^5 



University Studies. 



Vol. I. /^^y, 1890. No. 3. 



I. — On the Deterimnation of Specific Heat and of 



Latent Heat of Vaporization with the 



Vapor Calorimeter. 



By HAROLD N. ALLEN. 

 INTRODUCTION. 



JoLYji in 1886, and Bunsen,^ shortly afterwards, described 

 two similar pieces of apparatus intended to determine the 

 specific heat of substances by means of the condensation of 

 water vapor upon them. The name given by Bunsen to this 

 apparatus and adopted here is vapor calorimeter. Bunsen 

 also intended his instrument to be used in the determination 

 of the latent heat of vaporization of various liquids, and it 

 is the object of the present paper to describe experiments 

 testing the steam or vapor calorimeter in this direction. 

 A rough experimental instrument was first constructed, com- 

 bining to a certain extent the principles of Joly and of 

 Bunsen, and this proving fairly satisfactory, an apparatus 

 was made by a local tinman, which, while much less ex- 

 pensive than Joly's final form, worked in a very satisfactory 

 manner. 



A number of determinations of specific heat were made 

 with both instruments, to which however no further im- 



1 J. Joly (Dublin), Proc. Roy. Soc, Nov. 1886. 



- R. Bunsen, Wied. Ann. d. Chem. u. d. Phys., Band XXXL, 1887. 



University Studies, Vol. I., No. 3, July, iSgo. ^95 



