Hydrostatics and pneumatics / [Dionysius Lardner].

  • Dionysius Lardner
Date:
1831
Catalogue details

Licence: Public Domain Mark

Credit: Hydrostatics and pneumatics / [Dionysius Lardner]. Source: Wellcome Collection.

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    instituted on a larger scale. A balloon, constructed of a capacity exceeding 700 solid feet, rose in the same man- ner to an elevation of more than 600 feet. A balloon in the spherical form, but on a scale still larger, was next constructed: it contained 23,000 feet, and had a buoy- ancy capable of raising 500 pounds. It ascended in the atmosphere to a height of about 6000 feet. Hitherto the experiments were confined to the object of ascertaining the mere possibility of ascending in the atmosphere; and, in some cases, the effects produced on animal life at great elevations were tried, by sending up various animals contained in a basket of wicker-work suspended from the balloon. At length, in the latter end of the year 1783, a balloon was constructed at Paris, with a view to transport one or more persons into the higher regions of the atmosphere. This machine was composed of an elliptical bag, 74 feet in height and 48 in diameter. Immediately under an aperture in the bottom of the bag was suspended an iron grate within reach of the aeronaut, on which was placed the burning fuel to maintain the rarefaction within the balloon. An ascent was made to a height of about 3000 feet by M. Pilatre de Roziere and the marquis d’Arlandes. After this experiment various others succeeded in balloons constructed in the same manner. The first projector of these balloons conceived that the machine owed its buoyancy to the gas produced by the fire, and which with an elastic pressure equal to the air was specifically lighter; still the mechanical principle of the ascent was not mistaken. The step from fire balloons to balloons filled with gas specifically lighter than atmospheric air, of the same pressure, was now easy and obvious. The gas at present denominated hydrogen was submitted to a series of ex- periments, by which it was found that its specific gravity was only one seventh of that of common atmospheric air. It was obvious, therefore, that a balloon filled with this gas would have considerable buoyancy. Balloons were accordingly constructed and inflated with this gas, and