Planant sur l’Horizon. When they were as high as they chose to be, they made less Flame and suffered the Machine to drive Horizontally with the Wind, of which however they felt very little, as they went with it, and as fast. They say they had a charming View of Paris & its Environs, the Course of the River, &c but that they were once lost, not knowing what Part they were over, till they saw the Dome of the Invalids, which rectified their Ideas. Probably while they were employed in keeping up the Fire, the Machine might turn, and by that means they were desorientés as the French call it.
There was a vast Concourse of Gentry in the Garden, who had great Pleasure in seeing the Adventurers go off so chearfully, & applauded them by clapping &c. but there was at the same time a good deal of Anxiety for their Safety. Multitudes in Paris saw the Balloon passing; but did not know there were Men with it, it being then so high that they could not see them.
Développant du Gaz. That is, in plain English, burning more straw; for tho’ there is a little Mystery made, concerning the kind of Air with which the Balloon is filled, I conceive it to be nothing more than hot Smoke or common Air rarify’d, tho’ in this I may be mistaken.
Aiant encor dans leur Galerie les deux tiers de leur Approvisionement. That is their Provision of Straw; of which they carried up a great Quantity. It was well that in the hurry of so hazardous an Experiment, the Flame did not happen by any accidental Mismanagement to lay hold of this Straw; tho’ each had a Bucket of Water by him, by Way of Precaution.
One of these courageous Philosophers, the Marquis d’Arlandes, did me the honour to call upon me in the Evening after the Experiment, with Mr. Montgolfier the very ingenious Inventor. I was happy to see him safe. He informed me that they lit gently without the least Shock, and the Balloon was very little damaged.
This Method of filling the Balloon with hot Air is cheap and expeditious, and it is supposed may be sufficient for certain purposes, such as elevating an Engineer to take a View of an Enemy’s Army, Works, &c. conveying Intelligence into, or out of a besieged Town, giving Signals to distant Places, or the like.
The other Method of filling a Balloon with permanently elastic inflammable Air, and then closing it is a tedious Operation, and very expensive; Yet we are to have one of that kind sent up in a few Days. It is a Globe of 26 feet diameter. The Gores that compose it are red and white Silk, so that it makes a beautiful appearance. A very handsome triumphal Car will be suspended to it, in which Messrs. Robert, two Brothers, very ingenious Men, who have made it in concert with Mr. Charles propose to go up. There is room in this Car for a little Table to be placed between them, on which they can write and keep their Journal, that is take Notes of every thing they observe, the State of their Thermometer, Barometer, Hygrometer, &c which they will have more Leisure to do than the others, having no fire to take Care of. They say they have a contrivance which will enable them to descend at Pleasure. I know not what it is. But the Expence of this Machine, Filling included, will exceed, it is said, 10,000 Livres.
This Balloon of only 26 feet diameter being filled with Air ten times lighter than common Air, will carry up a greater Weight than the other, which tho’ vastly bigger was filled with an Air that could scarcely be more than twice as light. Thus the great Bulk of one of these Machines, with the short duration of its Power, & the great Expence of filling the other will prevent the Inventions being of so much Use, as some may expect, till Chemistry can invent a cheaper light Air producible with more Expedition.
But the Emulation between the two Parties running high, the Improvement in the Construction and Management of the Balloons has already made a rapid Progress; and one cannot say how far it may go. A few Months since the Idea of Witches riding thro’ the Air upon a Broomstick, and that of Philosophers upon a Bag of Smoke, would have appeared equally impossible and ridiculous.
These Machines must always be subject to be driven by the Winds. Perhaps Mechanic Art may find easy means to give them progressive Motion in a Calm, and to slant them a little in the Wind.