136 CALORIFIC POWER OF FUELS. 



feet per pound) is used, corresponding to a maximum of 14 

 per cent of carbonic acid in the waste gases, the loss in hydro- 

 gen is very small. With 12 per cent of carbonic acid the 

 hydrogen loss amounts to only a few thousandths. 



CALCULATION OF THE VOLUME FROM ANALYSIS. 



To calculate this volume, determine the weight of carbon 

 in a unit of volume, and knowing the weight of carbon fur- 

 nished by the coal, determine the volume corresponding to 

 the unit of weight. The unit of volume for the gas is the 

 cubic metre, and the unit of weight, the kilogram. 



Carbon exists in the waste gases as carbonic acid, carbonic 

 oxide, and hydrocarbons; when we do not know the compo- 

 sition of the hydrocarbons, we consider the carbon and hydro- 

 gen as free, and that the carbon is in the state of vapor. 



To determine the weight of carbon contained in these 

 different gases, reduce their volumes to kilograms, and by 

 means of their molecular (or equivalent) weights and that of 

 carbon make the calculation. 



i litre of CO 2 at o and 760 mm. weighs 1.966 grams. 

 i " " CO " " " " " " 1.251 

 I " " C vapor " " " 1.072 



Molecular weight of carbon ............... 12 



1 1 1 1 r*c\ 



^^a ................. 44 



" " CO .................. 28 



The weight of a volume v of carbonic acid is v X 1.966, 

 and as 44 of carbonic acid contain 12 of carbon, then the 

 weight of carbon would be as 44 : 12 or as 11:3. Then 



v X 1.966 X 3 

 - 2 - = 0.5362;. 

 3<5 



