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ACETYLENE
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ACETYLENE , klumene or ethine, a gaseous See also:compound of See also:carbon and See also:hydrogen, represented by the See also:formula C2H2. It is a colourless See also:gas, having a See also:density of o•92. When repa e alrties. prepared by the See also:action of See also:water upon See also:calcium See also:carbide, ~' , it has a very strong and penetrating odour, but when it is thoroughly purified from sulphuretted and phosphuretted hydrogen, which are invariably See also:present with it in See also:minute traces, this extremely pungent odour disappears, and the pure gas has a not unpleasant ethereal See also:smell. It can be condensed into the liquid See also:state by See also:cold or by pressure, and experiments by G. See also:Ansdell show that if the gas be subjected to a pressure of 21.53 atmospheres at a temperature of o° C., it is converted into the liquid state, the pressure needed increasing with the rise of temperature, and decreasing with the lowering of the temperature, until at -82° C. it becomes liquid under See also:ordinary atmospheric pressure. The See also:critical point of the gas is 370 C., at which temperature a pressure of 68 atmospheres is required for liquefaction. The properties of liquid and solid acetylene have been investigated by D. McIntosh (Jour. Chem. See also:Soc., Abs., 19o7, i. 458). A See also:great future was expected from its use in the liquid state, since a See also:cylinder fitted with the necessary reducing valves would See also:supply the gas to See also:light a See also:house for a considerable See also:period, the liquid occupying about Th- the See also:volume of the gas, but in the See also:United States and on the See also:continent of See also:Europe, where liquefied acetylene was made on the large See also:scale, several fatal accidents occurred owing fo its See also:explosion under not easily explained conditions. As a result of these accidents M. P. E. See also:Berthelot and L. J. G. Vieille made a See also:series of valuable researches upon the explosion of acetylene under various conditions. They found that if liquid acetylene in a See also:steel See also:bottle be heated at one point by a See also:platinum See also:wire raised to a red See also:heat, the whole See also:mass decomposes and gives rise to such tremendous pressures that no cylinder would be able to withstand them. These pressures varied from 71,o00 to roo,000 lb. per square See also:inch. They, moreover, tried the effect of See also:shock upon the liquid, and found that the repeated dropping of the cylinder from a height of nearly 20 feet upon a large steel See also:anvil gave no explosion, but that when the cylinder was crushed under a heavy See also:blow the impact was followed, after a See also:short See also:interval of See also:time, by an explosion which was manifestly due to the fracture of the cylinder and the ignition of the escaping gas, mixed with See also:air, from See also:sparks caused by the breaking of the See also:metal. A similar explosion will frequently follow the breaking in the same way of a cylinder charged with hydrogen at a high pressure. Continuing these experiments, they found that in acetylene gas under ordinary pressures the decomposition brought about in one portion of the gas, either by heat or the firing in it of a small detonator, did not spread far beyond the point at which the decomposition started, while if the acetylene was compressed to a pressure of more than 30 lb on the square inch, the decomposition travelled throughout the mass and became in reality detonation. These results showed clearly that liquefied acetylene was far too dangerous for See also:general introduction for domestic purposes, since, although the occasions would be rare in which the requisite temperature to bring about detonation would be reached, still, if this point were attained, the results would be of a most disastrous See also:character. The fact that several. accidents had already happened accentuated the See also:risk, and in Great See also:Britain the storage and use of liquefied acetylene are prohibited.
When liquefied acetylene is allowed to See also:escape from the cylinder in which it is contained into ordinary atmospheric pressure, some of the liquid assumes the gaseous See also:condition with such rapidity as to cool the See also:remainder below the temperature of -90° C., and convert it into a solid See also:snow-like mass.
