1807.] Newly Prepared Gases. 359 



The discharging power of tubes. 



(14) It has been shown that, if the gas with a uniform charge 

 p per c.c. be left in a tube for a time t, the density of the electri- 

 fication falls to a uniform value p, given by the equation 



Po__ 



1 + ap t 



where a is a constant. Now if we suppose that the velocity of a 

 gas as it passes along a tube be perfectly uniform and that no dis- 

 charging takes place due to accidental circumstances, the values of 

 t, p, and p , would be connected by the same equation, where now 

 t denotes the time that any portion of the gas takes to traverse 

 the tube, p and p being the densities of electrification on entering 

 and escaping from the tube. 



When the gas is given off by a current through an electrolyte, 



the volume q which enters the tube per second is known when the 



V 

 current is known : so that t = — where V is the volume of the 



9 



tube, and the above equation becomes 



The values of p and p are easily found and satisfy this equation 

 roughly, so that a can be determined ; its value however is greater 



than -==- found already. This is due to accidental discharging, as 



it can be shown that, even when the carrier is so large that the 

 small E.M.F. driving it to the side of the tube could have no 

 appreciable effect, still a measurable discharge takes place. 

 (See § 21.) 



(15) If the gas be run into an insulated inductor after 



traversing the tube, - — - is the ratio of the charge gained per 



minute by the tube to the charge gained per minute by the in- 

 ductor. These charges can be easily found by connecting the tube 

 and inductor alternately to the insulated quadrants of an electro- 

 meter. The tube G insulated in the manner described in § 10 was 

 used in these experiments, the gas examined being the hydrogen 

 given off by a current of 14 amperes from a dilute sulphuric acid 

 electrolyte. The following deflections n x and n 2 were obtained, ?? 1 

 being the deflection per minute when the tube is connected to the 



