 clime. With it also he coaxed the metals from their hiding places 
 
 97 
 
beneath the- earth, established the arts and manufactures, coined 
 money and opened the avenues of commerce. Jupiter, 'tis said, from 
 his throne on old Olympus, beheld this fire upon earth, inquired 
 what it meant, and when informed, his rage knew no bounds! 
 But fire burns on, from day to day, from age to age, and "tries 
 every man's work of what sort it is." 
 
 Once more, this time within a dozen years, has the chariot of 
 the sun again, even more truthfully than before, yielded a bit of 
 itself to our nineteenth century Prometheus, fitting climax to a 
 century prolific in marvels ! No need of mythology now, nor need 
 Jupiter rage again ! , Acetylene has penetrated to every civilized 
 land. It lights the path of man where'er he goes. Flowers turn 
 toward it as toward the sun itself, and man knows no other illumi- 
 nant so like the heavenly luminary. 
 
 The completed list of the possible useful applications of calcium 
 carbide and acetylene has not been made. So fruitful are these 
 marvelous substances in the development of new compounds like 
 cyanamid, not heretofore known except as a curiosity, of new 
 industries like the industry of dissolved acetylene, purely an inven- 
 tion of the last decade, that we no longer look on with wonder 
 when something new is proposed. 
 
 We have but to glance at one of the journals devoted to the 
 acetylene industry, and we read, on one page, of the manufacture of 
 tetra-chlor-acetylene, a derivative of acetylene made by the direct 
 action of chlorine upon it, and advertised as a cheap and excellent 
 solvent for organic substances, chlorine, phosphorus, fats and resins. 
 The substance is described as an oil, possessing an aromatic odor, 
 boiling at two hundred and ninety-six degrees Fahrenheit, and if it 
 can be sold at a price which places it in competition with other fat 
 solvents, an additional use for acetylene will here be found. 
 
 On another page we read of several patents which have been 
 taken out by a prominent German chemist for processes of manufac- 
 turing pure hydrogen by the aid of calcium carbide. Still further on 
 we are instructed as to the preparation of argon, by the assistance of 
 calcium carbide. Elsewhere we find a description of an oxy-acety- 
 lene crucible furnace for facilitating chemical operations, and again 
 of the synthesis of alcohol and related substances from acetylene, 
 and still again of the manufacture of lamp-black from the smoke of 
 the acetylene flame. 
 
 Indeed, the chemist finds acetylene an indispensable adjunct to 
 other reagents in a well-equipped chemical laboratory; he requires 
 it for its perfect light for polariscopic work and for reading many 
 end-reactions in volumetric analysis, as well as for developing the 
 highest heat available in the ordinary chemical laboratory, and for 
 
the occasional precipitation of certain metals. Again the chemist 
 finds in calcium carbide a most efficient desiccating agent, its marked 
 avidity for water rendering it impossible for any moisture to exist 
 in contact with it. 
 
 Nor are all these developing uses of acetylene and carbide merely 
 of a chemical character. We find acetylene growing in popularity 
 for use with the heliograph for signaling on land and sea, for surgical 
 uses in army and navy, where its penetrating character and correct 
 exposition of colors render it invaluable. We know not only that 
 carbide is one of the most useful agents for combating the deadly 
 phylloxera and other parasites of the vine, but that acetylene itself 
 is employed as an insecticide with no inconsiderable success. 
 
 The heat of the oxy-acetylene blowpipe flame has been utilized 
 for the preparation of artificial gems, though probably, as yet, with 
 a measure of success less brilliant than the gems themselves. In a 
 more humble way, acetylene heat is employed in the branding of 
 meats, and acetylene light for testing eggs. 
 
 To-night a million acetylene lights are burning in American 
 homes; thousands of acetylene searchlights scan the water from 
 yachts and sailing craft of every description ; thousands of automo- 
 biles are guided by the aid of penetrating acetylene lights ; hundreds 
 of vessels steer by the light of acetylene beacons. Passengers on 
 railroad trains are enjoying their evening meal and reading the 
 evening papers under the soft light of our beautiful illuminant, 
 while locomotive engineers drive their trains into veritable tunnels, 
 hollowed out of darkness and fog, by means of brilliant and efficient 
 acetylene headlights, the equal of which has never before been 
 known in the history of railroading. 
 
 Five hundred towns and villages derive their public and private 
 illumination from central plants where acetylene is generated; two 
 hundred thousand horsepower, developed by harnessing waterfall 
 and mountain torrent, are constantly absorbed in many factories 
 throughout the world for the production of carbide, while as many 
 tons of the marvelous product' are yearly poured out from fiery 
 furnaces which grumble and roar under the fierce strain. 
 