Acetylene is readily soluble in water, which at normal tem-
perature and pressure takes up a little more than its own volume
of the gas, and yields a See also:solution giving a See also:purple-red
Soluhllity precipitate with ammoniacal cuprous chloride and
of
acetylene. a See also: This fact having been fully demonstrated, acetylene dissolved in this way was exempted from the See also:Explosives See also:Act, and consequently upon this exemption a large business has grown up in the preparation and use of dissolved acetylene for See also:lighting motor omnibuses, motor cars, railway carriages, lighthouses, buoys, yachts, &c., for which it is particularly adapted. Acetylene was at one time supposed to be a highly poisonous gas, the researches of A. Bistrow and O. Liebreich having apparently shown that it acts upon the See also:blood in the same way as carbon monoxide to See also:form a See also:stable com- pPoropertilsononses. See also:pound. Very extensive experiments, however, made by Drs N. Grehant, A. L. Brociner, L. Crismer, and others, all conclusively show that acetylene is much less toxic than carbon monoxide, and indeed than See also:coal gas. When acetylene was first introduced on a commercial scale See also:grave fears were entertained as to its safety, it being represented that it had the See also:power of combining with certain metals, more especially See also:copper and silver, to chemical properties. form acetylides of a highly explosive character, and that even with coal gas, which contains less than 1%,. such copper compounds had been known to be formed in cases where the gas-distributing mains were composed of copper, and that accidents had happened from this cause. It was there-fore predicted that the introduction of acetylene on a large scale would' be followed by numerous accidents unless copper and its See also:alloys were rigidly excluded from contact with the gas. These fears have, however, fortunately proved to be unfounded, and ordinary gas fittings can be used with perfect safety with this gas. Acetylene has the See also:property of inflaming spontaneously when brought in contact with See also:chlorine. If a few pieces of carbide be dropped into saturated chlorine water the bubbles of gas take See also:fire as they reach the See also:surface, and if a See also:jet of acetylene be passed up into a bottle of chlorine it takes fire and See also:burns with a heavy red See also:flame, depositing its carbon in the form of See also:soot. If chlorine be bubbled up into a See also:jar of acetylene See also:standing over water, a violent explosion, attended with a flash of intense light and the deposition of carbon, at once takes See also:place. When the gas is kept in 'a small See also:glass holder exposed to See also:direct sunlight, the surface of the glass soon becomes dimmed, and W. A. See also:Bone has shown that when exposed for some time to the See also:sun's rays it undergoes certain polymerization changes which See also:lead to the deposition of a film of heavy See also:hydrocarbons on the surface of the See also:tube. It has also been observed by L. Cailletet and later by P. See also:Villard that when allowed to stand in the presence of water at a See also:low temperature a solid See also:hydrate is formed. Acetylene is The poly- readily decomposed by heat, polymerizing under its merizatlon See also:influence to form an enormous number of organic of compounds; indeed the gas, which can itself be directly acetylene. prepared from its constituents, carbon and hydrogen, under the influence of the electric arc, can be made the starting-point for the construction of an enormous number of different organic compounds of a complex character. In contact with nascent hydrogen it builds up See also:ethylene; ethylene acted upon by sulphuric acid yields See also:ethyl sulphuric acid; this can again be decomposed in the presence of water to yield alcohol, and it has also been proposed to manufacture See also:sugar from this See also:body. Picric acid can also be obtained from it by first treating acetylene with sulphuric acid, converting the product into phenol by solution in potash and then treating the phenol with fuming nitric acid. Acetylene is one of those bodies the formation of which is attended with the disappearance of heat, and it is for this See also:reason i?atio. termed an " endothermic " compound, in contradis- thermic tinction to those bodies which evolve heat in their nature of formation, and which are called " exothermic." Such acetylene. endothermic bodies are nearly always found to show considerable violence in their decomposition, as the heat of formation stored up within them is then liberated as sensible heat, and it is undoubtedly this property of acetylene gas which leads to its easy detonation by either heat or a shock from an explosion of fulminating See also:mercury when in contact with it under pressure. The observation that acetylene can be resolved into its constituents by detonation is due to Berthelot, who started an explosive See also:wave in it by firing a See also:charge of o•i See also:gram of mercury fulminate. It has since been shown, however, that unless the gas is at a pressure of more than two atmospheres this wave soon