TP 767 T-dT sat REESE LIBRARY _ru_n nl/v UNIVERSITY OF CALIFORNIA. Deceived Accession No. Ju^lt* J U . Clats No. Pure and Perfect Combustion Obtained the only Medal awarded for Light by the Royal Cornwall Polytechnic Society, 1897. ~ ACETYLENE GAS. ^ All Householders in Town or Country can make their own Gas by using the low pressure and only SAFE GENERATOR YET INVENTED. Commencing at each for a Complete Installation. Small Towns, Villages, Churches, Public Buildings, Private Residences, Shooting Boxes, Concert Halls, Theatres, Schools, Hospitals, Factories, Warehouses, Railway Stations, also Railway Carriages, Trams, 'Buses, Yachts, Carriages, and Vehicles of every description, can be immediately supplied with this Gas, producing the best known light of the present day. Offices : S*. Olave's House, Ironmonger Lane, LONDON, WHERE ALL COMMUNICATIONS SHOULD BE SENT. Sole Makers of the "ACT" Burner, which NEVER CLOGS. ADVERTISEMENTS. n. The "YAHR" Acetylene Cycle Lamp. The only Cycle Lamp in which the turning off stops Generation of Gas, and which can be re-lighted immediately upon being turned on. SIMPLEST, SAFEST, W CLEANEST, And Least Troublesome of any Lamp yet invented. CANNOT EXPLODE. Will Burn 7% hours. Weight about 16 ounces. All Nickel Plated. Pits ordinary Lamp Bracket. Wholesale from the Patentees and Makers : REHB HOLUDHY & SONS, Ltd. Acetylene Gas Engineers and Carbide Manufacturers, HUDDERSFIELD, ENGLAND. lit. ADVERTISED! The "FOWLER" PATENT PORTABLE GENERATOR FOR OPTICAL LANTERNS, PHOTOGRAPHERS, etc. Possesses the following Important Advantages : Perfect in Principle and Construction. ABSOLUTELY SAFE in use. Automatic Action. Steady Light. No Smoke. Possesses the following Important A dvantages : Gas Thoroughly Purified. Quantity of Gas generated may be regulated, or action stopped at any moment. No Loose Fittings. 5? Requires no fixing. Write for Catalogue and all particulars as to Sizes and Price. CALCIUM CARBIDE supplied at market prices. THE "FOWLER" ACETYLENE CAS CO., OFFICE AND WORKS 298, Marsh Lane, Bootle, LIVERPOOL. J. K. CLARKSON, T. R. FOWLER, Manager & Secretary. Consulting Engineer. ADVERTISEMENTS. The "FOWLER" PATENT GENERATOR. For Country Houses/ Churches, Schools, Factories, Railway Stations, etc., etc. *-J&&&~> Low Pressure, Entirely Automatic Gas envolved ONLY as consumed. ABSOLUTELY SAFE in the hands of any inexperienced person. Attention required, less than Five minutes daily. fGiacs The "Fowler" Generator has MANY most IMPORTANT advantages. Write for full particulars to The "FOWLER" Acetylene Gas Co., 298, Marsh Lane, Bootle, Liverpool* J. K. CLARKSON, Manager & Secretary. T. R. FOWLER, Consulting Engineer ADVERTISEMENTS. Artificial Sunlight ! ! Artificial Sunlig-ht ! ! BY ROYAL LETTERS PATENT. The Light of the Future. "THE SflFETY" flcetyleije Gas Generator Co., HALIFAX. Sole Patentees and Manufacturers of "The Safety" Acetylene Gas Generators for Lighting Churches, Factories, Houses, Hotels, Railway Stations. Schools, Shooting Lodges. Shops, and Stables, situated in the country, and other buildings. The illuminating power of Acetylene Gas is fifteen times that of coal gas. Does not pollute the atmosphere like coal gas. Has a very pungent smell, enabling the slightest leakage to be at once detected. The Safest, Simplest, Cheapest, and Most Perfect Apparatus on the market. Each Machine Tested before leaving the Works. Working Instructions sent with each Machine. Any person can do all that is necessary without risk. Nothing to get out of order. Gas generated automatically. Less attention required than demanded by an ordinary paraffin lamp. CERTIFIED BY A COMPETENT AUTHORITY. Prices and further particulars on application. ADVERTISEMENTS. The THORNTON-SCARTH PATENT ACETYLENE GENERATOR Of HIGHEST POSSIBLE QUALITY, STRENGTH & FINISH. Constructed on sound engineering principles, and each machine thoroughly tested before delivery. Registered Trade MarkTHORSCAR. Highest Awards at BERLIN (1st International Acetylene Exhibition) MANCHESTER, DUDLEY, EVESHAM, etc. No Levers, Chains, Ball-Cocks or anything else to get out of order. No Governors required, the low pressure being constant and self-regulating. No Safety-Valves necessary as the machine never makes too much gas. The Gas delivered Cool, Dry and PURIFIED. Sole Makers (Patented all over the World)- The Thornton-Scarlh Automatic Lighting Syndicate, Ltd, Vittoria Street, BIRMINGHAM. Also Makers of Special Lines in Burners and Fittings to the Trade. The Birmingham Carbide Co., Ltd.! /Ifcanufacturers ot JSeet (Slualttg Garbtfce of Calcium, Offlces-37, Vittoria St. BIRMINGHAM. Works Artillery St. Telegrams" Carbide, Birmingham, " ADVERTISEMENTS. READ HOLLIDAY A SONS, Ltd. PATENT AUTOMATIC ACETYLENE GAS GENERATOR Hundreds of these Machines in use ! Portable Machines for Contractors, Dock-yards, Canals, &c. Simplest and Best. These Machines will AUTOMATICALLY Feed Existing Gasometers of any size. Machines arc made all sixes to suit customers, and the methods of working arc very simple, There is nothing to grt out of order: and any person, maidservant,' gardener, or groom can re-Charge it iind do all that is necessary without risk. A t'c\v words as direc- tions are attached to every machine. This apparatus is constructed to generate the gas automatically as used. 'and when charged requires no further attention. The generators can he discharged of residual matter (lime) and RKVl LLKI) in a FEW MINUTKS, and in less time than an ordinary paraffin lamp can be trimmed and refilled. There is no danger of any excessive pressure in machines. Every Machine is tested before Icaviii},' the workshops to insure all beinjr perfect. These Machines comply with Insurance- tipOS. Special Apparatus made for Li,. per E.H.P. per hour. The reaction taking place upon the fusion of the elements calcium and carbon is expressed by the equation CaO + C 3 = CaC, -f- CO, which indicates that the combination of the calcium oxide with the carbon in forming the carbide is attended by the formation or liberation of carbon monoxide. Athough the proportions of lime and coke in the mixture fed to the furnace may be varied, yet the quantities of calcium and carbon in the carbide will always be the same, the combination of the elements with one another being gov- erned by their chemical affinities. The mass, or bloom, of carbide as taken from the furnace usually consists of from 80 to 85 per cent, pure carbide, the remainder being the outer covering of semi-fused material which, after being separated from the pure . carbide, is ground up and again fed into the furnace together with the fresh material. The current employed in the electric furnace is of large quantity, but of low intensity, i.e., the voltage being usually from 60 to 70, while the amperage is from 1,000 to COMMERCIAL PRODUCTION OF CALCIUM CARBIDE, ol 2,000, and the yield of pure carbide per E.H.P. per hour under these conditions has been found to be about 0*4 lb. Willson states that 1,200 Ibs. of coal dust (anthracite) and 2,000 Ibs. of powdered quicklime with expenditure of 180 E.H.P. will give in twelve hours 2,000 tbs. of carbide, the cost of which in America is said to be $15. L. M. Bullier, a French chemist, an assistant of Moissan's, has patented a process by which he claims to be able to produce carbide at a lower temperature than requisite under ordinary conditions. It consists in mixing a flux with the lime and carbon. The mixture specified consists of 56 parts quicklime and 36 parts carbon, to which is added 10 per cent, of fluoride of calcium fluor spar. This, he claims, makes the carbide more fluid, and easier to run off from the furnace. The first works established for the manufacture of carbide were at Spray, in North Carolina, where Mr. T. L. Willson had previously erected a plant for the production of aluminium by electrolitic process, and it was at this place, while endeavouring to produce metallic calcium by similar