"The Balloon-Hoax" - читать интересную книгу автора (Poe Edgar Allan)

The balloon is composed of silk, varnished with the liquid gum
caoutchouc. It is of vast dimensions, containing more than 40,000
cubic feet of gas; but as coal gas was employed in place of the more
expensive and inconvenient hydrogen, the supporting power of the
machine, when fully inflated, and immediately after inflation, is
not more than about 2500 pounds. The coal gas is not only much less
costly, but is easily procured and managed.
For its introduction into common use for purposes of aerostation, we
are indebted to Mr. Charles Green. Up to his discovery, the process of
inflation was not only exceedingly expensive, but uncertain. Two and
even three days have frequently been wasted in futile attempts to
procure a sufficiency of hydrogen to fill a balloon, from which it had
great tendency to escape, owing to its extreme subtlety, and its
affinity for the surrounding atmosphere. In a balloon sufficiently
perfect to retain its contents of coal gas unaltered, in quantity or
amount, for six months, an equal quantity of hydrogen could not be
maintained in equal purity for six weeks.
The supporting power being estimated at 2500 pounds, and the
united weights of the party amounting only to about 1200, there was
left a surplus of 1300, of which again 1200 was exhausted by
ballast, arranged in bags of different sizes, with their respective
weights marked upon them- by cordage, barometers, telescopes,
barrels containing provision for a fortnight, water-casks, cloaks,
carpet-bags, and various other indispensable matters, including a
coffee-warmer, contrived for warming coffee by means of slack-lime, so
as to dispense altogether with fire, if it should be judged prudent to
do so. All these articles, with the exception of the ballast, and a
few trifles, were suspended from the hoop overhead. The car is much
smaller and lighter, in proportion, than the one appended to the
model. It is formed of a light wicker, and is wonderfully strong for
so frail looking a machine. Its rim is about 4 feet deep. The rudder
is also very much larger, in proportion, than that of the model; and
the screw is considerably smaller. The balloon is furnished besides
with a grapnel, and a guide-rope, which latter is of the most
indispensable importance. A few words, in explanation, will here be
necessary for such of our readers as are not conversant with the
details of aerostation.
As soon as the balloon quits the earth, it is subjected to the
influence of many circumstances tending to create a difference in
its weight; augmenting or diminishing its ascending power. For
example, there may be a deposition of dew upon the silk, to the
extent, even, of several hundred pounds; ballast has then to be thrown
out, or the machine may descend. This ballast being discarded, and a
clear sunshine evaporating the dew, and at the same time expanding the
gas in the silk, the whole will again rapidly ascend. To check this
ascent, the only recourse is (or rather was, until Mr. Green's
invention of the guide-rope) the permission of the escape of gas
from the valve; but, in the loss of gas, is a proportionate general
loss of ascending power; so that, in a comparatively brief period, the
best-constructed balloon must necessarily exhaust all its resources,