500 Prof. McLennan and Mr. Found on Delta Radiation 



and about 2 cm. above it. When the pressure had been 

 reduced to below '001 mm. of mercury a current of 

 10 amperes was passed through the platinum wire of the 

 furnace for 15 minutes. This sufficed to vapourize the zinc 

 in the furnace and to deposit a good coating on the surface 

 of the zinc plate X. 



The furnace current was then cut off and the rod H was 

 raised as quickly as possible until contact was made with S 

 at 0. A positive potential of 80 volts was then applied 

 to P, and readings were taken with increasing magnetic 

 fields at intervals of a faw minutes for half an hour. 



The magnetic field was then cut off, and at the end of 

 55 minutes readings were again taken at intervals for half 

 an hour with electric fields ranging from zero to 80 volts. 

 At the end of 90 minutes a reading was taken with an 

 applied field of 80 volts and a magnetic field of 1200 gauss,, 

 and at the end of 190 minutes a reading was again taken 

 under the same conditions. 



All these readings are recorded in Tables V. and VI., and 

 curves drawn from them are shown in PL VII. figs. 6 and 7. 



Table V 



Zinc 



surface deposited from zinc vapour in a high vacuum. 



Voltage on 

 Polonium. 



Current 

 through 



Magnetic 

 field. 



Time since 

 surface 



Deflexion 

 per 



Current 

 XlO 5 





coils. 



Gauss. 



made. 



minute. 



e.s.u. 



Volts. 



amps. 





min. 



mm. 





+80 



zero 



zero 



5 



53 



166 



80 



•5 



240 



11 



52 



163 



80 



•95 



405 



15 



53 



166 



80 



1-65 



650 



18 



52 



163 



80 



23 



880 



23 



53 



166 f 



80 



2-8 



995 



28 



53 



166 



80 



36 



1160 



30 



53 



166 



zero 



zero 



zero 



55 



-21 



- 66 



2 







58 











6 



., 



t , 



60 



19 



60 



10 





5» 



62 



23 



72 



14 



)> >> 



65 



22 



69 ! 



20 





, 



67 



25 



78 



26 



M 



f 



70 



25 



78 



30 



n 





72 



25 



78 



40 



,, 



,, 



75 



25 



78 



HO 



,, 



,, 



77 



25 



78 



80 



" 



" 



85 



25 



78 



i 



