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



Temperature of Kesistence of 



the ice in the ice condenser 



platinum degrees. in megohms. 



-91'8 209-0 



-88-S 118-0 



-88-2 91-4 



-86-3 66-5 



-84-4 53-4 



-82-3 46-3 



-75-0 42-8 



— 707 43*4 



In the same way the resistance of the frozen ethylic alcohol con- 

 denser was taken at temperatures lying between —185° C, and about 

 — 160 C, as given in the table below. 



Table X. — Variation in Resistance of the Frozen Alcohol Condenser 

 Temperatures given in Platinum Degrees. 



Temperature of Resistance of 



the alcoliol in condenser in 



platinum degrees. megohms. 



-200-0° 14500-0 



— 190-0 45-0 



-186-5 9-7 



-168-0 l-o 



The above numbers cannot be considered as more than moderate 

 approximations, but they are sufficient to show the mode of variation 

 of resistance in the two cases. 



The values for the resistance of the ice and alcohol have been set 

 out in the two curves in figs. 3 and 4. 



These figures show that in the case of the alcohol, as soon as a tem- 

 perature of —-190° pt. is reached the resistance begins to fall with 

 great rapidity or the conductivity to go up. 



In the case of the ice the same rapid increase in conductivity 

 begins to take place at about —90°. 



We have designed a form of condenser which will enable us to 

 repeat these measurements and free them from some sources of error 

 due to the difference between the contraction of the metal plates of 

 the condenser and that of the dielectric; but pending such more 

 accurate measurements the above figures may be taken as showing 

 approximately the course of events when the ice and frozen alcohol 

 are heated up from the temperature of boiling liquid air. 



We add two tables, XI and XII, giving some recent determina- 

 tions of the dielectric constant of the ethyl alcohol, the results in 

 Table XII showing that evidence apparently exists of abnormal dis- 



