ELISHA MITCHELL SCIENTIFIC SOCIETY. 13 



hydrogen was io-nited at the jet and a lamp placed 

 under the tube so as to heat the carbide. In a little 

 while the colorless flame became luminous and remained 

 so a short time. A brownish, tarry matter condensed 

 in the cooler parts of the tube. The mass of the car- 

 bide assumed a dull grey tint and a ver}^ thin white sub- 

 limate collected at a short distance from where the tube 

 was heated. The ignition was carried on for five hours. 

 The driving off of this tarry matter seemed to be the 

 on]}' action. The substance on removal from the tube, 

 was still hard. On exposure to the air, it disintegrated, 

 and, if thrown into the water, it was decomposed, show- 

 ing the same behavior as the original carbide. 



Action of Air and of Oxygen. — Some fresh pieces of 

 the carbide were placed in the tube and heated while 

 dr}' air was passed over them. A luminous flame was 

 gotten as before and the same tarry matter was driven 

 off and then there seemed to be no further action. Tests 

 showed the carbide apparently unchanged at the end 

 of prolonged heating. 



Ox^^gen was then passed over some of the carbide 

 which was being moderateh^ ignited. No change was 

 observed after two hour's heating. If the temperature 

 was very high, such as that gotten in a combustion 

 furnace, the carbide glowed brightly, as if burning, 

 and a nearly white powder was obtained. The com- 

 bustion was imperfect, however, unless the tube was 

 very hot and the ignition prolonged. This refers not 

 merely to the graphitic carbon mixed with the carbide 

 but to the carbide itself. In several experiments the 

 substance withdrawn from the tube, after heating 

 some hours in oxygen, decomposed violently in water. 

 It may be added, as was to be expected, that carbon 

 dioxide had no appreciable action upon the carbide. 



