A primary astronomy .. . de is increased as the distance isdiminished; and diminished as the distance is increased. 2. These principles are still further illustrated in the following cut, in which theobserver is placed at three points, corresponding with the comparative distances ofSaturn, Herschel, and Neptune. THE SUN VIEWED FROM DIFFERENT POINTS. 4C^.-.«!:»:;»;;^:::::::::,::::....\S |H |N ; | ] Here the first observer on the left stands upon Saturn, and the sun fills a compara-tively large angle, as shown at A. From Herschel the angle is smaller, and at Neptuneit is still less. 3. By applyi
A primary astronomy .. . de is increased as the distance isdiminished; and diminished as the distance is increased. 2. These principles are still further illustrated in the following cut, in which theobserver is placed at three points, corresponding with the comparative distances ofSaturn, Herschel, and Neptune. THE SUN VIEWED FROM DIFFERENT POINTS. 4C^.-.«!:»:;»;;^:::::::::,::::....\S |H |N ; | ] Here the first observer on the left stands upon Saturn, and the sun fills a compara-tively large angle, as shown at A. From Herschel the angle is smaller, and at Neptuneit is still less. 3. By applying the principles thus illustrated to the 3un, as viewed from the severalplanets, we are enabled to determine his comparative magnitude, as seen from eachof these points. The following cut represents the comparative apparent magnitude of THE SUN AS SEEN FROM THE DIFFERENT PLANETS. FromN. H. S. Jupiter. Mars. 4. The relative apparent magnitude of the sun, as seen from different points in theSolar System, is as follows:. From Jupiter 6 Saturn 3| « Herschel 1§ Neptune 50 From Mercury 82£ Venus 44| Earth 32 Mars 21 The Asteroids, say 12 5. Let us continue our imaginary journey outward, beyond Neptune, toward thefixed stars, and in a short time the glorious sun, so resplendent and dazzling to ourview, will appear only as a sparkling star; and the fixed stars will expand to view as weapproach them, till they assume all the magnitude and splendor of the sun himself.] LESSOJST X. LIGHT AND HEAT OF THE PLANETS. 17 9. From what source are the Light and Heat of the Planetsderived ? PRIMARY ASTRONOMY. 41 From the Sun. 180. What effect does the variation in their distances have uponthem, in this respect ? It must make a great difference in their respective temperatures. [1. The following cut is designed to illustrate the PHILOSOPHY OF THE DIFFUSION OF LIGHT.
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Keywords: ., bookcentury1800, bookdecade1850, booksubjectastronomy, bookyear18
