2G0 Profs. J. Dewar and J. A. Fleming. Dielectric Constants 



VIII. Dielectric Constants of Frozen Electrolytes, Electrolysed freely in 

 the act of Freezing. 



Corrected galvanometer deflection with air as dielectric = 3'42 cm. 



for 100 volts. 



Mean 



Temperature galvanometer 

 in platinum deflection Dielectric 

 degrees. in centimetres. constant. Obseryations. 



(a) 5 per cent, aqueous solution of potassic 



hydrate electrolysed with 0*2 ampere 



and 8 volts. Evolved gas = 51 c.c. 



-200-0 3-85 71-4 Condenser charged with 1'434 volts. 



Electrical resistance of condenser 



5000 megohms when frozen. 



(b) Water electrolysed with 1*0 ampere. 



— 198-2 8-70 2-47 Condenser charged with 98 volts. 



Electrical resistance of condenser 

 5000 megohms when frozen. 



(c) "Water electrolysed with 2*1 amperes. 

 -198-0 8-G5 2-42 Condenser charged with 98'9 volts. 



It is evident that the action of electrolysis prior to, and during 

 freezing has no sensible effect on the subsequently measured di- 

 electric constant even though the surfaces of the cone condenser 

 are strongly polarised in the act of freezing the liquid dielectric. 



We have then paid some attention to the possible cause of the 

 high dielectric values of some substances at very low temperatures. It 

 is clear from the above described experiments with the Nernst bridge 

 that for organic bodies such as ethylic alcohol, amyl alcohol, ethylic 

 ether, and glycerine we obtain practically the same dielectric values 

 at the low temperature, both when they are measured by the galvano- 

 metric method with a switch frequency of 120, and when measured 

 by Nemst's method with a frequency of 350, or about three times as 

 great. 



On the other hand for certain other bodies such as the frozen dilute 

 hydrates of potassium and rubidium, and the oxide of copper 

 suspended in ice, the dielectric value at the low temperatures is 

 much diminished by increasing the frequency. 



Subsequently to the completion of the experiments described in this 

 paper the suggestion has been made by R. Abegg* that the high di- 

 electric values at low temperatures are due to polarization of the 



* < Wied. Ann.,' vol. 62, p. 249. 



