Astronomy for High Schools and Colleges

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H. Holt, 1881 - 512 pages
 

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Page 132 - The change of motion is proportional to the motive force impressed; and is made in the direction of the right line in which that force is impressed.
Page 132 - To every action there is always opposed an equal reaction: or, the mutual actions of two bodies upon each other are always equal, and directed to contrary parts.
Page v - ... the type. The portions in large type form a complete course for the use of those who desire only such a general knowledge of the subject as can be acquired without the application of advanced mathematics. The portions in small type comprise additions for the use of those students who either desire a more detailed and precise knowledge of the subject, or who intend to make astronomy a special study. From CA YOUNG, Professor in Princeton College : " I conclude that it is decidedly superior to anything...
Page 168 - ECLIPSES OF THE MOON. The mean distance of the moon from the earth is about 60 radii of the latter, while, as we have just seen, the length EV of the earth's shadow is 217 radii of the earth. Hence when the moon passes through the shadow she does so at a point less than three tenths of the way from E to V. The radius of the shadow here will be HYi44 of the radius EB of the earth, a quantity which we readily find to be about 4600 kilometres.
Page 132 - Every body continues in its state of rest or of uniform motion in a straight line, unless it is compelled to change that state by forces impressed upon it.
Page 123 - The square of the period of a planet is proportional to the cube of its mean distance from the Sun.
Page 175 - If the orbit of the moon around the earth were in or near the plane of the ecliptic there would be an eclipse of the sun at every new moon, and an eclipse of the moon at every full moon. But...
Page 29 - ... instant, and to define this position by the two co-ordinates right ascension and declination. Thus we know the position of this imaginary body just as we know the position of a star whose co-ordinates are given, and we may speak of its transit as if it were a bright material point in the sky. A mean solar day is the interval of time between two consecutive transits of the mean sun over the upper meridian. Mean noon at any place on the earth is the instant of the mean sun's transit over the meridian...
Page 65 - The magnifying power of the Compound Microscope is estimated as follows. First, the diameter of the image will be to that of the object as their respective distances from the lens. Secondly, the image is magnified by the eye-glass according to the principles of the single microscope, (Art.

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