Jauncey — Effect of a Magnetic Field. 



149 



Table I. Experiment, J. 



Ionizing agent : Homogeneous X-rays from copper 



Strength of magnetic field : 4200 gauss 



Gas ionized : Air, at atmospheric pressure 



Voltage across the ionization 

 Chamber A 



Ionization Current (slit readings) 



Without magnetic 

 field 



With magnetic 

 field 



Above saturation voltage 



641 

 027 

 634 

 637 



631 

 629 

 621 

 637 



Mean 635 Mean 629 



§ 3. Experiment II. Voltage below Saturation. 



The compensation arrangement of Experiment I was aban- 

 doned because the saturation voltage was less than 7 volts 

 which was too low and because a compensation method is not 

 desirable when the voltage-current relation is being determined, 

 the shape of the curve depending upon the absolute value of the 

 ionization-current. 



In this experiment primary X-rays entered the lead 

 chamber A directly, the distance between the electromagnet 

 and the X-ray tube being such that the bright spot was not 

 noticeably deflected by the magnetic field. The reciprocal of 

 the time for a given deflection of the gold leaf of the electro- 

 scope was taken as a measure of the ionization current. 



In this experiment the effect of a magnetic field on the 

 relation between the voltage and the ionization current was 

 examined. The results are shown in Table II. 



Table II. Experiment II. 



Ionizing agent 



• 

 • 



Primary X-rays 





Strength of mag 



letic field : 



4200 gauss 





Gas ionized 



; 



Air at atmospheric 



pressure 



Voltage across 

 chamber 



Ionization Current 



Without magnetic 

 field 



With magnetic 

 field 



With magnetic 



field 



(corrected values) 



15-0 



52 









22-5 



79 





80 



77 



45-0 



141 





148 



142 



67-5 



180 





199 



191 



120-0 



250 





268 



257 



187-5 



310 





324 



310 



