304 MB. JOHN LEIGH ON THE 



I append an analysis made, after the manner described above, 

 of gas from a cannel much used at the Manchester gas- 

 works. 



100 volumes of Ince Hall (Wigan) cannel gas required 

 for complete combustion 146'5 volumes of oxygen; 100 vo- 

 lumes of the same gas, being treated veith anhydrous sul- 

 phuric acid, lost 8*5 parts, consisting of olefiant and other 

 illuminating gases. 



The residual gas required 104 volumes of oxygen for 

 complete combustion. So that the 8*5 parts which had 

 been removed by the sulphuric acid, had required 42*5 parts 

 of oxygen for combustion. This gives the number 5 as the 

 expression in volumes of oxygen of each volume of the gas 

 removed by sulphuric acid ; and to these 8*5 parts are due 

 the chief portion of the illuminating power of the coal gas. 



This also proves what I before referred to, that the illumi- 

 nating gas in coal gas does not consist of olefiant alone, as 

 each volume of this gas requires only 3 volumes of oxygen 

 for combustion ; it is a mixture of olefiant gas with what I 

 would call trito and tetarto-carburetted hydrogen. It is 

 evident that, with so large a multiple as 5 for each volume 

 of illuminating gases, even small differences of the latter in 

 any sample of gas can be correctly indicated and expressed. 



Below is the composition of the particular sample of gas 

 taken in illustration. 



Ince Haix (Wigam) Caioiei. Gas. ^ 



Carbonic Acid 0*78 



Olefiant Gas and Illuminating Hydro-carbons) 



> 8*60 

 represented by 42'5 vols, of Oxygen > 



Atmospheric Air 432 



Nitrogen 0*19 



Hydrogen 41*00 



light Carburetted Hydrogen S3-83 



Carbonic Oxide 1135 



99-97 



