﻿S28 Mr. V. E. Pound on the Secondary Rays 



The next experiments that were performed were for the 

 purpose of finding out whether this same carbon would send 

 out secondary rays with its initial intensity if it were placed 

 in an atmosphere of hydrogen instead of air. The apparatus 

 was first filled with dry hydrogen, produced from zinc and 

 acidulated water, and left at atmospheric pressure for four 

 hours. Then, as before, a positive charge of 80 volts was 

 put on the polonium, the pump was started, and at a definite 

 interval of time after starting the pump, a series of readings 

 were taken on the rates at which the carbon electrode charged 

 up, and on the corresponding pressures of the hydrogen in 

 the apparatus. The readings are given in the following 

 Table. 



Table VIII. 



Hydrogen in Apparatus. 



Fatigued carbon electrode. Charge on polonium = 80 volts. 



Pressure of hydrogen 

 in vessel. 



Time from initial 



reading taken 4 minutes 



after starting pump. 



Current to 

 electrode. 



•006 mm. 



•003 „ 

 <-001 „ 

 <001 „ 

 <-001 „ 



minutes 



6 

 15 



31 „ 

 56 



24-5 



230 



22 



22 



22 



Next the apparatus was filled with hydrogen at atmospheric 

 pressure and left standing for eighteen hours. A series of 

 readings was taken as before, and these are given below. 



Fat: 



Table IX. 

 Hydrogen in Apparatus. 

 ;ued carbon electrode. Charge on polonium = 80 volts. 



Pressure of hydrogen 

 in vessel. 



Time from initial 



reading taken 4 minutes 



after starting pump. 



Current to 

 electrode. 



•005 mm. 

 •002 „ 



<-ooi „ 

 ■<-ooi „ 



minutes 



15 

 30 

 62 



257 



24-7 



24 



23-5 



235 



