Thomas Godfrey (6)

Thomas Godfrey (10 January 1704–November 1749) was a glazier, mathematician, astronomer, almanac-maker, and inventor, and an original member of the American Philosophical Society. Born in Bristol Township, Pennsylvania, he glazed windows for the State House and the residence of James Logan, who took an interest in the self-taught Godfrey and loaned him books. As part of Benjamin Franklin’s circle, Godfrey was a member of the Junto, a founder of the Library Company and the Philadelphia Contributionship, and an early supporter of the Pennsylvania Hospital. His Pennsylvania Almanac was published between 1730 and 1737; early numbers were printed by Franklin, who also rented Godfrey rooms in the building that housed his print shop. Godfrey’s trade dovetailed with his scientific pursuits. In 1730 he invented the mariner’s quadrant, an instrument used to calculate the altitude of a star from onboard a ship—and thus to establish the ship’s latitude—by observing the sun’s reflection in glass. But simultaneous to Godfrey’s announcement of his discovery, Royal Society vice-president John Hadley publicized his own nearly identical invention. Although Godfrey’s report on another instrument was published in the Royal Society’s Philosophical Transactions, his claims about the quadrant were never acknowledged. The two discoveries appear to have been independent, but the device still bears Hadley’s name today. In his later years, Godfrey taught astronomy and advised surveyors and cartographers. (PI, ANB, DAB)