486 



PROCEEDINGS OF THE AMERICAN ACADEMY. 



Hence, specific heat of hydrochloric acid of concen- 



1784.0 



iration HCl 200.0 HoO 



488.35 X 3.724 



= 0.9809 



The experimental data for this series are found in the accompanying 

 table. Several experiments where the manipulation was faulty were 

 rejected, but if they had been included the average would have re- 

 mained essentially unchanged. 



The Specific Heat of HCl 200 HoO. 



As will be seen, the maximum variation from the mean is 0.03 

 per cent. This experimental error is as low as could possibly be 

 expected. 



Heat of Dilution. 



It is obvious that this apparatus can be applied to the accurate de- 

 termination of the heat of dilution of any solution put into the burette 

 (>^, if water instead of sulphuric acid is placed in the platinum flask 

 (A'). The liquid to be diluted is run into the bottle as before, and there 

 mixes with a weighed amount of pure water. A series of three experi- 

 ments on the dilution of a concentrated solution of sodic hydroxide is 

 given below. The results are calculated in kilojoules, as the best 

 standard for permanent record ; in the experiments previously recorded 

 this was unnecessary because the method was a comparative one and 

 the dimension of heat energy was eliminated in the result. 0.100 litre 

 of pure water was contained in the platinum bottle. 



22 The corresponding values obtained from the results of Thomsen (loc. cit.) 

 and Marignac (loc. cit.) are respectively 0.979 and 0.983. 