 Millions of capital are profitably invested in no less than a 
 dozen different countries in the production of carbide and acetylene 
 and in its employment for light, heat and power; in autogenous 
 welding by the aid of the oxy-acetylene blowpipe; in dissolved 
 acetylene ; in calcium cyanamid ; and in all the lesser ramifications 
 of the general industry which it has been the province of this 
 pamphlet to point out. 
 
 In short, so many, and so varied, and so widely applicable are 
 the useful applications of acetylene and calcium carbide in aiding 
 
 99 
 
the operations of man, that we may truthfully say that acetylene 
 has most decidedly contributed a large share, as did Prometheus's 
 fire of old, to man's dominion over the earth. 
 
 BIBLIOGRAPHY. 
 
 Following is a list of the principal published works on calcium 
 carbide and acetylene: 
 Das Acetylen. J. H. Vogel, BerJ-in, 1900. 
 Acetylene. F. H. Leeds and W. J. A. Butterfield. Philadelphia, 
 
 1903. 
 Ueber Acetylenbeleuchtungsanlagen. J. Schultze. Leipsic, 1901. 
 Die Acetylen- und Calciumcarbidindustrie vom patentlichen Stand- 
 
 punkt. J. Ephraim. Halle, 1900. 
 Acetylene Gas, How to Make and Use It. C. N. Turner. New 
 
 York, 1903. 
 Acetylene, a Handbook for the Student and Manufacturer. V. B. 
 
 Lewes. London, 1900. 
 Acetylenkalender ftir 1900. Leipsic, 1899. 
 Das Acetylen in der Technik. F. B. Ahrens. Stuttgart, 1899. 
 Acetylenzentralen. J. H. Vogel. Halle, 1901. 
 Anleitung zur sicherheitstechnischen Priifung und Begutachtung 
 
 von Acetylen. N. Care. Berlin, 1902. 
 Calciumcarbid und Acetylen. Viebeck. Halle, 1897. 
 Calciumcarbid und Acetylen. Liebetanz. Leipsic, 1898. 
 Ueber Calciumcarbid und Acetylengas. Erdmann. Leipsic, 1895. 
 Die Calciumcarbid Industrie. Wangemann. Dresden, 1904. 
 Calciumkarbid und Acetylen. F. Dommer. Munich and Leipsic, 
 
 1898. 
 Calciumcarbid und Acetylen in Vergangenheit, Gegenwart und 
 
 Zukunft. Leipsic, 1897. 
 Le Carbure de Calcium et I'Acetylene. C. de Perrodil. Paris, 
 
 1897. 
 rficlairage a I'Acetylene. Capelle. Paris, 1897. 
 Elektrochemische Untersuchungen am Acetylen. Vienna, 1902. 
 Fiihrer durch die gesammte Calciumcarbid- und Acetylen-Literatur. 
 
 A. Ludwig. Berlin, 1899. 
 Handbuch fiir Acetylen in technischer und wissenschaftlicher Hin- 
 
 sicht. Caro, Ludwig und Vogel. Braunschweig, 1904. 
 Hauptmomente der Acetylen und Carbid Industrie. E. Fernderl. 
 
 Vienna, 1900. 
 Die Herstellung, Aufbewahrung und Verwendung von Acetylengas 
 
 und Lagerung von Carbid. J. Knappich. Halle, 1902. 
 
 100 
 
Hilgsbuch fiir Installationen von Acetylenbeleuchtungsanlagen. 
 
 Leipsic, 1900. 
 Jahrbuch fur Acetylen und Carbid. Altschul, Scheel und Vogel." 
 
 Halle, 1900. 
 Kalender fur Acetylentechniker. Schaefer. Berlin, 1899. 
 Zur Kentniss des Acetylens, ete. Heidelberg, 1892. 
 Katalog der zweiten Acetylen Fachausstellung. Cassel, 1899. 
 Lighting by Acetylene. Frederick Dye. New York, 1902. 
 Lighting by Acetylene. W. E. Gibbs, New York, 1898. 
 Methoden zur Bestimmung der Gasausbeute aus Calciumcarbid. 
 
 Herausgegeben vom deutschen Acetylenverein. Halle, 1900. 
 Die neue Concurrenten des Steinkohlengases. (Acetylen, Wasergas, 
 
 Luftgas.) Schaefer. Munich, 1900. 
 Praktisches Handbuch der Acetylenbeleuchtung und Calciumcarbid- 
 
 fabrikation. A. Ludwig. Berlin, 1898. 
 Some Reactions of Acetylene. J. A. Nieuwland. Notre Dame, 
 
 Ind., 1904. 
 Stand und Zukunft der Acetylenbeleuchtung. Ffoehlich und Herz- 
 
 feld. Berlin, 1895. 
 Taschenbuch fiir Acetylentechniker. Ludewig. Berlin, 1900. 
 Vormen des deutschen Acetylenvereines. Halle, 1901. 
 Vorschriften fiir Herstellung und Benutzung von Acetylen. Liebe- 
 tanz. Leipsic, 1899. 
 
