SIGNS WHEREBY TO JUDGE WHETHER THE BALLOON IS RISING OR FALLING.
SIGNS OF RISING.
Signs of Ascent or Descent.
16. 1. When the Aironaut perceives a Pressure upwards against the Soles of his Feet.
2. When some Objects, on the Surface of the Earth immediately below, diminish, and others disappear.
3. When an upper Cloud approaches or involves the Balloon.
4. When a lower Cloud leaves the Balloon.
5. When Rain Snow or Hail beat violently against the Top of the Balloon.
6. When Feathers, Balloon-Flag, or Ribbon seem to be drawn forcibly downwards.
7. When Objects on Earth, or among Clouds below the Balloon, rise and present themselves beyond those, which, the moment before, were thought most distant.
8. When the Balloon appears broader and shorter; also fuller at the Bottom; being more distended than at the first Ascent.
SIGNS OF DESCENT.
Signs of Descent.
17. 1. When the Aironaut perceives the Bottom of the Car withdrawing itself from the Pressure against the Soles of his Feet.
2. When Objects on Earth, and surrounding Prospects encrease in Magnitude and Number.
3. When a lower Cloud approaches or involves the Balloon.
4. When an upper Cloud leaves the Balloon.
5. When Weather beats against the Bottom of the Car or Balloon.
6. When Feathers, Balloon-Flag, or Ribbon appear to be drawn upwards.
7. When the most distant Objects set, and disappear.
8. When the Balloon seems taller; and its lower Hemisphere less distended, tho’ continuing tight.
SIGNS OF PROGRESSIVE HORIZONTAL MOTION.
Signs of progressive Motion deceitful.
18. These are equivocal and deceitful.
When the Aironaut has lost Sight of the Earth by intervening Clouds; the Balloon seems at Rest, and only the lower Clouds appear to move: whereas the contrary may be true, the Clouds may rest, and only the Balloon move.
In this Case, Attention must be paid to the half Mile white Flag, whose Situation and Motion must be observed, with respect to the Balloon, and to the Earth before the Cloud intervened. If the Flag retains its Situation with Respect to the Balloon, it may be inferred that no Change in the Direction has happened: if its Situation alters, the Sun or Compass is to be observed: and an Estimate made of the new Current of Air by which the Balloon is affected: its Velocity, Sound, Temperature, &c.
To descend when lost.
19. But to acquire a Certainty of course, it will be proper to descend below the Cloud: or move by Compass, Map, and a Knowledge of the Country: or try the long Cable ([Section 13].)
Signs of Wind horizontal.
20. It is likewise necessary to know the Signs of Wind, or Currents of Air.
SIGNS OF NEW AND SUDDEN HORIZONTAL CURRENTS.
When the Feathers, Balloon-Flag, or Ribbon, compared with Sun or Compass, take a new and sudden horizontal Direction.
21. of currents from above: properly named Waves Torrents and Tide of Air.
Signs of depressing Torrents and Tide of Air.
They are very frequent, and require to be guarded against: are sometimes or long Continuance, at other Times momentary: against the first throw out Ballast at the Height of a Quarter of a Mile, but not before, or as hereafter directed: when momentary, and above that Height, Nothing is to be apprehended: the Balloon will appear broader and recover its Form.
