274 



SCIENCE-GOSSIP. 



ACETYLENE, THE NEW ILLUMINANT. 

 By F. Winstoxe. 



T F half-a-dozen years ago our most able chemists 

 had been told that it were possible to obtain a 

 gas from a piece of builder's lime producing a light 

 more brilliant than electric light and cheaper than 

 paraffin, the statement would have been received 

 with a smile of derision or pity. Such, however, 

 is one of the most wonderful recent discoveries of 

 applied science. Like so many other important 

 inventions, this was the result of an accident, during 

 some experiments made by M. Henri Moissan, the 

 eminent Parisian chemist, to whom all honour is 

 due, not only for his discoveries, but because it is 

 his custom, without seeking reward, to throw them 

 open for the benefit of mankind. The Royal 

 Society of England has recognized this by con- 

 ferring upon him one of its highest tributes. It 

 was in the early part of 1892, when M. Moissan 

 ■was conducting a series of experiments with the 

 object of searching for new metals in some of our 

 common mineral substances, that this gas was 

 produced. These investigations were effected with 

 the aid of electrolysis, that is decomposition by a 

 very powerful electrical current passed through 

 the material under treatment. This current soon 

 raised the mineral mass in the furnace to a 

 temperature exceeding 5,000 degrees Fahr. It 

 will be difficult for those who have never seen a 

 molten mass in such an incandescent state to 

 understand the intensity of the heat ; but it need 

 only be stated that it is almost too great for human 

 •eyes to look into without probable injury to the 

 sight. By the aid of such intensity minerals are 

 in some instances quite changed in character and 

 constituents extracted from them which were little 

 suspected to form part of their constitution. 



It was while treating lime in this manner that 

 M. Moissan made the discovery which is rapidly 

 resulting in a revolution in the system of domestic 

 Sighting, especially in rural districts. He was 

 searching for a possible metal in lime, and had 

 placed in his furnace a quantity of material formed 

 of about two-thirds lime and one-third powdered 

 •carbon. Having raised the mass to about 5,000 

 degrees of heat, Fahr., it fluxed, or ran together, 

 and became a molten mass of treacle-like con- 

 sistency. M. Moissan tested some of this, but not 

 finding the metal for which he was seeking, he 

 'instructed one of his assistants to empty the furnace, 

 as he required it for further trials. The material 

 left being still very hot, was removed and, with the 

 object of more rapid cooling, thrown in a bucket 

 containing some water. To the astonishment of 

 the little group of investigators, when this material, 

 which in appearance was like a piece of dark grey 



crystalline rock, fell into the water it effervesced 

 violently. Finding it thus gave off a large quantity 

 of gas, someone threw into the bucket a lighted 

 match, with the result that there sprang forth 

 a volume of brilliant flame. To this simple in- 

 cident is due a discover}' which transcends in 

 value the most vivid expectations of any alchemist 

 of olden times. The alchemists hoped to turn 

 the baser metals into gold, but this modern 

 chemist had discovered a means of indirectly 

 turning into gold the products of two of our 

 most common minerals. 



Recognising the importance of the discovery, 

 the French savant fully investigated the material 

 and its product gas. He then read before the 

 French Academy of Sciences a paper upon the 

 subject, describing his process of manufacture of 

 acetylene gas for commercial purposes, and 

 presented a sample of pure crystalline calcium 

 carbide. In due course, on March 5th, 1894, this 

 paper appeared in the organ of the Academy 

 " Comptes Rendus," thus placing the discovery 

 freely in the hands of the public. Little more 

 than a year after Moissan's publication, the light 

 was burning brilliantly in several places in France, 

 Italy, Germany and America. With that curious 

 inaptitude to quickly grasp the benefits of new 

 inventions which characterizes English people, the 

 light was unknown for months later in Britain, 

 excepting to a few scientific people. 



The mass produced in the chemical furnace as 

 described has the chemical formula of one part of 

 calcium to two parts of carbon (CaC 2 ), and is 

 now known as carbide of calcium or calcic- 

 carbide. The gas evolved when this material is 

 combined with water has the chemical formula 

 C 2 H. 2 , and is called acetylene. The chemical 

 reaction being CaC 2 -h 2H,0 = CaOHoO + 

 C 2 H 2 , that is, calcium-carbide and water produce 

 lime and acetylene. This formula applies only to 

 calcium-carbide that is free of impurities. Much 

 of that which is at present used commercially 

 has other constituents, usually hydrogen, sul- 

 phuretted hydrogen and sometimes phosphuretted 

 hydrogen and ammonia. The name acetylene was 

 obtained from the supposed radical acetyle (C 2 H 5 ), 

 to which acetylene bears the same relationship 

 as ethylene (C 2 H.,) does to the radical ethyle 

 (C 2 H 5 ). During the many vicissitudes attending 

 its investigation several other names have been 

 given, but "acetylene" seems to be the one 

 that has survived. 



Acetylene gas has long been known to chemists 

 as an unpleasant smelling product, which arises 



