150 Jauncey — Effect of a Magnetic Field. 



In this table each of the values of the ionization current 

 in columns 2 and 3 is a mean of four or five readings, which 

 were taken alternately with and without the field. It is seen 

 that in the given set of readings the ionization current was 

 always slightly greater with the held than without. By chang- 

 ing the positions of the bulb this effect could be reversed, thus 

 showing that the effect is probably due to the field having a 

 small action on the cathode stream in the X-ray tube. When 

 187'5 volts was put across the chamber the reading was 310 

 without the field and 324: with the held. Since the results of 

 Experiment I have shown that the total ionization is unaltered 

 by a magnetic field if the strength of the ionizing agent re- 

 mains constant and since the ionization currents of 310 and 324 

 are nearly the saturation currents, the readings with the held 

 were all reduced in the ratio of 321 to 310 and these corrected 

 values are shown in the fourth column. 



From Table II it is seen that the corresponding numbers in 

 the second and fourth columns are almost identical, the small 

 differences observed not being greater than those due to ex- 

 perimental errors. Hence it is concluded that a magnetic field 

 has no effect on the saturation curve and therefore no effect on 

 the initial recombination of the ions. 



§4. Summary. 



1. A magnetic field of the intensity here used has no effect 

 on the total ionization produced by X-rays. 



2. A magnetic field of the intensity here used has no effect 

 on the initial recombination of the ions produced by X-rays. 



In conclusion, the author wishes to thank Professors Franklin 

 and MacNutt for their interest and help in this research. 



Physics Laboratory, Lehigh University, 



South Bethlehem, Pa., April 29, 1916. 



