The British mariner's assistant [electronic resource] : containing forty tables, adapted to the several purposes of trigonometry and navigation. To which are prefixed, an essay on logarithms, and navigation epitomized; Containing Rules for solving the most necessary Problems, with the Method of finding the Latitude at Sea, by Observations taken either before or after Noon, &c. &c. By Benjamin Donn. Master of the Academy at Kingston, near Taunton, Somersetshire, and Author of the Mathematical Essays, The Accountant, The Geometrician, &c.