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according action angle appears arising atmosphere attraction axis becomes bodies called cause changes chemical circumstances color comet consequence continued dark depends determined diameter diminishes direction distance disturbing earth ecliptic effect electricity equal equator existence experiments extends extremely fall fluid force give given glass gravitation greater half heat increase influence intensity known latitude length less light liquid magnetic mass matter mean measured miles moon motion move nature nearly NOTE object observations occasions opposite orbit particles passing period phenomena planets plate polarized poles position probably produce proportion proved quantity rays reflected refraction regard revolving rings rotation round satellites seen separated side similar solar solid sound space spectrum square stars substances surface take place temperature terrestrial theory tion transmitted variations varies vibrations waves whole wire
Page 19 - But, in the midst of all these vicissitudes, the length of the major axes and the mean motions of the planets remain permanently independent of secular changes. They are so connected by Kepler's law, of the squares of the periodic times being proportional to the cubes of the mean distances of the planets from the sun, that one cannot vary without affecting the other.
Page 22 - That day, as other solemn days, they spent In song and dance about the sacred Hill — Mystical dance, which yonder starry sphere Of planets and of fixed in all her wheels Resembles nearest; mazes intricate, Eccentric, intervolved, yet regular Then most when most irregular they seem; And in their motions harmony divine So smooths her charming tones that God's own ear Listens delighted.
Page 274 - The spark taken in the same manner from zinc, cadmium, tin, bismuth, and lead, in the melted state, gives similar results ; but the number, position, and colours of the lines vary in each case. The appearances are so different that, by this mode of examination, the metals may be readily distinguished from each other.
Page 70 - ... there is a meridian about 30° eastward of the moon, where it is always high water both in the hemisphere where the moon is and in that which is opposite. On the west side of this circle the tide is flowing, on the east it is ebbing, and on every part of the meridian at 90° distant it is low water.
Page 343 - Jupiter ; it then gradually diminished in splendor, and having exhibited all the variety of tints that indicate the changes of combustion, vanished sixteen months after its discovery, without altering its position. It is impossible to imagine anything more tremendous than a conflagration that could be visible at such a distance.
Page 324 - The periods of some comets are said to be of many thousand years, and even the average time of the revolution of comets generally is about a thousand years ; which proves that the sun's gravitating force extends very far. La Place estimates that the solar attraction is felt throughout a sphere whose radius is a hundred millions of times greater than the distance of the earth from the sun.
Page 2 - ... humility, by showing that there is a barrier which no energy, mental or physical, can ever enable us to pass: that, however profoundly we may penetrate the depths of space, there still remain innumerable systems, compared with which, those apparently so vast must dwindle into insignificance, or even become invisible; and that not only man, but the globe he inhabits — nay, the whole system of which it forms so small a part — might be annihilated, and its extinction be unperceived in the immensity...
Page 15 - ... planets, which do not compensate each other till after one, or even till after many revolutions of both bodies. A periodical inequality of this kind in the motions of Jupiter and Saturn, has a period of no less than 918 years. The radial force, or that part of the disturbing force which acts in the direction of the line joining the centers of the sun and disturbed planet, has no effect on the areas, but is the cause of periodical changes of small extent in the distance of the planet from the...