36 
AIR BALLOON. 
scientific persons of that capital, justly con- 
cluding tnat a similar experiment might be 
made by filling a bag with hydrogen gas, im- 
mediately attempted to verify the supposi- 
tion. A subscription for defraying the ex- 
pences that might attend the accomplishment j 
of the project, was immediately opened; 
persons of all ranks ran with eagerness to 
sign their names, and the necessary sum was 
speedily raised. Messrs. Roberts were ap- 
pointed to construct the machine, and Mr. 
Charles, professor of experimental philoso- 
phy, was appointed to superintend the work. 
The obstacles, which opposed the accom- 
plishment of this first attempt, were many ; 
but the two principal difficulties were to pro- 
duce a large quantity of hydrogen gas, and to 
find a substance sufficiently light to make the 
bag of, and at the same time impermeable to 
the gas. At last they constructed a globular 
bag of a sort of silk stuff, called lutestring ; 
which, in order to render it impervious to the 
gas, was covered with a certain varnish, said 
to consist of dissolved elastic gum. The di- 
ameter of this bag, which, from its ball-like 
shape, was called a balloon (and from this the 
name air balloons was derived), was 12 feet 
two inches French, or about 13 feet English. 
It had only one aperture, like the neck of a 
bladder, to which a stop-cock was adapted. 
The weight of the balloon, when empty, to- 
gether with the stop-cock, was 25 pounds. 
The attempts to fill this bag commenced 
on the 23d of August, 1783. But the ope- 
rators met with many difficulties and disap- 
pointments, from inadvertences, want of ma- 
terials, want of precaution, &c. so much so, 
that the accomplishment of the experiment, 
viz. the actual ascent of the balloon, did not 
take place before the 26th of the same month. 
On tne morning of that day the inflated bal- 
loon, having a small cord fastened to its 
neck, was permitted to rise only to the height 
of about 100 feet; but at five o’clock in the 
afternoon of the 27th, the balloon was disen- 
gaged from its fastenings, in the Champ de 
Mars, and rose majestically in the atmo- 
sphere before the eyes of a great many thou- 
sand spectators, and amidst a copious shower 
of rain. In about two minutes time it rose 
to the height of about 3123 feet. After re- 
maining in the atmosphere only f of an hour, 
this balloon feli in a field near Gonesse, a 
village about 15 miles from Paris. Its fall was 
attributed to a rupture that was found in it, 
and it was reasonably imagined, that the ex- 
pansion of the hydrogen gas, when the bal- 
loon had reached a much less dense part of 
the atmosphere, had burst it. When this 
balloon went up, it was found upon trial to 
be o5 pounds lighter than an equal bulk of 
common air. 
Thus in the years 1782 and 1783, it was 
ascertained that bags full of hydrogen gas, or 
of rarefied common air, either of which is 
lighter than common air in its usual state, 
would ascend into the atmosphere, and that 
they might take up considerable weights. 
Soon after the success of the first attempt, 
the Montgolfiers repeated the experiment in 
the open air, and with bags of different sizes ; 
but their first grand and public exhibition in 
the presence of a very respectable and nu- 
merous assembly, was made on the 5th of 
June, 1783, with an aerostatic machine or bag 
that measured 35 feet in diameter. The ma- 
chine, inflated by the rarefied air, ascended 
to a considerable height, and then fell at the 
distance of 7668 feet from the original place 
of ascension. This experiment was described 
and recorded with great accuracy ; and ac- 
counts of it were immediately forwarded to 
the court of France, to the academy of sci- 
ences, and almost as far as literary and enter- 
taining correspondence could reach. The 
younger Montgolfier, arriving at Paris not 
long after the above-mentioned public exhi- 
bition, was invited by the Academy of Sci- 
ences to repeat his singular aerostatic experi- 
ment; in consequence of which invitation, 
that gentleman began to construct an aerosta- 
tic machine of about 72 feet in height, at the 
expence of the academy. But while this 
operation was going on, and as a successful 
experiment with an inflammable air balloon 
had already been performed on the 27th of 
August, the project of making balloons be- 
came general ; and those who wished to make 
the experiment on the smallest scale soon cal- 
culated the necessary particulars, and found 
that the performance of the experiment was 
far from being either difficult or expensive. 
The baron de Beaumanoir, at Paris, by the 
suggestion of a Mr. Deschamps, was induced 
to try gold-beater’s skin, and soon made a 
balloon by gluing several pieces of that skin 
together. This balloon was no more than 
19 inches in diameter; it was of course easily 
filled with hydrogen gas; and on the 11th of 
September, 1783, it mounted with rapidity 
into the atmosphere. 
Mr. Montgolfier having completed his 
large balloon, agreeably to the desire of the 
academy, made a private experiment with it 
on the 11th of September, which succeeded. 
