near Hexham. He was educated at Hartforth school, near Richmond, Yorkshire, and at Trinity College, Cambridge. He was a friend, but not, as often stated, a pupil, of Dr. Samuel Parr (Remains of John Tweddell, 2nd ed. p. vii). He graduated B.A. and won the second chancellor's medal in 1790, proceeding M.A. in 1793. He gained all the Browne medals in 1788 and two of the three in 1789, and the members' prize in 1791. He was elected fellow of Trinity in 1792, and in the same year he published ‘Prolusiones Juveniles,’ being his prize compositions in Greek, Latin, and English.
Tweddell entered at the Middle Temple in 1792. But he had no taste for law, and wished to become a diplomatist. With the object of studying the manners and institutions of European and Asiatic peoples, and of making the acquaintance of foreign politicians and scholars, he started on a tour in the autumn of 1795, visiting Hamburg, Germany, Switzerland, Russia, Poland, and several parts of the east. During his travels he sent home a series of letters that show an accurate observation and the vastness of the stores of knowledge he was accumulating. But the main part of his time was occupied in entering in his journals in minute detail all that he learned. A large part of these journals was deposited at Pera with Thomas Thornton (d. 1814) [q. v.], as the volumes were too bulky to carry about. Tweddell engaged Preaux, an able French artist whom he met at Constantinople, to tour with him in Greece, and to assist him to copy at Athens ‘not only every temple and every archway, but every stone and every inscription, with the most scrupulous fidelity.’ While engaged in archæological work at Athens he died of fever on 25 July 1799. He was buried at his own request in the Theseum, and, as the result of the exertions of Lord Byron and others, a block of marble that had been cut from the bas-reliefs of the Parthenon was afterwards erected over his grave, with a Greek inscription written by the Rev. Robert Walpole. Many memorial verses were composed in Tweddell's honour by scholars of both universities.
After Tweddell's death Lord Elgin [see Bruce, Thomas, seventh Earl of Elgin], on arriving at Constantinople as ambassador to the Porte, ordered his collections to be sent to him. He stated that he consigned all that came into his hands to a friend of the family in England, and his chaplain, Dr. Philip Hunt, declared the statement to be true. The journals and pictures mysteriously disappeared, and Tweddell's brother subsequently accused Elgin of appropriating them. It is certainly remarkable that neither Elgin nor Hunt could at a later time give any clear account of the matter. But Tweddell's brother failed to prove his charge, and all that could be sustained against Elgin was considerable negligence and some indifference. His answer to the charge was not published till 1815. Tweddell's brother was supported by Dr. Clark, by Thornton, and by John Spencer Smith, Elgin's predecessor. The collections were never traced.
[The charges against Elgin are discussed in the Quarterly Review, 1815, xiv. 257, and Edinburgh Review, 1814, xxv. 285; Hunt's Narrative of what is known respecting the literary remains of J. T., London, 1816; Elgin's letter to the Edinburgh Review; Blackwood, vii. 179; Allibone's Dict.]
TWEDDELL, RALPH HART (1843–1895), engineer and inventor of the hydraulic riveter, son of Marshall Tweddell, a shipowner, was born at South Shields on 25 May 1843, and educated at Cheltenham College. In 1861 he was articled to R. & W. Hawthorn of Newcastle-on-Tyne, engineers. During his apprenticeship, on 9 May 1865, he took out a patent (No. 1282) for a portable hydraulic apparatus for fixing the ends of boiler tubes in tube plates. The pressure of water was from one to one and a half ton on the square inch. When the force-pump did not form part of the machine itself, the connection was made by a copper pipe, which was flexible to allow of the movement of the machine. The results were so encouraging as to suggest the employment of hydraulic power for machines used in boiler construction (Min. of Proc. of Institution of Civil Engineers, lxxiii. 65).
In 1865 he designed a stationary hydraulic riveting machine, which he patented on 23 Aug. 1866 (No. 2158). The plant, consisting of a pump, an accumulator, and a riveter, was first used by Thompson, Boyd & Co., of Newcastle. The work was done perfectly and at one-seventh of the cost of hand work. The surplus power was applied to hydraulic presses for ‘setting’ angle and tee irons, and it was proved that the wear and tear of the moulds and dies were greatly reduced. The difficulty, often found, of getting the work to the machine induced Tweddell to turn his attention to the design of a portable riveter. The first portable machine was made in 1871, and used by Armstrong, Mitchell, & Co. at Newcastle. Two years later the machine was employed in riveting in situ the lattice-girder bridge carrying Primrose Street over the Great Eastern railway at Bishopsgate Street
