station in London. This work was successfully accomplished, and since that time the plant has been used for riveting bridges in all parts of the world. Other uses of applying the portable machines were soon found, such as the riveting of locomotive boilers, gun-carriages, agricultural machinery, and wrought-iron under-frames for railway carriages, and progress was made in its application to the riveting of ships.
In 1874 the French government adopted Tweddell's system in their shipbuilding yard at Toulon (Proc. of Instit. of Mechanical Engineers, 1878, p. 346). A similar plant was subsequently erected at the shipyard of the Forges et Chantiers de la Loire at Penhouet, part of the town of St. Nazaire. The largest of the machines at Penhouet exerted fifty tons pressure, but one was constructed in 1883 for the naval arsenal at Brest with a pressure equal to a hundred tons. It is difficult to overestimate the importance of the changes which he effected in the construction of boiler, bridge, and shipbuilding works. Not only is the work turned out of a better and more reliable description, but without the aid of his machinery much of that now produced could not be accomplished.
He wrote papers ‘On Machine Tools and Labour-saving Appliances worked by Hydraulic Pressure,’ and on ‘Forging by Hydraulic Pressure’ (Min. of Proc. of Instit. of Civil Engineers, lxxviii. 64, and cxvii. 1). For the former he was awarded the Telford medal and premium. To the Institution of Mechanical Engineers he sent three papers, the most important being ‘On the Application of Water Pressure to Shop-tools and Mechanical Engineering Works’ (Proceedings, 1872 p. 188, 1874 p. 166, 1878 p. 45, and 1881 p. 293). The Society of Arts gave him a gold medal under the Howard Trust ‘for his system of applying hydraulic power to the working of machine tools, and for the riveting and other machines which he has invented in connection with that system’ (Journal of Soc. of Arts, xxxiii. 949). In 1890 he was awarded a Bessemer premium for a paper entitled ‘The Application of Water Pressure to Machine Tools and Appliances’ (Trans. Soc. of Engineers, 1895 p. 35). On 2 Dec. he was elected an associate of the Institution of Civil Engineers, and was made a member on 25 Feb. 1879. He was also a member of the Institution of Mechanical Engineers from 1867. He was a keen sportsman, and believed that he did better work for an occasional day's hunting, shooting, or fishing. He died at Meopham Court, near Gravesend, Kent, on 3 Sept. 1895, having married in 1875 Hannah Mary, third daughter of G. A. Grey of Milfield, Northumberland.
[Min. of Proc. of Instit. Civil Engineers, 1896, cxxiii. 437–40; Proc. of Instit. of Mechanical Engineers, 1895, pp. 544–6; Times, 11 Sept. 1895.]
TWEEDDALE, Marquises of. [See Hay, John, second earl and first marquis, 1626-1697; Hay, John, second marquis, 1645-1713 ; Hay, John, fourth marquis, d. 1762 ; Hay, George, eighth marquis, 1787- 1876; and Hay, Arthur, ninth marquis, 1824-1878.]
TWEEDIE, ALEXANDER (1794–1884), physician, was born in Edinburgh on 29 Aug. 1794, and received his early education at the Royal High School of that city. In 1809 he commenced his medical studies at the university of Edinburgh, and about the same time becoming a pupil of a surgeon to the Royal Infirmary, named Wishart, distinguished himself in Edinburgh for his skill in ophthalmic disease. On 1 Aug. 1815 Tweedie took the degree of M.D., and, turning his attention to surgical pathology, in 1817 became a fellow of the Edinburgh College of Surgeons. He was then elected one of the two house-surgeons to the Edinburgh Royal Infirmary, Robert Liston (1794–1847) [q. v.] being the other. In 1818 Dr. Tweedie commenced practice in Edinburgh with the view of devoting himself to ophthalmic surgery, but in 1820 he removed to London, took a residence in Ely Place, and on 25 June 1822 was admitted a licentiate of the College of Physicians. He became a fellow of the college on 4 July 1838, was conciliarius in 1853, 1854, and 1855, and Lumleian lecturer in 1858 and 1859. In 1866 he was elected an honorary fellow of the King's and Queen's College of Physicians in Ireland.
In 1822 he was appointed assistant physician to the London Fever Hospital, and in 1824, on the retirement of John Armstrong (1784–1829) [q. v.], physician to the hospital, an office which he filled for thirty-eight years. He resigned it in 1861, when he was appointed consulting physician and one of the vice-presidents. In 1836 he was elected physician to the Foundling Hospital; he was also physician to the Standard Assurance Company, examiner in medicine at the university of London, and was an honorary member of the Medical Psychological Association. He was elected a fellow of the Royal Society on 8 Feb. 1838. He died at his residence, Bute Lodge, Twickenham, on 30 May 1884, continuing to practise at the age of eighty-nine years.
