Joseph Louis Proust was a French chemist. He was best known for his discovery of the law of definite proportions in 1794, stating that chemical compounds always combine in constant proportions.
Joseph Proust
Jean-François Pilâtre de Rozier
Jean-François Pilâtre de Rozier was a French chemistry and physics teacher, and one of the first pioneers of aviation. He made the first manned free balloon flight with François Laurent d'Arlandes on 21 November 1783, in a Montgolfier balloon. He later died when his balloon crashed near Wimereux in the Pas-de-Calais during an attempt to fly across the English Channel. He and his companion Pierre Romain thus became the first known fatalities in an air crash.
Jean-François Pilâtre de Rozier
The first tethered balloon ascent on 15 October 1783 by Rozier
The first untethered balloon flight, by Rozier and the Marquis d'Arlandes on 21 November 1783.
Fatal accident at Wimereux, 15 June 1785.