# Dictionary of National Biography, 1885-1900/Neilson, James Beaumont

​NEILSON, JAMES BEAUMONT (1792–1865), inventor of the hot blast in the iron manufacture, was born on 22 June 1792 at Shettleston, a village near Glasgow. His father, Walter Neilson, originally a laborious and scantily paid millwright, became ultimately engine-wright at the Govan coal works, near Glasgow; his mother, whose maiden name was Marion Smith, was a woman of capacity and an excellent housewife. Neilson's education was of an elementary kind, and completed before he was fourteen. His first employment was to drive a condensing engine which his father had set up, and on leaving school he was for two years a ‘gig-boy’ on a winding-engine at the Govan colliery. Showing a turn for mechanics, he was then apprenticed to his elder brother John, an engineman at Oakbank, near Glasgow, who drove a small engine, and acted as his brother's fireman. Some attempts by the two brothers at field preaching came to an end through the opposition of his father, and John devoted his leisure to repairing the deficiencies of his early education. His apprenticeship finished, Neilson worked for a time as a journeyman to his brother, who rose to some eminence as an engineer, and who is said (Chambers) to have designed and constructed the first iron steamer that went to sea. At two-and-twenty Neilson was appointed, with a salary of from 70l. to 80l., engine-wright of a colliery at Irvine, in the working of which he made various improvements. A year later he married Barbara Montgomerie, who belonged to Irvine. She brought him a dowry of 250l., which enabled them to live when the failure of his Irvine master threw him out of employment, and they migrated to Glasgow. Here, at the age of twenty-five, he was appointed foreman of the Glasgow gasworks, the first of the kind to be established in the city. At the end of five years he became manager and engineer of the works, and remained connected with them for thirty years. Into both the manufacture and the utilisation of gas he introduced several important improvements, among them the employment of clay retorts, the use of sulphate of iron as a purifier, and the swallow-tail jet, which came into general use. In these early successes as an inventor he was aided by the new knowledge of physical and chemical science which he acquired as a diligent student at the Andersonian University, Glasgow. At the same time he was exerting himself zealously for the mental and technical improvement of the workmen under him, most of whom, Highlanders and Irishmen, could not even read. By degrees he overcame their reluctance to be taught, and, with the aid of the directors of the gas company, he succeeded in establishing a thriving workman's institution, with a library, lecture-room, laboratory, and workshop. In 1825 the popularity of the institute rendered enlargement of the building necessary, and Neilson delivered an excellent address to its members, which was published.
It was about this time that he was led to the inquiries which resulted in the discovery of the value of the hot blast in the iron manufacture. The conception was ​entirely opposed to the practice which an erroneous theory had caused to be universally adopted. Finding that iron, in greater quantity and of better quality, was turned out by the blast furnace in winter than in summer, the ironmasters had come to the conclusion that this was due to the greater coldness of the blast in winter than in summer. So strongly were they convinced of the truth of this theory that they had recourse to various devices for the artificial refrigeration of the blast. It is one of the chief merits of Neilson as an inventor that he discovered the baselessness of this theory, and convinced himself that the superior yield of the blast furnaces in winter was to be accounted for, partly at least, by the increased moisture of the air in summer. It was, however, the comparative inefficiency of the blast in a particular case, in which the blowing-engine, instead of being near the furnace, was half a mile distant from it, that drew Neilson's attention immediately to the experiments which led ultimately to his great invention. Neilson concluded that the effects of distance between the furnace and blowing-engine would be overcome if the blast were heated by passing it through a red-hot vessel, by which its volume, and therefore the work done by it, would be increased. Experimenting on gas and on an ordinary smith's fire, he found in the one case that heated air in a tube surrounding the gas-burner increased the illuminating power of the gas, and in the other that by blowing heated air instead of air at its ordinary temperature into the fire its heat was much more intense. Of course, the cause of the increase was that the fire had not to expend a portion of its caloric to heat the cold air poured into it in the ordinary way. Neilson was now on the verge of the fruitful discovery that the blast was to be made more efficient by heating it, not by refrigerating it. Owing to a deep-seated belief in the erroneous theory that cold benefited the blast, the ironmasters were reluctant to allow Neilson to try in their furnaces the effects of a substitution of the hot for the cold blast; and even those who were disposed to permit it strongly objected to the alterations in the arrangements of their furnaces which Neilson thought necessary for a fair trial of his invention. A trial under anything like adequate conditions was consequently long deferred. Its effects were first fairly tested at the Clyde ironworks, and with such success that Charles Macintosh [q. v.], the inventor of the well-known waterproof, Colin Dunlop, and John Wilson of Dundyvan entered into a partnership with Neilson for patenting the invention. Ultimately the partnership appears to have consisted of Neilson, Macintosh, and Wilson; Neilson being entitled to six-tenths of the profits, Macintosh to three-tenths, and Wilson to one-tenth (Neilson and Harford, p. 2). Separate patents were taken out in 1828 for England, Scotland, and Ireland, that for England being dated 11 Sept., those for Scotland and Ireland 1 Oct. The specification was dated 28 Feb. 1829. To encourage the employment of the hot blast by the trade, the charge for a license to smelt iron with the hot blast was fixed at a shilling a ton on all iron produced by the new process. In 1832 Neilson joined the Institution of Civil Engineers in London.
Neilson and others soon improved the apparatus. After five years' trial at the Clyde ironworks it was found that with the hot blast the same amount of fuel produced three times as much iron, and that the same amount of blast did twice as much work as the cold blast formerly. A subsidiary benefit was that, whereas with the cold blast coke—at least in Scotland—had to be used, with the hot blast raw coal could be, and was, substituted, with a great saving of expenditure. To Scotland the invention was an inestimable benefit. It made available the black band ironstone which, since its discovery by David Mushet [q. v.], had been almost useless in the iron manufacture. In 1839 the proprietor of one estate in Scotland derived a royalty of 16,500l. from the black band, although before the invention of the hot blast it had yielded him nothing (Smiles, p. 161). In the course of time the anthracite coal of England, which could not be used in smelting iron with the cold blast, was made available for that purpose by the invention of the hot blast. By 1835 the hot blast was in operation in every ironwork in Scotland save one, and there it was in course of introduction. Except in the case of a few special bands of iron, it is now in general use in Great Britain and out of it. It has been justly said that Neilson did for the iron manufacture what Arkwright did for the cotton manufacture.
Like Arkwright, Neilson was not allowed to enjoy undisturbed the fruits of his invention. He and his partners, by beginning legal proceedings, had compelled at least one firm to give up infringing their patent and to take out a license for using it, when towards 1840 an association of Scottish ironmasters was formed, each member of which bound himself, under a penalty of 1,000l., to resist, by every method which a majority should recommend, any practical acknowledgment of the validity of Neilson's patent. ​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.
F. E.