CONTRIBUTIONS FROM THE CHEMICAL LABORATORY 

 OF HARVARD COLLEGE. 



A NEW METHOD FOR THE DETERMINATION OF THE 

 SPECIFIC HEATS OF LIQUIDS. 



By T. W. Richards and A. W. Rowe. 



Presented May 13, 1908. Received April 29, 1908. 



During the course of an extended research upon heats of neutral- 

 ization now in progress, it became necessary to devise some method for 

 the accurate determination of the specific heats of the reacting solu- 

 tions. Obviously an accurate value for any thermochemical measure- 

 ment can only be obtained when the factors involved in the calculation 

 are accurately ascertained ; and it is well known that the existing data 

 on this subject are by no means satisfactory. The recognized sources 

 of error of the majority of the earlier methods and the discrepancies 

 observed in the values obtained by the different experimenters using 

 them ^ limit any dependence which can be placed in the constants 

 thus obtained. Further, the truth of the assumptions upon which 

 the corrections for their errors are based is by no means adequately 

 proved. To obviate the necessity of these corrections, and thus elim- 

 inate the uncertainty attending their use, a new method has been 

 devised. A brief discussion of the earlier forms of apparatus may 

 assist in a better understanding of the difficulties encountered in devis- 

 ing this method and the means by which they were surmounted. 



Of the various methods recorded, that of Andrews ^ has been, perhaps, 

 the most frequently used. This depended upon the transference of a 

 heated object or " calorifer " from a source of heat to the calorimeter, 

 \Vhich contained either water or the liquid to be studied. A compar- 



^ The following is a typical example : 



Specific Heat of NaOH 

 'fg Sp. Ht. Observer. 



49.5 0.816 Hammerl. 



25.6 869 Hammerl. 

 229 0.847 Thomsen. 



2 Pogg. Ann., 75, 335 (1848). 