means, that he discovered instead the method of producing calcium carbide, a material of much greater value and importance. In the plant at Spray, the nett E.H.P. at the electrodes was 169, the current being of 1,310 amperes at 100 volts. The mixture used consisted of 58 -5 per cent, of lime and 41 '5 per cent, of coke. This plant produced about 92 Ibs. of carbide per hour, the yield of pure carbide being 9*48 Ibs. per E.H.P. per day. The production of Acetylene per E.H.P. per day was 44 cubic feet. The yield from the carbide being at the rate of 5 cubic feet per lb. 52 ACETYLENE. There are now said to be eighteen Carbide Factories throughout the world, the most important being those at Niagara Falls and at Foyers, in Scotland ; the former owned by the Acetylene Light, Heat and Power Company, of Phila- delphia, and the latter owned by the Acetylene Illuminating Company, Limited, of London. In the furnaces employed at Niagara the negative electrodes consist of cast-iron crucibles, carried upon small trucks or trollies. These are run into the furnaces through openings in the sides, and when in position beneath the positive electrodes the leads are connected thereto by means of strong clamps. The positive electrodes, which are suspended above the crucibles, are composed of six slabs of carbon, each 4G inches long, 4 inches thick, by 8 inches wide, clamped together at their upper ends in a strong cast-iron holder, to which the copper leads are attached. In operation the upper electrode is lowered and contact made with the lower electrode, or crucible ; current is then turned on and the upper carbon raised, which establishes the arc. The prepared material is then fed in two streams into the arc and around the upper electrode to a depth of from two to three feet. The material passing into the arc is immediately fused and converted into carbide, which accumulates in the crucible after the manner of slag. When the crucible is filled the current is stopped, the trolley disconnected and withdrawn with its load of crucible and carbide, another trolley and crucible run into the furnace, and the operation repeated. Each furnace requires 500 H.P., and the production is about two and one-half tons (5,000 Ibs.) of carbide per day, or 10 ibs. per E.H.P. COMMERCIAL PRODUCTION OF CALCIUM CARBIDE. 53 The average yield of the electric furnaces at Foyers, is 8'5 Ibs. of pure carbide, per E.H.P. per day, the current employed being of 4,000 to 5,000 amperes at 55 to 65 volts. The yield of carbide per E.H.P. per twenty- four hours, as given by various authorities, varies from 9 Ibs. to 10' 6 Ibs. 9*5 Ibs. may be taken as a possible average. There are now believed to be four other Carbide Factories in operation in this country, besides the works at Foyers, and the production of carbide in Great Britain at the present time is said to be at the rate of 800 tons per annum. In Geneva, carbide is manufactured by the Municipal authorities, the electric light plant being utilized for the pur- pose during the daytime, when only a small percentage of the power is required for lighting purposes. The cost is found to be equivalent to 6 10s. per ton. The daily production is said to be about six tons. This method of utilizing generating plant during the day time might be followed with advantage by other Municipal or corporate owners of such plant as affording profitable employment and at the same time equalizing the load. CHAPTER V. CALCIUM CARBIDE: ITS COMPOSITION AND PROPERTIES. Calcium Carbide is a compound of the elements Cal- cium and Carbon, and is a crystalline, semi-metallic substance, having a specified gravity 2*26, its bulk being theoretically 12*25 cubic inches per pound. It consists of 62' 5 per cent. (by weight) of calcium, and 37 '5 per cent of carbon, expressed by the chemical formula CaC 8 . It is of a highly hygroscopic nature, and owing to its strong affinity for water, both in the vapour and liquid states, it readily absorbs moisture from the atmosphere, Acetylene being evolved in the process. Calcium carbide is not an explosible compound, nor does it possess any explosive properties, as erroneously attributed to it. But owing to its peculiar nature not being generally known and understood, and with a view to insuring public safety against any possible danger which might arise through ignorance or carelessness in the carriage or storage thereof, it is, by a Home Office Order, classed as a dangerous commodity, and made subject to the same general Regulations as petroleum and other so-called "dangerous" goods. Calcium carbide, being produced at the highest known degree of heat, it is in no way affected by high temperatures. But when water is applied to it in a closed vessel from CALCIUM CARBIDE. 55 which the gas has not a free exit, it may set up a pressure at which it becomes explosive and the heat evolved by the reaction, if not dissipated, may cause a rise of temperature to a degree sufficient to ignite the Acetylene : the liability to ignite spontaneously being greater if there be any sulphur or phosphorous present. Acetylene gas is evolved from the carbide by causing water to act upon it, either by bringing the water to the carbide or by dropping the carbide into water. In any case, by the application of water, a double decomposition takes place, the calcium of the carbide having a stronger affinity for oxygen than for carbon, separates therefrom, and combines with the oxygen of the water, forming oxide of calcium, or lime ; on the other hand, the carbon, having a stronger affinity for hydrogen than for calcium, separates from it and combines with the hydrogen of the water, forming Acetylene. The chemical reaction is expressed by the equation Ca 3 C 2 + 2H 2 = 2Ca(IIO) 2 + C 2 H 2 . meaning that the carbide in combining with the water is resolved into calcium- monoxide and Acetylene. The production of calcium carbide by the fusion of its elements being due to the action and expenditure of a consider* able amount of heat, the resulting material is an endothermic compound, hence the decomposition of carbide or similar substances is attended with the liberation of some of the heat expended in its production, and it is the evolution of this heat which causes the rise of temperature to take place when water is brought into contact with the carbide ; but only a certain pro- portion of the endothermic heat is liberated by this reaction. The residue remains locked up in the resulting gas until its 56 ACETYLENE. decomposition is brought about by combustion on combination with oxygen in the action of burning ; the heat then liberated raising the particles of carbon in the gas to a high temperature and corresponding degree of incandescence, hence the luminosity of the flame. The theoretical yield of gas from the carbide, if chemically pure, would be at the rate of 5*8 cubic feet per pound, but as chemical purity is not attainable when carbide is manufactured on an industrial scale, the yield from practically pure commercial carbide is from 5'5 to 5'6 cubic feet per pound. The average yield when "commercially pure" is 5'2 cubic feet per pound ; but for ordinary purposes it will be more approximately correct if the yield is assumed as 5 cubic feet, owing to the presence of a certain proportion of low quality material and to the hydra tion of the carbide through exposure to the atmosphere when being broken up arid packed, or otherwise handled. The quantity of water actually required or consumed in the decomposition of carbide is slightly over half a pound, i.e., *56 Ib. = 15*5 cubic inches per pound, and the combina- tion of this quantity of water with one pound of carbide, when practically pure, results in the formation of *40 Ibs. of Acety- lene (= 5*59 cubic feet), and 1*16 Ibs. of lime, but these proportions will vary considerably, according to the degree of purity or quality of the carbide. Carbide of* calcium manufactured by the Acetylene Illuminating Company, Limited, at Foyers, is guaranteed to yield an average of five cubic feet per pound. Carbide manufactured on the Continent rarely yields above an average of 4*6 cubic feet per pound. CALCIUM CARBIDE. 