476 HENEY A. ROWLAND 



of 426-75 at 14 -6, my value at this point being 427-52. The difference 

 amounts to 1 in 550 only. Giving the observations equal weight, this 

 would have been 1 in 430 nearly. The quantity 426-75 is what I find 

 at 18 C. So that my result at this particular temperature differs from 

 that of Joule only the amount that water changes in specific heat in 

 3-4C. 



Joule's value is less than my value to the amount given, but the value 

 from the properties of air, 430-7 at 14 C. is greater, although the 

 method can have little weight. 



It might be well to diminish my values by 1 part in 1000 so as to make 

 them represent the mean of Joule's and my own experiments. It is 

 seen that the experiment by the method of electric heating agrees very 

 exactly with the other experiments, because I have reduced it to my value 

 of the ohm. Hence I regard it as a very excellent confirmation of my 

 value of that unit. 

 Baltimore, February 16, 1880. 



