434 On the Benefits that may he expected 



amounted to 85 bushels. The strata of coal necessary for 

 the production of this quantity of lime require to be four 

 inches thick, and the time absolutely necessary for the prob- 

 ers* of calcination was, as stated already, *>0 hours. On 

 applying coke instead of coal, (which coke I obtained from 

 the same kind of coal,) the produce of lime may be increased 

 to nearly 30 per cent, from the same furnace, and the time 

 required to etTect the calcination of this quantity of lime- 

 stone is reduced to 39 hours : it also requires less attendance 

 and less labour, and the whole saving thus accomplished 

 amounts to more than 50 per cent, on the lime-kiln. 

 I have lately also employed coke for the burning of bricks. 

 My bricks are burnt in clamps made of bricks themselves. 

 The place for the fuel, or fire-place, is perpendicular, about 

 three feet high. The flues are formed by gathering or arch- 

 ing the bricks over, so as to leave a space between each of 

 a brick's breadth; and as the whole of the coal, if this fuel 

 be employed, must, on account of the construction of the 

 pile, be put in at once, the charge of the bricks is not, and 

 never can be, burnt properly throughout; and the inter- 

 ference of the legislature with regard to the measurement of 

 the clamp is a sufficient inducement for the manufacturer, 

 to allow no more place for coal than he can possibly spare: — . 

 the reason is obvious. If coke be applied instead of coal, 

 the arches or empty spaces in the clamp or pile, as well as 

 the strata of the fuel, may be considerably smaller: the heat 

 produced in this case is more uniform and more intense, and 

 a saving of 32 per cent, at least is gained. In the baking of 

 my own plaster stone (the compact sulphate of lime of a 

 reddish tinge) I also employ coke. The calcination of this 

 stone for manure I perform in a common reverberatory 

 furnace, and the men who conduct the process (who are 

 otherwise averse to every thing new) are much pleased with 

 the steadiness of the fire, and little attendance which the, 

 process requires, when coke is used instead of coal. These 

 are the few facts I wish to state to you, with regard to the- 

 useful application of this species of fuel, which, no doubt, 

 hereafter will become an object of ceconomy of incalcu' 

 advantage to individuals,- if its nature be better understood 

 2 (tea 



