RICHARDS AND ROWE. — THE SPECIFIC HEATS OF LIQUIDS. 483 



fully duplicated in the jacket and cover. At the end of some nine 

 minutes the final equilibrium was attained, the thermometer readings 

 becoming constant, at a temperature about four degrees above the 

 initial temperature. 



The calculation was exceedingly simple except for two features, each 

 of which concerned the sodic hydroxide. The first of these was a 

 correction needed because the alkaline solution had not exactly the 

 temperature of the calorimeter at the moment of delivery. If warmer, 

 the alkali brought with it a slight excess of heat ; if cooler, it caused 

 a slight deficiency. This correction was easily calculated by multiply- 

 ing the water equivalent of the alkaline solution by the difference of 

 temperature. When the alkali was too warm, this small product was 

 subtracted from the total ; when too cold, added. The other unusual 

 feature involved not the total amount of alkali, but only the excess of 

 this solution over and above the constant amount (19.30 grams) needed 

 to neutralize the acid. It was intended that the alkaline solution 

 should be of such concentration as to evolve enough heat on dilution 

 to raise itself through the range of temperature of the experiment. If 

 this were the case, it would not be necessary to know very exactly the 

 amount of the alkali ; any excess would not aifect the final temper- 

 ature. The alkali was made up as nearly as was possible on the basis 

 of the previously known data to accomplish this result, and was nearly 

 enough so for the present purpose. Its concentration was 8.97 normal. 



The data and calculation of a specimen experiment may now be 

 given without further preamble. 



Specimen Experiment with Water in Calorimeter. 



No. 4, February 27, 1908. 



Data concerning temperature : 



Initial temperature of calorimeter 16.489° 



Final temperature of calorimeter 20.237° 



Rise of temperature during experiment . . . 3.748° 



Temperature of sodic hydroxide 16.44° 



Ditference between this and initial temperature 0.05° 



Data concerning heat capacity, exjyressed^ in terms of the water-equivalent: 



Water in calorimeter 474.97 grm. 



Calorimeter and fittings, equivalent to . 11.35 " 

 103.71 grm. of dilute acid (sp. ht. = 0.94) . 97.49 " 

 19.3 grm. alkaline solution needed to neu- 

 tralize acid (sp. ht. = 0.84) 16.21 " 



Total heat capacity 600.02 grm. 



