340 DICKINSON AND OSBORNE: SPECIFIC HEAT OF ICE 



to 0?050C., the specific heat, S, in 20° calories at any temperature 

 6, of the four ice samples is represented within the limit of experi- 

 mental error by the equation: 



S = 0.5057 + 0.001863 9 - 79.75 - 



in which the constant I is assumed to represent the initial freez- 

 ing point of the specimen and has the following values: 



Sample I 



1 . 00125 



2 .00120 



3 0.00095 



4 0.00005 



From the fact that the term which represents the departure 

 of the specific heat from a linear function of the temperature 

 is found to depend on the purity, being less the purer the ice, it 

 is concluded that the specific heat of pure ice in 20° calories may 

 be closely represented by the equation: 



S = 0.5057 + 0.001863 d 



Determinations of the heat of fusion made upon three of the 

 samples used for the specific heat determinations gave the fol- 

 owing values: 



Sample Heat of Fusion 



No. Calzo/g 



1 79 . 68 



2 79.85 



4 79.75 



Mean 79 . 76 



The results of a previous investigation at the Bureau of Stand- 

 ards, using very different methods to determine the heat of fusion 

 of ice, give when corrected for the newly found value for specific 

 heat a mean value of 79.74 20° calories per gram. The mean 

 for the two investigations is: 79.75 20° calories per gram. For 

 the use of engineers a table of total heats of ice and water is 

 given expressed in B.t.u. per pounds at temperature from— 20°F. 

 to +100°F. 



