Page:Dictionary of National Biography volume 37.djvu/216

 Medhurst to whom a patent (No. 2525) for a washing and wringing machine was granted in the same year is identical with the subject of this memoir, as he is described as ‘a mathematical instrument maker, of Pentonville.’

About the beginning of the century Medhurst established himself as a machinist and ironfounder at Denmark Street, Soho, where the concern was carried on by his successors until a few years ago. He turned his attention to weighing machines and scales, and was the inventor of the ‘equal balance weighing machine,’ now in universal use, as well as of the scales which are to be found in almost every retail shop.

Medhurst was the first to suggest the ‘pneumatic dispatch,’ as it has since been called. This was not patented, his proposals being made public in ‘A New Method of Conveying Letters and Goods with great Certainty and Rapidity by Air,’ London, 1810. He proposed to convey small parcels or letters in tubes by compressed air, and heavy goods to the weight of a ton and a half through brick tunnels, which the carriage just fitted. In 1812 he published ‘Calculations and Remarks tending to prove the Practicability, Effects and Advantages of a Plan for the Rapid Conveyance of Passengers upon an Iron Railway, through a Tube of Thirty Feet in Area, by the Power and Velocity of Air,’ London, 1812, 8vo, pp. 19. He argued that an average speed of fifty miles an hour might be attained, and that passengers might be conveyed at a cost of a farthing per mile, and goods at a penny per ton per mile. The passengers were to travel inside the tunnel, but he hints at the possibility of driving a carriage on rails in the open air by means of a piston in a continuous tube between the rails. This was long afterwards known as the atmospheric railway. The subject was further developed in ‘A new System of Inland Conveyance for Goods and Passengers capable of being applied and extended throughout the Country, and of Conveying all kinds of Goods and Passengers with the Velocity of Sixty Miles in an Hour,’ London, 1827, 8vo, pp. 38. This pamphlet contains several illustrations showing the pumping engines and the details of the valve for opening and closing the longitudinal slit in the tube, a difficulty which has never yet been overcome, and has been the cause of failure of all the atmospheric railways hitherto tried. It does not appear that Medhurst had the opportunity of putting any of his schemes into practice, but he had a very clear conception of the conditions of the problem of atmospheric propulsion. He laid his plans before the post-office authorities, but the reply was not encouraging. He is also said to have invented a one-wheel clock, and to have been the actual inventor of the box-mangle, long known as ‘Baker's patent mangle,’ though no patent was obtained. Medhurst is occasionally referred to as a Dane, but this arose from the blunder of a French writer, who was misled by the address ‘Denmark Street’ (see Mechanics' Magazine, 1844, xli. 141). Copies of Medhurst's publications are exceedingly rare, but a complete set is to be found in the library of the Institution of Civil Engineers, Westminster.

Medhurst died in September 1827, and was buried at Shoreham on 10 Sept.

 MEDHURST, WALTER HENRY (1796–1857), missionary, was born in London on 29 April 1796. In the register-book of St. Paul's School, where his admission stands recorded on 27 July 1807, at the age of eleven, his father is described as William Medhurst, innkeeper, of Ross, N.B. After quitting the school he found occupation as a printer, first at Gloucester, and afterwards with the London Missionary Society. In their service, after a few months' study and preparation under Dr. Collison at Hackney College, he embarked for China in September 1816 as a missionary printer. His destination was Malacca. On the way the ship in which he sailed put in at Madras, and there he found a wife to share his labours. While working at the printing-press he made rapid progress in the knowledge of the Malay and Chinese languages, and developed a faculty of preaching. He was accordingly ordained by Dr. [q. v.] and his colleagues at Malacca on 27 April 1819. Of wiry frame, good health, and unfailing cheerfulness, he proved a most efficient missionary. Penang and Batavia were the scene of his earlier efforts. At Parapattan he established an orphan asylum. In 1836 he returned for a while to England. There he wrote his ‘China, its State and Prospects,’ published in 1838, with the view of stimulating interest in Chinese missions, and especially in a new version of the bible in Chinese, a work which, with the co-operation of friends, he was able to accomplish some years later. It is known as the ‘Delegates' Version.’ In 1838 he went back to Java. Thence, when the ports of Canton, Shanghai, and three others were opened to British merchants by the treaty of 29 Aug. 1842, he moved to Shanghai, and laboured there for fourteen years. On 10 Sept. 1856 he sailed with his wife and family from