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. Roberts, 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 everything 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 had 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.
I am sorry this Experiment is totally neglected in England, where mechanic Genius is so strong. I wish I could see the same Emulation between the two Nations as I see between the two Parties here. Your Philosophy seems to be too bashful. In this Country we are not so much afraid of being laught at. If we do a foolish thing, we are the first to laugh at it ourselves, and are almost as much pleased with a Bon Mot or a Chanson, that ridicules well the Disappointment of a Project, as we might have been with its Success. It does not seem to me a good reason to decline prosecuting a new Experiment which apparently increases the power of a Man over Matter, till we can see to what use that power can be applied. When we have learnt to manage it, we may hope some time or other to find Uses for it, as men have done for Magnetism and Electricity, of which the first Experiments were mere Matters of Amusement.
This Experience is by no means a trifling one. It may be attended with important Consequences that no one can foresee. We should not suffer Pride to prevent our progress in Science.
Beings of a Rank and Nature far superior to ours have not disdained to amuse themselves with making and launching Balloons, otherwise we should never have enjoyed the Light of those glorious objects that rule our Day & Night, nor have had the Pleasure of riding round the Sun ourselves upon the Balloon we now inhabit.
B. Franklin.
Passy, Dec. 1, 1783.
In mine of yesterday I promised to give you an account of Messrs. Charles & Roberts’ Experiment, which was to have been made this Day, and at which I intended to be present. Being a little indispos’d, & the Air cool, and the Ground damp, I declin’d going into the Garden of the Tuilleries where the Balloon was plac’d, not knowing how long I might be oblig’d to wait there before it was ready to depart; and chose to stay in my Carriage near the Statue of Louis XV, from whence I could well see it rise, & have an extensive View of the Region of Air thro’ which, as the Wind sat, it was likely to pass. The Morning was foggy, but about one o’clock the Air became tolerably clear; to the great satisfaction of spectators, who were infinite. Notice having been given of the intended Experiment several days before in the Papers, so that all Paris was out, either about the Tuilleries, on the Quays & Bridges, in the Fields, the Streets, at the Windows, or on the Tops of Houses, besides the inhabitants of all the Towns & Villages of the Environs. Never before was a philosophical Experiment so magnificently attended. Some Guns were fired to give Notice that the departure of the great Balloon was near, and a small one was discharg’d which went to an amazing height, there being but little Wind to make it deviate from its perpendicular Course, and at length the Sight of it was lost. Means were used, I am told, to prevent the great Balloon’s rising so high as might endanger its Bursting. Several Bags of Sand were taken on board before the Cord that held it down was cut, and the whole Weight being then too much to be lifted, such a Quantity was discharg’d as to permit its Rising slowly. Thus it would sooner arrive at that Region where it would be in equilibrio with the surrounding Air, and by discharging more Sand afterwards, it might go higher if desired. Between One & Two o’Clock, all Eyes were gratified with seeing it rise majestically from among the Trees and ascend gradually above the Buildings, a most beautiful Spectacle! When it was about 200 feet high, the brave Adventurers held out and wav’d a little white Pennant, on both sides their Car, to salute the Spectators, who return’d loud Claps of Applause. The Wind was very little, so that the Object, tho’ moving to the Northward, continued long in View; and it was a great while before the admiring People began to disperse. The persons embark’d were Mr. Charles, Professor of Experimental Philosophy, & zealous Promotor of that Science; and one of the Messieurs Robert, the very ingenious Constructors of the Machine. When it arrived at its height, which I suppose might be 3 or 400 Toises, it appeared to have only horizontal Motion. I had a Pocket Glass, with which I follow’d it, till I lost Sight first of the Men, then of the Car, and when I last saw the Balloon, it appear’d no bigger than a Walnut. I write this at 7 in the evening. What became of them is not yet known here. I hope they descended by Day-light, so as to see and avoid falling among Trees or on Houses, and that the Experience was completed without any mischievous Accident, which the Novelty of it & the want of Experience might well occasion. I am the more anxious for the Event, because I am not well informed of the Means provided for letting themselves gently down, and the Loss of these very ingenious Men would not only be a Discouragement to the Progress of the Art, but be a sensible Loss to Science and Society.
Tuesday Morning, December 2,—I am reliev’d from my Anxiety by hearing that the Adventurers descended well near l’Isle Adam, before Sunset. This Place is near 7 Leagues from Paris. Had the Wind blown fresh, they might have gone much farther.