 INDEX TO PERIODICAL LITERATURE. 
 List of Journals Reviewed. 
 
 American Architect Weekly, New York Am. Arch. 
 
 American Engineer and Rail- 
 road Journal Monthly, New York Am. Eng. & R. R. Jour. 
 
 American Gas Lighting Jour- 
 nal Weekly, New York Am. Gas Ltg. Jour. 
 
 American Institute of Electric- 
 al Engineers Monthly, New York Am. Inst. Elec. Eng. 
 
 American Journal of Science. . Monthly, New Haven Am. Jour. Scl. 
 
 American Manufactures and 
 Iron World Weekly, Pittsburg Am. Mfr. Ir. Wld. 
 
 Annales des Fonts et Chaussfis. Weekly, Paris Ann. d. Fonts et Chaussfis 
 
 Architect Weekly, London Arch't. 
 
 Automobile Monthly, New York. . . . .- . . Auto. 
 
 Builder Weekly, London Bldr. 
 
 Canadian Electrical News Monthly, Toronto Can. Elec. News. 
 
 Canadian Engineer .' Monthly, Toronto and 
 
 Montreal Can. Eng. 
 
 Cassler's Monthly Monthly, New York and 
 
 London Cassler's. 
 
 Colliery Guardian Weekly, London Col. Guard. 
 
 Compt. Rend, de 1' Academic 
 
 des Sciences Weekly, Paris Comptes Rendus. 
 
 Consular Reports Monthly, Washington Cons. Rep. 
 
 Cosmopolitan Magazine Monthly, New York Cosmop. 
 
 Country Life Monthly, New York Count. Life. 
 
 Domestic Engineering Weekly, Chicago Dom. Eng. 
 
 Electrical Engineer Weekly, London Elec. Eng. 
 
 Electrical Review Weekly, New York Elec. Rev. 
 
 Electrical Review Monthly, London Elec. Rev., Lond. 
 
 Electrical World Weekly, New York Elec. Wld. 
 
 Electrician Weekly, London Elect'n. 
 
 101 
 
Electricity Weekly, New York Elec. 
 
 Electrochemical and Metallur- 
 gical Industry Monthly, New York Blectrochem. Ina. 
 
 Electro-Techniker Bi-monthly, Vienna Elec. Tech. 
 
 Electrochemische Zeitschrift. . .Monthly, Berlin El'ch. Zeit. 
 
 Elettricita Weekly, Milan Elet. 
 
 Engineer Weekly, London Engr. 
 
 Engineering Weekly, London Engng. 
 
 Engineering Magazine Monthly, New York and 
 
 London Eng. Mag. 
 
 Engineering News Weekly, New York Eng. News. 
 
 Engineering EecoVd Weekly, New York Eng. Rec. 
 
 Engineers' Society oJ Western 
 , Pennsylvania Monthly, Pittsburg Eng. Sec. W. Pa. 
 
 Fire and Water Weekly, New York 
 
 Gas World Weekly, London Gas Wld. 
 
 GSnie Civil Weekly, Paris Gen. Civ. 
 
 Gtaie Moderne Weekly, Paris Gen. Mod. 
 
 Gesundbeits Ingenieor Semi-monthly, Munich. ... Gesund. Ing. 
 
 Glaser's Annalen fiir Gewerbe 
 
 und Bauwesen Semi-monthly, Berlin Glas. Ann. 
 
 GlUckauf Weekly, Essen, Germany . . Gltick. 
 
 Harper's Weekly Weekly, -New York I-Iarp. Wkly. 
 
 Heating and Ventilating Monthly, New York Heat. & Vent. 
 
 Horseless Age Weekly, New York H. Age. 
 
 Illustrated Carpenter and 
 
 Builder Weekly, London 111. Car. & Build. 
 
 lUustrirte Zeitscrhift. fiir klein 
 
 und Strassenhahnen Semi-monthly, Berlin 111. Zeit. Strass. 
 
 Indian and Eastern Engineer. Monthly, Calcutta Ind. & East. Eng. 
 
 Industries and Iron Weekly, London Ind. & Ir. 
 
 De Ingenieur Weekly, Hague Ing. 
 
 Iron Age Weekly, New York Ir. Age. 
 
 Iron and Coal Trades Review. Weekly, London Ir. Coal. Tr. Rev. ' 
 
 Journal of the Association of 
 
 Engineering Societies Monthly, Boston Jour. Assn. Eng. Soc, 
 
 Journal Gas Lighting Weekly, London Jour. Gas Ltg. 
 
