The Londoners only began to reconcile themselves to the use of coal when the wood within reach of the metropolis had been nearly all burnt up, and no other fuel was to be had. Archaeologia Cambrensis, 3rd Series, No. 34, April, 1863. Art. "Sussex Ironmasters in Glamorganshire." DUDLEY's Metallum Martis, 1665.

But one of the most curious passages in Dudley's Metallum Martis, is the following picture of the Dudley coal-field: "Now let me show some reasons that induced me to undertake these inventions. At present, for more than ten miles round Dudley Castle, iron works of one kind or another are constantly at work; no remains of mighty woodland are to be found.

As for Dudley's Metallum Martis, as it contained no specification, it revealed no secret; and when its author died, his secret, whatever it might be, died with him. Other improvements were doubtless necessary before the invention could be turned to useful account. Thus, until a more powerful blowing-furnace had been contrived, the production of pit-coal iron must necessarily have been limited.

This patent was taken out at the instance of his son Dud Dudley, whose story we gather partly from his treatise entitled 'Metallum Martis, and partly from various petitions presented by him to the king, which are preserved in the State Paper Office, and it runs as follows: Dud Dudley was born in 1599, the natural son of Edward Lord Dudley of Dudley Castle in the county of Worcester.

A few years later, he seems to have succeeded in obtaining the means of prosecuting his original invention; for in his Metallum Martis, published in 1665, he describes himself as living at Green's Lodge, in Staffordshire; and he says that near it are four forges, Green's Forge, Swin Forge, Heath Forge, and Cradley Forge, where he practises his "perfect invention."

By his own account, given in Metallum Martis, while in Scotland in 1637, he visited the Highlands as well as the Lowlands, spending the whole summer of that year "in opening of mines and making of discoveries;" spending part of the time with Sir James Hope of Lead Hills, near where, he says, "he got gold."