Phenix gazette. [volume] (Alexandria [D.C.]) 1825-1833, 1827-02-02
From the London Times of Nov. %.
BALLOONS.

from me LOndOn IfWeS OF 1fOO 20
BALLOONS.
A writer in a recent number OF Continental
publicatio recalls the public attention to the
subject of balloons, and expresses persuasion
that that invention will, on some future day, be
considered as Of much greater Importance than
i, has hitherto been He subjoins description
of the use which was made Of balloons in the
earlier periods ofthe Revolution, contributed by
an old officer of the name Of Contelle, who at
that time was appointed captain commandant
Of the balloon corps! and transcript ola manu-
script memoir on The same subject by NJ Meu-
nier, an offer Of engineers, and a member OF
the Academy Of Sciences. Some Of the most
remarkable tails are as follow:-
proposal having been made to the Com
mittee of Public Safety 10 employ balloons with
the armies, for the purpose Of observation, ii,
was accepted on condition that sui phuric acid
should not be employed in their imitation, sui
phur being scarce and necessary for the fabri-
cation of powder The means resorled to were
10 obtain the gas by the decomposition of wa.
ter on hot iron. A large apparatus for that
purpose, and balloon 81 feet in diameter, were
constructed BY M Coutelle, whose experiments
on the subject completely succeeded H. was
sent 10 the French army under General Jour
dan, at Maubeuge, and assembled repeatedly 10
the height Of 270 fathoms (the length Of the
cords by which he was retaned,) which gave
him an opportunity Of observing all the move
ments of the enemy. On several Of these occa-
sions he experienced great danger from tine
violence ofthe wind; and in one instance was mr..
ed at three times during his ascent, the balls
passing so near 10 the balloon, as to induce him
to fear that they had perforated it. The victory
! Of Fleurus was in great degree attributable In
| the advantage which the French derived from
the communications made to them by NJ Cou.
telle, from his aerial station, to the maneu,res
of the hostile army. From what reasons does
not appear, but the use Of balloons in military
| operation was soon after discontinued
NJ. Mennier's memoir is curious. Proposing
TO himself nothing less than the power Of max.
ing very long voyages, he had of course 10 con-
slider the means of sustaining the shocks OF
strong and adverse currents Of air, of stopping
and anchoring, Of raising himself and remain
ing at convenien, elevation, Of moving in a
calm, and Of modifying the direction and speed
! Of MS progress. Again, as none OF the mate
rails Of which air,balloons are composed are
absolutely inpermeable by the Hydrogen, it
was indispensable to discover how TO retain the
|
termne the size and shape of balloon that
should be capable Of transporting the appa,a a
tus, the observers and their instruments, and a
quantity Of provisions necessary for the long
est voyage they might be required to under
lake This skiIful mechanic conquered mum
Der of the above difficulties by putting sec
ond cover on his balloon. This outer cover was
Of linen, not permeable by the atmospheric air
Between the two covers there was considers
BILE space. A pipe, of the same fabric as the
| outer cover, communicated between thai space
and forcing pump fixed in the car. BY means
of this pump the air between the two covers
could be condensed, the volume Of the hydro
gen diminished, and thereby the mean specific
gravity of the fluid contained in the balloon in.
creased AS the cover was scarcely extendible
and as the cords on its outside would not al.
low il to change its shape, the volume OF the
balloon varied very little, while its weight in.
creased or diminished according 10 the NEAR
specific gravity Of the two gases which it con
tanned Thus when the aeronauts were at
grear elevation, all that it was necessary to dc
in order to descend, was to work the forcing
pump, by which the weight of the atmospheric
| all between the covers was increased, so tina,
the balloon would not remain suspended ex
cept in denser, that is to say in lower air Bal
last was thereby rendered unnecessary Wher
it was required to ascend, the opening OF I
valve allowed the compressed atmospheric all
to escape. BY this ingenious coutrivance, III,
aeronauts were enabled TO regulate their dis
lance from the earth, and as the currents of al,
at different degrees Of elevation frequently ru,
in opposite directions, 10 get into that curren
most favourable to the object they bad in view
Ia Gains, they made use Of oars, by which
however. they could not advance themselve.