Papers of the Board of Longitude : Correspondence regarding methods of establishing longitude by lunar methods other than lunar distances

Papers of the Board of Longitude

<p style='text-align: justify;'>This volume is a continuation from volume <a href='/view/MS-RGO-00014-00034'> (RGO 14/34)</a>. It contains additional correspondence in 28 numbered sections. Lunar methods of finding the longitude at sea - other than the lunar-distance method improved and championed by central actors such as Nevil Maskelyne [<a target='_blank' class='externalLink' href='http://collections.rmg.co.uk/collections/objects/379043.html'><img title="Link to RMG" alt='RMG icon' class='nmm_icon' src='/images/general/nmm_small.png'/></a>] and Tobias Meyer - are the subject of most letters. The correspondence mostly dates from 1782 to 1828. It is weighted, as are all of the RGO volumes, towards the later history and activities of the Board of Longitude.</p><p style='text-align: justify;'>This volume belongs to a series of RGO volumes into which the later Astronomer Royal George Airy [<a target='_blank' class='externalLink' href='http://collections.rmg.co.uk/collections/objects/13981.html'><img title="Link to RMG" alt='RMG icon' class='nmm_icon' src='/images/general/nmm_small.png'/></a>] sorted Board of Longitude correspondence regarding different types of schemes in 1858. The contents of volumes <a href='/view/MS-RGO-00014-00032'> (RGO 14/32)</a> and <a href='/view/MS-RGO-00014-00033'> (RGO 14/33)</a> discuss the lunar-distance method, <a href='/view/MS-RGO-00014-00034'> (RGO 14/34)</a> and <a href='' onclick='store.loadPage();return false;'>RGO 14/35</a> regard other lunar methods, <a href='/view/MS-RGO-00014-00036'> (RGO 14/36)</a> and <a href='/view/MS-RGO-00014-00037'> (RGO 14/37)</a> encompass astronomical methods employing Jupiter's moons and the planets and fixed stars, <a href='/view/MS-RGO-00014-00038'> (RGO 14/38)</a> deals with other methods and instruments including the use of chronometers, and <a href='/view/MS-RGO-00014-00039'> (RGO 14/39)</a> and <a href='/view/MS-RGO-00014-00040'> (RGO 14/40)</a> contain so-called 'impracticable' schemes.</p><p style='text-align: justify;'>Throughout its existence as an officially meeting and then standing institution, the Board of Longitude mainly pursued lunar distances amongst the astronomical schemes for finding longitude at sea. This became firmly embedded in the body's outlook and activities from the 1760s on especially as the proactive Commissioner and Astronomer Royal Nevil Maskleyne oversaw the testing, improvement and use of the method through its employment on expeditions and through the production of publications including the annual Nautical Almanac. However, the Board also periodically considered alternative lunar methods, many of which involved taking the altitude of the Moon. A number of the letters in this volume record the judgments passed upon these methods by Maskelyne and by other experts and practitioners, as well as the dates upon which the Commissioners heard the correspondence and sometimes took relevant actions, as is elaborated upon in other sources including the official Board minutes. For example, Maskelyne noted on the <a href='' onclick='store.loadPage(524);return false;'> back of a letter (RGO 14/35:506v)</a> from Nicholas May in 1782, that May should be informed that he could lay his longitude proposal before the Board as well as his explanation for the flux and reflux of the tides, but that he should be informed that Isaac Newton [<a target='_blank' class='externalLink' href='http://collections.rmg.co.uk/collections/objects/127461.html'><img title="Link to RMG" alt='RMG icon' class='nmm_icon' src='/images/general/nmm_small.png'/></a>] had already explained tidal movement.