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acts angle appear astronomy attraction authority axis believe body calculated called carried cause centre century circle complete consider continued Copernik course described died direction discovered discovery distance earth eccentricity ecliptic effect ellipse equal equator exactly explained fact fixed follows force further Galileo give given greater hence increased Italy Jupiter Kepler knowledge known less light lived mass mathematical mean method moon moon's motion move nature nearly never Newton observed orbit particle passed path period perturbing force physical planets position probably produced proportional proved radius reason relative represent rest result revolve rotation round satellites Saturn says seems seen showed side solar system space sphere stars supposed surface telescope theory thing thought tion true turned Tycho universe whole
Page 240 - If I have seen further than other men, it is because I have stood on the shoulders of giants.
Page 114 - I was sure of my discovery ; what, sixteen years ago, I urged as a thing to be sought; that for which I joined Tycho Brahe, for which I settled in Prague, for which I have devoted the best part of my life to astronomical contemplations ; — at length I have brought to light, and have recognised its truth beyond my most sanguine expectations.
Page 140 - Animals which move have limbs and muscles ; the earth has no limbs or muscles, therefore it does not move. It is angels who make Saturn, Jupiter, the sun, etc., turn round. If the earth revolves, it must also have an angel in the centre to set it in motion ; but only devils live there, it would therefore be a devil who would impart motion to the earth.
Page 131 - Every body continues in its state of rest or of uniform motion in a straight line, except in so far as it may be compelled by impressed forces to change that state.
Page 169 - that every particle of matter in the universe attracts every other particle, with a force whose direction is that of the line joining the two, and whose magnitude is directly as the product of their masses, and inversely as the square of their distances from each other.
Page 135 - Change of motion is proportional to the impressed force and takes place in the direction of the straight line in which the force acts.
Page 274 - Often I would keep myself awake that I might listen to their animating remarks, for it made me so happy to see them so happy. But generally their conversation would branch out on philosophical subjects, when my brother William and my father often argued with such warmth, that my mother's interference became necessary, when the names Leibnitz, Newton, and Euler sounded rather too loud for the repose of her little ones, who ought to be in school by seven in the morning.
Page 297 - Venus a pea, on a circle of 284 feet in diameter; the Earth also a pea, on a circle of 430 feet; Mars a rather large pin's head, on a circle of 654 feet; the Asteroids, grains of sand, in orbits of from.