Contact ivith Dielectrics. 



489 



Experiment 1. {Tinfoil Electrodes. 150 Volts.) 

 Table I. 



Load in 



Shunt, 



Deflexion, 



Deflexion, 



Total, 



grammes 



ohms. 



1 min. 



2 min. 



megohms. 



per cm. 2 











22-3 



1000 



345 



369 



26-8 



31-5 



tl 



379 



383 



24-4 



61-3 



„ 



450 



453 



20-6 



760 



700 



345 



347 



195 



90-8 



„ 



358 



359 



18-7 



105-3 





367 



369 



18-3 



119-8 





378 



378 



17-8 



197-2 



., 



430 



430 



15-6 



226-7 



500 



328 



329 



15-0 



256-1 



,, 



335 



335 



14-7 



282-1 





340 



340 



14-4 



311-5 



t 



343 



343 



14-3 



361-1 



„' 



357 



356 



13-8 



390-5 



^ 



360 



359 



136 



4491 



)} 



365 



363 



13-5 



543-3 



,' 



368 



368 



13-3 



449-1 



t) 



373 



370 



13-2 



390-5 



f} 



370 



368 



13-3 



315-0 



}j 



368 



367 



13-3 



256-1 



.j 



366 



365 



13-4 



196-8 



;j 



362 



360 



13-6 



149-7 



>? 



345 



344 



14-2 



90-8 



>} 



335 



334 



147 



317 



; , 



285 



287 



17-2 



22-3 





258 



259 



190 



197-2 



(J 



349 



348 



14-1 



361-0 



„ 



367 



367 



13-4 



544-1 



(J 



381 



379 



12-9 



22-3 



" 



266 



268 



18-5 



(The above table shows the effect of increase of load. The 

 electrical test at each load icas begun within 1 minute of 

 adjusting the load.) 



Comparing the first and fifth columns of Table I., the 

 resistance is seen to dimmish from 26*8 to 13*5 megohms as 

 the load increases from 22*3 grammes per cm. 2 to 449 - 1 

 grammes per cm. 2 ; and it is seen to attain a fairly constant 

 value at that load, which is not far from that used by 

 Mr. Rayner (400 grammes). Mr. Rayner took the precau- 

 tion of allowing 5 minutes for the load to settle before taking 

 a test, so that his results would probably be rather more 

 uniform than these. The increase of resistance as the load 

 diminishes takes place more slowly, and the value 19*0 

 megohms at minimum load is considerably less than the 

 initial value. The increase of load at this point to 361 

 grammes per cm. 2 lowers the megohms again to 13*4 ; and 

 the resistance is further reduced to 12*9 megohms when 

 Mr. Rayner's load is exceeded. When the minimum load is 