</p><p style='text-align: justify;'>Many of the projectors in this volume were repeat collaborators of the Board and of Maskelyne, such as the astronomers Francis Baily [<a target='_blank' class='externalLink' href='http://collections.rmg.co.uk/collections/objects/136488.html'><img title="Link to RMG" alt='RMG icon' class='nmm_icon' src='/images/general/nmm_small.png'/></a>], Fearon Fallows and William Garrard [<a target='_blank' class='externalLink' href='http://collections.rmg.co.uk/collections/objects/43086.html'><img title="Link to RMG" alt='RMG icon' class='nmm_icon' src='/images/general/nmm_small.png'/></a>]) or other relevant practitioners (such as the mathematician Thomas Beverley, the Naval Master Thomas Hedgcock, and the Royal Lieutenant and instrument inventor George Lindesay). (A number of treatises have also become divorced from their authors due to absent cover letters.) The projectors mostly hailed from Britain but included a small number of foreigners such as Don Anotonio Maria Jaci of Messina in Sicily, Le Duc de Duhamel of France (writing from County Durham), G. Riboult the head of the district of Simferopol in the Crimea (then in the Russian Empire), and Joseph Emanuel Pellizer of Spain. Pellizer corresponded with the Board for more than 20 years and at one point, in a letter now in<a href='/view/MS-RGO-00014-00012/'> RGO 14/12 (RGO 14/12:401)</a>, wrote that because his proposal had been forwarded by the Admiralty he was not violating the Commissioners' earlier order to never contact them again.</p><p style='text-align: justify;'>The majority of the projectors' schemes, tables and technologies revolved around taking lunar altitudes. A small number instead relied upon lunar transits (such as Malcolm Cowan, Le Duc de Duhamel, Fearon Fallows, J.B. Emmett), occultations of stars by the Moon (Francis Baily and Thomas Beverley), the horary angles of the Sun and Moon (George Lindesay), the variation of the Moon's right ascension (John Manderson), its times of rising and setting (unknown author), and its refraction and parallax and semi-diameter (William Garrard). Some of their letters deal with other matters related to longitude, navigation or science as well. For example, David Kirkpatrick of Liverpool discusses his artificial horizon, one of the instruments in which he tried to interest the Board from 1812 to 1815 and then again in 1826 - as is recorded in <a href='/view/MS-RGO-00014-00029'> (RGO 14/29)</a>.</p><p style='text-align: justify;'>The contents of this volume, like others in the RGO 14 archives, reflect the extent to which the activities of the Board of Longitude intertwined with those of other bodies, especially the Admiralty. They also show how the Board's running and activities involved as many or more interpersonal interactions and individual decisions as they did official meetings and communal decision-making. Some of this correspondence was sent to individual actors rather than to the relevant institutions. For example, Malcolm Cowan of Orkney's <a href='' onclick='store.loadPage();return false;'> letter (RGO 14/35:359)</a> of 1818 sought the opinion of Joseph Banks [<a target='_blank' class='externalLink' href='http://collections.rmg.co.uk/collections/objects/145444.html'><img title="Link to RMG" alt='RMG icon' class='nmm_icon' src='/images/general/nmm_small.png'/></a>]. Many letters further exhibit how common it was for longitude projectors to seek the Board's financial aid because of a litany of troubles. For example in 1813, Robert Pringle [<a target='_blank' class='externalLink' href='http://collections.rmg.co.uk/collections/objects/540873.html'><img title="Link to RMG" alt='RMG icon' class='nmm_icon' src='/images/general/nmm_small.png'/></a>] of Messina <a href='' onclick='store.loadPage();return false;'> wrote (RGO 14/35:517)</a> on behalf of his friend Don Anotonio Maria Jaci that his 'unremitted application to study has so injured his sight that he is now almost deprived of it and consequently [...] is actually reduced to the necessity of living on the bounty of his friends'.