iOO 
Iron . 
can be placed of the time when an acre of ground from 
which the wood has been cut, will replace its original 
quantity : nor of the average cubic feet of wood on an 
acre. Mushet, conjectures these at 2000 cubic feet and 
18 years ; but the kind of wood, and the climate, and 
the soil, will make so much difference, that there is no- 
thing like certainty. Pine in this country I imagine 
would replace itself in 16 years, chesnut in 12, oak in 20. 
Of Pit-coaL The first intimation of the use of pit-coal 
for smelting, that I know of, is in Pryce’s Mineralogy of 
Cornwall ; but Becher early in the reign of Charles the 
2nd proposed its use among the iron furnaces. The fob 
lowing brief history of its introduction is from Mushet, 7 
Phil. Mag. 37. 
The advantages which individuals derived from the 
manufacture of iron had induced many to engage in it. 
The business in point of extent seemed only limited to the 
supply of wood. New erections, for want of a proper 
supply of materials, became impracticable : those 
already engaged were more anxious to preserve their sup- 
ply, however much circumscribed, than to listen to inno- 
vation, which, by substituting pit- coal for the charcoal of 
wood, would give to the new establishing manufacturer a 
great superiority in the market. It was also highly pro- 
bable that many of the iron works then established were 
at a considerable distance from pit-coal, the universal in-? 
troduction of which would have proved fatal to their in- 
terests. Under such unfavourable circumstances, the dis- 
covery, or rather the practicability, of making pig-iron 
with pit- coal, we find announced by Simon Sturtevant, 
Esq. in the year 1612, who upon application, was favour-? 
edwith a patent from king James for the exclusive manu- 
facture of iron with pit- coal in all its branches for thirty- 
one years. In return, the said Simon Sturtevant bound 
himself to publish his discoveries, which afterwards ap- 
peared in quarto under the title of his Metallic^ 
