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. [Sidenote: 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.) [Sidenote: 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_. [Sidenote: 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. CHAPTER IV. PREPARATIONS FOR ASCENT. [Sidenote: Preparations for Ascent.] Section 22. Before half past I, Mr. Lunardi had inflated his Balloon in the finest Manner; and having, with the most obliging and spirited Attention, made such Preparations, and taken such Precautions, as he thought were necessary to ensure the Success of the Expedition; sent to inform Mr. Baldwin (who continued purposely absent, that he might not disturb or precipitate the Process; but that every Circumstance shoud be conducted with Deliberation and without Hurry) that all Things were ready for his Departure. [Sidenote: The Public reminded of the Necessity of preserving order during the Inflation of Balloons.] 23. And Mr. Baldwin takes this Opportunity of returning his best Thanks to his Friends and the Public, on the Day of Ascent, for keeping +the small Circle clear+, by strictly adhering to the Words of the Advertisement, which declared, “that in order to prevent an interruption of the Process in the Inflation of the Balloon, no Persons _were_ to be admitted +within the circle+, except those Gentlemen who politely undertook +in turn+ to hold the Lines which detained the Balloon.”