Up in the Clouds: Balloon Voyages, R. M. Ballantyne [top e book reader .txt] 📗

portion of air into the globe it would be rendered heavier than before, and might thus be made to descend. This was in fact the statement of the principles on which fire-balloons were afterwards constructed and successfully sent up, excepting that air heated by fire, instead of fire itself, was used.

Others who came after Albert of Saxony held the same theory, but they all failed to reduce it to practice, and most of these men coupled with their correct notions on the subject, the very erroneous idea that by means of masts, sails, and a rudder, a balloon might be made to sail through the air as a ship sails upon the sea. In this they seem to have confounded two things which are dissimilar, namely, a vessel driven through water, and a vessel floating in air.

The fallacy here may be easily pointed out. A ship is driven through water by a body in motion, namely, wind, while its rudder is dragged through a body comparatively at rest, namely, water; hence the rudder slides against or is pushed against the water, and according as it is turned to one side or the other, it is pushed to one side or the other, the stern of the ship going along with it, and the bow, of course, making a corresponding motion in the opposite direction. Thus the ship is turned or “steered,” but it is manifest that if the ship were at rest there would be no pushing of the rudder by the water—no steering. On the other hand, if, though the ship were in motion, the sea was also flowing at the same rate with the wind, there would be no flowing of water past the ship, the rudder would not be acted on, and the vessel could not be steered.

Now a balloon, carried by the wind, cannot be steered by a rudder, because it does not, like the ship, rest half in one medium which is in motion, and half in another medium which is at rest. There is no sliding of any substance past its side, no possibility therefore of pushing a rudder against anything. All floats along with the wind.

If, however, the balloon could be made to go faster than the wind, then steering would at once become possible; but sails cannot accomplish this, because, although wind can drive a ship faster than water flows, wind cannot drive a substance faster than itself flows.

The men of old did not, however, seem to take these points into consideration. It yet remains to be seen whether steam shall ever be successfully applied to aerial machines, but this may certainly be assumed in the meantime, that, until by some means a balloon is propelled faster than the wind through the atmosphere, sails will be useless, and steering, or giving direction, impossible.

It was believed, in those early times, when scientific knowledge was slender, that the dew which falls during the night is of celestial origin, shed by the stars, and drawn by the sun, in the heat of the day, back to its native skies. Many people even went the length of asserting that an egg, filled with the morning dew, would, as the day advanced, rise spontaneously into the air. Indeed one man, named Father Laurus, speaks of this as an observed fact, and gravely gives directions how it is to be accomplished. “Take,” says he, “a goose’s egg, and having filled it with dew gathered fresh in the morning, expose it to the sun during the hottest part of the day, and it will ascend and rest suspended for a few moments.” Father Laurus must surely have omitted to add that a goose’s brains in the head of the operator was an element essential to the success of the experiment!

But this man, although very ignorant in regard to the nature of the substances with which he wrought, had some quaint notions in his head. He thought, for instance, that if he were to cram the cavity of an artificial dove with highly condensed air, the imprisoned fluid would impel the machine in the same manner as wind impels a sail. If this should not be found to act effectively, he proposed to apply fire to it in some way or other, and, to prevent the machine from being spirited away altogether by that volatile element, asbestos, or some incombustible material, was to be used as a lining. To feed and support this fire steadily, he suggested a compound of butter, salts, and orpiment, lodged in metallic tubes, which, he imagined, would at the same time heighten the whole effect by emitting a variety of musical tones like an organ!

Another man, still more sanguine than the lest in his aerial flights of fancy, proposed that an ascent should be attempted by the application of fire as in a rocket to an aerial machine. We are not, however, told that this daring spirit ever ventured to try thus to invade the sky.

There can be no doubt that much ingenuity, as well as absurdity, has been displayed in the various suggestions that have been made from time to time, and occasionally carried into practice. One man went the length of describing a huge apparatus, consisting of very long tin pipes, in which air was to be compressed by the vehement action of fire below. In a boat suspended from the machine a man was to sit and direct the whole by the opening and shutting of valves.

Another scheme, more ingenious but not less fallacious, was propounded in 1670 by Francis Lana, a Jesuit, for navigating the air. This plan was to make four copper balls of very large dimensions, yet so extremely thin that, after the air had been extracted, they should become, in a considerable degree, specifically lighter than the surrounding medium. Each of his copper balls was to be about 25 feet in diameter, with the thickness of only the 225th part of an inch, the metal weighing 365 pounds avoirdupois, while the weight of the air which it should contain would be about 670 pounds, leaving, after a vacuum had been formed, an excess of 305 pounds for the power of ascension. The four balls would therefore, it was thought, rise into the air with a combined force of 1220 pounds, which was deemed by Lana to be sufficient to transport a boat completely furnished with masts, sails, oars, and rudders, and carrying several passengers. The method by which the vacuum was to be obtained was by connecting each globe, fitted with a stop-cock, to a tube of at least thirty-five feet long; the whole being filled with water; when raised to the vertical position the water would run out, the stop-cocks would be closed at the proper time, and the vacuum secured. It does not seem to have entered the head of this philosopher that the weight of the surrounding atmosphere would crush and destroy his thin exhausted receivers, but he seems to have been alarmed at the idea of his supposed discovery being applied to improper uses, such as the passing of desperadoes over fortified cities, on which they might rain down fire and destruction from the clouds!

Perhaps the grandest of all the fanciful ideas that have been promulgated on this subject was that of Galien, a Dominican friar, who proposed to collect the fine diffused air of the higher regions, where hail is formed, above the summit of the loftiest mountains, and to enclose it in a cubical bag of enormous dimensions—extending more than a mile every way! This vast machine was to be composed of the thickest and strongest sail-cloth, and was expected to be capable of transporting through the air a whole army with all their munitions of war!

There were many other devices which men hit upon, some of which embraced a certain modicum of truth mixed with a large proportion of fallacy. Ignorance, more or less complete, as to the principles and powers with which they dealt, was, in days gone by, the cause of many of the errors and absurdities into which men were led in their efforts to mount the atmosphere. Our space, however, forbids further consideration of this subject, which is undoubtedly one of considerable interest, and encircled with a good deal of romance.

Turning away from all those early and fanciful speculations, we now come to that period in the history of balloon voyaging, or aeronautics, when true theories began to be philosophically applied, and ascending into the skies became an accomplished fact.