228 W. G. Mixter — Heat of Comhustion of Hydrogen. 



which he exploded electrolytic gases in a Biinsen calorimeter. 

 His method is good but perhaps more liable to error because of 

 the small volume of gas taken, than the methods of Thomsen 

 and S. and W. The writer used the bomb method. 



The mean of the last four results in the table is 34023^ If 

 Thomsen's and S. and W.'s be weighted twice the last two, the 

 result is essentially the same, namely 34022°. It is highly 

 probable that this value is accurate in the third figure and that 

 the total error is not more than one tenth of one per cent. It 

 is the mean of closely agreeing results of different investigators 

 who used four different methods not subject to the same con- 

 stant error, excepting that of the specific heat of water at dif- 

 ferent temperatures, and this error is small. This value, 34020 

 calories, is the heat of combustion of one gram of hydrogen at 

 constant pressure with formation of liquid water at 0° and in 

 terms of the calorie at 20°. For a gram-molecule it is 





H=l. 



H=l-008. 



At 0° 



68040° 



68580° 



u 18° 



67900° 



68440° 



In conclusion the writer desires to express his indebtedness 

 to Professors Hastings and Bumstead for their valuable sugges- 

 tions and assistance. 



