12 JOURNAI. O^ THE 



what. The average is about 200 cc. to the gram of 

 carbide. 



If the gas be ignited, as it is evolved, it gives a smoky 

 flame; if it be considerably diluted, as one part of gas 

 to from six to ten of air, a flame of great brilliancy and 

 intensity is gotten. A company has been formed to 

 introduce this as an illuminant upon the market. The 

 cheapness of the materials used and the ease with 

 which the gas can be found ought to make it a valuable 

 and useful addition to our illuminants. If too large 

 a proportion of air be admixed a very violent explosion 

 can be brought about by igniting it. In some cases we 

 have noticed the flame rapidly travelling backwards 

 along a rubber tube towards the gasometer in which 

 the gas was stored. One explosion taught us that care 

 was necessary in handling the mixture. 



Several analyses were attempted of the carbide, but 

 for obvious reasons failed to give very satisfactory 

 results. In the first place there was uncombined car- 

 bon present, also a small portion of a tarry matter, 

 which could be detected by heating to high tempera- 

 tures, and lastly, the specimens worked upon were sev- 

 eral months old and in spite of careful keeping, had 

 been slightly acted upon by the air and so contained 

 uncombined lime or calcium carbonate. Moissan gives 

 C 2 Ca as the formula calculated from his analyses. This 

 would agree well with the decomposition by water; 

 C^Ca+HO.^C^H^ + CaO. 



Action of Hydrogen upon the Carbide. — Dry hydro- 

 gen has no action upon this carbide in the cold. Sev- 

 eral small pieces of the carbide were placed in a piece 

 of combustion tubing, drawn out at one end to a point 

 suitable for testing the flame. Dry hydrogen was then 

 passed over it and as soon as the air was expelled the 



