OP THE MANUFACTURE Of GAS. 



77 



SOin. barometrical pressure, consumes 2 cubic feet of oxygen 

 during its combustion, and generates 1 cubic foot of carbonic 

 acid, yielding a quantity of heat capable of heating 51bs. 14oz. 

 of water from 32^ to 212^, or causing a rise of temperature 

 from 60'^ to SO'S*^ in a room containing 2,500 cubic feet 

 of. air. 



1 cubic foot of carbonic oxide at the same temperature 

 and pressure, consumes during combustion i a cubic foot of 

 oxygen, generates one cubic foot of carbonic acid, and affords 

 heat capable of raising the temperature of lib. 14oz. of 

 water from 32° to 212'', or that of 2,500 cubic feet of air 

 from 60° to 66'6°. 



1 cubic foot of hydrogen at the same temperature and 

 pressure consumes i a cubic foot of oxygen, generates no 

 carbonic acid, and yields heat capable of raising the tempera- 

 ture of lib. 13oz. of water from 32° to 212°, or that of 2,500 

 cubic feet of air from 60° to 66'4°. 



This comparison shows that light carburetted hydrogen is 

 very objectionable as a diluent, not only on account of the 

 carbonic acid which it generates, but also by reason of the 

 very large quantity of oxygen which it consumes, and the 

 very great amount of heat which, in relation to its volume, 

 it evolves on combustion, the consumption of oxygen being 

 four times and the absolute thermal effect more than three 

 times as great as that of either of the other gases. 



The quantity of heat evolved by the combustion of equal 

 volumes of carbonic oxide and hydrogen, is nearly, and the 

 amount of oxygen consumed quite the same, but the carbonic 

 acid evolved from the first gives a decided preference to 

 hydrogen as the best diluent. 



The same comparison also shows that when the gas is to be 

 used for heating purposes, and the products of combustion 

 are carried away, light carburetted hydrogen is by far the 

 best diluent. 



The experiments of Dulong on the absolute thermal effect 