 Journal Franklin Institute ... Monthly, Philadelphia. ... .Tour. Fr. Inst. 
 
 Journal of the Society of Arts. Weekly, London ....... t . Jour. Soc. Arts. 
 
 Journal of the Society of 
 
 Chemical Industry Semi-monthly, London. ... Jour. Soc. Chem. Ind. 
 
 Knowledge Weekly, London Knowl. 
 
 Ladies' Home Journal Monthly, Philadelphia. . . . Lad. Home Jour. 
 
 Mechanical Engineer Weekly, Manchester, Bug. . Mech. Eng. 
 
 Memoirs de la Socifit^ des In- 
 
 genieurs Civils de France. . Monthly, Paris Mem. Soc. Ing. Civ. 
 
 Metal Worker Weekly, New York Met. Work. 
 
 Mining and Scientific Press. . Weekly, San Francisco. ... Min. & ScL Press. 
 
 Municipal Journal and Engi- 
 neer Monthly, New York Munic. Jour. & Eng. 
 
 Nature Weekly, London 
 
 New Science Review Quarterly, New York New Sci. Rev. 
 
 Oesterreiehische Monatschrjft 
 fiir den OetCentlichen Bau- 
 dienst Monthly, Vienna Oest. Monat. 
 
 Oesten-eichische Wochenschrift 
 fiir den Oeffentlichen Bau- 
 dienst Weekly, Vienna Oest. Woch. 
 
 Oesterreiehische Zeitschrift fur 
 
 Berg und Hiittenwesen. ... Weekly, Vienna Oest. Zeit. Berg. Hiitt 
 
 Plumber and Decorator Monthly, London Plum. & Dec. 
 
 Popular Science Monthly, New York Pop. Sci. 
 
 Practical Engineer Weekly, London Prac. Eng. 
 
 Proceedings Iowa Railway 
 
 Club Pro. Iowa Ry. Club. 
 
 Progressive Age Semi-monthly, New York. . I'ro. Age. 
 
 Railroad Gazette Weekly, New York R. R. Gaz. 
 
 Railway Age Weekly, Chicago Ry. Age. 
 
 Railway and Engineering Re- 
 view Weekly, Chicago Ry. & Eng. Rev. 
 
 Revue General des Sciences. . Weekly, Paris Rev. Sci. 
 
 Revue Technique Semi-monthly, Paris Rev.-Tech. 
 
 Revue Universelle des Mines. . Monthly, LiSge Rev. Univ. d. Mines 
 
 Sanitary Plumbing Semi-weekly, New York . . . San. Plumb. 
 
 Schweizerische Bauzeitung. . . Weekly, Zurich Schw. Bauz. 
 
 Science Weekly, New York Sci. 
 
 Scientific American Weekly, New York Sci. Am. 
 
 Scientific American Supple- 
 ment Weekly, New York Sci. Am. Sup 
 
 Sibley Journal of Engineer- 
 ing Monthly, Ithaca, N. Y Sib. Jour. 
 
 Stahl und Eisen Semi-weekly, Diisseldorf, . . S. und E 
 
 Stevens Institute Indicator. . Quarterly, Hoboken, N. J..Stev. Inst Ind 
 
 Technology Quarterly Mass. Institute of Tech- 
 
 „ , . uology, Boston Tech. Quar. 
 
 Western Electrician Weekly, Chicago. ..,,,,,, West. Elec. 
 
 102 
 
ZeUchrftfUr Elektrochemle. Weekly, Halle Zelt. El'ch. 
 
 Zeltschrlft des Oesterrelcblscb- 
 
 en ItiKcnleur und Arcbitek- 
 
 ten Verelnes Weekly, Vienna Zelt. Oest. Ing. 
 
 ZeltHcbrlft des Verelnes 
 
 Deutacher Ingenleure Weekly, Berlin Zelt. Deatsch. Ing. 
 
 Index. 
 
 Account of the First Production of Calcium Carbide and Acetylene 
 
 in the United States. F. P. Venable. Am. Mfr. Ir. Wld., 
 ^ Dec. i6, 1898. 
 Acetylene. F. S. Slocum. Pro. Age, June i, 1895. 
 Acetylene. W. W. Goodwin. Pro. Age, Nov. 15, 1895. 
 Acetylene. New Sci. Rev., Jan., 1896. 
 Acetylene. Objections to the Use of Acetylene in Liquid Form. 
 
 Eng. Rec, Feb. 8, 1896. 
 Acetylene. Fire and Water, Mar. 6, 1897. 
 
 Acetylene. A Lecture. V. B. Lewes. Pro. Age, Dec. 15, 1897. 
 Acetylene. Rev. Tech., Feb. 25, 1898. 
 Acetylene. W. H. Tozer. Prac. Eng., Mar. 4, 1898. 
 Acetylene. Cantor Lectures. V. B. Lewes. Am. Gas Ltg. Jour. 
 
