The geography of the heavens, and class-book of astronomy: (1858)
Burritt, Elijah H. (Elijah Hinsdale), 1794-1838, Mattison, Hiram, 1811-1868 · New York, Mason brothers · leaf 312
er is gone, so that the raysare not so soon refracted to afocus. In this case, the focal dis-tance is equal to the diameter ofthe sphere formed by extendingthe convex surface of the lens;while with the double-convex lens,the focal distance is only equal to the radius of such sphere. In the cut, the… … RAYS DISPERSED BY REFRACTION.
Constellations · Stars
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