Sunday, July 26, 2015

The first American invention

By day, Thomas Godfrey was a glazier -- a man who installed glass windows -- in colonial America. But on nights and weekends, he studied science and math. He wrote mathematical problems (and their solutions) and astronomical data for Benjamin Franklin's almanac and his weekly newspaper. Along with the wealthy and influential Quaker merchant, James Logan, Godfrey was a founding member of Benjamin Franklin’s Junto Club in 1727. They discussed the arts, science, and philosophy. This was quite a social circle for a man of modest means with no formal education. But this is America, land of the free, home of the brave, and nation of upward mobility. Godfrey knew math and glass. He put them together to invent a navigational device that is still in use today.

But credit for the sextant went to an Englishman, who may not have invented it.

Franklin's friendship with Godfrey went beyond the Junto Club, as the printer included the glassman in founding the Pennsylvania Hospital, the American Philosophical Society, and the public library in Philadelphia.

Godfrey was 1 when his father died. His mother apprenticed him to a glazier at age 12. This was a good trade, and he was good at it. He installed the windows at Independence Hall, after installing the windows at Logan's mansion. Logan was good friends with William Penn. It helps to have friends in high places.

But Godfrey had a thirst for knowledge. He read every book he could fund and when he ran out of books in English, he taught himself to read Latin. One of the Latin books he read was Sir Isaac Newton's "Principia Mathematica," which is how he and Logan became friends. Logan was a botanist.

Still, Godfrey had to earn a living. One day while installing windows, he noticed a girl with a pail of water in the reflection of the glass. At that moment he noticed that the sky was reflecting in the pail of water. The glass had acted as a mirror, as had the pail of water.

These are common occurrences. But putting the two together allowed him gave him an idea for improving the quadrant. Logan encouraged him. In 1730, he came up with a double reflecting quadrant, which was the forerunner of the sextant. This allowed navigators to use something besides the sun and the horizon to determine position, which meant they could now determine their longitudinal position (east-west) as well as their latitude (north-south) based on the time of day.

In October 1730, George Stewart, a mariner, brought Godfrey a quadrant which he turned into the first double reflecting quadrant. Stewart tested it on a trip to Jamaica and on a voyage to Newfoundland.

Here is where the history gets murky. While there is no doubt that Godfrey invented the sextant, Englishman Thomas Headley may have invented it as well. Or he may have come in possession of the idea or even a model of the sextant from a sailor in Jamaica. At any rate, James Hadley, vice president of the Royal Society in London, told society members that he had invented a sextant in the spring of 1731.

A dispute arose over who invented it. Logan wrote to Dr. Edmund Halley (of Halley's Comet fame) to vouch for Godfrey, as did Stewart. The instruments were slightly different so it is more likely than not that this was a dual invention made independently by two men who had no communication between them. The Royal Society credited both men.

In the meantime, Godfrey had a falling out with Franklin, who had rented him and his family rooms beginning in 1727. In his memoirs, Franklin wrote that Godfrey was "a self-taught mathematician, great in his way" but who "knew little out of his way, and was not a pleasing companion, as like most great mathematicians I have met with, he expected precision in every thing, and was ever denying and distinguishing upon trifles, to the disturbance of all conversation."

Godfrey died of alcoholism in 1749. As with his birth in 1704, the exact date of his death no longer is known. But at his gravesite at Laurel Cemetery what is important about him is remembered: his invention more than 250 years later. And it should be. It was the first important invention in America.

My first collection of "Exceptional Americans" is available here. And the Kindle version is here.


  1. Of course, the sextant was no good without an accurate chronometer. Without knowing the precise time, longitude was impossible to determine. Yes. I consider myself a mathematician, and as such I am "distinguishing upon trifles", Most good computer programmers are. After all, one missing comma, one misplaced quote sign, and the program will fail.