The Elements of Astronomy: A Non-mathematical Textbook for Use as an Introduction to the Subject in Colleges, Universities, Etc., and for the General Reader

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McGraw-Hill Book Company, Incorporated, 1926 - 307 pages

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Page 82 - Newton generalized the law of attraction into a statement that every particle of matter in the universe attracts every other particle with a force which varies directly as the product of their masses and inversely as the square of the distance between them; and he thence deduced the law of attraction for spherical shells of constant density.
Page 140 - The orbit of each planet is an ellipse with the sun at one focus. 2. The line which joins a planet to the sun sweeps over equal areas in equal intervals of time.
Page 140 - The cubes of the mean distances of the planets from the sun are proportional to the squares of their times of revolution.
Page 109 - ... polarities in the northern and southern hemispheres. "As the cycle progresses the mean latitude of the spots in each hemisphere steadily decreases, but their polarity remains unchanged. The high-latitude spots of the next ns-year cycle, which begin to develop more than a year before the last lowlatitude spots of the preceding cycle have ceased to appear, are of opposite magnetic polarity.
Page 135 - The known principal planets, in order of their distance from the Sun are: Mercury, Venus, Earth, Mars. Jupiter, Saturn, Uranus. Neptune, and Pluto.
Page 199 - These twelve parts are called the signs of the zodiac and are named after the constellations which occupy them. The names of the signs of the zodiac are: Aries, Taurus, Gemini, Cancer, Leo, Virgo, Libra, Scorpio, Sagittarius, Capricornus, Aquarius, and Pisces.
Page 18 - When a ray of light passes from a rarer to a denser medium, it is bent toward a perpendicular drawn to the surface of the denser medium.
Page 10 - On account of the asymmetrical distribution of sea and land, a shift in water mass will tilt the axis of rotation with respect to the body of the Earth.
Page 22 - ... if the axis of the earth were perpendicular to the plane of its own orbit round the sun, the following three consequences would be inevitable:— I.
Page 55 - ... the spectrum. The Doppler-Fizeau principle, which is one of incalculable importance in Astronomy, may be stated as follows: When the distance between an observer and a source . of light is increasing, the lines of the spectrum lie farther to the red than their normal positions, and when the distance is diminishing they lie farther to the violet, the displacement being proportional to the relative velocity of recession or approach. The formula for the change of wave-length of a spectral line is...

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