See also:dies out, and the decomposition is only propagated a few inches from the detonator. Heated in contact with air to a temperature of 48o° C., acetylene ignites and burns with a flame, the See also:appearance of which varies with the way in which it is brought in contact with the air. With the gas in excess a heavy lurid flame emitting dense volumes of See also:smoke results, whilst if it be driven out in a sufficiently thin See also:sheet, it burns with a flame of intense brilliancy and almost perfect whiteness, by the light of which See also:colours can be judged as well as they can by daylight. Having its ignition point below that of ordinary gas, it can be ignited by any red-hot carbonaceous See also:matter, such as the brightly glowing end of a See also:cigar. For its See also:complete See also:combustion a volume of acetylene needs approximately twelve volumes of air, forming as products of combustion carbon dioxide and water vapour. When, however, the air is present in much smaller ratio the combustion is incomplete, and carbon, carbon monoxide, carbon dioxide, hydrogen and water vapour are produced. This is well shown by taking a cylinder one-See also:half full of acetylene and one-half of air; on applying a light to the mixture a lurid flame runs down the cylinder and a See also:cloud of soot is thrown up, the cylinder also being thickly coated with it, and often containing a See also:ball of carbon. If now, after a few moments' interval to allow some air to diffuse into the cylinder, a See also:taper again be applied, an explosion takes place, due to a mixture of carbon monoxide and air. It is probable that when a flame is smoking badly, distinct traces of carbon monoxide are being produced, but when an acetylene flame burns properly the products are as harmless as those of coal gas, and, light for light, less in amount. Mixed with air, like every other combustible gas, acetylene forms an explosive mixture. F. Clowes has shown that it has a wider range of ex-plosive proportions when mixed with air than any of the other combustible gases, the limiting percentages being as follows: Acetylene . 3 to 82 Hydrogen 5 to 72 Carbon monoxide 13 to 75 Ethylene . 4 to 22 Methane . . 5 to 13 The methods which can be and have been employed from time to time for the formation of acetylene in small quantities are exceedingly numerous. Before the commercial See also:production of calcium carbide made it one of the most Methods of easily obtainable gases, the processes which were most See also:auction. largely adopted for its preparation in laboratories were: first, the decomposition of ethylene bromide by dropping it slowly into a boiling solution of alcoholic potash, and purifying the evolved gas from the volatile bromethylene by washing it through a second See also:flask containing a boiling solution of alcoholic potash, or by passing it over moderately heated soda See also:lime; and, second, the more ordinarily adopted See also:process of passing the products of incomplete combustion from a See also:Bunsen burner, the flame of which had struck back, through an ammoniacal solution of cuprous chloride, when the red copper acetylide was produced. This on being washed and decomposed with hydrochloric acid yielded a stream of acetylene gas. This second method of production has the great See also:drawback that, unless proper precautions are taken to purify the gas obtained from the copper acetylide, it is always contaminated with certain chlorine derivatives of acetylene. See also:Edmund See also:Davy first made acetylene in 1836 from a compound produced during the manufacture of See also:potassium from potassium tartrate and See also:charcoal, which under certain conditions yielded a See also:black compound decomposed by water with consider-able violence and the See also:evolution of acetylene. This compound was afterwards fully investigated by J. J. See also:Berzelius, who showed it to be potassium carbide. He also made the corresponding See also:sodium compound and showed that it evolved the same gas, whilst in 1862 F. See also:Wohler first made calcium carbide, and found that water decomposed it into lime and acetylene. It was not, however, until 1892 that the almost simultaneous discovery was made by T. L. Willson in See also:America and H. See also:Moissan in See also:France that if lime and carbon be fused together at the temperature of the electric See also:furnace, the lime is reduced to calcium, which unites with the excess of carbon present to form calcium carbide. The cheap production of this material and the easy liberation by its aid of acetylene at once gave the gas a position of commercial importance. In the manufacture of calcium carbide in the electric furnace, lime and See also:anthracite of the Manufachighest possible degree of purity are employed. A See also:ture of See also:good working mixture of these materials may be taken calcium as being too parts by See also:weight of lime with 68 parts carbide. by weight of carbonaceous material. About 1.8 lb of this is used up for each pound of carbide produced. The two See also:principal processes utilized in making calcium carbide by See also:electrical power are the See also:ingot process and the tapping process. 
