Letters to the editor written in the guise of a woman were one of Franklin’s earliest and favorite forms of satire. The present example is the only instance we have seen of his crafting this sort of spoof in France. Whether it was truly intended for publication or simply meant to amuse his friends is not known; no mention of it has been found in any of his correspondence, and it never appeared in print. Despite its obvious appeal, the piece lay unidentified among Franklin’s papers until the present edition was launched.9

Franklin drafted this letter in French. The heavily labored manuscript shows him trying to refine his wording, correct the genders of his nouns, and wrestle his verbs into the proper form. He had his grandson Benny Bache prepare a fair copy, which suffers from Benny’s occasional spelling errors, and that copy was shown to a Frenchman—possibly Le Roy—who interlined a few suggestions, which we note in annotation. We publish the text as Franklin wrote it.

The problem so ingeniously solved by this female “subscriber” (“abonnée” is in the feminine) was one that French scientists were considering in the summer of 1783: how to generate the lightest and least expensive gas to fill a balloon. In late July, when Montgolfier announced his plan to demonstrate a machine aérostatique in Paris, scientists began speculating on what mysterious substance he could be using. Based on the calculations he had submitted, they realized that whatever it was, it could never achieve the levity of the newly discovered air inflammable (hydrogen), which was ten times lighter than air. Generating a sufficient quantity of hydrogen, however, would be painstaking and very expensive. As noted elsewhere in this volume, a team led by the physicist Jacques-Alexandre-César Charles raised public money to fabricate a balloon and fill it with l’air inflammable. Their highly publicized work culminated in a launch on August 27 witnessed by thousands of delighted spectators who, it seems, could talk of little else for weeks. When describing the experiment to Joseph Banks on August 30, Franklin mentioned a few of the fanciful applications that were being discussed, ranging from manned flight to refrigeration.1

Ascribing a date to this manuscript has posed its challenges, but we think it likely that Franklin wrote it in the giddy aftermath of Charles’s August 27 experiment. According to this “abonnée,” even a fool such as herself knew that there existed a substance ten times lighter still than l’air inflammable and available in abundance.