Line of Position Navigation

Includes reprint of Thomas A. Sumner's A new and accurate method of finding a ship's position at sea, by projection on Mercator's chart (Boston: T. Groom, 1843) as well as translations of Marcq Saint-Hilaires's Note sur la determination du point (originally published in Revue maritime et coloniale, Oct. 1873) and Calcul du point observe (originally published in Revue maritime et coloniale, Mar.-Aug. 1875).