Robert Mushet
Robert (Forester) Mushet (1811-1891), born in the Forest of Dean, Gloucestershire, of a Scots father (David, 1772-1847) himself a noted contributor to the metallurgy of iron and steel, is, like the American William Kelly, considered by many to have been a victim of Bessemer's astuteness—or villainy. Because of Robert Mushet's preference for the quiet of Coleford, many important facts about his career are lacking; but even if his physical life was that of a recluse, his frequent and verbose contributions to the correspondence columns of the technical press made him well-known to the iron trade. It is from these letters that he must be judged.
In view of his propensity to intervene pontifically in every discussion concerning the manufacture of iron and steel, it is somewhat surprising that he refrained from comment on Bessemer's British Association address of August 1856 for more than fourteen months. The debate was opened over the signature of his brother David who shared the family facility with the pen.[22 ] Recognizing Bessemer's invention as a "congruous appendage to [the] now highly developed powers of the blast furnace" which he describes as "too convenient, too powerful and too capable of further development to be superseded by any retrograde process," David Mushet greeted Bessemer's discovery as "one of the greatest operations ever devised in metallurgy."[23 ] A month later, however, David Mushet had so modified his opinion of Bessemer as to come to the conclusion that the latter "must indeed be classed with the most unfortunate inventors." He gave as his reason for this turnabout his discovery that Joseph Martien had demonstrated his process of "purifying" metal successfully and had indeed been granted a provisional patent a month before Bessemer. The sharp practice of Martien's patent lawyer, Mushet claimed, had deprived him of an opportunity of proving priority of invention against Bessemer. Mushet was convinced that Martien's was the first in the field.[24 ]
Robert Mushet's campaign on behalf of his own claims to have made the Bessemer process effective was introduced in October 1857, two years after the beginning of Bessemer's experiment and after one year of silence on Bessemer's part. Writing as "Sideros"[25 ] he gave credit to Martien for "the great discovery that pig-iron can, whilst in the fluid state, be purified ... by forcing currents of air under it ...," though Martien had failed to observe the use of temperature by the "deflation of the iron itself"; and for discovering that—
when the carbon has been all, or nearly all, dissipated, the temperature increases to an almost inconceivable extent, so that the mass, when containing only as much carbon as is requisite to constitute with it cast steel ... still retains a perfect degree of fluidity.
This, says "Sideros," was no new observation; "it had been before the metallurgical world, both practical and scientific, for centuries," but Bessemer was the first to show that this generation of heat could be attained by blowing cold air through the melted iron. Mushet goes on to show, however, that the steel thus produced by Bessemer was not commercially valuable because the sulphur and phosphorous remained, and the dispersion of oxide of iron through the mass "imported to it the inveterate hot-short quality which no subsequent operation could expel." "Sideros" concludes that Bessemer's discovery was "at least for a time" now shelved and arrested in its progress; and it had been left "to an individual of the name of Mushet" to show that if "fluid metallic manganese" were combined with the fluid Bessemer iron, the portion of manganese thus alloyed would unite with the oxygen of the oxide and pass off as slag, removing the hot-short quality of the iron. Robert Mushet had demonstrated his product to "Sideros" and had patented his discovery, though "not one print, literary or scientific, had condescended to notice it."
"Sideros" viewed Mushet's discovery as a "spark amongst dry faggots that will one day light up a blaze which will astonish the world when the unfortunate inventor can no longer reap the fruits of his life-long toil and unflinching perseverance." In an ensuing letter he[26 ] summed up the situation as he saw it:
Nothing that Mr. Mushet can hereafter invent can entitle him to the merit of Mr. Bessemer's great discovery ... and ... nothing that Mr. Bessemer may hereafter patent can deprive Mr. Robert Mushet of having been the first to remove the obstacles to the success of Mr. Bessemer's process.
Bessemer still did not intervene in the newspaper discussion; nor had he had any serious supporters, at least in the early stage.[27 ]