118 



CONTRIBUTIONS TO THE KNOWLEDGE 



diminishes that of light carburetted hydrogen, thus decreasing 

 the vitiating effect upon the atmosphere and the oppressive 

 heat of the apartments in which the gas is consumed. 



6. In addition to these positive advantages, the use of this 

 process does not incur any additional expense in the working 

 of the apparatus, or the wear and tear of retorts ; it involves 

 no alterations in the construction of furnaces and apparatus 

 at present employed in gas manufactories conducted on the 

 old system. 



TABLE SHEWING THE QUANTITY OF COAL OR CANNEL RE- 

 QUISITE FOR PRODUCING LIGHT EQUAL TO 1000 SPERM 

 CANDLES, EACH BURNING 10 HOURS, AT THE RATE OF 120 

 GRS. PER HOUR. 



Name of CoaL 



Wigan cannel (Ince Hall) 

 Wigan cannel (Balcarres) 



Boghead cannel 



Lesmahago cannel 



Newcastle cannel . . 



Newcastle coal (Pelton) 

 Methyl cannel 



