ELECTRIFICATION OF AIR, VAPOUR OF WATER, AND OTHER GASES. 209 



and then the experiments were done exactly as already described in 49, except that 

 carbonic acid gas was let in instead of air. The machine, in the two sets of experi- 

 ments summarised below kept the needle points at a potential of 8000 volts positive. 



ELECTRIFICATION OF CARBONIC ACID GAS BY ELECTRIFIED NEEDLE POINTS. 



53. The nearly perfect annulment of the electrification by 10 minutes of the 

 electrified needle point in carbonic acid, and by 5 minutes (50, 51) in common 

 air, is very wonderful. So far as we can see at present, its explanation seems to be 

 a conductive quality, such as that first discovered, we believe, by SCHUSTER, produced 

 throughout the carbonic acid, and throughout the air, by continued electric disruptive 

 action. 



54. It was noticed in some of the experiments with the carbonic acid cylinder 

 that, when it was lying on its side on the table beside the glass vessel, C, and when 

 the gas issued in a jerky manner, the electrification found was invariably negative, 

 even when the needle points were positive. This was, of course, due to the boiling 



* This first experiment was made with the carbonic acid gas which had been in the glass cylinder 

 overnight. 



f For explanation of this negative electricity in the gas with no electrification of the needle points, 

 see 54. 



VOL. CXCI. A. 2 E 



