Metallum Martis

Metallum Martis; or "Iron made with Pit-Coale, Sea-Coale, &c. And with the same Fuell to Melt and Fine Imperfect Mettals, And Refine perfect Mettals" by Dudd Dudley is the earliest known reference to the use of coal in metallurgical smelting.

Many attendant difficulties had to be overcome before this fuel could be applied to the purpose of smelting iron. Dudley does not describe in his book how he was using coal, only that he was and in so doing laid the foundation work for future discoveries.

It is most probable that in substituting coal for wood as a fuel, he would further subject the coal to a process not unlike that employed in charcoal-production. The result would be what is called Coke; and as Dudley informs us, he followed up his first experiment with a second blast, by means of which he was enabled to produce good marketable iron. His success was also in part due to an improvement of the blast process which he contrived for the purpose of keeping up the active combustion of the fuel.

A significant feature of his great work 'Metallum Martis' is a map showing Dudley Castle where he correctly identifies the order and geographic layout of strata of coal and ironstone under survey.

Considered to be the earliest of recorded geological maps, 'Metallum Martis' marks a turning point in the evolution of scientific rationale concering the recording and interpretation of geological information. It is considered to have been made at Castle Hill in Dudley by Dud Dudley in 1665.