In the former, the anthracite and lime are ground and carefully mixed in the right proportions to suit the chemical actions involved. The arc is struck in a crucible into which the mixture is allowed to flow, partially filling it. An ingot gradually builds up from the bottom of the crucible, the carbon electrode being raised from time to time automatically or by See also:hand to suit the diminution of resistance due to the shortening of the arc by the rising ingot. The crucible is of metal and considerably larger than the ingot, the latter being surrounded by a mass of unreduced material which protects the crucible from the intense heat. When the ingot has been made and the crucible is full, the latter is withdrawn and another substituted. The process is not continuous, but a See also:change 'of crucibles only takes two or three minutes under the best conditions, and only occurs every ten or fifteen See also:hours. The essence of this process is that the See also:coke and lime are only heated to the point of See also:combination, and are not " boiled " after being formed. It is found that the ingot of calcium carbide formed in the furnace, although itself consisting of pure crystalline calcium carbide, is nearly always surrounded by a crust which contains a certain proportion of imperfectly converted constituents, and therefore gives a See also:lower yield of acetylene than the carbide itself. In breaking up and sending out the carbide for commercial See also:work, packed in air-tight drums, the crust is removed by a See also:sand blast. A statement of the amount made per kilowatt See also:hour may be misleading, since a certain amount of loss is of See also:necessity entailed during this process. For instance, in See also:practical working it has been found that a furnace return of o•504 lb per kilowatt hour is brought down to 0.406 lb per kilowatt hour when the material has been broken up, sorted and packed in air-tight drums. In the tapping process a fixed crucible is used, lined with carbon, the electrode is nearly as big as the crucible and a much higher current density is used. The carbide is heated to complete liquefaction and tapped at short intervals. There is no unreduced material, and the process is considerably simplified, while less expensive plant is required. The run carbide, however, is never so See also:rich as the ingot carbide, since an excess of lime is nearly always used in the mixture to act as a See also:flux, and this remaining in the carbide lowers its gas-yielding power. Many attempts have been made to produce the substance without See also:electricity, but have met with no commercial success. Calcium carbide, as formed in the electric furnace, is a beauti- ful crystalline semi-metallic solid, having a density of 2.22, and showing a fracture which is often shot with iridescent Properties colours. It can be kept unaltered in dry air, but the of calcium carbide. smallest trace of moisture in the atmosphere leads to the evolution bf minute quantities of acetylene and gives it a distinctive odour. It is infusible at temperatures up to 2000° C., but can be fused in the electric arc. When heated to a temperature of 245° C. in a stream of chlorine gas it becomes incandescent, forming calcium chloride and liberating carbon, and it can also be made to See also:burn in See also:oxygen at a dull red heat, leaving behind a See also:residue of calcium carbonate. Under the same conditions it becomes incandescent in the vapour of See also:sulphur, yielding calcium sulphide and carbon disulphide; the vapour of See also:phosphorus will also unite with it at a red heat. Acted upon by water it is at once decomposed, yielding acetylene and calcium hydrate. Pure crystalline calcium carbide yields 5.8 cubic feet of acetylene per pound at ordinary temperatures, but the carbide as sold commercially, being a mixture of the pure crystalline material with the crust which in the electric furnace surrounds the ingot, yields at the best 5 cubic feet of gas per pound under proper conditions of See also:generation. The volume of gas obtained, however, depends very largely upon the form of apparatus used, and while some will give the full volume, other apparatus will only yield, with the same carbide, 34 feet. The purity of the carbide entirely depends on the purity of the material used in its manufacture, and before this fact had been fully grasped by manufacturers, and only the purest material obtainable employed, it contained notable quantities of compounds which during its decomposition by water yielded a somewhat high See also:pro-impurities. portion of impurities in the acetylene generated from it. Although at the present time a marvellous improvement has taken place all See also:round in the quality of the carbide produced, the acetylene nearly always contains minute traces of hydrogen, See also:ammonia, sulphuretted hydrogen, phosphuretted hydrogen, See also:silicon hydride, See also:nitrogen and oxygen, and sometimes minute traces of carbon monoxide and dioxide. The formation of hydrogen is caused by small traces of metallic calcium occasionally found See also:free in the carbide, and cases have been known where this was present in such quantities that the evolved gas contained nearly 20 % of hydrogen. This takes place when in the manufacture of the carbide the material is kept too See also:long in contact with the arc, since this overheating causes the See also:dissociation of some of the calcium carbide and the solution of metallic calcium in the remainder. The presence of free hydrogen is nearly always accompanied by silicon hydride formed by the combination of the nascent hydrogen with thesilicon in the carbide. The ammonia found in the acetylene is probably partly due to the presence of See also:magnesium nitride in the carbide. On decomposition by water, ammonia is produced by the action