ON THE EXCESSIVE DIMINUTION OF OBJECTS ON THE SURFACE OF THE EARTH, TO A SPECTATOR SITUATED ABOVE THE REGION OF CLOUD, AT THE BAROMETRIC HEIGHT OF NEAR A MILE AND HALF, PERPENDICULAR. [Sidenote: Recapitulation of the Scenery below.] Section 223. The Earth’s Surface was presented to the Eye throu’ a _circular_ Opening as already described. This Opening discovered a _Plain_, smooth and level as a Die: a Sort of _shining_ Carpet, enriched with an endless Variety of Figures depicted _without_ Shadow, as on a Map: what was really Shadow forming a separate Colour, and not considered at the Time, as _Shadow_. The Objects were distinctly marked, and perfectly known to be Miniatures of the Face of Nature. All was _Colouring_: no Outline: yet each Appearance curiously defined by a striking Contrast of simple Colours, which served to distinguish the respective Boundaries with most exact Precision, and inconceivable Elegance. +Red+ Rivers, +yellow+ Roads, Enclosures +yellow+ and _light_ +green+, Woods and Hedges _dark_ +green+, were the only Objects clearly distinguishable, and their Colouring extremely vivid. The Sun’s Rays reflected from the Surface of the Sea, and other Waters, dazzled the Sight. +All+ living Creatures were invisible. 224. The Area of each Inclosure, computed to contain a certain Number of Acres, was seen from above under the Form of a Miniature Picture of a certain Magnitude or visible Extension, perpetually diminishing, as the Eye recedes to a greater Distance. And the Case is similar, whether the Miniature be seen from _above_, or _along_ the Ground. The Miniature also lessens as the Distance encreases, according to a certain Proportion so exactly;[49] That, 1. If the _Distance_ and _Magnitude_ of a tangible Object be known by Mensuration; a Judgment is formed, and Laws laid down, for its corresponding _Miniature_ on the Eye. 2. If the _Miniature_ be seen, and _Distance_ known by Mensuration; the Mind forms a Judgment of its tangible _Magnitude_. 3. And lastly, if the _Miniature_ be seen, and _Magnitude_ of a tangible Object is known by Mensuration; the Mind makes an Effort, to the Estimation of its Distance from the Eye. These are some, among many Modes of Comparison, by which the Mind acquires a tolerable Degree of Proficiency, in estimating _Distances_ of familiar Objects, _known_ from the Appearance of their respective Miniatures on the Fund or Bottom of the Eye. And so far most Theories agree. But such _ocular_ Test is only true, while the Comparison is made in _nearly_ the same Medium.