 Dec. 12, 19 and 26, 1898, Jan. 9,, 1899. 
 Acetylene. Engr., Mar. 17, 1899. 
 Acetylene. BIdr., Nov. 25, 1899. 
 Acetylene. V. B. Lewes. Jour. Soc. Arts, 1899, pages 105, 117, 
 
 129 and 141. 
 Acetylene. J. W. Woodall & F. Windham. Arch't, Feb. 20, 1903. 
 Acetylene. Wet Process. Heat & Vent.,' Oct. 15, 1898. 
 Acetylene and Its Adaptability as a Motive Power for Vehicles. 
 
 E. C. Oliver. Sci. Am. Sup., Nov. 17, 1900. 
 Acetylene Apparatus. T. O'C. Sloane. Sci. Am. Sup., Apr., 1896. 
 I'Acetylene et ses Applications. M. E. Hubon. Mem. Soc. Ing. 
 
 Civ. Feb., 1899. 
 Acetylene for Auto-cars. Sci. Am., Apr., 1900. 
 Das Acetylen und seine Bedeutung als Beleuchtungsmittel. Karl 
 
 Thomas. Two articles. Zeit. Deutsch. Ing., Apr. 30 and May 
 
 7, 1900. 
 Acetylene Blowpipe. Eng. Mag., July, 1903. 
 
 Acetylene on Board Ships. V. B. Lewes. Gas Wld., Apr. 10, 1897. 
 Acetylenbrenner, Ueber. A. Weber. Sch. Bauz., Jan. 29, 1898. 
 Acetylene and Calcium Carbide. H. Fowler. Nature, Mar., 1898. 
 Acetylene and Car Lighting. P. H. Conradson. Ry. & Eng. Rev., 
 
 July 25, 1896. 
 Acetylene Car Lighting on Great Northern. Ry. Age, Nov. 30, 
 
 1906. 
 
 103 
 
Die Acetylen-Centrale fiir die Beleuchtting von Schonsee. Paul 
 
 Wolff. Glas. Ann., June i, 1899. 
 Acetylene Coach Lighting. Ry. & Eng. Rev., Apr. 21, 1906. 
 Acetylene v. Coal -Gas or Electricity. H. Allen. Sci. Am. Sup., 
 
 Dec. I, 1906. 
 Acetylene Congress at Frankfort. Jour. Gas Ltg., Nov. 15, 1898. 
 Acetylene Congress at Nuremberg. Engr., Loncl, Nov. 17, 1890. 
 I'Acetylene, Au Concours Agricole. Gen. Mod., May i, 1897. 
 I'Acetylene Dissous. Rev. Tech., Mar. 25, 1897. 
 I'Acetylene Dissous et ses Principales Applications. A. Janet, 
 
 Gen. Civ., July 18, 1903. 
 I'Acetylene Dissous et ses Principales Applications. F. Bourdil. 
 
 Mem. Soc. Ing. Civ., Nov., 1903. 
 Acetylen, Einige Weitere Mittheilungen ueber. Glas. Ann., Mar. 
 
 15, 1897. 
 Acetylene for Enriching Gas Produced from Lean Coals. T. 
 
 Vautier. Pro. Age, Dec. i, 1897. 
 Acetylene versus Ethylene. Engr., Dec. 16, 1898. 
 Acetylene Exhibition and Congress at Budapest. Engr., Aug. 11, 
 
 1898. 
 Acetylene Explosions. Editorial. Am. Gas Ltg. Jour., Feb. 14, 
 Acetylene Explosions. Sci. Am., Feb. 5, 1898. 
 Acetylene Explosions. Editorial. Am. Gas Lgt. Jour., Feb. 14, 
 
 1898. 
 Das Acetylen und seine Explosions-Gefahrlichkeit. Glas. Ann., Apr. 
 
 I, 1897. 
 Acetylene as an Explosive. Engr., Oct. 23, 1896. 
 Acetylene Flame. E. L. Nichols. Jour. Fr. Inst., Nov., 1900. 
 Acetylene Gas. W. R. Addicks. Am. Gas Ltg. Jour. M'ar. 9, 
 
 1896. 
 Acetylene Gas. George Black. Can. Elec. News, July, 1896. 
 Acetylene Gas. T. Glover. Gas Wld., Feb. 26, 1898. 
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 107 
 
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 108 
 
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 109 
 
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 110 
 
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 Ill 
 
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 112 
 
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 113 
 
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 114 
 
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 Dec. I, 1900. 
 Oxy-Acetylene Lamp. Sci. Am. Sup., May 20, 1905. 
 Oxygen Flame. C. H. Sharp. Translation. Am. Inst. Elec. Eng., 
 
 Dec, igoi. 
 Papers Read at the Acetylene Congress, as Taken from the Report 
 
 of Herr Liebetanz. Serial. Jour. Gas Ltg., Oct. 17, 1899. 
 
