THE USE OF ACETYLENE.
ACETYLENE GAS indiscriminately used— at least in the present stage of its development— is not to be encouraged, as is shown by the many destructive conflagrations, often accompanied by loss of life, which have followed upon its employment. Those who are making use of it apparently forget—many of them do not know—that it is one of the most, inflammable gases known, being of the hydrocarbon type, and in its combustible properties alone possessing much in common with other gases or mixtures of gases of the same class. It is not merely that it is explosive-that is an essential quality of benzine, coal, or natural gas, mill dust, coal breakers, etc. Its principal danger is that, under certain conditions, not present to the combustible materials already alluded to, it is liable to explode and cause great destruction. This condition, though simple, is not generally familiar to the public; hence the risks accompanying its use. The condition is that oxygen shall be present in sufficient quantities, and likewise be so mixed with the gas or finely divided combustible as to produce combustion and support it, after ignition has taken place and it may be noticed that the materials which go towards making up acytylene, gas are peculiarly liable to spontaneous combustion, and besides afford to the firebug the easiest possible facilities for incendiarism As a rule, the air supplies the oxvgen; wherefore, a certain definite admixture of the outer air with this gas renders it explosive, so that, combustion ensuing, more or less on the moment, a considerable amount of heat is generated. When this heat is imparted to the gases of combustion, by its immediate expansion its volume increases to such an extent as to cause the vessel into which it is contained to burst and cause great damage. Acetylene, therefore, is harmless only so long as it is kept in an absolutely airtight vessel, whether a small tank or the generator itself. But, just as soon as the vapor escapes and comes in contact with the oxygen present in the air, the combination of the vapor with the oxygen will almost certainly be the parent of an explosion, should any fire be brought in contact with it. Every explosion of non-liquefied acetylene gas that has hitherto taken place is traceable to this. Calcium carbide of itself is of sufficiently good quality that there can never be present in the gas phosphorus enough to cause spontaneous combustion when air is admitted to it. If such a gas should be produced, its smell wouid be so offensive that no one would take the carbide—for whatever smell acetylene has is ihe result of the phosphureted and sulphureted hydrogen contained in it, and these impurities have their primal existence in the lime and carbon which are made use of to form the carbide under the influence of electric heat. No one, therefore, should attempt to generate acetylene unless the generators are situated out of of doors in well ventilated sites, and the generators should be filled and cleaned only by daylight. Liquefied acetylene gas is altogether dangerous,on account of the liquefaction demanding a pressure of at least sixty-eight atmospheres—one highly dangerous in itself and not admitting the slightest defect in the apparatus. Fire chiefs and fire marshals should profit by these hints and govern themselves accordingly.