of See also:steam or of nascent hydrogen on the nitride, the quantity formed depending very largely upon the temperature at which the carbide is decomposed. The formation of nitrides and cyanamides by actions of this See also:kind and their easy See also:conversion into ammonia is a useful method for fixing the nitrogen of the atmosphere and rendering it available for manurial purposes. Sulphuretted hydrogen, which is invariably present in commercial acetylene, is formed by the decomposition of See also:aluminium sulphide. A. Mourlot has shown that aluminium sulphide, See also:zinc sulphide and See also:cadmium sulphide are the only sulphur compounds which can resist the heat of the electric furnace without decomposition or volatilization, and of these aluminium sulphide is the only one which is decomposed by water with the evolution of sulphuretted hydrogen. In the See also:early samples of carbide this compound used to be present in considerable quantity, but now rarely more than no % is to be found. Phosphuretted hydrogen, one of the most important impurities, which has been blamed for the haze formed by the combustion of acetylene under certain conditions, is produced by the action of water upon traces of calcium phosphide found in carbide. Although at first it was no uncommon thing to find % of phosphuretted hydrogen present in the acetylene, this has now been so reduced by the use of pure materials that the quantity is rarely above o•15 %, and it is often not one-fifth of that amount. In the generation of acetylene from calcium carbide and water, all that has to be done is to bring these two compounds into contact, when they mutually react upon each other with the formation of lime and acetylene, while, if there be sufficient water present, the lime combines with it to form calcium hydrate. Calcium carbide. Water. Acetylene. Lime. Ca C2 + See also:H2O = C21-12 + CaO Lime. Water. Calcium hydrate. CaO + H2O = Ca(HO)2 The decomposition of the carbide by water may be brought about either by bringing the water slowly into contact with an excess of carbide, or by dropping the carbide into an excess of water, and these two See also:main operations again may be varied by innumerable ingenious devices by which the rapidity of the contact may be modified or even eventually stopped. The result is that although the forms of apparatus utilized for this purpose are all based on the one fundamental principle of bringing about the contact of the carbide with the water which is to enter into See also:double decomposition with it, they have been multiplied in number to a very large extent by the methods employed in See also:order to ensure See also:control in working, and to get away from the dangers and inconveniences which are inseparable from a too rapid generation. In attempting to classify acetylene generators some authorities have divided them into as many as six different anera- classes, but this is hardly necessary, as they may be tors. divided into two main classes—first, those in which water is brought in contact with the carbide, the carbide being in excess during the first portion of the operation; and, second, those in which the carbide is thrown into water, the amount of water present being always in excess. The first class may again be subdivided into generators in which the water rises in contact with the carbide, in which it drips upon the carbide, and in which a See also:vessel full of carbide is lowered into water and again with-See also:drawn as generation becomes excessive. Some of these generators are constructed to make the gas only as fast as it is consumed at the burner, with the See also:object of saving the expense and See also:room which would be involved by a storage-holder. Generators with devices for regulating and stopping at will the action going on are generally termed " automatic." Another set merely aims at developing the gas from the carbide and putting it into a storage-holder with as little loss as possible, and these are termed Genera-See also:Lion of acetylene from carbide. " non-automatic." The points to be attained in a good generator are: i. Low temperature of generation. 2. Complete decomposition of the carbide. 3. Maximum evolution of the gas. 4. Low pressure in every See also:part of the apparatus. 5. Ease in charging and removal of residues. 6. Removal of all air from the apparatus before generation of the gas. When carbide is acted upon by water considerable heat is evolved; indeed, the action develops about one-twentieth of the heat evolved by the combustion of carbon. As, however, the temperature See also:developed is a See also:function of the time needed to complete the action, the degree of heat attained varies with every form of generator, and while the water in one form may never reach the boiling-point, the carbide in another may become red-hot and give a temperature of over 800° C. See also:Heating in a generator is not only a source of danger, but also lessens the yield of gas and deteriorates its quality. The best forms of generator are either those in which water rises slowly in contact with the carbide, or the second main See also:division in which the See also:car-bide falls into excess of water. It is clear that acetylene, if it is to be used on a large scale as a domestic illuminant, must undergo such processes of purifica- tion as will render it harmless and innocuous to See also:health See also:Puri tnfica_ and property, and the sooner it is recognized as ab- solutely essential to purify acetylene before consuming it the sooner will the gas acquire the popularity it deserves. The only one of the impurities which offers any difficulty in removal is the phosphuretted hydrogen. There are three sub-stances which can be relied on more or less to remove this compound, and the gas to be purified may be passed either through acid copper salts, through