57 Professor Lewes has patented a formula for the pre- paration of carbide which on decomposition shall give off a gas burning with a non-smoking flame. The claim is for mixing with the,- lime and coke or charcoal a certain proportion of black oxide of manganese. Gas evolved from this carbide would be diluted with methane^ or " marsh gas" (CH 4 ), which would serve as a diluent of the Acetylene, and so tend to make the combustion thereof more complete by reason of the reduction in the pro- portion of carbon to hydrogen. It is possible that the light emitted by the combustion of the mixed gas would not be so nearly white as from pure Acetylene, owing to the fact that methane burns with a yellowish flame. The Author is not aware as to whether any carbide has been made according to Professor Lewes' formula, but if carbide could be formed of such materials as to yield a non- smoking gas, one of the greatest difficulties in the use of Acetylene would be at once overcome. Carbide may be rendered less hygroscopic by saturation with mineral oil, and a process has been patented for such treatment thereof, whereby it is claimed that its susceptibility to the action of water is considerably reduced. It consists in steeping the carbide, soon after being taken from the furnace and while still hot, in heavy mineral oil or tar. The advantage resulting from any method of rendering the carbide less susceptible to the action of water would be that the reaction of decomposition, being somewhat retarded and therefore less vigorous, the temperature would not rise to so high a degree as when the chemical action is unrestrained. 58 ACETYLENE. Any process, therefore, which accomplishes this end, even though imperfectly, would be of advantage, inasmuch as it tends to insure the evolution of gas in a more pure state and to prevent possible loss by polymerization, which takes place in more or less degree, according to the temperature developed when the same is excessively high. CHAPTER VI. GENERATING SYSTEMS AND APPARATUS. The simplicity of the process by which calcium carbide may be decomposed and Acetylene evolved therefrom renders the generation of this gas a very easy matter, and the apparatus employed may be of most simple and inexpensive character, consisting of a Generator and Gasometer, or both may be com- bined in one. The process, although the reverse of complex, is at the same time most wonderful as an example of the marvels of chemical affinity, the spontaneous reaction set up by the contact of water with carbide is of a compound character, and is attended by secondary chemical phenomena. Some know- ledge, therefore, of the physical conditions involved is most essential before any experiments are entered upon in this field of practical chemistry. Calcium carbide is decomposed by the action of water thereon, due to the chemical affinity of its elements for the elemental constituents of water ; and on the other hand, water is decomposed in the process of combination with the carbide, the double reaction taking place being represented by the equation, Ca 2 C 2 + 2II 2 = 2Ca(HO) 2 + C 2 II 2 . expressing the fact that the compound of calcium and carbon 60 ACETYLEXE. combining with water produces two new compounds, oxide of calcium (lime) and Acetylene. Calcium carbide being an endothermic compound, con- siderable heat is evolved during the process of decomposition, and if there be not sufficient water in the generating apparatus to dissipate such heat, or, if no provision be made for cooling the gas, it comes away hot and highly charged with water vapour which not only reduces its illuminating power, but may cause trouble by condensation in the pipes. There are, generally speaking, three systems under which the gas may be generated ; they may be termed the " Automatic " or "Dry," the " Non- Automatic " or "Wet," and the " Retarded Reaction" system, the latter being a species of compromise between the automatic and non-automatic systems. All apparatus embody one or other of these principles and vary only in arrangement of parts and detail of construction. In the automatic system, a certain quantity of carbide is usually contained in a closed vessel and water admitted thereto in more or less quantity as gas is required, the flow of water to the carbide being governed or regulated either by the quantity or pressure of the gas generated ; the gas as evolved from the carbide, either flowing into and raising the bell of a gasometer, or, on the other hand, displacing water and setting up a hydraulic balance. In the first case, the increase in quantity does not set up a correspondingly increased pressure, as once the weight of the gasometer is balanced by the pressure of the gas, its rising to accommodate more gas does not, of course, cause any increase in the pressure thereon. GENERATING SYSTEMS AND APPARATUS. 61 In the second case, when the gas is caused to displace a certain body of water at a given initial pressure, that pressure is increased as the gas accumulates and displaces a correspond- ingly increased volume of water, and such pressure continues to increase until the whole of the balancing water is raised to a higher level unless such water be allowed to overflow at a predetermined point at which the maximum desired pressure is reached. On the conditions of operation being reversed, i.e., when the water is required to displace the gas, the pressure of the latter decreases as the head of water becomes reduced, so that with this arrangement there is a constantly varying pres- sure of gas. This disability is met and to & large extent neutralized by the use of regulating valves, by which the pres- sure of the gas, as delivered to the service pipes, is maintained at an approximately even level, although the pressure in the generators may vary considerably. This system has many advocates, and it certainly possesses the one great advantage of extreme simplicity ; the compensating medium being a fluid as differing from a mechanical contrivance, such as a rising and falling bell, the liability to derangement is consequently reduced to a minimum, and when gas apparatus is in the charge of persons having no scientific or mechanical knowledge this is a recommendation. In actual practice slight variations of pressure are of little or no consequence as effecting the degree of light, pro- viding the pressure does not fall much below one and one-half inches of water, and so reach the smoking point. The displacement system, therefore, while being perhaps more suitable for comparatively small installations, it possesses 62 ACETYLENE features of distinct advantage where domestic servants or other untechnical or inexperienced persons are concerned. Where the accommodation of a large and widely -varying quantity of gas is required the gasometer system would appear to be most suitable, as providing large storage area, and as obviating the possibility of any fluctuations of pressure. The legal restrictions as to pressure practically preclude the storage of a large quantity of gas under a high head of water. In all automatic generators the evolution of the gas, in greater or less quantity, goes on continuously until the carbide is spent, the whole of the water admitted each time being absorbed by the carbide. The chemical reaction proceeds vigorously untiVall free water is absorbed. The undecomposed carbide, owing to its highly hygroscopic nature, absorbs moisture from the hydrate, or spent portion of the carbide, until all water is decomposed, so that, although the actual contact of the carbide with the water may be intermittent, the generation of gas is practically continuous, although variable in quantity. The hydrate, according to the conditions or form of apparatus, may contain from 10 to 25 per cent, of water, the greater part of which the undecomposed carbide will, if not separated therefrom, absorb through the agency of capillary attraction. In some forms of apparatus the carbide is contained in a vessel separated from the gas holder, and as the container of the latter descends through withdrawal of gas, it operates a valve by which water is admitted to the carbide, and as the gas bell again rises it closes the same and stops the flow of water. In another form of automatic generator the carbide is GENERATING SYSTEMS AND APPARATUS. 