Macintosh, Charles (DNB00)

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MACINTOSH, CHARLES (1766–1843), chemist and inventor of waterproof fabrics, son of George Macintosh of Glasgow, merchant, and of Mary Moore, was born at Glasgow on 29 Dec. 1766. His maternal uncle was Dr. John Moore [q. v.], the father of General Sir John Moore [q. v.] He was educated at the grammar school at Glasgow, and afterwards at a school at Catterick Bridge, Yorkshire. As a youth he was placed in the counting-house of Mr. Glasford, a Glasgow merchant, but all his spare hours were devoted to science, especially to chemistry, and he attended the lectures of Dr. William Irvine [q. v.] at Glasgow, and later those of Dr. Joseph Black at Edinburgh. Tired of the life of a clerk, he embarked before he was twenty years of age in the manufacture of sal ammoniac. In 1786 he introduced from Holland the manufacture of sugar of lead, and about the same time he commenced making acetate of alumina. He also made important improvements in the manufacture of Prussian blue, and invented various processes for dyeing fabrics. In 1797 he started the first alum works in Scotland, the material employed being the aluminous schists of the exhausted coal mines at Hurlet, near Paisley. He subsequently became connected with Charles Tennant of St. Rollox chemical works, near Glasgow, and it seems that he was the actual inventor of the method of making chloride of lime, or bleaching powder, patented in Tennant's name in 1799, the manufacture of which was the source of great wealth to the proprietors of the St. Rollox works. Macintosh retired from the concern in 1814. He established in 1809 a yeast manufactory in the Borough, but it failed in consequence of the opposition of the London brewers.

In 1825 Macintosh obtained a patent (No, 5173) for converting malleable iron into steel, by exposing it at a white heat to the action of gases charged with carbon, such, for instance, as common coal gas. The conversion was completed in a few hours, while the process of 'cementation,' as it is called, requires several days, but the method did not answer commercially, on account of the practical difficulty of keeping the furnace gas-tight at the high temperature required. The specification of the patent was drawn up with the assistance of Dr. Wollaston, and the theory of the process was the subject of an exhaustive paper by Dr. Hugh Colquhoun (Annals of Philosophy, 1826, xii. 2), who carried out the early experiments in connection with the invention. The method was not altogether new when Macintosh took out his patent, for Professor Vismara had presented a paper on the subject to the Royal Institute of Milan in 1824, which was published in 'Giornale di Fisica,' 1825, viii. 190. Macintosh took great interest in the manufacture of iron, and he rendered much assistance to James Beaumont Neilson [q. v.] in 1828 in bringing his ' hot-blast 'process into use. Neilson assigned to him a share in the patent, and Macintosh thus became a party to the tedious and costly litigation which ensued, and which was only brought to a close in May 1843, a few months before his death.

Among the operations carried on by Macintosh was the treatment of the refuse of gas-works for obtaining various useful products, and it was his endeavour to utilise the coal naphtha obtained as a by-product in the distillation of tar that led to the invention of the waterproof fabrics with which his name is associated. Taking advantage of the known solvent action of naphtha on india-rubber, he took out a patent in 1823 (No. 4804) for making waterproof fabrics by cementing two thicknesses together with india-rubber dissolved in naphtha. Works were started in Manchester for carrying out the invention, Messrs. Birley supplying a portion of the requisite capital, and in 1825 Thomas Hancock took out a license under the patent, which eventually led to a partnership with the Manchester firm [see Hancock, Thomas]. Many practical difficulties had to be overcome, but the material soon came into use, and as early as April 1824 Macintosh was in correspondence with Sir John Franklin on the subject of a supply of waterproof canvas bags, air-beds, and pillows for use on an arctic expedition. The early difficulties in introducing 'macintoshes,' owing to the ignorance of the tailors and their unreadiness to follow Macintosh's advice in making up waterproof garments, are amusingly described by Hancock (Narrative, p. 52, &c.) Eventually the manufacturers took the work of making the garments into their own hands. The trade fell off considerably upon the introduction of railways, when travellers were not so much exposed to the weather as in stage-coaches. In 1836 Macintosh won an action for an infringement of the patent by Everington & Son, a firm of silk mercers, in Ludgate Street, of which Wynne Ellis [q. v.] was a member. Several of the most eminent scientific men of the day gave evidence at the trial, which excited much interest. The proceedings, reported in full in the 'Mechanics' Magazine,' xxiv. 529, &c., comprise a complete history of the invention. The works at Manchester were gradually enlarged, and the manufacture of all kinds of india-rubber articles was undertaken. The concern is still carried on.

Macintosh's connection with the manufacture of india-rubber was almost accidental, and has somewhat obscured his fame as a chemist. His discoveries in that branch of science led to his election in 1823 as a fellow of the Royal Society. He died at Dunchattan, near Glasgow, on 25 July 1843. He married in 1790 Mary Fisher, daughter of Alexander Fisher of Glasgow, merchant.

[George Macintosh's Memoir of Charles Macintosh, 1847 ; Abstracts of Papers communicated to the Royal Society, v. 486 ; Thomas Hancock's Narrative of the India-rubber Manufacture, 1857, pp. 52-62, 72-3, 81, 101.]

R. B. P.