CHAPTER LV.
ON THE NECESSITY OF ASCERTAINING THE PROPER MODES OF DIRECTION, BY DIFFERENT AND FREQUENT EXPERIMENTS.
On the Necessity of frequent Experiments, in different Modes of Direction.
Section 296. THE Necessity of making frequent Experiments, in order to prove how far the Balloon is capable of Direction, by different Combinations of the mechanical Powers, is so apparent; that no Balloon shoud rise a second Time, without the Application of Machinery to that End.
Each Candidate for Fame, as Proprietor of a Balloon for public Exhibition, ought to vie in his Pretensions to a Superiority of Manouvres.
Their respective Performances woud appear in the public Papers; and Decisions be made to the Advantage of the Art.
For it is probable, that by such Comparison chiefly;—the comparison of experimental Blunders and Mistakes, and not by an Union of Theory and Practice, cemented by liberal Patronage, the Balloon can arrive to any Degree of Perfection, in a Country, which is the Scene of perpetual Contention: where the Sum of Life seems devoted but to party; and where the precious Time of the great is sunk in Luxury, and their exalted Talents lost in the Labyrinth of Politics.
Precautions to secure a Landing.
297. To strive against the Stream is proverbially impossible: and it woud be literally so, to attempt by any Kind of Machinery to force the large Surface of a Balloon, with any Degree of Velocity, against a Stream of air. ([Section 201].)
Ships, which have the Aid of an Element 800 Times denser than the air, are obliged to wait in Port, till the Wind is favourable. But neither is this considered as an Argument against maritime Navigation: nor does the Perfection of the Balloon require its Ascent in a Storm: tho’ the Preference due to the Balloon, on such Occasion, woud be decisive in its Favour: as the latter woud presently surmount the Wind, and lie to, in the calm Air above it.
Sect. 298. Art. 1. By Wings, or some propulsive Machinery, acting forcibly in a Direction required, and with Ease to the Operator; two useful Manouvres may be attempted, and will frequently be found successful.
First Manouvre: to secure the Landing in windy Weather.
298. Art. 2. First, To retard the Course of the Balloon during its Descent; in such a Manner, as to prevent the Wind from damaging the Machine, or snapping the Cable: and thus to land with Safety, and at the smallest Distance beyond the Place assigned.
Preparatory Apparatus: and Signal-Rope.
298. 3. A silken, or other light Rope is to be provided: and to run throu’ a snatch Block fastened to a rudder, or to the car, as in Crosbie’s Balloon.[98]
Which Rope alone woud lessen immediate and unforeseen Danger, by using the Balloon as a Sail, if it actually alighted on the Water.
298. Art. 4. The same Rope being a Mile, or a Mile and Half in Length; the Whole, or a Part of it, might be suffered to run off the Wheel, and, falling on the Surface below, in misty Weather, woud serve as a Signal to determine whether the Aironaut was over Land, or Water.
Also by winding up his Wheel, he might, if the Weather was moderate, bring himself down to the Grapple, which might be so contrived as to run down the Rope, and remain at the Bottom, by Means of a Knot, or other Check.
He might also loose his Grapple, and rise again: or when down; pull the Valve-Cord, and land.
298. 5. With a second short Cable, snatch Block and Grapple, he woud be able to moor the Balloon, from which, he might, by procuring the Country People to load the Car with fresh Ballast equal in Weight to himself;—get out, and even leave the Balloon in their Care.
The Precaution of knowing whether he was over a fresh Water-Lake, (for he might hear the Sea) might be useful in misty and low cloudy Weather by Day, or during the Night; without expending Gass in the exploratory Descent.
298. 6. To facilitate the landing, the Signal-Rope may be used to the greatest Advantage, particularly in windy Weather; by lowering out a Part, or the Whole, whether a Mile, or Mile and half, so that the Grapple may take Effect on the Ground, at the Distance of its Length by Estimation, short of the Place where the Balloon is intended to land.
As soon as the Grapple holds; it is in the Option of the Aironaut, to tye Parcels of his Ballast loosely round the Cable, to run downwards along with it.
(For which Purpose, Iron-Rings with Spring-Swivels, which open by Pressure of the Fingers, and shut of themselves, might answer better than the leathern Thongs, as the former might be put, in an Instant, round the Cable, and woud run down quicker.)
These Parcels of Ballast are to be sent down, in Succession, till the Balloon has acquired such Degrees of false levity, as will be sufficient to counteract that Tendency which the Wind will have to depress the Car of the Balloon forcibly on the Surface, so long as it is connected with the Grapple on the Ground.
298. 7. When this Point is effected, the Balloon will remain suspended in the Air; and being acted upon by the Wind, will be pressed into a Direction approaching to an horizontal Line, in Proportion to the encreasing Power of the Wind.
And here the Necessity of having the Cable fastened to a Center above the Car, in order to retain its Perpendicularity, is most evident.
The Aironaut, in this Situation, may venture to wind up the Cable gradually, and descend, to the Grapple.
298. 8. Secondly: When the different Currents of Air, have been tried by Descent and Ascent of the Pioneer-Balloon,[99] and found to be all unfavourable; the Aironaut is to rise still higher, into a Calm, pursue his Course horizontally in the blue serene, by propulsive Machinery: estimating the Velocity, by the evident Resistance of the half Mile white Flag described in Section 12, 13. and 12, 15. hanging at a proper Distance below, and of that which hangs loosely at the Side of the Car, to shew a Change in the Direction of the Wind, (then made by a Resistance of the Air): or he may judge o£ the Velocity and Direction, by the Flight of a Feather, repeatedly let loose at certain Intervals of Time.
