Iron . 
10? 
■ 
coals will be easily procured from one acre of measure-, 
j ment where the stratum measures four and a half to five 
feet thick. An observation strikes us forcibly here, that, 
great as the consumption of wood is, a sufficient extent 
of country can from time to time replace any given quaiv 
jj tity. No facts, however, which have hitherto come un- 
der our observation^ warrant us to suppose the re-forma- 
jj tion of pit-coah 
In preparing pit-coal for the blast furnace, well under* 
stood among manufacturers by the term eoaking , flat sur- 
faces are appropriated. These are firmly beat and pud- 
dled over with clay, so as to pass the necessary cartage 
! without furrowing or loosening the earth. These spaces 
form squares, more or less oblong, and are called hearths ; 
upon which the pieces of coal are regularly placed in c lin- 
ing to each other. Great care is taken to place each piece 
i upon the ground layer on its acutest angle, in order that 
I the least surface possible may come in contact with the 
j ground. By this means, large interstices are preserved 
for the admission and regular communication of the air 
necessary to excite and effect complete ignition. 
The quantity of coaks charred in one heap or hearth, is 
various at different, and even at the same works. Forty 
tons of coals is amongst the smallest fires, and some 
hearths again will admit of 80 or 100 tons. The length 
of the fire is in proportion to the quantity of coals built : 
the breadths and heights are also subject to no determinate 
standard ; but are from 30 to 50 inches high, and from 9 
to 16 feet broad. In building each fire, they reserve a num- 
ber of vents reaching from top to bottom, into which the 
burning fuel is introduced. This is immediately covered 
by small pieces of coal beat hard into the aperture : these 
repress the kindling fire from ascending, and oblige it to 
geek a passage by creeping along the bottom, which is 
