carried on in Sheffield. Heath came over to this country, and obtained a patent, bearing date the l5th of April, 1839, for the employment of carburet of manganese (that is, manganese in the metallic state) in the manufacture of cast steel: an invention of very great utility, as by its use cast steel of excellent quality could be produced from British iron that had been smelted with mineral fuel. Such steel possessed the property of welding either to itself or to malleable iron. The Sheffield cutlers were thus enabled to weld iron tangs on to the cast-steel blades of table-knives, and also to weld many other similar articles: a process which was not successfully carried on previous to the use of metallic, or carburet of, manganese under Heath's patent.

Mr. Heath, in his specification, does not confine his claim to the use of carburet of manganese in crucible steel melting, but distinctly claims "the use of carburet of manganese in any process whereby iron is converted into cast steel." All that Heath claimed lapsed and became public property when his patent expired, and the right to use carburet of manganese "in any process whereby iron is converted into cast steel" became common property by this publication, even if the patent were invalid. Heath was fully justified in making this general claim, because the results obtained depended on an inevitable chemical law, viz.: whenever metallic manganese, with its powerful affinity for oxygen, is put into molten iron containing disseminated or occluded oxygen, a union of the oxygen and the manganese follows as an inevitable consequence of their strong affinity for each other, wholly irrespective of the process employed in the manufacture of the iron or steel so treated.

In consequence of this successful invention of Heath's, no British iron that has been smelted with mineral fuel is ever made into cast steel in Sheffield without the employment of carburet of manganese. In the early days of Heath's invention, he supplied the carburet in small packages to his licensees; he made this by the deoxydation of black oxide of manganese mixed with coal-tar, or other carbonaceous matter, in crucibles heated in an ordinary air furnace. This was a costly process, and as the demand increased he suggested to his licensees that it would be cheaper to put a given quantity of oxide of manganese and charcoal powder into their crucibles, along with the cold pieces of bar iron or steel to be melted. These materials would, when sufficiently heated, chemically react on each other, and produce the requisite quantity of carburet of manganese in readiness to unite with the steel as soon as the latter passed into the fluid state. But Heath's licensees said, "This is not precisely your patent, Mr. Heath," and they claimed the right to carry out this suggestion without paying him any royalty. This was the cause of some eight or nine years of litigation, by which poor Heath was ultimately ruined, although his patent was established by a final decision of the House of Lords -- alas! only too late; for Heath died a broken-hearted, ruined man, wholly unrewarded for his valuable invention.

Thus we see that both in the use of a carburet, and also by the use a mixed powder, consisting of oxide of manganese and carbon, Heath's process has been successfully and commercially carried on from the date of his patent, in 1839, up to the present hour.

Now, as my converting process was specially intended to deal with iron that had been smelted with mineral fuel, it will be readily understood how disastrous it would have been to me, if, by the action of another patentee, I had been prevented from using manganese; for if manganese, in some form or other, were absolutely necessary for the production of steel of good quality from iron smelted with mineral fuel, it would follow that if the use of manganese, in all its known forms and combinations when applied to the Bessemer process, could be patented, thus becoming the exclusive property of some other persons, then I should have been rendered utterly powerless, and my invention could not have been worked without the permission of the holders of these patents, and I should consequently have been wholly at their mercy.

This part of my narrative turns upon a patent obtained by Mr. Joseph Gilbert Martien, on September 15th, 1855, about a month before I took out my first steel patents. Mr. Martien's invention referred to improvements in the manufacture of iron and steel. He was at that time engaged at the Ebbw Vale Works, either on the staff of that company or as an independent experimentefacture of steel at my Sheffield works, this difficulty about mild steel plates was strongly felt when using British coke-made iron. I attained