Another of his bagatelles was “Dialogue between Franklin and the Gout,” in which Gout explains his frequent and unwelcome visits as due simply to Franklin’s indolence; he plays chess too much and exercises too little. The “Ephemera” was printed as a bagatelle, and so was “The Whistle,” an expanded version of the little story he had once told his son William.
His intellectual curiosity had not slackened during his years in France. War or no war, he continued to observe natural phenomenon, write and reflect on scientific matters, and keep up with the newest discoveries and inventions.
He attended meetings of the Royal Society of Medicine, to which he had been elected in 1777, and of the French Academy of Science. In 1782, he watched Antoine-Laurent Lavoisier perform an experiment with the gas he had named oxygen—Joseph Priestley’s “dephlogistated air.” He wrote to Jan Ingenhousz, a Dutch scientist, about differences between the Leyden jar and Volta’s new electrophorus, and to Edward Nairne, an English friend, about the comparative humidity of the air in London, Philadelphia and Passy.
To a French friend, Count de Gebelin, he discoursed on the characteristics of the various Indian languages. When de Gebelin commented that some Indian words sounded Phoenician, Franklin dived into archaeological speculations:
If any Phoenicians arrived in America, I should rather think it was not by the accident of a storm but in the course of their long and adventurous voyages; and that they coasted from Denmark and Norway over to Greenland, and down southward by Newfoundland, Nova Scotia, etc., to New England; as the Danes themselves certainly did some ages before Columbus.
He wrote a paper on the phenomenon of the aurora borealis (the northern lights) for the French Academy of Science, sent notes to Marie Antoinette’s physician, Felix Vicq d’Azyr, on the length of time infection could remain in the body after death, and investigated a story of some workmen in the Passy quarry who claimed to have found living toads shut up in solid stone.
In a letter to another friend, the Abbé Soulavie, he pondered on why there were coal mines under the sea at Whitehaven and oyster shells in the Derbyshire mountains—indications of great geological changes in the past. Was it possible that the surface of the earth was a shell “capable of being broken and disordered by the violent movements of the fluid on which it rested?” Admittedly, this was only a guess: “I approve much more your method of philosophizing, which proceeds upon actual observations....”
He still tinkered with inventions, and for his own comfort devised the first bifocal glasses, so he could see both near and far without changing his spectacles.
He was old enough to be serious all the time, but he never could resist a hoax, even with his scientific friends. To the eminent French physician Georges Cabanis he confided that in the forests of North America he had observed a bird which “like the horned screamer or the horned lapwing, carries two horned tubercles at the joints of the wings. These two tubercles at the death of the bird become the sprouts of two vegetable stalks, which grow at first in sucking the juice from its cadaver and which subsequently attach themselves to the earth in order to live in the manner of plants and trees.”
The inspiration for this weird creation of his imagination was perhaps the “vegetable animal” he thought he saw on the gulf weed he had fished out of the Gulf Stream at the age of twenty. His friend Cabanis, suspecting nothing, dutifully reported it in one of his books, taking only the precaution to note that “in spite of the great veracity of Franklin, I cite it with a great deal of reserve.”