63 carried in a species of basket attached to the top of the gas bell or container, which, on descending, causes the carbide to be dipped into the water, gas thereupon being evolved raises the bell and lifts the carbide clear of the water. In one class of automatic apparatus in which the pressure of the gas is caused to displace water, the carbide is usually placed in a tray or basket, located in a certain fixed position in regard to the water-level, the water being depressed therefrom or rising thereto as the pressure of the gas increases or decreases. In a modified form of apparatus embodying this principle the water, on rising as the pressure of the gas is reduced, overflows at a certain point, and is conducted by suitable means to the vessel containing the carbide, the normal level of the water in the gas vessel being maintained by a supply governed by a ball- valve or other equivalent device. This general principle has been embodied in apparatus in a variety of ways by ingenious inventors, but none, so far as the Author is aware, have overcome the one disadvantage thereof, the varying pressure. A circumstance which should not be lost sight of in the design of the apparatus is the fact that not .only does the undecomposed carbide, absorb water from the hydrate, but owing to the heat evolved by the action of decomposition, some of the water is thereby vapourized and the gas evolved comes away charged in more or less degree with moisture, some or all of which may condense upon the undecomposed carbide and cause evolution of gas, in addition to that due to the principal reaction, and provision should therefore be made UNIVERSITY 64 ACETYLENE for this additional gas, generated after that resulting from the direct action of the water upon the carbide. When automatic generators are employed some pro- vision should be made for cooling the gas before allowing it to pass into the piping, otherwise it may carry with it more or less moisture in the form of aqueous vapour, which will con- dense in the pipes and cause trouble by "popping" or stoppage. The presence of water vapour in the gas also lowers its illum- inating value, and at the same time renders the gas more dangerous, owing to the fact that if ammonia, sulphur or phos- phorous be derived from the carbide, such water vapour carries with it the free ammonia, sulphur or phosphorous, or ammonium sulphide, which tend to render the gas more explosive, at the same time causing it to give off, in burning, deleterious pro- ducts of combustion, which would not be the case if the gas were cool and dry. Further, if ammonia be present in any appreciable quantity, it, together with the moisture, may form, on contact with copper, acetylide of copper, which is an explosive com- pound, and ignites either through the agency of calorific heat or that developed by percussive action. In the "non-automatic" system a quantity of carbide sufficient to yield a certain volume of gas is put into a vessel or "generator" containing, comparatively, a large body of water. The carbide, being immersed in and surrounded by the water, the gas evolved in bubbling through the same becomes not only cooled but washed, and thereby freed from much impurity, which otherwise would remain associated therewith, unless separated therefrom by purification. The gas generated on the non-automatic system is GENERATING SYSTEMS AND APPARATUS. 65 usually stored in gasometers of capacities designed to hold the quantity of gas required for use during certain periods. This system possesses one great advantage in the fact that all risk of excessive pressure, high temperature, or escape of gas is avoided. But on the other hand, it has the disadvan- tage of necessitating, for a given quantity of gas, much more bulky and costly apparatus than the automatic system, but where space occupied is not of serious consequence the non-automatic system insures the preparation of the gas in the best possible condition for use, i.e., thoroughly cooled and washed, before passing to the piping and burners. A system of generating which has much to recommend it has been patented by Mr. Frederick Dresser, A.M. Inst., C.E., and which the Author has termed the " Retarded Reaction '* process. It is a species of compromise between the automatic and non-automatic methods, and consists in enclosing the car- bide in bags, composed of canvas or other porous material of somewhat close texture, before immersion in water. Immediately water penetrates the bag and comes into contact with the carbide reaction commences and gas is evolved, which distends the bag and prevents the direct contact of the water with the carbide, at the same time the bag being rendered buoyant, it rises up within the generator to a height determined by the length of a cord or chain to which it is attached. The gas, in passing through the interstices of the fabric of which the bag is composed, is split up into a number of minute streams and is thereby brought into intimate contact with the water, which not only insures the thorough cooling, 6 ACETYLENE. but; the perfect washing of the gas, and further the direct contact of the water with the carbide being prevented by the distension of the bag, the process of decomposition is thereby retarded, and the temperature due to the reaction does not rise to a degree sufficient to affect the gas detrimentally. The generation of the gas at a comparatively low temperature is thus insured. This is a matter of considerable importance not only as avoiding the contingencies already referred to, but as obviating the possible polymerization and loss of some of the gas- When the decomposition of the carbide is complete, the bag is withdrawn, bringing away the whole of the residuum. The bags after being emptied and dried are again charged ready for use. This system overcomes one disadvantage of the ordinary non-automatic process in the fact that the withdrawal of the residuum of each charge obviates the necessity for the frequent emptying and cleaning of the .generators. All generators, whether upon the automatic or non- automatic systems, should be so designed as to insure the exclusion of all or nearly all air before the generation of gas commences, otherwise an explosive mixture may be formed which may ignite through the issuing gas and air "firing . back." This, of course, would only be probable if no burners or those having large orifices were employed. Another important reason for the exclusion of practi- cally all air from apparatus before the generation of gas is commenced, is to obviate the possibility of explosion through spontaneous ignition of the gas. Some specimens of carbide GENERATING SYSTEMS AND APPARATUS. G7 have been found to contain calcium phosphide in sufficient quantity to cause the Acetylene given off to be impregnated to such an extent with phosphoretted hydrogen as to ignite spontaneously in the process of generation. Although this may be a remote contingency when " commercially pure " carbide is used, yet the possibility of such action taking place and constituting a source of danger is a strong argument in favour of precaution as to exclusion of air from generators. Generators of the automatic order should be so designed and constructed as to avoid any material escape and loss of gas or introduction of any large quantity of air when removing the