</p><p style='text-align: justify;'>All of the above themes also appear in the <a href='' onclick='store.loadPage();return false;'> first section (RGO 14/35:272)</a> of letters in this volume, which date from 1813 to 1827 and regard the efforts of the Naval Master Thomas Hedgcock to garner attention and rewards for his method of finding the longitude and setting the rates of chronometers at sea via observations of the Moon's altitude. Hedgcock originally lobbied the Admiralty for monetary assistance, but the Secretary of the Admiralty John Croker [<a target='_blank' class='externalLink' href='http://collections.rmg.co.uk/collections/objects/136519.html'><img title="Link to RMG" alt='RMG icon' class='nmm_icon' src='/images/general/nmm_small.png'/></a>] turned the matter over to the Secretary of the Board of Longitude, Captain Thomas Hurd [<a target='_blank' class='externalLink' href='http://collections.rmg.co.uk/collections/objects/540752.html'><img title="Link to RMG" alt='RMG icon' class='nmm_icon' src='/images/general/nmm_small.png'/></a>]. The two men often added brief notes on the backs of the documents, which they exchanged. On the <a href='' onclick='store.loadPage(24);return false;'> back (RGO 14/35:281v)</a> of the initial letter, Croker scribbled on 15 April 1813 that he did not see how this method would prove an advantage over those already in use. He referred it to 'the Hydrographer' -- Hurd was also hydrographer to the Admiralty -- who concurred. On 15 February 1815, Hedgcock <a href='' onclick='store.loadPage();return false;'> asked (RGO 14/35:285)</a> Hurd for assistance in getting lunar observations from Greenwich so that he could prepare to go before the Board, because he feared that Maskleyne would deny him. On 1 June 1815, the Secretary <a href='' onclick='store.loadPage();return false;'> informed (RGO 14/35:287)</a> him that the Board did not approve of his scheme and would not support its publication.</p><p style='text-align: justify;'>On 24 August 1815, Hedgcock <a href='' onclick='store.loadPage();return false;'> responded (RGO 14/35:288)</a> by explicitly requesting money because he had spent so much time ashore to perfect his scheme, and because there were 'two instances where I have been invalided by exposing myself particularly to the Sun'. He also cited his being on half pay and having an aged mother and two nephews, whose father had been injured in Naval service twelve years before. Since the Board of Longitude would not give him any assistance and Maskelyne would not try his scheme at Greenwich, Hedgcock then <a href='' onclick='store.loadPage();return false;'> tried (RGO 14/35:292)</a> the Admiralty once more - although Croker forwarded this letter to Hurd as well. In February 1816, the projector <a href='' onclick='store.loadPage();return false;'> tried (RGO 14/35:295)</a> to move things along by threatening to take his case to the House of Commons as had other longitude actors including, most famously, John Harrison [<a target='_blank' class='externalLink' href='http://collections.rmg.co.uk/usercollections/f9c8ad8b198e42bb44947210a901f7bb.html'><img title="Link to RMG" alt='RMG icon' class='nmm_icon' src='/images/general/nmm_small.png'/></a>]. That September, he <a href='' onclick='store.loadPage();return false;'> requested (RGO 14/35:296)</a> the interference of the Board if their influence could aid him in his 'precarious pecuniary circumstances'.</p><p style='text-align: justify;'>Beginning in 1818, Hedgcock <a href='' onclick='store.loadPage();return false;'> specified (RGO 14/35:301)</a> that his financial needs did not exceed 150 pounds. From 1819 to 1827, he repeatedly sent the Admiralty and the Board (via its new Secretary Thomas Young (see <a target='_blank' class='externalLink' href='http://www.bbc.co.uk/arts/yourpaintings/paintings/thomas-young-17731829-216072'>portrait</a> at BBC Your Paintings) lengthier descriptions of his method and evidence of its use at sea (such as <a href='' onclick='store.loadPage();return false;'> here (RGO 14/35:306)</a>). He also sent printed pamphlets of his explanations (including <a href='' onclick='store.loadPage();return false;'> this (RGO 14/35:314)</a> and later <a href='' onclick='store.loadPage();return false;'> this (RGO 14/35:324)</a>) and once, in 1821, an <a href='' onclick='store.loadPage();return false;'> explanation (RGO 14/35:312)</a> of how to find solar and sidereal time as a basis for all types of longitude solutions. The Board appears to have never given Hedgcock monetary support or its approval.</p><p style='text-align: justify;'>Alexi Baker<br />History and Philosophy of Science<br />University of Cambridge<br /></p>