 The Patait Side of Acetylene Gas. Pro. Age, July 15, 1897. 
 Petroleum Acts. Order in Council Relating to Calcium Carbide. 
 
 London, 1897. 
 Physiological Action of Acetylene. W. H. Birchmore. Elec. Eng., 
 
 Nov. 13, 1895. 
 Physiological Efifects of Acetylene. T. Oliver. Pro. Age, June i, 
 
 1898. 
 Poisonous Action of Acetylene. M. N. Grehant. Elec. Eng., Dec. 
 
 II, 1895. 
 Poisonous Properties of Acetylene. R. Rosemann. Pro. Age, Mar. 
 
 I, 1896. 
 Portable Applications of Acetylene. Eng. Mag., Oct., ,1903. 
 Position of Calcium Carbide and Acetylene. Engr., Sept. 13, 1901. 
 Possibilities of Acetylene. Am. Gas Ltg. Jour., Oct. 14, 1895. 
 Practical Use of Acetylene. Paper Read before Western Gas Asso- 
 ciation. Pro. Age, June 15, 1896. 
 Present Position of Acetylene Lighting. Paul Wolff. Jour. Gas 
 
 Ltg., Nov. 8 and 15, 1898. 
 Present and Prospective Supply of Calcium Carbide. Cons. Rep., 
 
 July 6, 1898. 
 Principle of Acetylene Lamps. S. W. Rushmore. Auto., Jan. 2, 
 
 1904. 
 The Principles of Illumination from the Standpoint of the Acetylene 
 
 116 
 
Engineer. Van Rensselaer Lansingh. Read before the Interna- 
 tional Acetylene Association, Atlantic City, June id, 1906. 
 Priority in Discovery of Commercial Method of Making Calcium 
 
 Carbide. A. C. Fraser. Pro. Age, Feb. i, 1898. 
 Priority in Electrical Process for Making Calcium Carbide. L. K. 
 
 Boehm. Pro. Age, May 15, 1898. 
 Proceedings of the International Acetylene Association. Annual 
 
 since 1898. 
 Production of Synthetic Alcohol. H. W. Wiley and H. Schreiber. 
 
 Read before the Am. Phil. Soc, Apr. 20, 1907. 
 Products of the Explosion of Acetylene. W. G. Mixter. Am. Jour. 
 
 Sci., Jan., 1900. 
 Progress in the Acetylene Gas Industry. J. B. C. Kershaw. Elec. 
 
 Rev., Oct. 6, 1899. 
 Purification of Acetylene. Sci. Am., May 5, 1900. 
 The Purification of Acetylene. Jour. Gas Ltg., June 14, 1898. 
 Purification of Acetylene. Abstract. Jour. Gas Ltg., Dec. 30, 1902, 
 Purification of Acetylene by Means of Chloride of Lime. Engr., 
 
 Nov. 3, 1899. 
 Purification and Combustion of Acetylene. Ullman. Sci. Am. Sup., 
 
 June 1 8, 1904. 
 Quality of Calcium Carbide. Jour. Gas Ltg., May 7, 1898. 
 Railway Carriage Lighting. H. Gerdes. Gas Wld., May i, 1897. 
 Railway Carriage Lighting by Compressed Oil Gas and Acetylene. 
 
 Bork. Engr., Sept. 19, 1898. 
 Railway Carriage Lighting and the Latest Experiments with Acety- 
 lene. Ry. & Eng. Rev., Dec. 4, 1897. 
 Railway Lighting by Acetylene Gas. J. S. Seymour. Ry. & Eng. 
 
 Rev., Aug. 24, 1 90 1. 
 Rapport General sur le Concurs d'Appareils a Acetylene, Paris, 1906. 
 Die Reaktiongleichung bei der Calcium-carbid-Reduktion. B. Neu- 
 
 man. Zeit. El'ch., Oct. 2, 1902. 
 Die Reaktionsgieichung bei der Calcium-carbid-Reduktion. Fr. von 
 
 Ktigelgen. Zeit. El'ch., Oct. 9, 1902. ^ 
 
 Real Value of Acetylene as an Illuminant. Engr., Mar. 31, 1899. 
 Recent Facts about Acetylene. S. E. Filman. Cosmop., Nov., 1897. 
 Recent Research on Acetylene. G. E. Brown. Pro. Age, July 15, 
 
 1897. 
 Recherches sur les Derives Metalliques de I'Acetylene. Berthelot & 
 
 Delepine. Compt. Rend., Aug. 14, 1899. 
 Regulations for Acetylene Lighting at Berlin. Translation. Pro. 
 
