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COOKE, THOMAS (1807–1868), optician, the son of a poor shoemaker, was born at Allerthorpe in the East Riding of Yorkshire on 8 March 1807. His education was limited to two years at the national school, after which he was put to his father's trade. Poring over the narrative of Captain Cook's voyages, he was fired with the desire to emulate them. He studied navigation diligently, and was on the point of engaging himself for a seaman, when his mother's tears persuaded him to seek a less distant livelihood. Renewed application fitted him, at the age of sixteen, to open a school in his native village, which he continued until his removal to York about 1829. There, during seven years, he supported himself by teaching, while his spare moments were devoted to the study of mathematics and practical mechanics. Optics attracted him, and his first effort towards telescope-construction was with one of the reflecting kind. But the requisite metals cost money, and he turned to refractors, finding cheap material in the bottom of a common drinking-glass. Methods of shaping and polishing were gradually contrived, and, after a laborious process of self-initiation, he at length succeeded in producing a tolerable achromatic, afterwards purchased by Professor Phillips of Oxford, his constant friend and patron. He was now induced, by offers of countenance from many quarters, to enter upon business as an optician.

His first important order was from Mr. William Gray, F.R.S., for a 4½-inch equatorial, and so effectually had glass manufacture in England been obstructed by an oppressive excise duty, that the undertaking was then regarded as of no small moment. It was succeeded in 1851 by a commission from Mr. Pattinson of Gateshead for one of seven inches aperture, lent in 1856 to Professor Piazzi Smyth for his celebrated expedition to Teneriffe. Its successful execution added so much to Cooke's reputation and business that an extension of his premises became necessary. He accordingly erected new workshops, afterwards known as the Buckingham Works, in Bishop-hill, York, and removed his establishment thither in 1855. It consisted at that time of five or six workmen and one apprentice; when he died above one hundred persons were in his employment.

The enterprise by which he gained European celebrity was undertaken in September 1863. In the previous year Alvan Clark of Boston had turned out a refractor of 18½-inches aperture. Mr. Newall, a manufacturer of submarine cables at Gateshead, now committed to Cooke the onerous task of producing one of no less than twenty-five inches. So considerable an advance in size involved difficulties overcome only by unremitting patience and ingenuity. The destruction of colour was rendered highly arduous by the magnitude of the lenses, and their weight menaced at every moment the permanence of their figure. The optical part of the commission was completed early in 1868. A huge object-glass, twenty-five inches across and of the highest quality in form and finish, was ready to be placed in the tube. But its maker, worn out by the anxieties attendant on so vast an undertaking, died on 19 Oct. 1868. The great telescope was mounted in the following year. It is still the largest, and is believed to be the best refractor in the United Kingdom, though its qualities have been obscured by the murky air of Gateshead. Among the novelties introduced in its fittings was that of the illumination, by means of Geissler vacuum-tubes, both of micrometer-wires and circle-graduations. A seven-inch transit-instrument formed an adjunct to it.

Cooke has been called the ‘English Fraunhofer.’ He restored to this country some portion of its old supremacy in practical optics. He brought the system of equatorial mounting very near to its present perfection. The convenience of observers had never before been so carefully studied as by him, and observation owes to his inventive skill much of its present facility. By his application of steam to the grinding and polishing of lenses their production was rendered easy and cheap and their quality sure. His object-glasses were pronounced by the late Mr. Dawes (perhaps the highest authority then living) ‘extremely fine, both in definition and colour’ (Monthly Notices, xxv. 231). And the facility given by his method to their construction brought comparatively large instruments within the reach of an extensive class of amateur astronomers.

A pair of five-foot transits, constructed by Cooke for the Indian Trigonometrical Survey, were described by Lieutenant-colonel Strange before the Royal Society on 16 Feb. 1867 (Proc. R. Soc. xv. 385). They were among the largest portable instruments of their class, the telescopes possessing a clear aperture of five inches.

Cooke invented an automatic engine, of excellent performance, for the graduation of circles, and was the first to devise machinery for engraving figures upon them. He perfected the astronomical clock, and built nearly one hundred turret-clocks for public institutions and churches. Admirable workmanship was combined, in all his instruments, with elegance of form, while the thoroughness characteristic of his methods was exemplified in the practice adopted by him of cutting his own tools and casting his own metals. Simplicity, truthfulness, and modesty distinguished his private character. He was admitted a member of the Royal Astronomical Society in 1859, and contributed to its proceedings a paper, ‘On a new Driving-clock for Equatorials’ (Monthly Notices, xxviii. 210). He left two sons, well qualified to carry on his business.

[Monthly Notices, xxix. 130; Athenæum, 1868, ii. 534; Les Mondes, xviii. 331.]

A. M. C.