See also:bleaching See also:powder or through chromic acid. In experiments with these various bodies it is found that they are all of them effective in also See also:ridding the acetylene of the ammonia and sulphuretted hydrogen, provided only that the surface See also:area presented to the gas is sufficiently large. The method of washing the gas with acid solutions of copper has been patented by A. See also:Frank of See also:Charlottenburg, who finds that a concentrated solution of cuprous chloride in an acid, the liquid being made into a See also:paste with kieselguhr, is the most effective. Where the production of acetylene is going on on a small scale this method of See also:purification is undoubtedly the most convenient one, as the acid present absorbs the ammonia, and the copper salt converts tha phosphuretted and sulphuretted hydrogen into See also:phosphates and sulphides. The vessel, however, which contains this mixture has to be of earthenware, See also:porcelain or enamelled See also:iron on See also:account of the free acid present; the gas must be washed after purification to remove traces of hydrochloric acid, and care must be taken to prevent the complete neutralization of the acid by the ammonia present in the gas. The second process is one patented by Fritz See also:Ullmann of See also:Geneva, who utilizes chromic acid to oxidize the phosphuretted and sulphuretted hydrogen and absorb the ammonia, and this method of purification has proved the most successful in practice, the chromic acid being absorbed by kieselguhr and the material sold under the name of "Heratol." The third process owes its inception to G. See also:Lunge, who recommends the use of bleaching powder. Dr P. See also:Wolff has found that when this is used on the large scale there is a risk of the ammonia present in the acetylene forming traces of chloride of nitrogen in the purifying-boxes, and as this is a compound which detonates with considerable See also:local force, it occasionally gives rise to explosions in the purifying apparatus. If, however, the gas be first passed through a scrubber so as to See also:wash out the ammonia this danger is avoided. Dr Wolff employs purifiers in which the gas is washed with water containing calcium chloride, and then passed through bleaching-powder solution or other oxidizing material. When acetylene is burnt from a 000 See also:union jet burner, at all ordinary pressures a smoky flame is obtained, but on the pressure being increased to 4 inches a magnificent flame results, free from smoke, and developing an See also:illuminating value of 240 candlesper 5 cubic feet of gas consumed. Slightly higher values have been obtained, but 240 may be taken as the See also:average value under these conditions. When acetylene was first introduced as a commercial illuminant in See also:England, very small union jet nipples were utilized for its See also:consumption, but after burning Burners. for a short time these nipples began to carbonize, the flame being distorted, and then smoking occurred with the formation of a heavy See also:deposit of soot. While these troubles were being experienced in England, attempts had been made in America to use acetylene diluted with a certain proportion of air which permitted it to be burnt in ordinary See also:flat flame nipples; but the danger of such admixture being recognized, nipples of the same class as those used in England were employed, and the same troubles ensued. In France, single jets made of glass were first employed, and then P. Resener, H. See also:Luchaire, G. Ragot and others made burners in which two jets of acetylene, coming from two tubes placed some little distance apart, impinged and splayed each other out into a butterfly flame. Soon afterwards, J. S. Billwiller introduced the See also:idea of sucking air into the flame at or just below the burner tip, and at this juncture the Naphey or Dolan burner was introduced in America, the principle employed being to use two small and widely separated jets instead of the two openings of the union jet burner, and to make each a minute bunsen, the acetylene dragging in from the See also:base of the nipple enough air to surround and protect it while burning from contact with the steatite. This class of burner forms a basis on which all the later constructions of burner have been founded, but had the drawback that if the flame was turned low, insufficient air to prevent carbonization of the burner tips was drawn in, owing to the reduced flow of gas. This See also:fault has now been reduced by a cage of steatite round the burner tip, which draws in sufficient air to prevent deposition. When acetylene was first introduced on a commercial scale attempts were made to utilize its great heat of combustion by using it in See also:conjunction with oxygen in the oxyhydrogen See also:blowpipe. It was found, however, that when using acetylene under low pressures, the burner tip became so heated as to cause the decomposition of some of the gas before combustion, the jet being choked up by the carbon which deposited in a very dense form; and as the use of acetylene under pressures greater than one See also:hundred inches of water was prohibited, no advance was made in this direction. The introduction of acetylene dissolved under pressure in acetone contained in cylinders filled with porous material See also:drew See also:attention again to this use of the gas, and by using a See also:special construction of blowpipe an oxy-acetylene flame is produced, which is far hotter than the oxy-hydrogen flame, and at the same time is so reducing in its character that it can be used for the direct autogenous See also:welding of steel and many See also:minor metallurgical processes. Additional information and CommentsThere are no comments yet for this article.
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