The wonders of the heavens, being a popular view of astronomy, including a full illustration of the mechanism of the heavens; embracing the sun, moon, and stars, with descriptions of the planets, comets, fixed stars, double stars, the constellations, the galaxy, or milky-way, the zodiacal light, aurora borealis, or norhtern lights, meteors, clouds, falling stars, aërolites, &c (1837)
Bradford, Duncan. [from old catalog] · Boston, American stationers company · leaf 352
s thedifficulty of working metals as perfect as glass,induced him to suggest this improvement. Let a bbe the great speculum, and r a, r b parallel raysfrom a distant object reflected to a focus at F ; thecone of rays, however, is intercepted by the achro-matic prism c d, and refracted to/, where a… … mean refractive power, the loss of light by trans-mission through the two prisms, says Brewster, willnot exceed six hundred rays out of ten thousand,as the light transmitted through a lens of glass, ac-cording to Herschel, is nine thousand four hundredand eighty-five out of ten thousand incident…
Astronomy
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