92 



CONTKIBDTIONS TO THE KNOWLEDGE 



jet of gas for the candle, as proposed by Mr. King and Mr. 

 Wright ; but yet the impossibility of accurately ascertaining 

 the consumption of the candle, at the moment when the gas- 

 jet is made equal to it, renders the experiments still liable to 

 small inaccuracies. The following results are all corrected 

 to those which would have been obtained by using a sperm 

 candle burning 120 grs. per hour; and one of these candles 

 burning 10 hours, is taken as the standard with which to com- 

 pare the total quantity of light yielded by a given volume of 

 gas. Thus, when it is stated that the total quantity of gas 

 produced from 1 cwt. of coal, when burnt at the rate of 5 feet 

 per hour, is equal to 546 candles, it is intended that the 

 light afforded by the gas is equal to that yielded by 546 

 sperm candles, each burning 10 hours, and at the rate of 

 120 grs. per hour. 



The following are the results of the experiments : — 



WIGAN CANNEL, (INCE HALL.) 



I.— WITHOUT WATER GAS. 



Cannel used 1 cwt. 



Gas prodaced 545 cubic feet. 



Coke left 74 lbs. 



Time occupied 3h. 20m. 



ILLUMINATING POWER OF GAS. 



Total gas produced when burnt at 5 feet per hour, yields 

 light = 240*8 sperm candles. 



