plea that this silver had been produced by a new method, it is self-evident that the claim could not here be substantiated. To admit it would have been simply to destroy all future great inventions; the whole idea is too absurd to require further argument.

On September 22nd, 1856, Mr. Mushet took out yet another patent, claiming the employment of one of nature's compounds: a compound which steel-makers have used for the production of steel as far back as the history of steel-making extends, and which consists of iron found in the mine associated, or combined, with manganese and oxygen. Such ore, when smelted, produces a pig iron which contains iron, carbon, manganese, silicon, and generally phosphorus, sulphur, and other matters in small quantities, in combination with the iron. In his third patent Mr. Mushet did not mention my name, or designate any patent of mine, as the invention which he proposed to improve by the use of spiegeleisen; and again the Crown and the public were told that, for the purposes of his invention, "the iron may be purified by the action of air in the manner invented by Joseph Gilbert Martien," as will be seen by the following quotation, reproduced from a printed copy of Mushet's specification, published by the Commissioners of Patents:-

The iron may be purified by the action of air, in the manner invented by Joseph Gilbert Martien, or in any other convenient manner. The triple compound or material which I prefer to use is pig or cast iron made from spathose ore, such ore and the pig or cast iron made from it containing a proportion of manganese, as well as the iron and carbon of which cast iron is usually composed.

If Mr. Mushet had taken the trouble to examine my early patents for the manufacture of steel, he would have found that the re-carburation of converted metal by the addition thereto of molten pig iron, was perfectly well understood, and had been patented by me more than a year prior to the date of either of his three manganese patents. Mr. Mushet also appears to have entirely overlooked my description of the several modes of making alloys in my process, as set forth in my patent, dated May 13th, 1856, sixteen weeks prior to the date of either of his three patents. This description was not given for the purpose of claiming any such alloys, but, on the contrary, its object was to disclaim the right to make alloys in my converter of any metals previously used in the trade to form an alloy with steel, and by such disclaimer and publication to prevent anyone from obstructing me in the free use of all such well- known alloys. In order to show what I really did say in my patent, I give a copy of the paragraph from my specification.

When employing fluid metal for alloying with malleable iron or steel, I pour it through an opening in the converting vessel, so that it may fall direct into the fluid mass below; but when employing metal in a solid form, I put it into the upper chamber through the door g, and allow it to acquire a high temperature, after which it may be pushed with a rod, through the opening d, into fluid iron or steel; and when using salts or oxides of metals for the purpose of producing an alloy or mixture with the iron or steel, I prefer to introduce such salts or oxides in the form of powder at the tuyéres, or to put them into the vessel previous to running in the fluid metal. I would observe, that I am aware that zinc, copper, silver, and other metals have before been combined with iron and steel otherwise manufactured, I therefore make no general claim thereto.

This paragraph clearly points out how such alloys are to be made, and I mention as examples, silver alloys, once used and greatly esteemed as "silver steel"; also alloys of zinc, patented as a detergent to carry off phosphorus from steel; I also mention copper as used in stereo metal for the manufacture of guns in Austria, and other metals heretofore used in steel-making. Surely, after I had thus published and disclaimed the use of any alloys previously used, no one could obtain a valid patent for alloying steel in my process with metals used to alloy steel then in common use.

The result of my early experiments in re-carburising confirmed the view I had taken from the first, viz., that it was best to stop the por the conversion of iron into cast steel."

William Vickers, A.D. 1839. "Manufacture of Cast Steel." Wrought-iron borings and scraps are melted with oxide of manganese and carbon in crucibles to produce cast steel.