from the Nature of Coal Gas. 433 



than it is now. In reading the ingenious observations of 

 Mr. Accum * with regard to this subject, who states that 

 the effects of different kinds of fuel may be learnt from the 

 time required to heat a given quantity of water, &c, the 

 determining, from the quantity of fuel consumed, the ceco- 

 nomical application of different sorts of combustible matters, 

 to ascertain the cost of the one when compared with the 

 cost of the other, particularly arrested my attention with 

 regard to the ceconomicai application of coke, when com-, 

 pared with fuel of other kinds now in use. 



ft will not, I am persuaded, be regarded as indicating a 

 wish to detract in the smallest degree from the well-earned 

 credit due to the talents and skill of this chemist, so respect- 

 ably known to the screntific public, when I venture to state 

 that I am inclined to believe he has rather over-rated the 

 power of coke, in stating it as three to onef , unless his 

 coke be considerably better than mine obtained from Welsh 

 culm. My experiments in the rough way gave about two 

 to one, comparing it with coal weight for weight. I have 

 also no doubt that coke might be advantageously employed 

 in the smelting- houses. 14 pounds of brass can be fused in 

 a portable chemical furnace, by means of coke, in 48 mi? 

 nutes, which, with compact wood charcoal, I could not ac- 

 complish in less than 1 hour and a quarter. The difference 

 with regard "to price in this case is very remarkable. When 

 the coke made from Welsh culm is once completely ig- 

 nited, (which it readily is, if not de carburet ted too much,) 

 it throws out a very compact and steady heat, and yields 

 but a very slight sulphureous odour ; and this ceases when ft 

 is fully ignited. It lasts a longer time -in a state of ignition 

 than charcoal of wood in a quadruple proportion, and its 

 heat is constantly equal, and of almost the same intensity. 

 It also requires less trouble and attendance. 



Having slated above, (and as is indeed well known,) that 

 the brilliancy of the light produced during the combustion 

 of coal s,as is far superior to oil or caudles, and being; de- 

 sirous to know to what this preeminence was owing, I made 



* The Report, 5ic., page S4. + Ibid. 



£ e 3 a number 



