﻿4 MORRlS-AlREY & SPENCER, Resistivity of Carbon. 



It was found that the results obtained before the 

 liquid air had quite evaporated were not consistent, 

 observations made on different days showing wide 

 deviations (see Fig. i). The cause seemed to be that 

 whilst the coils were only partially immersed in the liquid, 

 the temperature fluctuated very much. The method was 

 then slightly modified and the final arrangement is 

 shewn in Fig. 2. 



46«/O r 



2 50° -2.00' -ISO" ~ioo° 



■TEMPLROTORe 



Fig. i. 



The carbon loop and platinum thermometer were 

 carried down into a thick brass cylinder, which was 

 supported by rods fastened to the wooden cover of the 

 apparatus. Liquid air was poured in and replenished at 

 intervals until the brass cylinder had been cooled down to 

 the temperature of liquid air. Measurements of the 

 resistance were then made, and when these gave steady 

 values, the liquid air was poured out and observations of 

 the resistances made as quickly as possible. Owing to 

 the large heat capacity of the cylinder, the rise in 



