National Maritime Museum Manuscripts : Navigational workbook: notes and working on horizontal vibrations and chronometers at Greenwich and Hartwell

Fisher, George

National Maritime Museum Manuscripts

<p style='text-align: justify;'>After George Fisher had returned from two Arctic voyages, the first with David Buchan on board HMS Dorothea in 1818, the second with William Parry in 1821 on HMS Fury , he continued his research into the effect of environmental conditions on the rate of chronometers. Of particular interest was the variation of the going rate of a chronometer in relation to its proximity to metal, particularly shipboard iron. This workbook is filled with data, variations in the rates of chronometers in different situations as well as error rates for the clocks used as standards in Fisher’s work. The volume gives a useful insight into his continued interest in the effect of magnetic force and other external factors on the regularity of chronometers, whilst overseeing the construction and planning of a new observatory at the Royal Hospital School in Greenwich after his retirement from the Navy.</p><p style='text-align: justify;'>The workbook contains error rates for a variety of chronometers including some made by the renowned makers of the day, for <a href='' onclick='store.loadPage(4);return false;'> example (FIS/20:2-3)</a> there are the rates of an Arnold and Dent chronometer taken in 1837 toward the end of the Edward John Dent and John Roger Arnold’s Strand based partnership. The workbook also includes people that collaborated with Fisher, for example several investigations were conducted with Mr E Riddle, the same man whose paper was read on the 14th of March 1828 at the Astronomical Society of London, entitled <i>‘On finding the rates of time keepers’</i> and who, along with Fisher, assisted at Greenwich with the Observatory’s observation of the Solar Eclipse of the 8th of October 1847. Fisher and Riddle worked together on <a href='' onclick='store.loadPage(12);return false;'> observations (FIS/20:10)</a> on the rates of chronometers made on August 25th and 26th 1837. They performed more <a href='' onclick='store.loadPage(26);return false;'> comparative observations (FIS/20:24)</a> later on in the year as well on 14th September.</p><p style='text-align: justify;'>There is also the <a href='' onclick='store.loadPage(33);return false;'> work (FIS/20:31)</a> on comparisons of the longitude of the Observatories of Greenwich and Paris taken by twelve different chronometers. Additionally there are <a href='' onclick='store.loadPage(51);return false;'> measurements (FIS/20:49)</a> of the vibrations in the direction of a series of needles taken in various places in England, Plymouth for example, as well as various ports overseas, for example Bermuda, Portugal, Antigua and Barbados. The dates for the measurement ranges from 1834 to 1837 whilst Fisher was resident in Greenwich, having retired from the Navy on half-pay and taken up the Headmastership of the Royal Hospital School in 1834, so who collected the data is unknown. This serves as a reminder of the importance of informal networks between men of science and serving naval and commercial officers in the procurement of data from across the globe. Later in the workbook there is a collection of data that Fisher has entitled <a href='' onclick='store.loadPage(75);return false;'> “An abstract of observations made in the West Indies and North America upon the intensity of magnetic force by various authorities” (FIS/20:73)</a> Here the men whose data Fisher is using are named, among them is Edward Sabine and later we see him using the data on the <a href='' onclick='store.loadPage(87);return false;'> vibrations made in a dipping needle (FIS/20:85)</a> by Captain Sir E Home.</p><p style='text-align: justify;'>Note that the text is inverted in the volume from folios 49 to 88.</p><p style='text-align: justify;'>Sophie Waring<br />History and Philosophy of Science<br />University of Cambridge<br /></p>