A new
current separated the aerial voyagers, but the parachute, with
its canine passenger, reached the ground safely a short time
after Blanchard had landed from his balloon.
Experience has proved that, in the case of a descending
parachute, if the rapidity of the descent is doubled the
resistance of the air is quadrupled; if the rapidity is triple
the resistance is increased ninefold; or, to speak in language of
science, the resistance of the air is increased by the square of
the swiftness of the body in motion. This resistance increases
in proportion as the parachute spreads, and thus the uniformity
of its fall is established a minute after it has been disengaged
from the balloon. We can, therefore, check the descent of a body
by giving it a surface capable of distension by the action of the
air.
Garnerin, in the year 1802, conceived the bold design of letting
himself fall from a height of 1,200 feet, and he accomplished the
exploit before the Parisians. When he had reached the height he
had fixed beforehand, he cut the rope which connected the
parachute with the balloon. At first the fall was terribly
rapid; but as soon as the parachute spread out the rapidity was
considerably diminished.
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