Elements of astronomy: accompanied with numerous illustrations, a colored representation of the solar, stellar, and nebular spectra, and celestial charts of the northern and the southern hemisphere (1875)
Lockyer, Norman, Sir, 1836-1920 · New York, D. Appleton and company · leaf 239
nd made to converge to c, which point iscalled the Focus. 419. If we hold a common burning-glass (which is abi-convex lens) up to the Sun, and let the light that passesthrough it fall on a piece of paper, the rays will be broughtto a focus; and if the paper is held at a certain distancefrom the… … Fig. 94.—Bi-convex «Lens, throwing an Inverted Image. lens at b a, every point of the arrow, sending a ray to everypoint in the surface of the lens. Each point of the arrow,in fact, is the apex of a cone of rays resting on the lens,and a similar cone of rays, after refraction, paints everypoint of…
Astronomy
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