24th August

On this day in 1804, the first balloon ascent made for scientific purposes was by Jean-Baptiste Biot and Joseph-Louis Gay-Lussac from the garden of the Conservatoire des Arts. They achieved a height of 4000 metres and measured magnetic, electrical, and chemical properties of the atmosphere at various heights.

The postage stamp of one of today's mathematicians at THIS LINK was issued in 1954.