484 



PROCEEDINGS OF THE AMERICAN ACADEMY. 



Total heat observed =^ &00m X Z.li8° .... 2248.87 cal. (18°) 

 Correction for heat needed to warm 20.9 



grm. alkaline solution through 0.05° . . +0.88 " 

 Total heat, corrected, from neutralization of 103.71 



grams acid 2249.75 cal. 



2249.75 

 Heat evolved from 100 grm. dilute acid ^ " '' — 2169.3 cal. 



This process was repeated until there seemed to be no doubt as to 

 the exact amount of heat evolved by the heat of neutralization of 

 exactly 100 grams of this particular dilute acid by a slight excess of this 

 particular alkaline solution under these perfectly definite conditions. 

 The data and results of a series follow. 



In the following table, Ti is the initial temperature of the system 

 and T^ — Ti is the observed rise. The other values are self-explanatory. 



Results with Water. 



The maximum variation from the mean here is only 8 parts in 22,000, 

 or about 0.02 per cent. As will be seen upon inspection, the correction 

 for the difference in temperature of the alkali is sometimes additive 

 and sometimes subtractive in the different experiments, hence the con- 

 cordance of the observed results in connection with these values is 

 excellent testimony as to the accuracy of the correction. 



The amount of heat evolved by the neutralization of 100 grams of 

 sulphuric acid under these conditions was now used as the standard 

 in warming various definite solutions through about the same range 

 of temperature. In order to accomplish this purpose, the solutions 



