Constants of Pure Ice, fyc, at Low Temperatures. 325 



Temperature 

 in platinum 

 degrees. 



Galvanometer 



deflection 

 in centimetres. 



Dielectric 

 constant. 



-81%3 



13-9 



28-4 



-747 



1565 



31*9 



-69-5 



1-8 



515 



-61-5 



1-98 



56-8 



-52-5 



2-05 



59-0 



Observations. 

 Charging voltage 20'0 



Charging voltage 1*43 



The glycerine, like the other electrolytes examined, fell rapidly in 

 resistance as the temperature rose, as shown in the following 

 table : — 



Resistance of Glycerine Condenser. 



Temperature 

 in platinum 

 degrees. 



-200 



-129 



-90 . 



-44 



greater than 

 about 



Kesistance of 



condenser 

 in meghoms. 



25,000 

 25,000 1 

 800 

 9 



It is seen that the glycerine acts as do all the other electrolytes so 

 far examined, its resistance falls as its dielectric constant increases. 



In order to examine and compare the behaviour of water and 

 glycerine with some non-electrolytic dielectrics, we selected for 

 examination nitrobenzol and ethylene dibromide. Of these bodies, 

 one, viz., mononitrobeuzol, has, at the ordinary temperature and in 

 the liquid state, a somewhat high dielectric value. The following 

 are the results for ethylene dibromide : — 



Dielectric Constant of Ethylene Dibromide. 



Frequency of contact maker 120. Galvanometer deflection with air 

 as dielectric in the condenser = 326 cm. for 100 volts. 



Observations. 

 Charging voltage 100-8 



Temperature 



Galvanometer 





in platinum 



deflection 



Dielectric 



degrees. 



in centimetres. 



constant. 



-20L7 



9-45 



2-72 



-197-8 



9-32 



2-68 



-177-6 



9-35 



2-69 



— 145-5 



9-40 



2-71 



-102-2 



9-50 



2-77 



-78-0 



10-00 



2-79 



-60-6 



10-20 



2-95 



—48-0 



10-25 



. 2-97 



-30-8 



10-30 



2-98 



90,000 ohms cut out of 

 galvanometer circuit, 

 no change in deflection. 



