National Maritime Museum Manuscripts : Letters relating to Andrew Mackay's teaching activities and publications

Mackay, Andrew

National Maritime Museum Manuscripts

<p style='text-align: justify;'>A series of several letters sent from Andrew Mackay, a well-known teacher of mathematics, navigation, geography and naval architecture, to Trinity House concerning the publication of the third edition of his The theory and practice of finding the longitude at sea or on land. Trinity House is a Corporation that received its Royal Charter in 1514 from King Henry VIII, which by the late eighteenth century held a powerful maritime position in England, deriving a great deal of wealth from its monopoly over licensing pilots in the River Thames and the levying of duties from the many private lighthouses in Britain. Alongside this, Trinity House's Brethren had prominent socio-political standing, as they were frequently called as experts to court for cases concerning events at sea.</p>. <p style='text-align: justify;'>For this reason we can easily understand why, in the <a href='' onclick='store.loadPage(1);return false;'> opening pages (MKY/9: 1:1-1:2)</a> of this document, Mackay was asking for help from Trinity House. It should also be remembered that in the late eighteenth century there was a whole slew of popular mathematical and navigational texts competing for status, so having Trinity House underwrite Mackay's text would lend it crucial epistemological as well economic support.</p><p style='text-align: justify;'>The <a href='' onclick='store.loadPage(27);return false;'> remainder of the document (MKY/9: 9:1-9:22)</a> is range of testimonies compiled by Mackay, in the hope of demonstrating to those at Trinity House a range of positive responses for his character and praise for the first edition of his The theory and practice of finding longitude. That the first of Mackay's testimonies is from the Astronomer Royal Nevil Maskelyne is very relevant. It should be noted that Mackay's text isn't simply a testament of the ways by which longitude could be found in the late eighteenth and early nineteenth century, rather it functions as a manifesto in support of the astronomical methods that should be deployed to find longitude. Indeed, in the introduction to all the early editions of The theory and practice of finding longitude, Mackay wrote that 'It is well known, that every chronometer hitherto contrived is subject to irregularities…Upon this and other accounts therefore, their accuracy is very much to be suspects, so that at present they are chiefly used for experiment, or to connect observations.'(p.vii, intro, 193 ed.) Continuing the support for an astronomical, rather than just a chronometric solution to the problem of longitude was something that really concerned Nevil Maskelyne. As Astronomer Royal and as a member of the Board of Longitude, he had a deep-seated interest in promoting the continued production and use of the Nautical Almanac - something which the Royal Observatory at Greenwich was almost exclusively geared up for producing.</p><p style='text-align: justify;'>Eóin Phillips<br />History and Philosophy of Science<br />University of Cambridge<br /></p>