502 



PROCEEDINGS OF THE AMERICAN ACADEMY. 



The values of ^H and AjE!, computed from these data, are given in 

 Table XXI. and Figure 22. II absorbs heat on passing to V and ab- 

 sorbs work. The internal energy of V is greater, therefore, than that 



of II. 



TABLE XXI. 



Latent Heat, etc., on the Equilibrixjm Cuhve, Ice II-Ice V. 



The Curve V-L. 



V was the second variety of ice found in this present work, the first 

 being that stable at higher pressures, namely VI. It seems worth while 



to give here a short account 

 of the actual order of the 

 experiments, as it illus- 

 trates well the capricious 

 character of these reactions. 

 Ice V was first found at 

 —S°. An experiment was 

 being run on the change of 

 volume of ice VI when pass- 

 ing to water. Pressure 

 was being decreased ; it 

 had passed over the equi- 

 librium pressure and a 

 sufficient interval of time 

 had elapsed to allow the 

 Figure 22. The latent heat and the change pressure to automatically 

 of internal energy when II passes to V. restore itself to the equi- 



librium value. The change 

 to V occurred without warning. By good fortune, a reading at the 

 bridge was being made at the particular instant, so that the entire 



-35" 



-33° -3l' -£3 -27 

 TEMPERATURE 



-25" 



