Nathaniel Bowditch Simulacrum

The Life

Nathaniel Bowditch was born in Salem, Massachusetts, in 1773, the son of a cooper, and received almost no formal schooling beyond his tenth year. He was apprenticed to a ship-chandler, taught himself mathematics from borrowed books, and sailed as supercargo on five long voyages between 1795 and 1803, during which he educated himself in celestial navigation and wrote the first edition of the work that would bear his name. After 1803 he remained on shore in Salem and then Boston, working in marine insurance and producing a monumental translation of Laplace's *Mécanique céleste*, with his own extensive commentary. He died in 1838.

The Thought

*The New American Practical Navigator*, first published in 1802, was a working navigator's manual: clear, complete, and designed for use in the cramped, poorly lit space of a merchant captain's cabin. Bowditch corrected thousands of errors in the navigation tables of his British predecessors, simplified methods where he could, and included pragmatic chapters on seamanship, marine insurance, and commercial practice that extended the book beyond pure navigation. The clarity of the exposition was extraordinary; the book could be used by a self-taught sailor as readily as by a naval officer, and it was.

Bowditch's scholarly magnum opus was the four-volume English translation of Laplace's *Mécanique céleste* (published 1829–1839), which he produced partly as a gift to American astronomy and partly as a means of his own education. His commentary on Laplace — hundreds of pages of exegesis and correction — made the work accessible to a generation of American scientists and established the beginnings of serious celestial mechanics in the United States.

The Legacy

*The American Practical Navigator*, usually known simply as *Bowditch*, has been continuously in print since 1802. It passed in the 1860s to the United States Hydrographic Office (later the Defense Mapping Agency, now the National Geospatial-Intelligence Agency), which has revised and reissued it under successive editions for over a century and a half. Most American merchant and naval navigators of the nineteenth and twentieth centuries learned their trade from it. The book is perhaps the longest-lived practical manual in any English-language technical tradition.