In the first process of fusing the ironstone, coal had been used for some time with increasing success; but the question arose, whether coal might not also be used with effect in the second or refining stage.

Two of the foremen, named Cranege, suggested to Mr.
Reynolds that this might be performed in what is called a reverberatory furnace,[7] in which the iron should not mix with the coal, but be heated solely by the flame.

Mr.Reynolds greatly doubted the feasibility of the operation, but he authorized the Cranege, to make an experiment of their process, the result of which will be found described in the following extract of a letter from Mr.Reynolds to Mr.
Thomas Goldney of Bristol, dated "Coalbrookdale, 25th April, 1766":-- ....

"I come now to what I think a matter of very great consequence.
It is some time since Thos.

Cranege, who works at Bridgenorth Forge, and his brother George, of the Dale, spoke to me about a notion they had conceived of making bar iron without wood charcoal.