Editing Jacques Charles (section)

==Hydrogen balloon flights==

===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/>

===First crewed hydrogen balloon flight===
[[File:Premier aérostat à vx021g18h 0 z603qz54h.tiff |320px|right|First flight of a gas air balloon on 1 December 1783]]
[[File:Jacques Charles Luftschiff.jpg|thumb|320px|right|Contemporary illustration of the first flight by Charles with Nicolas-Louis Robert, 1 December 1783. Viewed from the [[Place de la Concorde]] to the [[Tuileries Palace]] (destroyed in 1871)]]

At 13:45 (1:45 PM) on 1 December 1783, Charles and the Robert brothers launched a new crewed balloon from the [[Tuileries Palace|Jardin des Tuileries]] in Paris.<ref name=FAI/><ref name=EcceF/> Charles was accompanied by Nicolas-Louis Robert as co-pilot of the 380-cubic-metre, hydrogen-filled balloon.<ref name=FAI/><ref name=EcceF/> The envelope was fitted with a hydrogen release valve and was covered with a net from which the basket was suspended. Sand ballast was used to control altitude.<ref name=FAI/> They ascended to a height of about 1,800 feet (550 m)<ref name=EcceF/> and landed at sunset in [[Nesles-la-Vallée]] after a 2-hour, 5-minute flight covering 36&nbsp;km.<ref name=FAI/><ref name="Fid Green"/><ref name=EcceF/> The chasers on horseback, who were led by the [[Duc de Chartres]], held down the craft while both Charles and Nicolas-Louis alighted.<ref name="Fid Green"/>

Charles then decided to ascend again, but alone this time because the balloon had lost some of its hydrogen. This time it ascended rapidly to an altitude of about 3,000 metres,<ref name="Fid Green"/><ref name="Britannica 2"/> where he saw the sun again. He began suffering from aching pain in his ears so he "valved" to release gas, and descended to land gently about 3&nbsp;km away at {{ill|Tour du Lay|fr|Bois de la Tour du Lay}}.<ref name="Fid Green"/> Unlike the Robert brothers, Charles never flew again,<ref name="Fid Green"/> although a hydrogen balloon came to be called a ''Charlière'' in his honour.

It is reported that 400,000 spectators witnessed the launch, and that hundreds had paid one crown each to help finance the construction and receive access to a "special enclosure" for a "close-up view" of the take-off.<ref name="Fid Green"/> Among the "special enclosure" crowd was [[Benjamin Franklin]], the diplomatic representative of the [[United States|United States of America]].<ref name="Fid Green"/> Also present was Joseph Montgolfier, whom Charles honoured by asking him to release the small, bright green, pilot balloon to assess the wind and weather conditions.<ref name="Fid Green"/>

This event took place ten days after the world's first crewed balloon flight by [[Jean-François Pilâtre de Rozier]] using a [[Montgolfier brothers]] [[hot air balloon]]. [[Simon Schama]] wrote in ''[[Citizens: A Chronicle of the French Revolution|Citizens]]'':
{{blockquote|Montgolfier's principal scientific collaborator was M. Charles,&nbsp;... who had been the first to propose the gas produced by [[vitriol]] instead of the burning, dampened straw and wood that he had used in earlier flights. Charles himself was also eager to ascend but had run into a firm veto from the King, who from the earliest reports had been observing the progress of the flights with keen attentiveness. Anxious about the perils of a maiden flight, the King had then proposed that two criminals be sent up in a basket, at which Charles and his colleagues became indignant.<ref name="Schama p125"/>}}

{{clear}}
[[Image:Airship designed by Jean-Baptiste Marie Meusnier de La Place.jpg|220px|left|thumb|Meusnier's dirigible]]

===Further ballooning activities===
The next project of Charles and the Robert brothers was to build an elongated, steerable craft that followed [[Jean Baptiste Meusnier]]'s proposals (1783–85) for a dirigible balloon. The design incorporated Meusnier's internal ''ballonnet'' (air cells), a rudder and a method of propulsion.<ref name="BioDic HisTec"/>

Charles chose never to fly in this craft, but on 15 July 1784, the brothers flew for 45 minutes from [[Saint-Cloud]] to [[Meudon]] with M. Collin-Hullin and [[Louis Philippe II, Duke of Orléans|Louis Philippe II, the Duke of Chartres]] in ''La Caroline''. It was fitted with oars for propulsion and direction, but they proved useless. The absence of a 'gas release valve' meant that the duke had to slash the 'ballonnet' to prevent rupture when they reached an altitude of circa {{convert|4500|m|ft|-2}}.<ref name=FAI/><ref name="FAA Oct 2001"/>

On 19 September 1784, the Robert brothers and M. Collin-Hullin flew for 6 hours 40 minutes, covering 186&nbsp;km from Paris to [[Beuvry]] near [[Béthune]]. This was the first flight over 100&nbsp;km.<ref name=FAI/><ref name="FAA Oct 2001"/>
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