residuum and re-charging with fresh carbide. Carbide, when decomposed, becomes greater in both bulk and weight, the increase being about 75 per cent, in bulk, and (when wet), 25 per cent, in weight, so that ample provision should be made in automatic generators for this swelling up, and no carbide vessel should be charged to a greater extent than 50 per cent, of its total capacity. The actual quantity of water required and absorbed in the decomposition of carbide is at the rate of *51b. = 15-5 cubic inches per lb. of carbide. In non-automatic generators, the vessel should have a capacity or water area of about one cubic foot per pound of carbide to be introduced at one time. This proportion insures the temperature of the water never rising to a degree higher than that termed " sensibly warm." Provision should be made for the withdrawal of the residuum and so obviate the necessity for emptying the generator, as each time the water is renewed it must be again 68 ACETYLEXE. saturated with gas before any appreciable quantity is given off r and the loss of gas thus occasioned may be avoided by atten- tion to this point. A quantity of fresh water, equal to the consumption r should be added each time the generator is re-charged. CHAPTER VII. PURIFYING AND DRYING. Acetylene generated from " Commercial " carbide is always more or less impure ;' if, therefore, its highest illu- minating power is to be developed, and at the same time perfect safety in its use insured, and its combustion is to be unattended with deleterious products, it should be both purified and dehydrated or dried. The gas from British made carbide, although practi- cally pure, is always impregnated in greater or less proportion with other compounds, usually sulphuretted and phosphoretted hydrogen and ammonia, the average amount being about two per cent. The presence of sulphuretted hydrogen is due to either sulphur in the coke or gypsum in the lime, employed in the manufacture of the carbide, or to both. The phosphoretted hydrogen is formed by some of the hydrogen combining with traces of phosphorous in the carbide, derived from the coke or due to the presence of phosphoric acid in the lime. The presence of ammonia in Acetylene is doubtless due to its formation by the combination of its elements during the process of decomposition of the carbide by the water and of the water by the carbide. 70 ACETYLENE. Ammonia (NII 3 ) is never formed, nor can it be pro- duced by the direct combination of its elements, nitrogen and hydrogen, and is only formed upon the decomposition of compounds containing these elements, when hydrogen in the nascent condition comes into contact with nitrogen. It is therefore reasonable "to assume that its formation takes place simultaneously with the formation of the Acetylene and of the calcium oxide 'by the combination of the hydrogen of the water with the nitrogen associated with the carbon of the carbide. The greater part of the ammonia thus formed is, how- ever, retained by the hydrate or spent carbide, its presence being distinctly discernable in the residuum when being removed from the generating -apparatus. Ordinary carburetted hydrogen illuminating gas, as obtained by the destructive distillation of coal, is always charged in greater or less degree with sulphuretted-hydrogen, carbon-dioxide, and ammonia, which compounds are to a large extent separated therefrom by the process of purification, which consists in first passing the gas through water, by which the greater part of the ammonia is absorbed, then, over or through slaked lime or iron oxide mixed with sawdust, which absorbs the sulphur and carbonic acid, and finally by passing the gas through dilute sulphuric acid to remove the remaining traces of ammonia. Coal gas, although purified in this manner, is seldom or never free from the compounds which the purifying process is designed to eliminate. These compounds form the deleterious products of combustion, which constitute the principal objection to coal gas as an illuminant. PURIFYING AND DRYING. 71 On the other hand Acetylene, owing to the small per- centage of impurity. present, is more easily and at the same time perfectly purified, and the separation therefrom of deleterious elements is not a matter of very great difficulty. The simplest method by which Acetylene may be purified is by passing the gas through a mass of broken-up coke saturated with sulphuric acid. The gas in forcing its way through the mass is split up into a number of streams, and is thus brought into intimate contact with the acid which absorbs not only the ammonia and moisture, but a large pro- portion of other impurities, if any be present. The gas may also be freed from ammonia by passing it through coke or pumice stone saturated with hydrochloric acid. The coke or other material employed as the vehicle for the purifying medium should be cleansed periodically by washing with water, and the same may be re-used any number of times Gas produced from very impure carbide should also be passed through or over slaked lime or iron oxide mixed with some neutral granular material for the purpose of separating therefrom all traces of sulphuretted hydrogen. To insure the best results being attained, it is desirable to cool the gas thoroughly before purifying, and thus cause the moisture in suspension in the form of vapour to condense and separate from the gas, and by this means reduce the quantity to be absorbed by the purifying and dehydrating media. Gases may be dehydrated or dried by passing through or over highly hygroscopic liquid or solid substances, or materials. Gas passed through concentrated sulphuric acid becomes purified and at the same time deprived of all moisture present owing to the affinity of the acid for water. 72 ACETYLENE. For merely dehydrating after purification by other means, crystallized chloride of calcium (Capl,) is perhaps the best and most simple medium, and when employed, this material should be broken up into small pieces, such as would pass through a grid having meshes one inch square ; but for large quantities of gas the pieces may be of greater size, but the quantity must be proportionately increased. The drying material should be contained in a vessel having a perforated diaphragm or grid a short distance from the bottom, beneath which the gas is admitted. This is for the purpose of preventing any moisture of condensation being absorbed by the dehydrating medium. A tap or other means should be provided for withdrawing the water from time to time. Crystallized chloride of calcium may be revivified and its hygroscopic properties renewed by heating to the tempera- ture of redness. Dr. Pictet recommends passing the gas successively through a concentrated solution of calcium chloride, then through sulphuric acid 40 per cent, concentration, then wash- ing in a solution of lead salts, and finally drying by passing through crystallized chloride of calcium ; this may be requsite in the case of very impure gas, but when made from 41 commercially pure " carbide such elaborate treatment is unnecessary, except when the gas is to be compressed to the liquid state. Absolute purity is then a sine qua non. Under ordinary conditions, the gas will be thoroughly purified by being passed through material saturated with sulphuric or hydrocloric acid, and afterwards drying by passing through calcium chloride. PURIFYING AND DRYING. 