THE LOST SCIENCE OF JOHN "LONGITUDE" HARRISON by William S. Laycock (Kent, England): Brant Wright Associates Limited, 1976. First edition, first printing; Limited and numbered. This is copy number 21, stamped '21' to the limitation half-title page. SIGNED by the author to the title page. Illustrated with twelve quality black-and-white plates, and with one-hundred forty-four figure drawings. An in-depth account of Harrison's elusive scientific calculations on the accuracy of determining longitude while on a ship at sea, shown by the methods used in several types of clocks that he invented. Harrison, a clock maker who created the marine chronometer, invented several sea clocks and longitude watches that would retain accuracy at sea in spite of ship movement and humidity. This work explains various methods of calculating longitude by the clocks, and has details of their machinations and construction. Publications containing this detailed information are quite elusive. Well preserved. Lightly bumped to the lower spine end, first few pages show a tiny crimp to the lower corner tips, else near fine in red-clay linen with gilt embossed titles to the spine; in a near fine dust jacket with just a touch of fading to the lower spine panel end, slightly rubbed crimps to the upper and lower spine edges and corner tips, a tiny tear to the lower edge of the front flap fold; original printed prices 'USA: $45.75 18.75' still intact to the front inner flap. Quarto; 159 pages; appreciation; preface; bibliography; index. FREE SHIPPING TO THE USA. PLEASE VIEW OUR STORE FOR MORE FIRST EDITION ILLUSTRATED BOOKS THANKS! Created by Seller's Assistant Basic.