298 PROCEEDINGS OF THE AMERICAN ACADEMY. 



The single set of observations, made July 30, at a temperature near 

 75° is hardly worth taking into account here, the uncertainty of observa- 

 tions at such a temperature being great, as we have seen. 



According to the evidence thus far we have, from the May and June 

 observations. 



As the change of A' with change of temperature appears to be small in 

 any case, it becomes important to consider the change of specific heat of 

 water with change of temperature ; for all values which precede are 

 given on the assumption that the specific heat of water is 1 at all tem- 

 peratures used. 



Winkelmann, in Part II. of Volume II., p. 340, gives a table of the 

 specific heats of water, which he has deduced from a formula proposed 

 by himself after a discussion of the results obtained by numerous experi- 

 menters. Til is table gives : — 



Revising, in accordance with this table, the values of K last given 

 above, we get, 



at 20°.9 K= 0.1494 



" 38°.9 « = 0.1485 



" 56°.2 " = 0.1453 (?) 



" 74°. 7 " = 0.1447 (?) 



" 27°.6 " = 0.1505 



" 56° .8 " =0.1458 