On the following day another experiment 
was made with the same, before the commis- 
saries of the academy, and a vast number of 
other spectators ; but this experiment, in con- 
sequence of a violent shower of rain, was at- 
tended with partial success : and the aerostat 
was considerably damaged. 
A similar machine was speedily con- 
structed by the same Mr. Montgolher, by 
whom the experiment was performed at Ver- 
sailles on the 19th of September, before the 
royal family of France, and an innumerable 
concourse of spectators. The preparation 
for filling the machine with rarefied air consist- 
ed of an ample scaffold, raised some feet above 
the ground; in the middle of which there 
was a well or chimney, about 16 feet in dia- 
meter ; in the lower part of which, near the 
ground, the fire was made. The aperture of 
the balioon was put round the chimney or 
well, and the rest of it was laid down over 
the well and the surrounding scaffold. As 
soon as the fire was lighted the machine be- 
gan to swell, acquired a convex form, stretch- 
ed itself on every side, and in 1 1 minutes 
time, the cords being cut, the machine as- 
cended, together with a wicker basket or 
cage, which was fastened to it by means of a 
rope, and in which a sheep, a cock, and a 
duck, had been placed. These were the first 
animals that ever ascended with an aerostatic 
machine. The apparatus rose to the height 
of about 1440 feet, and remained in the at- 
mosphere during eight minutes; then fell 
at the distance of about 10,200 feet from 
Versailles, with the animals safe in the 
basket. 
After the success of this experiment with 
the animals, &c. and when ten months had 
scarcely elapsed since Mr. Montgolfier made 
his first experiment of this sort, Mr. Pilatre 
de Rozier publicly offered himself to be the 
lirst adventurer in the newly invented ma- 
chine. His offer was accepted, his courage 
remained undaunted, and pn the 15th of Oc- 
tober, 1783, he actually ascended into the 
atmosphere, to the astonishment of a gazing 
multitude. The balloon with which he as- 
cended was of an oval shape, its height being 
about 74, and its horizontal diameter 48 feet. 
The aperture or lower part of the machine had 
a wicker gallery about three feet broad, with 
a ballustrade both within and without, about 
three feet high. The inner diameter of this 
gallerv, and of the neck of the machine whic h 
passed through it, was nearly 16' feet. In 
the middle ot this aperture an iroagrate or 
brazier was supported by means of chains, 
which caine down from tire sides of the ma- 
chine. In this construction, when the ma- 
chine was up in the air, with a fire lighted in 
the grate, it was easy for a person who stood 
in the gallery, and had fuel with him, to keep 
up the lire in the opening of the machine, by 
throwing the fuel on the grate through port- 
holes made in the neck of the machine ; by 
which means the machine might be kept up 
as long as the person in its gallery thought 
proper, or till he had no fuel to supply the fire 
with. 
The first aerial voyage, with an inflamma- 
ble air balloon, was performed subsequent to 
the above-mentioned experiment, viz. on the 
1st of December, 1783. Mr. Charles and 
Mr. Robert, who had constructed a balloon 
of this sort, as has been already mentioned, 
were the first adventurers. The balloon was 
globular, its diameter being 27-| feet. A net 
went over the upper hemisphere, and was 
fastened to a hoop, which went round the 
middle of the balloon. From this hoop ropes 
proceeded, and were fastened to a boat which 
swung a few feet below the balloon. In 
order to prevent the bursting of the machine 
by the expansion of the gas in an elevated re- 
gion, a valve was made on the upper part of 
it, which, by pulling a string, would open 
and let out part of the gas. There was like- 
wise a long silken pipe, through which the 
balloon was filled. 
The apparatus for filling it consisted of se- 
veral wooden casks placed round a large tub 
full of water, every one of which had a long 
tin tube, which terminated under a vessel or 
funnel, that was inverted into the water of the 
tub. A tube then proceeded from this fun- 
nel, and communicated with the balloon, 
which stood just over it. Iron filings and di- 
luted sulphuric acid were put into the casks ; 
and the gas which was extricated from those 
materials passed through the tin tubes, then 
through the water of the tub, and, lastly, 
through the tube of the funnel into the bal- 
loon. See the Plate, fig. 1. 
When Messrs. Charles and Robert placed 
themselves in the boat, they had with them 
proper philosophical instruments, provisions, 
clothing, and some bags full of sand, by way 
of ballast. With this preparation they as- 
cended at three quarters after one o’clock. At 
the time they went up, the thermometer, 
Fahrenheit’s scale, stood at 52 degrees, the 
mercury in the barometer stood at 27 inches, 
from which they deduced their altitude to be 
nearly 600 yards. During the rest of their 
voyage the mercury in the barometer moved 
