AN IMPROVED METHOD FOR DETERMINING SPECIFIC 

 HEATS OF LIQUIDS, WITH DATA CONCERNING DILUTE 

 HYDROCHLORIC, HYDROBROMIC, HYDRIODIC, NI- 

 TRIC AND PERCHLORIC ACIDS AND LITHIUM, 

 SODIUM AND POTASSIUM HYDROXIDES. 



By Theodore W. Richards and A. W. Rowe. 

 Received, May 20, 1913. 



In a previous communication ^ the authors described a new and 

 accurate method for the determination of the specific heats of liquids, 

 based upon the adiabatic procedure originally outlined by one of us.^ 

 Any method for this purpose demands an exact quantitative source 

 of heat; and in the present case the device employed was the libera- 

 tion in parallel experiments of known amounts of heat by the neutrali- 

 zation of an acid with a base. The neutralization was carried out in 

 the center of a calorimetric system consisting primarily either of water 

 or of the liquid under observation. By observing the relative tempera- 

 ture rise in the system when first water and subsequently the other 

 liquid filled the calorimeter, (or better, by so arranging the parallel 

 experiments as to secure uniform temperature changes in the two 

 cases, comparing the relative weight of liquid used with that of the 

 original amount of water) a direct determination of the relative heat 

 capacities of the two systems was rendered possible. The chief ad- 

 vantage of such methods involving the comparison of one set of data 

 with another is that possible errors of direct determination appear in 

 all experiments and are thus eliminated by cancellation. 



As originally outlined, the method had one distinct objection, 

 namely, the alkali was at first contained in a reservoir outside the 

 calorimetric system and at a temperature usually somewhat dift'erent 

 from the latter. Although the difi^erence was carefully deterpiined 

 and a suitable correction applied for the heat thus abstracted from or 



1 Richards and Rowe, Proc. Am. Acad., 43, 475 (1908); Zeit. phys. Chem. 

 64, 187 (1908). 



2 Richards, Henderson and Forbes, Proc. Am. Acad., 41, 3 (1905). 



