534 



Dr. M. W. Travers and Mr. A. G. C. Gwyer. [Jan. 11, 



The gas thermometer was the same as was used in the liquid air 

 experiments. As, however, the volume of the bulb was known only 

 at 100, 0, and - 185 C.,* the volume at - 80 was calculated by 

 means of a parabolic formula with two constants. We have taken as 

 our values for the volume 



100 24-332 c.c. 



24-262 



78 24-216 



-185 24-162 



The arrangement of the thermometers and the vacuum-vessels was 

 the same as in the liquid air experiments, the only difference in the 

 manner of carrying out being that the bath was stirred at intervals. 

 The following are the results : 



A. 



= 7-3319 ohms. 



a = 0-003899. 



B. 



K = 7-3319 ohms. 



a - 0-003899. 



Though these results point to the conclusion that a mixture of solid 

 carbonic acid and alcohol varies in temperature by less than one degree 

 over a period of more than 36 hours, it is only during the first few 

 hours that it remains steady enough for this purpose. Taking the first 

 three observations of each set we obtain the result 



MeanT,*. Mean T.H. scale. A. 3(calc.). 



-80-79 -78-23 2'56 1-84 



' Phil. Trans.,' A, vol. 200, p. 138. 



