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 142
sun.The nature of this variation will be easily under-stood by placing a black spot upon a commonglobe, and observing the different shapes which itassumes while the globe is made to revolve aboutits axis. When the spot is near the middle of thesuns disc, its breadth is then greater, but… … -f,5 where are given the appearances of a spot onseven successive days, as observed by Helve-lius. Hence it is obvious th^t these spots areupon the surface of the sun, and that theirmotion across his disc from east to west is pro-duced by the revolution of the sun about hisaxis. The time in which…
Astronomy
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