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61 машинный прогон
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62 Bain, Alexander
[br]b. October 1810 Watten, Scotlandd. 2 January 1877 Kirkintilloch, Scotland[br]Scottish inventor and entrepreneur who laid the foundations of electrical horology and designed an electromagnetic means of transmitting images (facsimile).[br]Alexander Bain was born into a crofting family in a remote part of Scotland. He was apprenticed to a watchmaker in Wick and during that time he was strongly influenced by a lecture on "Heat, sound and electricity" that he heard in nearby Thurso. This lecture induced him to take up a position in Clerkenwell in London, working as a journeyman clockmaker, where he was able to further his knowledge of electricity by attending lectures at the Adelaide Gallery and the Polytechnic Institution. His thoughts naturally turned to the application of electricity to clockmaking, and despite a bitter dispute with Charles Wheatstone over priority he was granted the first British patent for an electric clock. This patent, taken out on 11 January 1841, described a mechanism for an electric clock, in which an oscillating component of the clock operated a mechanical switch that initiated an electromagnetic pulse to maintain the regular, periodic motion. This principle was used in his master clock, produced in 1845. On 12 December of the same year, he patented a means of using electricity to control the operation of steam railway engines via a steam-valve. His earliest patent was particularly far-sighted and anticipated most of the developments in electrical horology that occurred during the nineteenth century. He proposed the use of electricity not only to drive clocks but also to distribute time over a distance by correcting the hands of mechanical clocks, synchronizing pendulums and using slave dials (here he was anticipated by Steinheil). However, he was less successful in putting these ideas into practice, and his electric clocks proved to be unreliable. Early electric clocks had two weaknesses: the battery; and the switching mechanism that fed the current to the electromagnets. Bain's earth battery, patented in 1843, overcame the first defect by providing a reasonably constant current to drive his clocks, but unlike Hipp he failed to produce a reliable switch.The application of Bain's numerous patents for electric telegraphy was more successful, and he derived most of his income from these. They included a patent of 12 December 1843 for a form of fax machine, a chemical telegraph that could be used for the transmission of text and of images (facsimile). At the receiver, signals were passed through a moving band of paper impregnated with a solution of ammonium nitrate and potassium ferrocyanide. For text, Morse code signals were used, and because the system could respond to signals faster than those generated by hand, perforated paper tape was used to transmit the messages; in a trial between Paris and Lille, 282 words were transmitted in less than one minute. In 1865 the Abbé Caselli, a French engineer, introduced a commercial fax service between Paris and Lyons, based on Bain's device. Bain also used the idea of perforated tape to operate musical wind instruments automatically. Bain squandered a great deal of money on litigation, initially with Wheatstone and then with Morse in the USA. Although his inventions were acknowledged, Bain appears to have received no honours, but when towards the end of his life he fell upon hard times, influential persons in 1873 secured for him a Civil List Pension of £80 per annum and the Royal Society gave him £150.[br]Bibliography1841, British patent no. 8,783; 1843, British patent no. 9,745; 1845, British patent no.10,838; 1847, British patent no. 11,584; 1852, British patent no. 14,146 (all for electric clocks).1852, A Short History of the Electric Clocks with Explanation of Their Principles andMechanism and Instruction for Their Management and Regulation, London; reprinted 1973, introd. W.Hackmann, London: Turner \& Devereux (as the title implies, this pamphlet was probably intended for the purchasers of his clocks).Further ReadingThe best account of Bain's life and work is in papers by C.A.Aked in Antiquarian Horology: "Electricity, magnetism and clocks" (1971) 7: 398–415; "Alexander Bain, the father of electrical horology" (1974) 9:51–63; "An early electric turret clock" (1975) 7:428–42. These papers were reprinted together (1976) in A Conspectus of Electrical Timekeeping, Monograph No. 12, Antiquarian Horological Society: Tilehurst.J.Finlaison, 1834, An Account of Some Remarkable Applications of the Electric Fluid to the Useful Arts by Alexander Bain, London (a contemporary account between Wheatstone and Bain over the invention of the electric clock).J.Munro, 1891, Heroes of the Telegraph, Religious Tract Society.J.Malster \& M.J.Bowden, 1976, "Facsimile. A Review", Radio \&Electronic Engineer 46:55.D.J.Weaver, 1982, Electrical Clocks and Watches, Newnes.T.Hunkin, 1993, "Just give me the fax", New Scientist (13 February):33–7 (provides details of Bain's and later fax devices).See also: Bakewell, Frederick C.DV / KF -
63 Barnack, Oskar
SUBJECT AREA: Photography, film and optics[br]b. 1879 Berlin, Germanyd. January 1936 Wetzlar, Germany[br]German camera designer who conceived the first Leica camera and many subsequent models.[br]Oskar Barnack was an optical engineer, introspective and in poor health, when in 1910 he was invited through the good offices of his friend the mechanical engineer Emil Mechau, who worked for Ernst Leitz, to join the company at Wetzlar to work on research into microscope design. He was engaged after a week's trial, and on 2 January 1911 he was put in charge of microscope research. He was an enthusiastic photographer, but excursions with his large and heavy plate camera equipment taxed his strength. In 1912, Mechau was working on a revolutionary film projector design and needed film to test it. Barnack suggested that it was not necessary to buy an expensive commercial machine— why not make one? Leitz agreed, and Barnack constructed a 35 mm movie camera, which he used to cover events in and around Wetzlar.The exposure problems he encountered with the variable sensitivity of the cine film led him to consider the design of a still camera in which short lengths of film could be tested before shooting—a kind of exposure-meter camera. Dissatisfied with the poor picture quality of his first model, which took the standard cine frame of 18×24 mm, he built a new model in which the frame size was doubled to 36×24 mm. It used a simple focal-plane shutter adjustable to 1/500 of a second, and a Zeiss Milar lens of 42 mm focal length. This is what is now known as the UR-Leica. Using his new camera, 1/250 of the weight of his plate equipment, Barnack made many photographs around Wetzlar, giving postcard-sized prints of good quality.Ernst Leitz Junior was lent the camera for his trip in June 1914 to America, where he was urged to put it into production. Visiting George Eastman in Rochester, Leitz passed on Barnack's requests for film of finer grain and better quality. The First World War put an end to the chances of developing the design at that time. As Germany emerged from the postwar chaos, Leitz Junior, then in charge of the firm, took Barnack off microscope work to design prototypes for a commercial model. Leitz's Chief Optician, Max Berek, designed a new lens, the f3.5 Elmax, for the new camera. They settled on the name Leica, and the first production models went on show at the Leipzig Spring Fair in 1925. By the end of the year, 1,000 cameras had been shipped, despite costing about two months' good wages.The Leica camera established 35 mm still photography as a practical proposition, and film manufacturers began to create the special fine-grain films that Barnack had longed for. He continued to improve the design, and a succession of new Leica models appeared with new features, such as interchangeable lenses, coupled range-finders, 250 exposures. By the time of his sudden death in 1936, Barnack's life's work had forever transformed the nature of photography.[br]Further ReadingJ.Borgé and G.Borgé, 1977, Prestige de la, photographie.BC -
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