73 When gas is to be stored, its purification is most essential, as the impurities present may cause corrosion of the metal of the gasometers and other parts of the apparatus, and danger through leakages arise. CHAPTER VIII. STORAGE OF ACETYLENE. There are certain conditions under which artificial illumination may be required which, owing to circumstances, render inconvenient, if not altogether preclude the generation of gas or electricity when and where required, and it is in cases of this nature that gas stored in certain quantities in a concentrated form perhaps most nearly realizes the ideal. Ordinary coal or oil gas, compressed and stored in steel cylinders or flasks is, at the present time, being extensively used for lighting railway carriages, buoys, and for other pur- poses where a good and portable light is necessitated by the circumstances of the case. Acetylene stored in this way and under similar con- ditions affords illuminating material in both quantity and quality of light, far in excess of any other hydro-carbon com- pound, and for that reason it, in comparison with other illuminating media, possesses a very high value. The manufacture of Acetylene at central depots and the supplying of the same in highly concentrated form is in vogue in America, France and other countries, works having been established for producing and compressing the gas and supplying same in bottles or flasks for train lighting and other purposes. STORAGE OF ACETYLENE. Although gas or other highly expansive body stored under great pressure is to some extent undesirable, owing to the ever-present risk of explosion, yet the system, in the case of gas for illuminating purposes, possesses such great advan- tages that, notwithstanding the objection thereto on the score of risk, the system is much in favour, and the dangers thereof are more problematical than real. When it is considered that the flasks and cylinders employed are made of a strength sufficient to withstand as much as ten times the strain to which they are subject in practice, and that, in addition thereto, they are perhaps more severely tested than any other commercial article, the probability of accident through bursting is most remote. The most serious accidents which have so far occurred through explosions of Acetylene have been in connection with the compression of the gas, but at the same time have been traceable to impurity of the gas, to want of knowledge of its properties when under pressure, or to neglect of proper pre- caution. There are three methods or systems under which Acetylene may be stored 1. In the gaseous condition. 2. By absorption in neutral fluid. 3. By liquif action. The relative space occupied by a given volume stored under the three conditions being, approximately : In gaseous conditions ... 2000 '0 By absorption in liquid ... 6*6 In liquified condition ... 5'0 76 ACETYLENE. The gaseous condition being assumed as at usual pressures up to the equivalent of three inches of water. But at whatever pressure stored, the space occupied by a given volume is in the inverse ratio to the pressure. The limit of pressure in generators and gasometers fixed by the Home Office Regulations as to storage and carriage of Acetylene is 1^ atmospheres = '73 Ib. per square inch above atmosphere, gas stored at pressures over this limit being subject to the provisions of the Explosives Act. When Acetylene is stored in the gaseous condition in gasometers at ordinary pressures, the holders should be con- structed with internal domes so that the water area exposed to the gas may be as small as possible, for the purpose of avoiding loss of gas by absorption. The liquid employed for sealing the gas bell should be a saturated salt or alkaline solution, for the reason that such solutions absorb little or no gas, and do not freeze except at extremely low temperatures ; stoppage of apparatus by freezing in cold weather is thus avoided. Acetylene may conveniently be stored by absorption in acetone and other liquids, and its explosive properties are greatly decreased, if not entirely destroyed, by solution in a neutral fluid. The co-efficient of expansion of Acetylene solution is much lower than that of liquified Acetylene, so that vessels in which such solutions are stored may be filled, the risk of accident through bursting being relatively less. The fluid capable of absorbing tlve largest amount of Acetylene, and which again gives up practically the whole volume is Acetone (C 3 TI G O). It is a limpid, mobile, combust- STORAGE OF ACETYLENE. 77 ible liquid, of a specific gravity of '814. It burns with a white, smokeless flame, and even when mixed with an equal volume of water is still inflammable. At ordinary atmospheric pressure and at a temperature of 27 C, acetone will absorb twenty-five times its volume of Acetylene, and its absorptive capacity increases nearly in direct ratio to pressure. At a pressure of 175 to 180 Ibs. per square inch, one volume of acetone will absorb 300 volumes of Acetylene. On relieving the pressure the gas passes out, and the exhausted liquid can again be charged. The absorptive capacity of acetone decreases in the inverse ratio to its temperature, so that at 57C it only absorbs about half the quantity it is capable of absorbing at 27C. Acetylene may be liquified at pressures varying ac- cording to temperature from 325 Ibs. per square inch at 0C to 700 Ibs. per square inch at 35 C, the necessary pressure in- creasing in proportion to rise of temperature. Under these conditions it becomes a mobile, highly refractory liquid of a specific gravity of 0'43, weighing 28 '15 Ibs. per cubic foot,, the ratio of the gaseous to the liquid conditon being 396:1. Although the system possesses great advantages, the danger is also great, as unless the gas be perfectly pure and the temperature kept at or below the freezing point of water there is a risk of explosion during the process of compression, and it is a fact that the majority of the accidents which have occurred through explosions of Acetylene have been in con- nection with the compression and liquification of the gas. For ship and buoy lighting storage in the liquified form is imperative, owing to the conditions rendering the employment of generating apparatus or gasometers practically^ 78 ACETYLEXE. impossible; the system is therefore peculiaily applicable and advantageous in these cases. Although the tendency of Acetylene in this condition to expand under the influence of heat, causes high pressures to be set up in the cylinders or flasks in which it is stored, yet if proper precaution be taken to keep them at a low temperature the danger is remote. At temperatures up to 83C the pressure in the cylinders would not exceed 700 Ibs. per square inch, and even when the temperature is raised to 46C the pressure does not exceed 1,000 Ibs. per square inch. So that when it is con- sidered that flasks or cylinders used for the storage of com- pressed gas are usually tested at pressures up to 3,000 hbs. per square inch, it is obvious that a good margin of safety exists. In comparison with the storage of certain quantities of gas under the foregoing conditions, the quantity of carbide necessary to yield say 2000 cubic feet of gas at the rate of 1 ib. per 5 cubic feet would be 400 Ibs., having a bulk measurement of but slightly over 3 cubic feet. But, as a set-off against this, the apparatus necessary to the evolution of the gas would, together with the carbide, occupy considerably more space for a given quantity than the gas in the liquified condition, and further, the difficulties and dangers attending the generation of gas on shipboard, more particularly in rough weather, point to the employment of Acetylene in the com- pressed form as the best under the circumstances. CHAPTER IX. ACETYLENE AS A MOTIVE POWER. Acetylene, although applicable as a motive power, is not an economical source of energy, and if the combustion be at all imperfect, difficulties arise "owing to deposit of carbonaceous matter in the cylinders and passages of engines in which used. The thermo-dynamic value of Acetylene compared with coal gas has been ascertained to be from 2 -7:1 to 2'8:1. But, in view of the fact that the cost of this gas is, at the present price of carbide, about 34/- per 1,000 cubic feet, and that an equivalent dynamic value at the higher ratio in coal gas would cost only about 7/6, there is little likelihood of Acetylene being employed for power purposes, while the price of carbide remains at 20 per ton. But, although Acetylene would be a comparatively costly agent for the development of dynamic energy, yet, some particulars of the results of experiments conducted for the purpose of determining its dynamic value are of interest as affording data enabling comparison of the thermo-dynamic value of Acetylene with that of coal, coal gas, and mineral oil. Experiments in the use of Acetylene for motors have been made by M. Ravel, in France, who found that 11*45 cubic feet of the gas developed one I.H.P. per hour, whereas 34'4 cubic feet of coal gas was required for an equal power in the same engine. 