 Age, Jan. i, 1898. 
 Reply of Houston, Kennelly and Kinnicutt to Criticisms on the Pro. 
 
 116 
 
Age. Report Concerning Cost of Carbide of Calcium. Pro. 
 
 Age, July 15, 1896. 
 Reply of Pro. Age Commissioners to Criticisms on the Cost of tht 
 
 Carbide of Calcium. Pro. Age, July 15, 1896. 
 Report of the Acetylene Exhibition Committee. Engr., Mar. 3, 
 
 1899. 
 Reporf on Present Status of Manufacture of Carbide of Calcium 
 
 and Acetylene Gas. Houston, Kennelly and Kinnicutt. Pro. 
 
 Age, Apr. 15, 1896. 
 Report on the Use of Acetylene Gas by the Canadian Government 
 
 as an Illuminant for Aids to Navigation. Albert Ross, Capt. 
 
 U. S. N., Member of the Light House Board, Washington, D. C. 
 Restrictions placed on Carbide of Calcium in England. Pro. Age, 
 
 Apr. I, 1897. 
 Results of Practical Experiments with High Pressure Acetylene 
 
 Lighting. H. T. Hauer. Pro. Age, July 15, 1901. 
 Risks in the Use of Calcium Carbide and Acetylene. E. V. French. 
 
 Eng. News, Feb. 23, 1899. 
 Salvator Acetylene Searchlight. Sci. Am. Sup., Nov. 25, 1905. 
 Science of a Light. H. Maxim. Harp. Wkly., Jan. 23, 1904. 
 Serpollet Acetylene Generator. Sci. Am., Feb. 10, 1900. 
 Simple Generation of Acetylene and Its Purity. Jour. Gas Ltg., 
 
 July 2, 1901. 
 A Sober Account of Acetylene. W. E. Gibbs. Jour. Gas Ltg., Aug. 
 
 23, 1898. 
 Solutions of Acetylene and Their Explosive Properties. Berthelot & 
 
 Vieille. Pro. Age, Sept. i, 1897. 
 Some Facts about Acetylene Gas. J.. C. McMynn. Elec. Rev., 
 
 Jan. 24, 1896. 
 Some Facts about the Purification of Acetylene Gas. Theo. Kaut- 
 
 ney. Dom. Eng., Sept. 15, 1900. 
 Some Enemies of Acetylene. Engr., Apr. 27, 1900. 
 Some More Enemies of Acetylene. Engr., June i, 1900. 
 Some New Uses for Calcium Carbide. Engr., Jan. 18, 1901. 
 Some Notes on Calcium Carbide Manufacture. Elec. Rev., Lond., 
 
 Sept. 20, 1 90 1. 
 Some Properties of Acetylene Gas. Abstract. Ad. Bouvier. Sci. 
 
 Am., Sept. 3, 1898. 
 Some Properties of Calcium Carbide. Venable and Clark. Am. 
 
 Gas Ltg. Jour., page 528, 1895. 
 Studien iiber die Reduzierende Kraft des Calciumcarbids. Kiigel- 
 
 gen. Zeit. El'ch., Apr. 11, 18 and 25, 1901. 
 
 117 
 
Studies of the Explosive Properties o:^ Acetylene. Bertlielot &. 
 
 Vieille. Pro. Age, Dec. i, 1896. 
 Symposium on Car Lighting. Ry. Age, Feb. 20, 1903. 
 Some Theoretical Aspects of Acetylene Manufacture. Engr., June 
 
 24, 1898. 
 La Soudure Autogene des Metaux. Andre Binet. Gen. Civ., May 
 
 23, 1903- 
 La Soudure Autogene des Metaflx.- P. Dumesnil, Mem. Soc. Ing. 
 
 Civ., Nov., 1905; 
 Specifications for an Acetylene Gas Generating Apparatus for Fort 
 
 McPherson, Ga. Eng. News, Feb; 4, 1904. 
 Storage of Calcium Carbide. Pro. Age, Mar. i, 1897. 
 The Technical Analysis of Calcium Carbide and Acetylene and the 
 
 Purifying of the Latter. Lunge and Cedercreutz. Pro. Age, 
 
 Dec. 15, 1897, also Gas Wld., Jan. i, 1898. 
 The Technology of Acetylene. Review of Lewes' Book. Jour. Gas 
 
 Ltg., Aug.' 21, 1900. 
 Three Phase Currents in the Manufacture of Calcium Carbide in 
 
 Italy. Cesare Pio. Elec. Wld. & Elec. Eng., Aug. 5, 1899. 
 Town Lighting by Acetylene. Augustine Davis. Munic. Jour. & 
 
 Eng., July, 1903; Oct., 1903; and Mar., 1904. 
 Town Lighting with Acetylene. Pro. Age, Dec. i, 1898. 
 The Truth about Acetylene Gas. Albert Stetson. Elec, Feb. 12, 
 
 1896. 
 Two Systems of Using Acetylene Gas for Car Lighting. E. G. 
 
 Fisher. Abstract. Eng. News, Oct. i, 1903. 
 Usine a Gas Riche et a Acetylene. H. Guerin. Gen. Civ., Oct. 26, 
 
 1901. 
 The Utilization of Acetylene. Engr., Aug. 19, 1898. 
 Utilization of no Volt Electric Circuits for Small Furnace Work. 
 
