The geography of the heavens : and class-book of astronomy : accompanied by a celestial atlas (1860)
Burritt, Elijah H. (Elijah Hinsdale), 1794-1838, Mattison, Hiram, 1811-1868 · New York : Mason Brothers · leaf 314
* focus atthe circle cave lens disperses pa-rallel rays, as if theydiverged from the cen-ter of a circle formedby the convex surfaceproduced. In this cut, the parallel raysA are dispersed by the double-concave lens C, as shown atB; and their direction, asthus refracted, is the sameas if they… … which is the center of a circle formed by the 679. Common spectacles, opera-glasses, burning-glasses, andrefracting telescopes are made by converging light to a focus, bythe use of double-convex lenses. The ordinary burning-glass, which may bebought for a few shillings, is a double-convexdisk of…
Constellations · Stars
Internet Archive · Library of Congress · Public Domain Mark 1.0. Free to use for anything.