80 ACETYLENE These figures would appear to prove that Acetylene possesea a thermo-dynamic value compared with coal gas of 3:1, but this result was obtained with doubtless practically pure Acetylene, as against a possibly low quality coal gas. 34'4 cubic feet may be necessary, in the case of French gas, for the development of one I.H.P. per hour, but that quantity, compared with the consumption of British gas in the latest types of British-made engines, is excessively high. The average consumption per horse-power-hour in this country being from about 20 cubic feet in small engines to 1 6 cubic feet in larger engines. Experiments upon a somewhat larger scale made by Herr Von Ihering, in Germany, shewed Acetylene to have a thermo-dynamic value of 2*7 as compared with coal gas and from the conditions under which the experiments were made and the results obtained, and taking into consideration the nature and properties of Acetylene, it is reasonable to suppose that in proportion as the size of the motor is increased, Acety- lene should give relatively more favourable results and that a value of 3:1, as compared with coal gas might be realized. Acetylene has been employed experimentally in the engine of a motor cycle, a mixture containing but six per cent, of gas being used. The results are said to have been very satisfactory. Liquified Acetylene would appear to be particularly suitable as a motive power for light vehicles owing to the small bulk and weight of a comparatively large quantity. The low ignition temperature of Acetylene and air mixtures (480C), was found to make the firing of the charge an easier matter than in the case of coal gas. But it was also FAS A MOTIVE POWEB. 81 found that the suddenness of the explosion owing to the rapidity of the flame propagation rendered it difficult to utilize the whole of the energy capable of being developed by a given volume of Acetylene. The best explosive effect, i.e., the highest pressure developed by detonation of a certain volume of mixed gas and air is produced when the gas is about 8*0 per cent, of such volume, but'the best~effect in an engine has been found to be realized when the gas bears a proportion of 6 '8 to 7'0 per cent, to the total volume, as with this percentage the propa- gation of the flame of ignition is not so rapid as with mixtures having higher proportions of .gas, hence the explosion is not of so sudden a character and the impetus given to the piston is consequently more effective owing to the duration of the ex- plosion being greater than when the mixture contains a higher percentage of gas. The calorific value of Acetylene, per volume, when burned on the Bunsen system is about 2 '5 times that of ordinary coal gas. The calorific values of various heat giving agents per pound, expressed in British Thermal Units, also their relative values, taking coal as the standard, are as follows : Relative B.T.U. per pouud. Value. 1. Coal '(good steam) ... 14,500 ... I'OO 2. Coal Gas 17,800 ... 1'22 3. Petroleum 20,500 ... 1-41 4. Acetylene 21,170 ... 1'46 Owing to the higher specific gravity of Acetylene the number of cubic feet per pound is only 13*45, as compared 82 ACETYLENE. with 28' 79 for coal gas, hence the apparently slight difference in calorific value per pound. The British Thermal Unit is the standard of calorific value, and signifies the amount of heat necessary to raise one pound of water 1 F., i.e., from 39- 1 to 40- 1 F., deduced from Joule's determination of the mechanical equivalent of heat. Calcium carbide and liquified Acetylene have each been suggested as fuel for steamships, and having regard to the calorific value of the latter, compared with coal and petroleum, it would appear to have advantages. The gas in the carbide form is out of the question, its heat value on a basis of five cubic feet per Ib. being but 7,870 B.T.U. per ft). In view of the present cost of carbide, it would be idle to discuss the application of Acetylene to motive power pur- poses, either ashore or afloat ; but from the data herein given, the relative calorific value of Acetylene in comparison with other heat-giving agents may be estimated, and in the event of the price of carbide being reduced to a point at which the use of Acetylene would be economical, the figures may prove useful. CHAPTER X. ACETYLENE APPLIED TO ARTS AND INDUSTRIES. The possibility of forming organic compounds from inorganic originals or bases was first proved by the discovery that cyanogen (CN) could be produced synthetically, and con- stituted the first link in the establishment of the relationship now known to exist between organic and inorganic compounds. This was followed by the discovery that Ethine or Acetylene could be produced synthetically by the direct com- bination of its elements and this latter discovery formed the explanation of one of the most wonderful of natural phenomena, throwing, as it did, considerable light upon those mysterious workings of Nature by which vast stores of both liquid and gaseous hydro-carbons have been built up, and which have proved of such great value to mankind. Prior to this discovery hydro-carbon compounds were thought to be obtainable only by the decomposition of com- pounds of organic origin. The possibility of producing cyanogen and ethine and from them a wide range of organic compounds has effectually removed the line of demarkation between organic and inorganic chemistry, previously thought to exist. The varying proportions in which carbon and hydrogen combine is almost infinite, each one forming a distinct com- pound, differing from other compounds of the same elements. 84 ACETYLENE The derivatives of the hydro-carbon compounds are also practically infinite in their number and variety, carbon and hydrogen possessing affinities for and combining freely with a large number of other elements. Acetylene, being a compound of hydrogen and carbon, possessing properties other than those of high photometric value as an illuminant and calorific value as a source of energy, its possible industrial applications are many and various. From Acetylene a large number of other hydro-carbon compounds may be derived by different methods of treatment and by the employment of various chemical re-agents, it is thus possible to obtain, through its agency, compounds of an organic nature from purely inorganic mineral substances. Acetylene, on being heated in confinement to the tem- perature of dull redness, is converted into Benzene, C 6 H 6 . Benzene, again being heated in confinement to tempera- ture of bright redness, is transformed into Naphthaline, C 10 H 8 , from which by combination with Bromide, Chlorine and other elements may be produced an infinite variety of com- pounds, all of an interesting nature scientifically, some having a high value commercially, not the least of which being the dye-stuffs, "Magdala Red" and "Campobello Yellow." Acetylene may also be converted, by combination with nascent hydrogen, into Ethylene (C 2 H 4 ), which, on being dis- solved in sulphuric acid, forms Ethylsulphuric acid (C 2 H G SO 4 ), which, upon being distilled with water, yields Ethyl-alcohol, or "Alcohol." Alcohol, C 2 H 6 0, as indicated by the formula, is a com- pound of carbon, hydrogen and oxygen. Acetylene consisting of the first two elements, it only remains to add the third, APPLIED TO ARTS AND INDUSTRIES. 