Editing Jacques Charles (section)

===First hydrogen balloon===
[[File:WasserstoffballonProfCharles.jpg|thumb|250px|left|The balloon built by Charles and the Robert brothers is attacked by terrified villagers in Gonesse. Some of them even started attacking him because they weren't used to things flying.]]
Charles conceived the idea that hydrogen would be a suitable lifting agent for balloons having studied the work of [[Robert Boyle]]'s ''[[Boyle's Law]]'' which was published 100 years earlier in 1662, and of his contemporaries [[Henry Cavendish]], [[Joseph Black]] and [[Tiberius Cavallo]].<ref name=FAI/> He designed the craft and then worked in conjunction with the [[Robert brothers]], Anne-Jean and Nicolas-Louis, to build it in their workshop at the ''[[Place des Victoires]]'' in Paris.<ref name="Fid Green"/> The brothers invented the methodology for the lightweight, airtight gas bag by dissolving [[rubber]] in a solution of [[turpentine]] and [[varnish]]ed the sheets of [[silk]] that were stitched together to make the main envelope. They used alternate strips of red and white silk, but the discolouration of the varnishing/rubberising process left a red and yellow result.<ref name=FAI/>

Charles and the Robert brothers launched<ref name=Sci&Soc/> the world's first [[hydrogen]] filled [[balloon]] on 27 August 1783, from the [[Champ de Mars]], (now the site of the [[Eiffel Tower]]) where [[Ben Franklin]] was among the crowd of onlookers.<ref name=EcceF/> The balloon was comparatively small, a 35 cubic metre sphere of rubberised silk,<ref name=FAI/> and only capable of lifting about 9&nbsp;kg (20&nbsp;lb).<ref name=EcceF/> It was filled with hydrogen that had been made by pouring nearly a quarter of a tonne of [[sulphuric acid]] onto a half a tonne of scrap iron.<ref name=EcceF/> The hydrogen gas was fed into the balloon via [[lead]] pipes; but as it was not passed through cold water, great difficulty was experienced in filling the balloon completely (the gas was hot when produced, but as it cooled in the balloon, it contracted). Daily progress bulletins were issued on the inflation; and the crowd was so great that on the 26th the balloon was moved secretly by night to the Champ de Mars, a distance of four kilometres.<ref name=TodinSci/>

The balloon flew northwards for 45 minutes, pursued by chasers on horseback, and landed 21 kilometers away in the village of [[Gonesse]] where the reportedly terrified local peasants destroyed it with pitchforks<ref name=EcceF/> or knives.<ref name="Fid Green"/> The project was funded by a subscription organised by [[Barthelemy Faujas de Saint-Fond]].<ref name=Sci&Soc/>