360 



Preliminary Note on the 



multiplying by one thousand, to reduce the number of figures 

 0-04868 per atmosphere at temperatures from i to 4 C. 



The manometer (No. 2) was compared with this piezometer. 

 The temperature of the manometer was 12-5 C., while tin- 

 piezometer was enveloped in ice in the receiver. The ice was 

 thus melting under the same pressure as the instrument was 

 undergoing, consequently the piezometer was not exposed 

 really to precisely the same temperature at each succeeding 

 experiment. For our present purpose, the effect of the possible 

 variation in volume due to this thermic cause is negligible, 

 and we assume that the indications of our piezometer are com- 

 parable with those obtained in deep ocean waters. In a future 

 communication I hope to return to this point. 



TABLE I. Comparison of Manometer No. 2 at 12-5 C. 

 with Piezometer K, No. 4, in Ice melting under Pressure. 



In Table I we have in the first column the number of 

 observations at each approximately identical pressure from 

 which the average values of the manometer reading under A, 



