188 



PROCEEDINGS OF THE AMERICAN ACADEMY. 



intervals. The complete neutralization within the platinum bottle was 

 abundantly proved by the constancy of the readings of the thermom- 

 eter after six or eight minutes. 



This reaction within the platinum bottle furnished heat which 

 raised the outer liquid under investigation about four degrees in 

 temperature. Because the source of heat was completely surrounded 

 by the calorimetric liquid, which in turn was adequately stirred, 

 irregularity of heating effects during the mixing of the acid and alkali 

 could not be attended by any thermal loss. F'rom the curve showing 

 the rise of temperature with time (Figure 3), it is clear that 95 percent 



1 



10 



i 3 4 5 6 7 8 



■ Time in Minutes 



Figure 3. Temperatures in degrees and time in minutes are plotted as 

 ordinates and abscissae respectively. At the expiration of three minutes the 

 inner stirring was greatly increased by the raising and lowering of the inner- 

 most vessel. 



of the rise occurs during the first five minutes. This somewhat 

 rapid rise was easily paralleled in the outer vessel by adding acid so 

 that there was no difficulty in making the calorimetric operation 

 fully adiabatic. 



The total heat capacity of the apparatus was equivalent at first 

 to 12.24 grams of water, made up as follows: 252.22 grams of plati- 

 num constituting the calorimeter, stirrer, bottle, cap and suspension, 

 together with the small alkali container within the bottle, was assumed 

 to have the specific heat 0.0324, a value taken as the most probable 

 after comparing a large number of recent determinations. This 

 platinum contained a little iridium, but not enough to affect seriously 

 its specific heat. The 3.3 grams of rubber had a water equivalent 

 equal to 1.59.^ Later a heavier rubber stopper was used, increasing 



7 Haldane, Gee and Terry, Report, Brit. Ass., 59, 516 (1889). 



