14th February 2013 by CW LONDON CALLING: A SHORT WALK IN HOROLOGICAL HISTORY C9 Harrison BlueChronometerJohn Harrison For someone with a keen interest in all things related to watchmaking, a short stroll in the capital city will uncover fascinating aspects of horological history at almost every turn. The route described here of just over a mile covers developments in the watchmaker’s of such significance that they changed not only horology but navigation and scientific measurement and thus concept of time itself. We begin at Tower 42 in Bishopsgate, the site of the first Gresham college: Thomas Tompion 1639–1713 ‘The Father of English Clockmaking’ Tompion was a blacksmith by trade but came to London in 1671 to join the Clockmakers’ Company and soon found employment with the physicist Robert Hooke. Tompion’s watches developed a reputation for superb craftsmanship and mechanical ingenuity and Hooke and Tompion collaborated on some of the first watches with balance springs. A true polymath, Hooke was Professor of Geometry at Gresham college and Curator of Experiments at the Royal Society, itself formed at Gresham College following a lecture by the then Professor of Astronomy, Sir Christopher Wren. It was at Gresham that Hooke introduced Tompion to the leading scientists and intellectuals of the period and he received many important commissions. Tompion’s workshop would build about 5,500 watches and 650 clocks until his death in 1713 and he would be called the greatest English watch, clock and instrument maker of his time. Find out more about Gresham College and Tompion’s circle here Down Old Broad St and along Bartholomew Lane to the Guildhall and the Clockmakers‘ museum: John Harrison’s first wooden longcase clock movement. In 1713, the year Tompion died, John Harrison, a 20 year old carpenter, built his first clock. Although there was nothing particularly revolutionary about the mechanics of the clock movement – it was a poor timekeeper owing to its wooden construction, this example of Harrison’s determined genius would ignite his lifetime’s vocation and mark the beginning of an extraordinary horological journey. Signed ‘John Harrison 1713’ in ink on the calendar wheel, this modest looking creation was nonetheless a statement of intent and as Harrison painstakingly developed his technique, his mastery of the clockmaker’s art would revolutionise timekeeping and navigation for the next two hundred years. Find out more about the Clockmaker’s Company and their breath-taking collection, here. Along Newgate St to 17 Red Lion Square: Harrison’s masterpieces Red Lion Square, just a mile from the Clockmakers’ Museum is where John Harrison lived most of his life of which he dedicated the greater part to solving what was known as the ‘Longitude problem’. While he lived at Red Lion Square, Harrison devoted many years of experimentation to creating a series of timekeepers which would be sufficiently accurate at sea to win the prize of £20,000 offered by the British Government. His fourth timekeeper met the exacting requirements of the Admiralty, but after a protracted dispute, he was required to produce a further timekeeper, the H5, which was sea trialled by the King himself before the prize was reluctantly awarded. It was an astonishing triumph of determination and innovation and one which would have a profound effect on what was then the world’s foremost maritime power. A comprehensive history of Harrison and the Longitude Problem can be found at the Royal Naval Museum, Portsmouth Round the corner to 119 High Holborn: Thomas Earnshaw’s workshop While John Harrison’s work proved the theory that timekeepers of sufficient accuracy and reliability could be made for marine use, his timekeepers, though brilliant in conception were very complicated, very difficult to make and very expensive. Building on the development of Harrison’s work by John Arnold, it was another London maker, Thomas Earnshaw who developed what were now known as ‘chronometers’ which were practical to produce and fit for daily life at sea. From his workshop at 119 High Holborn, Earnshaw began producing chronometers to a design that survived almost unchanged until the advent of electronics and satellite navigation. Earnshaw’s chronometer no. 506 was carried on HMS Beagle between 1831 and 1836 on a voyage to circumnavigate the globe and establish a chain of points around the world of accurately known longitude. This was also the voyage that carried Charles Darwin who was afterwards inspired to write his book about the theory of evolution, On the Origin of Species. Find out more about Thomas Earnshaw.