It’s a stretch to claim Benjamin Franklin as a fellow geophysicist. But I think we have more claim to him than the optometrists who consider Franklin a fellow glasses-maker. (Franklin invented bifocals.) Franklin, whose birthday is today, studied lightning and ocean currents and had ideas about plate tectonics. Earth physics. He also had a few things to say about science and religion – we’ll get to that in a moment.

Most of the readers of this blog (about 60% of you) live in the USA. So you know this great American hero of The Revolution. For the rest of the readers, I’ll recap just a few of the many highlights of Franklin’s life.

Ben Franklin was born on this day (January 17) in 1706. His father was a rather ineffective merchant of soaps and candles and Ben was the youngest son in the family of 17 children – the family had little money, so Ben had a very short formal education. About two years, actually. At age 10, he was pulled from school to help his father make soaps and tallow candles. As a teenager, Ben Franklin apprenticed as a newspaper printer for his older brother. His brother wouldn’t let him write for the paper, so Ben discreetly submitted tidbits of gossip and news under the pseudonym Mrs Silence Dogood. James Franklin was outraged when he discovered he’d been duped into printing his little brother’s gossip. So at age 17, Ben Franklin became a fugitive – he broke the law by running away from his apprenticeship. He left Boston and went to Philadelphia.

Ben Franklin opened his own publishing shop in Philadelphia, perhaps a risky move for a fugitive. He published Poor Richard’s Almanac which became a wellspring of wholesome adages. These included didactic witticisms like “Time is money“, and “Success has ruined many a man.” The sort of profundities that modern philosophers such as Deepak Chopra and Eckhart Tolle now make millions publishing. Banalities paid well in those days, too. With the cash, Franklin cobbled together a chain of newspapers that extended from Charleston, South Carolina, up to the New England states. Franklin made most of his money as a publisher and author.

The uneducated fugitive founded the American Philosophical Society (1743) and the first hospital in America (1751). Multi-talented Franklin is the first American chess player known by name – he wrote an essay, The Morals of Chess, in which he expounded upon attributes a good chess player employs: Foresight, Circumspection, and Caution. The man also loved music: he played the violin and harp, and wrote a notable string quartet. (Follow this link to hear it performed with a full orchestra and with the glass harmonica he invented.)

Ben Franklin always had a revolutionary spirit and his writings were filled with liberal sentiments of American independence and republicanism. He was imprisoned (briefly) for publicly airing his thoughts about England’s king and the king’s intentions for America. Eventually Franklin helped write the Declaration of Independence. When Thomas Jefferson sent Ben Franklin a copy to be edited, Franklin changed an important line. “We hold these truths to be sacred and undeniable…” became instead an assertion of rationality: “We hold these truths to be self-evident…” The use of the word sacred, said Franklin, inserted a sense of religiosity that he wanted kept out of government documents. Benjamin Franklin was a deist – a person who accepts that a god of some sort likely exists, but who rejects prayer and numinous texts and sees no role for divinity in the affairs of humans or natural events. And like many deists of his day, Franklin also had a strong scientific curiosity.

Franklin famously flew a kite to investigate lightning – it was an electrifying experience. With proof that lightning is electricity, he invented lightning rods – iron spires that can attract bolts of lightning and transfer their power safely to the ground. This invention prevented house and barn fires and saved thousands of lives.

In a totally different scientific endeavour, Franklin figured out and named the Gulf Stream – he had mariners take temperature and flow measurements in the Atlantic, then he put together all the data into the first map of the warming current, in 1768.

It is not surprising that Benjamin Franklin also had clever geological insights. He observed that the horrific Icelandic volcano Laki, which erupted in 1783 while he was living in Europe, had caused the dreadful winter weather felt on the continent in 1784. Franklin noted the season began with heavy smoke and fog, which he speculated were caused by volcanic ash. Franklin was the first scientist to grasp the volcano-weather relationship.

On the Theory of the Earth, a 1782 message to French geologist Abbé Giraud-Soulavie, Franklin described the way islands and continents might move about on the Earth’s surface. In his letter, he construes how an island he observed might have obtained its twisted, convoluted layers of rock:

“Some part of it having been depressed under the sea, and other parts, which had been under it, raised up. Such changes in the surface parts of the globe seem to me unlikely to happen if the Earth were solid to the centre. I therefore imagine that the internal parts might be a fluid more dense than any of the solids we are acquainted with, which therefore might swim in and upon that fluid. Thus the surface of the Earth would be a shell, capable of being broken and disordered by the violent movements of the fluid on which it rested.”

Benjamin Franklin described an Earth with thick, dense fluid inside which causes the surface crust to be violently broken and mobile – no one else would come closer to describing the modern theory of plate tectonics for almost two hundred years. But his comment, a mere speculation, was not noticed by geologists. And if it had been, they had no way to test its validity. However, this letter further panegyrizes the brilliance of the man with a brain that seemed to think about everything. So we celebrate Ben Franklin today, on the 309th anniversary of his birth. And perhaps imbue ourselves with this pithy poem:

“If you would not be forgotten

As soon as you are dead and rotten,

Either write things worth reading,

Or do things worth the writing.” – Ben Franklin, 1738