 Sci. Am. Sup., Aug. 27, 1898. 
 Ueber die Verbrennung des Kohlenstofis bei der Calcium Carbid- 
 
 Reduktion. Fr. v. Kiigelgen and W. Halle. Zeit. El'ch., 
 
 May 14, 1903. 
 Ueber Versuche mit Acetylen Beleuchtung in Bergwerken. G. 
 
 Franke. Oest. Zeit. Berg. Hiitt. Berlin, 1901. ^ 
 
 Versuche mit der Wolf'schen Azetylen Sicherheitslampe. H. Bey- 
 ling. Gliick., July 8, 1905. 
 Velocity of Acetylene Detonations. Sci. Am. Sup., July 28, 1900. 
 Sur la Vitesse de Detonations de I'Acetylene. Berthelot and Le 
 
 Chatelier. Compt. Rend., Aug. 28, 1899. 
 Welding by Acetylene. Ry. & Eng. Rev., Jan. 20, 1906, 
 
 118 
 
Welding, a New System of. A. H. Sexton. Mech. Eng., June 17, 
 
 1905- 
 Zur Wertbestimmung elektrischer Kraft. O. Schmidt. Zeit. El'ch., 
 
 Aug. I, 1901. 
 Wet and Dry Generators. H. F. Fuller. Heat & Vent, Oct. 15, 
 
 1898. 
 Will there be a Carbide' Industry? W. H. Birchmore. Eng. News, 
 
 Jan. 30, 1896. 
 The Wilmington Explosion. W. A. Jones. Am. Gas Ltg. Jour., 
 
 Jan. 24, 1898. 
 Die Wirkung der deutschen Arbeitversicherung. Gesund. Ing., Apr. 
 
 30 and May 15, 1897. 
 Die Zweite Internationale Acetylen-Ausstellung in Budapest, 1899. 
 
 Karl Neudeck. Zeit. Oest. Ing., Jan. 12, 19 and 26, 1900. 
 Zweite' Internationaler Congress for Carbid und Acetylen Industrie. 
 
 H. Koechlin. Oest. Monat., Mar., 1900. 
 
 THE ACETYLENE PRESS. 
 
 The following are the principal journals especially devoted to 
 the acetylene and calcium carbide industries: 
 
 United States. 
 
 The Acetylene Journal. Published monthly (48 pages) by the 
 Acetylene Journal Publishing Co., 324 Dearborn St., Chicago, 111. 
 Edited by Elias A. Long; official organ of the International Acety- 
 lene Association; price fifty cents per year; now in its tenth year. 
 
 England. 
 
 Acetylene. Published monthly (24 pages) at 46 Southampton 
 Buildings, Chancery Lane, London, W. C. Edited by F. H. Leeds ; 
 official organ of the Acetylene Association ; price three shillings per 
 year; now in its sixth year. This journal replaces an earlier peri- 
 odical known as the Journal of Acetylene Lighting, which was issued 
 monthly from 1898 to 1902. 
 
 Germany. 
 
 Zeitschrift fiir Calciumcarbid-Fabrikation, Acetylen-und-Klein- 
 Beleuchtung. Published weekly (8 pages) at Kommandantenstr. 
 M. Berlin S. W. Edited by J. H. Vogel ; official organ of the Ger- 
 
 119 
 
man Acetylene Association; price sixteen marks per year; now in 
 its twelfth year. 
 
 Acetylen in Wissenschaft und Industrie. Published semi- 
 monthly (i2 pages) by Carl Marhold, Halle. Edited by Theodor 
 Kautny; price sixteen marks per year; now in its eleventh year. 
 
 France. 
 
 Revue des ficlairages. Published semi-monthly (12 to 16 pages) 
 at 104 Boulevard de Clichy, Paris. Edited by R. Granjon; price 
 eight francs per year ; now in its thirteenth year. 
 
 Bulletin Officiel de I'Union des Proprietaires d'Appareils a 
 Acetylene. Published monthly at 104 Boulevard de Clichy, Paris. 
 Price three and a half francs per year. 
 
 120