A high-school astronomy: in which the descriptive, physical, and practical are combined .. (1859)
Mattison, Hiram, 1811-1868 · New York, Mason brothers · leaf 22
A Convex Surface is one thatis swollen out like the outside ofa bowl. A Concave Surface is one thatis hollowed out like the insideof a bowl. CONVEX AND CONCAVE SURFACES. 15. Spheres,and Spheroids. Hemispheres, … A Sphere is a globe or loll, everypart of the surface of which is equidis-tant from a point within, called itscenter. This isthe ordinary definition; but in Astronomy, the termis applied to the apparent concave of the heavens, as if it werethe actual concave surface of a hollow sphere.
Astronomy
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