A richly illustrated, detailed account of wristwatch chronometers and the rigorous testing they must undergo to become certified. Over 400 photos document this crowning achievement of the watchmakers art while information about testing methods, procedures, and guidelines make it clear how great a challenge it has been. A compilation of participating makers based on Swiss Testing Agencies' yearly reports from 1925 and the Swiss Observatories' reports is included as is a guide to current values.

Maritime chronometers are rare and precious items, crafted with care and precision, to provide an accurate means of measuring time and determining longitude at sea. Developed in the eighteenth century, these beautiful instruments were produced for the next two hundred years to the same design, and played a significant role in the growth of maritime trade, ultimately helping to shape the world as we know it today. In The Marine Chronometer, the author explains the workings of the chronometer and highlights some of the most significant makers and provides hints for maintenance. Topics covered include: -The problem of longitude -The early sea clocks -Developments in France and England -The mechanism of the chronometer -Caring for chronometers AUTHOR John Cronin studied horology at Bradford Technical College, where he was awarded a gold medal and a British Horological Institute prize for the national exams, before being elected to Fellowship of the Institute. John was the winner of the 1994 Artist Craftsman competition of the Worshipful Company of Clockmakers and is now closely involved with ICON [the Institute of Conservation]. He is one of just ten horologists who have gained accreditation with the institute as professional conservators, and is the only member specializing in chronometer work. SALES POINTS * Provides a comprehensive history of this intriguing piece of navigational equipment * An invaluable reference work for maritime history enthusiasts and clock collectors * Explains the working of the chronometer and provides hints for care and maintenance * Superbly illustrated with 146 colour photographs * John Cronin is a Fellow of the British Horological Institute and is one of only ten horologists with the Institute of Conservation ILLUSTRATIONS 146 colour photos *

The Marine Chronometers at Greenwich is the fifth, and largest, of the distinguished series of catalogues of instruments in the collections of the National Maritime Museum. Housed at the Royal Observatory Greenwich — the 'home of time' and the Prime Meridian of the world — this extraordinary collection, which includes the celebrated marine timekeepers by John Harrison (1693-1776), is generally considered to be the finest of its kind in existence. The book is however much more than just a catalogue, and includes an accessible and engaging history of the chronometer, revealing why these instruments were important in our scientific and cultural history, and explaining, in simple terms, how they worked and were used. A comprehensive Glossary and Bibliography are included to ensure any technicalities are explained and that the reader has suggestions for useful 'further reading'. Over 480 photographs and illustrations, including many fine macro-photographs and line drawings, illustrate the 'jewel-like' beauty of the chronometer's construction and explain the function and subtleties of its mechanism. A chapter on 'How the Chronometer was Made', describes the fine sub-division of labour used to create these special machines, from bare metal, right up to delivery on board ship, and brief biographies of the makers tell the human story behind this important nineteenth-century industry. Another chapter, 'The Evolution of the Chronometer', aimed at collectors, historians and curators, provides clearly structured information on assessing and dating the chronometer, something many find difficult. And, for the dedicated specialist, there is extensive tabulated data on the technical structure of this important collection, a unique resource for future research.