R. Bunsen — Calorimetric Investigations. 



will only mention here that the latent heat of melti 

 results already, with an accuracy which leaves n 



corresponds to — ^ grams of melted ice. The constant W„, 

 determined from equation (8), gives the number of scale divi- 

 sions which correspond to one of the units of heat defined in 

 the beginning of this treatise. One scale division of the colori- 

 meter corresponds therefore to ^units of heat. If I denotes 



the latent heat of melting for water, then will y^ give the 

 weight of ice, expressed 

 scale division. There 



^^WJ^v ^''' according to equation (2), /= ^-^. 

 If the above found values 



^5=0-00085257 W„=14-660 W„=M-654 



be substituted in the equation, there is obtained for the latent 

 heat of melting of water 1 : 80-01 



80-04 

 In the mean, 80-025 



The value found by other observers by the method of mix- 

 ture is, according to Regnault, 79-4; Person, 80-0; Hess, 80-3. 



The heat of combustion of gases may be determined by 

 means of the ice calorimeter with far greater accuracy than has 

 been possible with any of the methods previously at our dispo- 

 sal. From the heat of combustion of hydrogen it follows with 

 the aid of equation (4), that 10 cubic centimeters of this gas at 

 C. and 0'76 mercury pressure, would produce by their com- 

 bustion with oxygen an oscillation of 453 scale divisions on the 

 instrument employed in the experiments just described. It is 

 therefore sufficient to burn a very small quantity of gas, and 

 therefore one easily to be prepared in a state of purity, m the 

 calorimeter, and to observ-e the oscillation on the scale thereby 

 produced, in order to obtain directly the heat of combustion, 

 expressed in units of heat, without any of the corrections, m 

 part very uncertain, which were previously unavoidabla 



