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Papers of the Board of Longitude : Papers regarding Arnold and Earnshaw's chronometers and claims for reward

Papers of the Board of Longitude

<p style='text-align: justify;'>This volume contains letters from John Arnold (see <a target='_blank' class='externalLink' href=''>portrait</a> at the British Museum) (and later, his son, John Roger Arnold (see <a target='_blank' class='externalLink' href=''>portrait</a> at the Science Museum Group) and Thomas Earnshaw [<a target='_blank' class='externalLink' href=''><img title="Link to RMG" alt='RMG icon' class='nmm_icon' src='/images/general/nmm_small.png'/></a>]. Arnold and Earnshaw both claimed rewards from the Board of Longitude in recognition of the quality of their timekeepers. However, confusion over the patenting of the sprint detent escapement led to a protracted encounter. Correspondence from the watchmakers is broken up with occasional testimonies from Admiralty and East India Captains and agents concerning the quality their work. Alongside <a href='/view/MS-RGO-00014-00026'> (RGO 14/26)</a> and <a href='/view/MS-RGO-00014-00027'> (RGO 14/27)</a>, this volume makes up a substantial part of the documentation of the dispute.</p><p style='text-align: justify;'>This volume begins with John Arnold's letters to the Board in 1783 concerning the going of his timekeepers. It ends with his son's concerned letter to the Board in 1809 about Thomas Earnshaw's 1808 appeal to the public in which he claimed certain members of the Board and the Arnold family had cheated him. Arnold and Earnshaw's initial contestations over the patenting of the spring detent escapement arose from Earnshaw's claim that Arnold's patent in 1782 was based not on his own discovery but on seeing it at another watchmakers shop. The volume records the reactions of both watchmakers to the Board's decision to both £3000 reward for their work developing timekeepers and their subsequent disclosure of their principles of design and construction.</p><p style='text-align: justify;'>Of particular significance in this volume are the documents relating to the Board's attempts to understand the claims made by Earnshaw and Arnold over the spring detent escapement. On March 3, 1803 the Board of Longitude had voted for Earnshaw to be rewarded £3000, in recognition of the apparently superior going of his timekeepers at the Royal Observatory compared to other timekeepers that had been submitted. This was on the condition that he disclosed the principles of the construction of his timekeeper [<a target='_blank' class='externalLink' href=''><img title="Link to RMG" alt='RMG icon' class='nmm_icon' src='/images/general/nmm_small.png'/></a>] so that other members of the watchmaking community could both comprehend and replicate his design. Entering into this process, however, meant that the Board came up against the contested claims by Earnshaw and Arnold (with the forceful backing of Joseph Banks [<a target='_blank' class='externalLink' href=''><img title="Link to RMG" alt='RMG icon' class='nmm_icon' src='/images/general/nmm_small.png'/></a>])to have been the first to devise the spring detent escapement. This had clearly been an issue for Earnshaw since the early 1780s, but the Board of Longitude had not at that point been obliged to sort it out. On June 2 1803 we see that the Board called before them several witnesses from the watchmaking trade who were asked to testify to matters relating to the invention of the spring detent escapement. Their answers often contradict one another but both the content and the manner of their responses offer a fascinating insight into aspects of the London clockmaking trade. Equally interesting are the type of questions asked by the Board. They go past solely concerning the patent dispute, but also asking questions related specifically to the capacity for production. It is interesting to compare this concern for replication and cost with the contents of the initial act.</p><p style='text-align: justify;'> Equally significant in the volume, however, is the amount of correspondence from users of the timekeepers supplied by the Board. Alongside their particular concern to comment on the quality of the timekeepers to the Board of Longitude, this is particularly interesting because it suggests that many timekeepers were being bought by individual Captains and officers as private buyers.</p><p style='text-align: justify;'>Eóin Phillips<br />History and Philosophy of Science<br />University of Cambridge<br /></p>

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