RICHARDS. — SOURCE OF CHEMICAL HEAT. 



405 



These questions cannot be answered at present. The total amount of 

 work done in any case cannot be computed without a knowledge of the 

 compressibility of the substances involved throughout the total range of 

 volume, as has already been said. Unfortunately no suitable data exist 



10 



20 



300 

 30 



400 500 600 700 800 kilo joules. 

 40 50 60 cubic centimeters. 



2NaBr 

 2KBr 

 CaBro 

 ZnBro 

 SrBrg 

 CdBro 

 BaBro 



2C1K 



2BrK 



2IK 



capable of satisfying the conditions of the problem. Before long I hope 

 to present such data, and to formulate answers to both questions ; for 

 the present the following unsatisfactory approximation is suggested as 

 being better than nothing. 



From the study of many allied data I have been able to form an ap- 

 proximate evaluation of the compressibilities of sodium and chlorine. 



