Collins, A. Frederick (Archie Frederick), 1869- · New York, London, D. Appleton and company · leaf 154
inal direction, or refracted. A convex lens, see Fig. 146, is a lens which is thicker inthe middle than it is at the edges. A convex lens is used formagnifying an object; or forforming an image so that itcan be magnified by anotherlens as in a telescope, for form-ing an image on the screenof a… … FIg. 144.—Prism. 134 THE BOOK OF THE STARS holding a sheet of paper, or the hand under the lens and lettingthe sunlight pass through it; where the spot of light is smallest jr^N 1 ^ xj Fig. 145.—Peism Forming a Spectrum. and brightest there is the focus. The distance of this point fromthe lens is…
Astronomy · Stars
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