3. Nathaniel Bowditch and the American Practical Navigator
Nautical navigation was as much an art as it was a science at the beginning of the 19th century, with accurate determination of a ship’s location often dependent on the relative skill and mathematical ability of its officers. Nathaniel Bowditch, a mathematician, actuary, and astronomer, published the New American Practical Navigator in 1802, a guide for seamen which provided accurately calculated celestial tables, tide tables, and other information of use to those at sea. The book was so influential that in the 21st century, in an age of global positioning systems, it is still carried onboard every commissioned vessel of the United States Navy.