Olmsted, Denison, 1791-1859. [from old catalog] · New York, R. B. Collins · leaf 67
ay bedone either by a convex lens, or by a concave mirror. Aconvex lens is a flat piece of glass, having its two facesconvex, or spherical, as is seen in a common sun glass.Every one who has seen a sun glass, knows that whenheld towards the sun it collects the solar rays into asmall bright circle… … the tube of a telescope. At the front end, or at the endwhich is directed towards the object, (which we willsuppose to be the moon,) is inserted a convex lens,L, which receives the rays of light from the moon, andcollects them into the focus at a, forming an image ofthe moon. This image is viewed…
Astronomy
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