If it be allowed, for the Sake of Illustration, to compare great Things with small; he found himself suspended in the central Concave of an unmeasurable Crater Bowl or Bason; and considerably above the Rim or Margin, so as to peep fairly over it: for by looking straight before him, while the Balloon continued gently turning on its vertical Axis, he coud see quite round into the Blue.
The Earth was the Miniature-Picture[14] painted on the Bottom of the Bowl, on the Inside. The Sides of the Bowl next the Bottom were rather obscure: as the Objects, on the Surface of the Earth not immediately under the Eye, being foreshortened, were indistinct, either on Account of their immense Distance, or by mere Accumulation of Vapours, and mixed with Haze and Cloudiness.
The Comparison carried on.
From thence to the Top of the Bowl, was fantastically grouped, spotted, and dash’d with Clouds dense and luminous, in the strangest and most grotesque Forms; still smaller and more numerous, as the Eye was more extended: The Rim or Margin ending, not in a fringed Border; but in a plain smooth Line; to represent the amazing Distance, at which, the upper Surfaces of Clouds in Perspective lost all their rugged mountainous and fringed Shapes; and terminated even and smooth: making a perfect horizontal Ring in the Heavens, somewhat below the Eye of the Observer. The whole formed a glorious Concave: and the Imagination was lost in the surrounding distant Azure.[15]
Apparent Altitude of the Balloon when stationary.
The apparent Heights proportioned to the barometric Height.
49. Considering more attentively the Dimensions of this vast Amphitheatre; as he long continued apparently in the same Spot, and seemed to himself a mere Atom floating invariably in the Center of the empty Space; yet as a sole thinking Being there, whose Mind was bent on estimating the Extent of his View, so accurately defined by the circular Horizon of dense accumulated Vapour; and judging, as of other Distances, by the natural Eye alone; pointing downwards on Objects which were only distinguishable when immediately below it, frequently no more than the Circuit of a Mile on the Earth’s Surface, the vertical Boundary of the profound Abyss; all else being obscured by Haze, or removed from Sight by Volumes of intervening Cloud; he coud not divest himself of the Idea, but that the apparent Depth below him was at least seven Miles: three from the Earth to the upper Surface of the superior Clouds,[16] and four above them.[17]
OBJECTION REMOVED.
Improbability of a concave Appearance of the Clouds and Earth, lessened, by a familiar Illustration.
50. Some may find a Difficulty in conceiving, how the whole Prospect of Clouds and Earth together coud put on a concave Appearance: both of which were in Reality convex, with Respect to the Situation of the Observer in the Car.