HOLMAN. — CALORIMETRY. 245 



Investigations on Light and Heat made and pubushed whollt or in part with 

 Appropriation from the Romford Fund. 



XIII. 



CONTRIBUTIONS FROM THE PHYSICAL LABORATORY OF 

 THE MASSACHUSETTS INSTITUTE OF TECHNOLOGY. 



XLVII. — CALORIMETRY : METHODS OF COOLING 

 CORRECTION. 



' By Silas W. Holmax. 



Presented November 13, 1895. 



The following general method of treating the cooling correction is 

 applicable to nearly all non-continuous calorimetric processes, such as 

 the measurement of specific heats by the '' method of mixture," of heat 

 of combustion by the Berthelot or Mahler bomb, etc. It is reliable in 

 ordinary practice within the limits of error imposed by the thermom- 

 etry and by irregularity of conditions as to surroundings. 



Following the brief statement of the " General Method " is that of 

 a " special case " of that method, and of a " Modified Method." These 

 are supplemented by a demonstration of the "Theory of the Methods," 

 and a " Critique." 



The procedure in the modified method is supposed to be new. Be- 

 yond that fact this paper claims the attention merely of those who 

 desire a concise working statement of a method of cooling correction 

 which has stood the test of practice. 



General Method. 



Procedure. — Start with the water of the calorimeter at any con- 

 venient temperature, e. g. about that of the air. If there is a water 

 jacket around the calorimeter, let that be stirred thoroughly once for 

 all, or, better, continuously. Record its temperature at the beginning 

 and end of the measurements as a possibly useful check. 



Let the water of the calorimeter be stirred thoroughly, continu- 

 ously, and at a uniform rate. Record times and temperatures of the 



