English navigator John Davis (ca. 1550-1605), though remembered chiefly as a northern explorer, sailed many seas, took part in naval fighting, and invented a nautical instrument.

John Davis, a Devonshire man, was friendly with the Gilbert and Raleigh families and at times sailed with members of both. One of the most proficient seamen of his day, he published both a practical and a theoretical work on navigation. The backstaff he invented for finding altitudes of heavenly bodies at sea (so named because the pilot using it turned his back to the sun) held the field for a century and a half.

Davis made his first exploration voyage in 1585 in search of the Northwest Passage to the Orient. He rounded Cape Farewell in Greenland, and went north to Godthaab (64°N) before crossing Davis Strait to Cumberland Gulf in Baffin Island, where the lateness of the season compelled his...