At the same time several English ironmasters were individually making use of the hot blast while refusing to take out licenses. The first action brought by the owners of the patent after the formation of the Scottish association was a test one, Neilson v. Harford, tried in the Court of Exchequer in May and June 1841. The most plausible of the pleas urged by the defendants was a vagueness in that part of the specification which described the air-vessel or receptacle in which the blast was to be heated before entering the furnace. The ‘form or shape’ was said to be ‘immaterial to the effect.’ The presiding judge considered that the specification should have here been more explicit, and on this issue entered judgment for the defendants, although the jury had pronounced a verdict generally favourable to the validity of the patent. The full court, however, decided in favour of the plaintiffs, and the lord chancellor granted an injunction against the defendants. With this terminated the contest between the patentees and English ironmasters. It was renewed in Scotland in April 1842, when a Scottish jury gave a verdict against the Household Coal Company, mulcting them in 3,000l. damages for having infringed the patent. Nevertheless in May 1843 the validity of the patent was again tried in the court of session, on a scale which made the action Neilson v. Baird a cause célèbre. The defendants were the Bairds of Gartsherrie, who, after taking out a license for the use of the blast, continued to use it while ceasing to pay for it. The trial in Edinburgh lasted nine days, more than one hundred witnesses were examined, and the costs of the action were computed to have amounted to 40,000l. at least. It was admitted, on the part of the defendants, that during ten years they made 260,000l. net profit on hot-blast iron. The lord president summed up strongly in favour of the plaintiffs, and the jury gave a verdict against the defendants. The plaintiffs claimed 20,000l.; the jury granted them 11,876l. This was the last lawsuit in which the validity of the patent was tried. In a memoir of Neilson, which claims to be authoritative (Chambers), he is described as discouraged and broken down at the time when he received news of a ‘final decision of the House of Lords’ in his favour. There is no record in the Law Reports of any such decision. The last reference in them to proceedings in the House of Lords belongs to February 1843, when that house affirmed one clause in a bill of exceptions tendered, on the part of the Household Coal Company, to the summing-up of the Scottish judge who presided at the trial already mentioned. This decision of the House of Lords was unfavourable rather than favourable to Neilson, and might have led to a new trial, which was actually talked of but did not take place. The Scottish patent had expired in September, and the English patent in October 1842.
Resigning, in easy circumstances, the managership of the Glasgow gasworks, Neilson retired in 1847 to a property in the Isle of Bute, belonging to the Marquis of Bute, whose friendship he enjoyed. In 1851 he removed to an estate which he had purchased in the Stewartry of Kircudbright, where he was active in promoting local improvements, and founded an institution similar to that which he had established for the workmen of the Glasgow gasworks. Among the honours conferred on him was his election in 1846 to fellowship of the Royal Society. In 1859, in the course of a discussion on Mr. H. Martin's paper on ‘Hot Ovens for Iron Furnaces,’ read at Birmingham before the Institution of Mechanical Engineers, Neilson gave an interesting account of the steps by which he had arrived at his invention. Neilson was a man of strict integrity and of somewhat puritanical rigour. At the disruption he left the established church of Scotland, and joined the free church. He died 18 Jan. 1865 at Queenshill, Kirkcudbrightshire.
[The chief account of Neilson is in Smiles's Industrial Biography, chap. ix. This is supplemented by the memoir in Chambers's Biographical Dictionary of Eminent Scotsmen, which is said to be based on information supplied by Neilson's son. See also Proc. Institution of Civil Engineers, xxx. 451. There is an excellent account of the hot blast and its history in the volume on Iron and Steel in Percy's Metallurgy. In the article Iron in the ninth edition of the Encyclopædia Britannica, p. 317, the respective merits of the hot and cold blasts are succinctly stated. A full report of the trial Neilson v. Harford was published in 1841, and of Neilson v. Baird in 1843. There is a copy of the former, but not of the latter, in the library of the British Museum. The library of the Patent Office contains copies of both. Adequate notices of the various lawsuits in which Neilson and his partners were involved are given in Webster's Patent Cases, in Clark and Finnelly's Reports of Cases decided in the House of Lords, and in the Reports of Cases decided in the Court of Session, sub annis.]
NEILSON, JOHN (1778–1839), benefactor of Paisley, born in Paisley on 14 Dec. 1778, was the younger son of John Neilson, grocer in Paisley, and Elizabeth Sclatter, his wife. John entered his father's business, and before 1812 became, with his elder brother James, a partner in the firm, which was