374 Profs. J. Dewar and J. A. Fleming. On the Dielectric 



XL Dielectric Constant of Oxide of Copper (CuO). 

 (Suspended in water.) 

 (14*55 per cent, of oxide.) 

 Corrected galvanometer reading when the condenser has air as 

 dielectric = 4*07 cm. for 100 volts. 



Observations. 

 Condenser charged to 1*434 volts. 





Mean 





Temperature 



galvanometer 





in platinum 



deflection 



Dielectric 





in centimetres. 



constant. 



— 1957 



9-40 



161 



— 185*0 



9*25 



158 



-174*8 



9*52 



163 



-164*3 



9*60 



164 



-159*0 



9*50 



162 



-151*2 



9*60 



164 



-141*3 



9*90 



169 



-130*0 



10*30 



176? 



-124 2 



1110 



190? 



-1205 



1215 



207? 



It will be noticed that the dielectric constant of the ice having iu 

 suspension particles of oxide of copper has an exceedingly high value, 

 even at the temperature of liquid air, and, moreover, shows no signs 

 of becoming reduced. We suspected that this might be due to the 

 conductivity of the oxide of copper particles, which, though separated 

 and insulated by ice at a low temperature in such fashion that the 

 whole mass is a good insulator, may yet raise the value of the average 

 dielectric constant. 



"We tried suspending sulphide of copper in ice, but in this case 

 found the material, as a whole, had such conductivity that we could 

 not make any dielectric measurement by the method used. With 

 this exception, all the other frozen oxides and hydrates suspended or 

 dissolved in ice had a very high resistance. 



We then tried dissolving the oxide of copper in ammonia. 



XII. Dielectric Constant of Oxide of Copper (CuO). 

 (Dissolved in ammonium hydrate.) 

 (10 per cent, solution.) 

 Corrected galvanometer deflection when the condenser had air as 

 dielectric = 4*15 cm. for 100 volts. 

 Mean 



Temperature galvanometer 

 in platinum deflection Dielectric 

 degrees. in centimetres, constant. Observations. 



— 201-3 10-2 2*39 Condenser charged to 987 volts. 



-178*0 2-0 2-34 Condenser charged to 19*8 volts. 



-132*2 2*35 2*77 



