252 



Mr Townsend, On Electricity in Gases [Feb. 8, 



must be the gas is supported by a series of experiments of quite 

 a different kind which were done with the negative oxygen from 

 the caustic potash cell. A small inductor containing some 

 sulphuric acid in the bottom was insulated and connected to the 

 quadrants, and the charged oxygen then admitted, the spot of 

 light having gone n x divisions negative. The inductor was then 

 corked and the acid shaken up with the gas for 1^ minutes and 

 then again insulated and connected to the quadrants, when on 

 removing the cork and blowing out the oxygen it was found that 

 the spot of light went in the positive direction, giving say n 2 

 divisions. This showed that the gas retained n 2 /n 1 of its original 

 charge. The actual values obtained in two experiments of this 

 sort were n x = 56, n 2 = 36 and n Y = 66, n. 2 = 39. This experiment 

 was repeated with strong pyrogallic acid instead of sulphuric acid 

 and it was found that a considerable fraction, about 45 per cent., 

 of the charge remained on the gas, and could be blown out. The 

 pyrogallic acid was left in the inductor and some strong caustic 

 potash added, and a fresh quantity of charged oxygen was then 

 put in and shaken up with the potassium pyrogallate for exactly 

 the same time, 1J minutes, as in the case of pyrogallic acid, and it 

 was now found that only about 8 per cent, of the charge could be 

 blown out, showing that, of the 45 per cent, which would have 

 remained if no absorption of oxygen had taken place, more than 

 eight parts in ten have now been removed from the air in the 

 inductor. The numbers which were obtained in three expei'iments 

 of this kind are given in the following table; n x the charge (in 

 divisions of the scale) put into / when it contained pyrogallic acid, 

 and n 2 the charge which was blown out after shaking up with the 

 acid for 1^ minutes, n-l the charge put in after KOH had been 

 added, and n 2 the charge blown out after shaking up Avith the 

 pyrogallate for 1^ minutes. 



16. If the electrification resides on the drops when the cloud 

 is formed, it ought to be possible to diselectrify the gas by forming 

 a cloud in it and then letting the cloud fall in a vessel. This is in 

 fact what does occur, for if the gas be thoroughly dried by passing 

 it through two sulphuric acid bottles and then let into an 

 inductor with sulphuric acid in the bottom only a very slight 



