Description
Letter Signed ‘Andrew Mackay’, to Mr. Nourse, Bookseller in the Strand, soliciting subscriptions to his new work, mentioning “the uncertainty of the sale of scientific books”, referring to reviews, offering to supply copies of “the book on the Longitude already published”. 2¼ pages, 9 x 7 inches, address panel, some paper repairs, light dust soiling. Aberdeen, 25 August 1794. “I have published proposals for a treatise on Navigation, and another on Astronomy, at the end of a work by me upon the Longitude published last year, of which it is probably you may take a part. The Navigation will be about the same size as the treatise on the Longitude …” Andrew Mackay (1760–1809), Scottish mathematician, known as a teacher of navigation. Mackay contributed to the theory of navigation, and was a calculator of mathematical tables. His works include The Theory and Practice of finding the Longitude at Sea or on Land: to which are added various Methods of Determining the Latitude of a Place by Variation of the Compass: with new Tables, published by subscription, 1793, 2 vols.; 2nd edit., with author’s portrait, 1801; 3rd edit. 1810. In this work is given an account of a new method of finding the longitude and latitude of a ship at sea, together with the apparent time, from the same set of observations; for which the author had received the thanks of the boards of longitude of England and France.