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



power it is required to find. The gases after passing through 

 D are led into an inductor by means of the tube T, the inductor 

 / being used for oxygen and 1 ' for hydrogen. By connecting I to 

 the electrometer while a fixed current is going through the cell 

 the quantity of electricity Q x which the gas carries with it through 

 D per minute can be found, and then, with the same current 

 through the cell, D can be connected to the quadrants and the 

 quantity of electricity Q 2 which the gas leaves behind per minute 

 can be obtained. When D consists of a sulphuric acid bottle H 

 and a tube of glass wool W, it is found, when the gases from the 

 sulphuric acid and caustic potash cells are examined, that they 

 have a large charge when they enter an inductor. This charge 

 depends very little on the liquid which is in H, but is considerably 

 reduced by packing the wool very tight in W. The discharging 



power „ n varies according to the rate at which the gas is sent 



through the apparatus ; this can be seen by increasing the current 

 through the cell. But as this is almost a self-evident fact we will 

 pass on from it and describe a series of more important experi- 

 ments. 



12. In the following experiments the discharger D between 

 P and Q consisted of a bottle H into which various liquids could 

 be placed and also a tube of glass wool W. Instead of leading 

 the gas from the cell directly into P, it was passed first through a 

 bottle H' outside the screen so that on putting sulphuric acid into 

 H' the gas was led into D perfectly dry, and by substituting 

 water for the sulphuric acid in H' the gas entered P carrying 

 with it a cloud. The liquid whose effect upon the charge on the 

 gas is to be tested is placed in H, and sulphuric acid in H', and 

 after the current has been running for a sufficiently long time to 

 drive out the uncharged air from the apparatus, D is connected to 

 the quadrants and the number of divisions N 2 which the spot of 

 light on the electrometer scale passes over per minute is observed. 

 The inductor / is then connected to the quadrants and D put to 

 earth, and the number of divisions N x that the spot passes over 

 per minute, due to the charged gas entering i", is then found. 

 It is necessary to blow all electrified gas out of / before begin- 

 ning to find N-y, as this number would be diminished if any 

 electrified gas were to be escaping from I while the observations 

 were being made. The sulphuric acid is then removed from H' 

 and water put in its stead, and two similar numbers N 2 and iV/ are 

 then obtained, the same current flowing through the cell as when 

 JSf 2 and iVj were being determined. 



The following table contains the numbers thus obtained for 

 sulphuric acid, water, and potassium iodide solution, in H. 