85 oxygen, together with the additional quantity of hydrogen requisite, and the synthesis of alcohol is thereby effected. The production of alcohol, practically direct from calcium carbide, may be effected in the following manner : Calcium carbide and metallic zinc are treated together with water, acidulated with sulphuric acid. Acetylene and hydrogen are thus evolved together, and the latter, being in the nascent state, readily combines with the Acetylene. This combination results in the production of Ethylene C 2 H 4 . This gas, upon being passed into a vessel containing concentrated sulphuric acid (H 2 SO 4 ), combines in certain pro- portion with both the oxygen and hydrogen thereof, forming ethylsulphuric acid (C 2 H 6 SO 4 ). This compound, upon distilla- tion with water, is resolved into alcohol and sulphuric acid, the former being obtained by condensation of the vapour by passing same through a coil, surrounded with cold water in the usual manner. It will thus be seen that the synthetic production of Acetylene on a commercial scale is likely to effect, beneficially, various industries, and not the least will be the manufacture of spirituous liquors, which will be free from those dangerous essences which are said to be always present in alcohol obtained from vegetable sources. The future prospects of Acetylene as an illuminant, and as applied to arts and manufactures will be largely dependent upon the production of calcium carbide at a price which will permit of and insure economy in its use. When it is considered that the actual' cost of production of this commodity is about one-third of its selling price, the possibility of the present mar- ket price being considerably reduced is more than prospective. ACETYLENE The cost of Acetylene for lighting purposes, as com- pared with the cost of coal gas, is easily computed. The present price of carbide is 20 per ton = 20/- per cwt. Assuming an average yield of five cubic feet per lb., the cost of Acetylene, at this rate, would be 35s. 8^d. per 1,000 cubic feet. To compare the cost with that of coal gas, this amount must be divided by, at least, fifteen, which gives 2s. 4^d. as the cost of an equivalent in candle-power hours. This com- pares favourably with 2s. 9d., the present price of coal gas in Liverpool, and which price may be regarded as a fair average. In view of the fact, that a number of manufactories are now producing calcium carbide in more or less quantities, and the prospect of the price being reduced in the near future. Acetylene may yet prove to be the most economical of all illuminants, and its application to various industrial purposes become a fait accompli. HOME OFFICE AND FIRE INSURANCE REGULATIONS. Calcium carbide having been classed as a " Dangerous" commodity, it has been made subject to the provisions of the Petroleum Acts and to the general Home Office Regulations governing the storage and conveyance of same, in addition to which, an Order in Council was issued in February, 1897, containing special Regulations and Provisions regarding calcium carbide, and empowering Municipal Authorities to issue Local Regulations to be applicable within the areas over which they hold jurisdiction. Calcium carbide, in quantities up to five pounds, may be stored without a license, providing that the same be kept in APPLIED TO ARTS AND INDUSTRIES. 87 lots of one pound or under in separate air-tight metal recep- tacles. If it is desired to store more than five pounds in one place, a license to do so must be obtained, the cost of which is five shillings. These licenses are issued by the Local Authorities, are granted for periods of twelve months, and the conditions thereof are according to the Home Office Regulations under the Petroleum Acts. Abstracts of the Local Regulations are issued by the Municipal Authorities of all large towns, and copies thereof may be obtained gratis. In Liverpool, copies of the Local Regulations may be procured on application at the Licensing Department, Muni- cipal Offices, Dale Street. The Fire Insurance Regulations as to location of Acetylene Gas Apparatus, and storage of the gas and of calcium carbide, which were at one time unreasonably stringent, having now been modified, small generating appara- tus, in which the charge of carbide does not exceed two pounds is now permitted within insured premises, providing proper precautions be taken to prevent leakage, and provision made for the escape of surplus gas into the outer atmosphere. Large apparatus must be placed outside the insured premises, and a cut-off or stop tap must be provided in the piping conveying the gas to the insured buildings, such tap to be placed as near as possible to the generating or storage ap- paratus. Provision must also be made for allowing surplus gas 88 ACETYLENE. to escape into the outer atmosphere should the pressure rise to a higher degree than four ounces per square inch. The storage of liquified Acetylene is absolutely pro- hibited upon insured premises, and insurance companies are agreed not to admit liability for damage due to the explosion of Acetylene gas occurring elsewhere than in the building which is, or the contents of which are the subject of the in- surance. The future prospects of Acetylene will largely depend upon two conditions or factors, i.e., the price of carbide and the amount of interest taken in its application, and intelligence exercised in its use. That the price of carbide will be considerably reduced in the near future is more than probable, but whether such enthusiasm will be aroused in regard to Acetylene as will lead to a general desire for a better knowledge of its properties, and thereby a modification of the prejudice which still obtains, remains to be seen. But there is little doubt that, with a better understanding of the subject, a further relaxation of both the Legislative and Fire Insurance restrictions would follow as a natural consequence. Even under present conditions, Acetylene is proving a great boon in its various applications, and there is every pro- bability of its being more generally adopted and valued at its true worth, as its advantages become better known, ADVERTISEMENTS. VIIT. flCETYIiEflE GAS RPPflfrflTUS EXLEY & CO/S TYPE " B" IHSTALLATION w. 2 or 4 GENERATORS ACKNOWLEDOKI) TO RE THE Simplest and Most Efficient in the Market* Each Generator works independently, another coming into operation automatically when one is exhausted. Our Generators are in use in all parts of this Country and the Colonies. Highest Testimonials have been received. Any one can manage our Machines after reading printed instructions supplied therewith. Working Pressure from 8 ins. to 10 ins. water displacement, or under \ Ib. per square inch. Gas Cooled and Purified before entering service pipes. EXLEY & CO., Original Patentees & Makers, Byram St., HUDDERSFIELD, IX CE An Ret If Gu THIS BOOK IS DUE ON THE LAST DATE STAMPED BELOW AN INITIAL FINE OP 25 CENTS WILL BE ASSESSED FOR FAILURE TO RETURN THIS BOOK ON THE DATE DUE. THE PENALTY WILL INCREASE TO SO CENTS ON THE FOURTH DAY AND TO $1.OO ON THE SEVENTH DAY OVERDUE. 13 1935 APR 22 1943 JAN 18 1944 JUL 27 1944 UEC RtC'D LC APR 1G 1957 ITlAi TES iplete tions :les, -*-" interns "* les, tc. LD 21-1007n-8, ... , s.w. YB 15419 ADVERTISEMENTS. The complies with the cannot accumulp has no screws A.C.T. Lamp regu! > th has a ge' is the' . as 76 Z, ir The T- YCLES, >RIAQES, 'ORS or YACHTS. Cements. .np. the market. An f is the ligh .U. I is clipped Dunces. .uminium. sting Oil Lamps, is the lightest, cheapest, and safest in the market. to the frame, like a pump. will give Gas for six hours. (j6B6rf the Generator and Lamp is less than the ordinary Oil Lamp Price, LAMP GENERATOR In Nickel, 56 10/6 In Aluminium, 6/- 12/- Further particulars will be furnished by The Acetylene Gas Light, Power, & Calcium Carbide Co., Ltd. 18, Ironmonger Lane, LONDON, E.G.