122 Profs, ^y. E. Ayrton aiid J. Perry on 



It is rather difficult to determine how much the results were 

 affected by polarization and how much by the lowering of the 

 temperature. We give, however, the results (in a tabulated 

 form) as we obtained them: — 



A. 



Time of short- 

 circuiting, in 



fl ection 

 immediately 



Highest 

 deflection. 



Time taken to 

 arrive at high- 

 est deflection, 



Temperature, 

 in degrees 



minutes. 



on insulating. 





in minutes. 



(Jentigrade. 



i 





240 1 



1 st time quickly 

 2nd time slowly 



I about 0° 



i 





240 



3 



-4°. 







207 



2 



^ 



1 

 i 





203 

 196 





1 falling gra- 





190 





dually. 



i 





178 









r 



176 



[ quickly. 





3 



\ 



diminishing to 



— 12° 





1 



89 



J 





B. 



] 



nearly 



210 



8 



15° to l°-5 



1 



jj 



151 



9 



-l°to -5°-5 



1 



" 



170 



... 



-6° 



C. 



1 



184 



203 



51 



+ 2°-6 



1 



184 



203 



H 



+2°-6 



3 



168 



204 





4-2°-6 



7 



156 



204 





+2°-6 



10 



150 



167 



i 



- 1°-5 to -2°-7 



1 



153 



175 



6 



-3°to-3°-5 



3 



154 



179 



7 





7 





195-5 



25 



-5°to-9°-5 



7 





208-5 



60 



-12° 



It is possible that the deflection 208"5 would always have 

 been obtained had the zinc plate been left sufficiently long- 

 insulated after short-circuiting. The plate and box, however, 

 were always short-circuited when the rise in the electromotive 

 force had apparently ceased. 



To separate, to a certain extent, the effects due to polariza- 

 tion from those due to difference of temperature the following 

 experiments were made. The zinc plate and copper box were 

 alternately short-circuited for two minutes and insulated for 

 two minutes, the temperature being kept constant at + 22°*5 C. 

 This being repeated six times, reduced the deflection 231, 



