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1 Hipp, Matthäus
[br]b. 25 October 1813 Blaubeuren, Germanyd. 3 May 1893 Zurich, Switzerland[br]German inventor and entrepreneur who produced the first reliable electric clock.[br]After serving an apprenticeship with a clock-maker in Blaubeuren, Hipp worked for various clockmakers before setting up his own workshop in Reutlingen in 1840. In 1842 he made his first electric clock with an ingenious toggle mechanism for switching the current, although he claimed that the idea had occurred to him eight years earlier. The switching mechanism was the Achilles' heel of early electric clocks. It was usually operated by the pendulum and it presented the designer with a dilemma: if the switch made a firm contact it adversely affected the timekeeping, but if the contact was lightened it sometimes failed to operate due to dirt or corrosion on the contacts. The Hipp toggle switch overcame this problem by operating only when the amplitude of the pendulum dropped below a certain value. As this occurred infrequently, the contact pressure could be increased to provide reliable switching without adversely affecting the timekeeping. It is an indication of the effectiveness of the Hipp toggle that it was used in clocks for over one hundred years and was adopted by many other makers in addition to Hipp and his successor Favag. It was generally preferred for its reliability rather than its precision, although a regulator made in 1881 for the observatory at Neuchâtel performed creditably. This regulator was enclosed in an airtight case at low pressure, eliminating errors due to changes in barometric pressure. This practice later became standard for observatory regulators such as those of Riefler and Shortt. The ability of the Hipp toggle to provide more power when the clock was subjected to an increased load made it particularly suitable for use in turret clocks, whose hands were exposed to the vagaries of the weather. Hipp also improved the operation of slave dials, which were advanced periodically by an electrical impulse from a master clock. If the electrical contacts "chattered" and produced several impulses instead of a single sharp impulse, the slave dials would not indicate the correct time. Hipp solved this problem by producing master clocks which delivered impulses that alternated in polarity, and slave dials which only advanced when the polarity was changed in this way. Polarized impulses delivered every minute became the standard practice for slave dials used on the European continent. Hipp also improved Wheatstone's chronoscope, an instrument that was used for measuring very short intervals of time (such as those involved in ballistics).[br]Principal Honours and DistinctionsHonorary doctorate, University of Zurich 1875.Further ReadingNeue deutsche Biographie, 1972, Vol. 9, Berlin, pp. 199–200."Hipp's sich selbst conrolirende Uhr", Dinglers polytechnisches Journal (1843), 88:258– 64 (the first description of the Hipp toggle).F.Hope-Jones, 1949, Electrical Timekeeping, 2nd edn, London, pp. 62–6, 97–8 (a modern description in English of the Hipp toggle and the slave dial).C.A.Aked, 1983, "Electrical precision", Antiquarian Horology 14:172–81 (describes the observatory clock at Neuchâtel).DV -
2 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 -
3 Shortt, William Hamilton
SUBJECT AREA: Horology[br]b. 28 September 1881d. 4 February 1971[br]British railway engineer and amateur horologist who designed the first successful free-pendulum clock.[br]Shortt entered the Engineering Department of the London and South Western Railway as an engineering cadet in 1902, remaining with the company and its successors until he retired in 1946. He became interested in precision horology in 1908, when he designed an instrument for recording the speed of trains; this led to a long and fruitful collaboration with Frank HopeJones, the proprietor of the Synchronome Company. This association culminated in the installation of a free-pendulum clock, with an accuracy of the order of one second per year, at Edinburgh Observatory in 1921. The clock's performance was far better than that of existing clocks, such as the Riefler, and a slightly modified version was produced commercially by the Synchronome Company. These clocks provided the time standard at Greenwich and many other observatories and scientific institutions across the world until they were supplanted by the quartz clock.The period of a pendulum is constant if it swings freely with a constant amplitude in a vacuum. However, this ideal state cannot be achieved in a clock because the pendulum must be impulsed to maintain its amplitude and the swings have to be counted to indicate time. The free-pendulum clock is an attempt to approach this ideal as closely as possible. In 1898 R.J. Rudd used a slave clock, synchronized with a free pendulum, to time the impulses delivered to the free pendulum. This clock was not successful, but it provided the inspiration for Shortt's clock, which operates on the same principle. The Shortt clock used a standard Synchronome electric clock as the slave, and its pendulum was kept in step with the free pendulum by means of the "hit and miss" synchronizer that Shortt had patented in 1921. This allowed the pendulum to swing freely (in a vacuum), apart from the fraction of a second in which it received an impulse each half-minute.[br]Principal Honours and DistinctionsMaster of the Clockmakers' Company 1950. British Horological Society Gold Medal 1931. Clockmakers' Company Tompion Medal 1954. Franklin Institute John Price Wetherill Silver Medal.Bibliography1929, "Some experimental mechanisms, mechanical and otherwise, for the maintenance of vibration of a pendulum", Horological Journal 71:224–5.Further ReadingObituary, 1971, Proceedings of the Institution of Civil Engineers 56:396–7.F.Hope-Jones, 1949, Electrical Timekeeping, 2nd edn, London (a detailed but not entirely impartial account of the development of the free-pendulum clock).See also: Marrison, Warren AlvinDVBiographical history of technology > Shortt, William Hamilton
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4 Riefler, Sigmund
SUBJECT AREA: Horology[br]b. 9 August 1847 Maria Rain, Germanyd. 21 October 1912 Munich, Germany[br]German engineer who invented the precision clock that bears his name.[br]Riefler's father was a scientific-instrument maker and clockmaker who in 1841 had founded the firm of Clemens Riefler to make mathematical instruments. After graduating in engineering from the University of Munich Sigmund worked as a surveyor, but when his father died in 1876 he and his brothers ran the family firm. Sigmund was responsible for technical development and in this capacity he designed a new system of drawing-instruments which established the reputation of the firm. He also worked to improve the performance of the precision clock, and in 1889 he was granted a patent for a new form of escapement. This escapement succeeded in reducing the interference of the clock mechanism with the free swinging of the pendulum by impulsing the pendulum through its suspension strip. It proved to be the greatest advance in precision timekeeping since the introduction of the dead-beat escapement about two hundred years earlier. When the firm of Clemens Riefler began to produce clocks with this escapement in 1890, they replaced clocks with Graham's dead-beat escapement as the standard regulator for use in observatories and other applications where the highest precision was required. In 1901 a movement was fitted with electrical rewind and was encapsulated in an airtight case, at low pressure, so that the timekeeping was not affected by changes in barometric pressure. This became the standard practice for precision clocks. Although the accuracy of the Riefler clock was later surpassed by the Shortt free-pendulum clock and the quartz clock, it remained in production until 1965, by which time over six hundred instruments had been made.[br]Principal Honours and DistinctionsFranklin Institute John Scott Medal 1894. Honorary doctorate, University of Munich 1897. Vereins zur Förderung des Gewerbefleisses in Preussen Gold Medal 1900.Bibliography1907, Präzisionspendeluhren und Zeitdienstanlagen fürSternwarten, Munich (for a complete bibliography see D.Riefler below).Further ReadingD.Riefler, 1981, Riefler-Präzisionspendeluhren, Munich (the definitive work on Riefler and his clock).A.L.Rawlings, 1948, The Science of Clocks and Watches, 2nd edn; repub. 1974 (a technical assessment of the Riefler escapement in its historical context).See also: Marrison, Warren AlvinDV
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