On this day in 1802, Harvard College awarded Nathaniel Bowditch an honorary Master's Degree. The Salem-born astronomer, mathematician, and navigator was almost entirely self-educated. His formal schooling ended when he was ten. While apprenticed to a ship chandler, he taught himself mathematics, astronomy, Latin, Greek, and French. Later, during his years at sea, he began working on The New American Practical Navigator, the first complete and accurate handbook of navigation tables. The Practical Navigator was published in 1802. It is still in print, and in use, over two centuries later. Tradition has it that no sailor left port without a Bible, a chest of clothes, a mother's blessing, and his copy of Bowditch.