Chapter LIX
Reading edition
SUPERIORITY OF THE AIR-BOTTLE TO AN INTERIOR BALLOON.
Section 314. THE Air-Bottle can be attended with no Sort of Danger. For, if it burst; the only Effect is to raise the Balloon: which is made to descend, at Pleasure, by opening either the lower or upper Valve.
Whereas an interior Balloon condensed with common Air, presses against the surrounding exterior Gass: and the Gass, against the inside of the great Balloon, when the latter is in an elevated and rarefied Atmosphere; which Atmosphere, in Proportion to its Height, makes less Resistance to the Outside of the great Balloon: and thereby encreases its Tendency to a Rupture.
By the Application of the Air-Bottle, which will be to a Balloon, what an Air-Bladder, or Swim is to a Fish; a concomitant Advantage is derivable.
For the common Balloon and Air-Bottle, which may be called a double balloon, will, in their present imperfect State, be able to remain a Day, or perhaps a Couple of Days in the Air: there being no Loss of Gass: unless by Evaporation, throu’ the Pores of the Silk.
And this Advantage of a double Balloon may be effected with little expence (except that of a complete Net) to the different Proprietors, who may make alternate Voyages, with the Balloons thus united: one being inflated with Gass; the other occasionally with three or more Atmospheres of common Air condensed.
