8. We date this letter based on two clues: Le Roy’s suggestion that if BF wishes to witness Montgolfier’s experiment he should leave Passy around 3 P.M., and the allusion to fog. Among the six occasions on which Montgolfier launched balloons in Paris, three of them—the trials on Sept. 12 and 19 and on Nov. 21—took place earlier in the day. The much-anticipated experiment of Oct. 19, based on semiprivate, preliminary trials conducted on Oct. 15 and 17 (whose times are unknown), was scheduled for 4:30 P.M. According to the Jour. de Paris, the day was foggy, as the previous several days had been. Contemporary accounts, however, reported that the skies were clear at the time of the launch: Gillispie, Montgolfier Brothers, p. 47.

9. Montgolfier’s October trials were the first manned balloon ascensions, designed to perfect techniques for controlling altitude and landing. His balloon was similar in size and design to the one destroyed on Sept. 12. Below the base he added a wicker gallery from which passengers could feed a burner suspended inside the balloon. The vessel remained tied to the ground with ropes. The passenger during the first tests was Jean-François Pilatre de Rozier, who had applied unsuccessfully to the Académie des sciences in August for permission to fly in Montgolfier’s balloon at Versailles (XL, 550).

Réveillon was inundated with requests from the public to observe these experiments. As the date approached, he announced that the first trials could be attended only by the principals and scientists. His courtyard was small, and he would notify his correspondents as to when they could come: Jour. de Paris, Oct. 11, 1783. After the first trial on Oct. 15, however, news of the first-ever manned flight spread, partly through the efforts of Pilatre himself. Large crowds gathered for the following two experiments. On Oct. 19, before more than 2,000 spectators, Pilatre flew four times, twice with a co-pilot, ascending and descending at will and finally remaining at a height of 324 feet for at least nine minutes: Gillispie, Montgolfier Brothers, pp. 45–8; Barthélemy Faujas de Saint-Fond, Description des expériences de la machine aérostatique de MM. de Montgolfier … (Paris, 1783), pp. 268–78. We have found no evidence that BF attended any of the October trials.

1. Marc-René, marquis de Montalembert (1714–1800), military engineer, general, and member of the Académie des sciences, owned a house at 136 rue de la Roquette, where his wife hosted a popular salon: Larousse; Hillairet, Rues de Paris, 11, 365. The residence was in the same faubourg as Réveillon’s manufactory but northwest of it and therefore somewhat closer to Passy.