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adeo æquales anno appears areæ Astronomy atque adeo axis Biographia Britannica Birch bodies calculations Cambridge celeritas centre centripeta centripetal force ciety cipia circular motion comets conatus copy corpus curve David Gregory demonstration distance distantiæ diurnal motion duplicate proportion earth ejus ellipseos ellipsis Encyclopædia Britannica erit ether Fatio Flamsteed Fluxions force gravity Gregory hæc Halley Halley's Hooke Hooke's Hugenii Hugens hyperbola hypothesis Isaac Newton latus rectum Leibnitz letter likewise lineam manuscript mathematical medii mention moon moon's motus Newton occasion Oldenburg orbit original Paget paper Pemberton phænomena Phil Philosophy Picard's planets Principia Principia Mathematica printed probably projectiles Prop proportionalis proposition published puncto quæ quam quod ratio reciprocally recta referred Royal Society says scholium seems sent shews squares sunt suppose supposition tempori temporibus theorem theory thing third book thought tion Trans Transactions umbilicus writing written
Page 62 - But to derive two or three general principles of motion from phaenomena, and afterwards to tell us how the properties and actions of all corporeal things follow from those manifest principles, would be a very great step in philosophy, though the causes of those principles were not yet discovered. And therefore I scruple not to propose the principles of motion above mentioned, they being of very general extent, and leave their causes to be found out.
Page 73 - The proof you sent me I like very well. I designed the whole to consist of three books ; the second was finished last summer, being short, and only wants transcribing, and drawing the cuts fairly. Some new propositions I have since thought on, which I can as well let alone. The third Wants the theory of comets.
Page 38 - This depends upon three suppositions: — first, that all celestial bodies whatsoever have an attraction or gravitating power towards their own centres, whereby they attract not only their own parts and keep them from flying from them, as we may observe the earth to do, but that they do also attract all the other celestial bodies that are within the sphere of their activity...
Page 34 - And as the earth, so perhaps may the sun imbibe this spirit copiously, to conserve his shining, and keep the planets from receding further from him ; and they that will may also suppose that this spirit affords or carries with it thither the solary fuel and material principle of life, and that the vast ethereal spaces between us and the stars are for a sufficient repository for this food of the sun and planets.
Page 30 - The third I now design to suppress. Philosophy is such an impertinently litigious lady, that a man had as good be engaged in lawsuits as have to do with her.
Page 55 - Mr Wood ! — This is the greatest discovery in nature that ever was since the world's creation. It never was so much as hinted by any man before. I know you will do him right. I hope you may read his hand. I wish he had writ plainer, and afforded a little more paper.
Page 31 - Now is not this very fine ? Mathematicians, that find out, settle, and do all the business, must content themselves with being nothing but dry calculators and drudges ; and another, that does nothing but pretend and grasp at all things, must carry away all the invention, as well of those that were to follow him, as of those that went before.
Page 54 - The second supposition is this, that all bodies whatsoever that are put into a direct and simple motion will so continue to move forward in a straight line till they are, by some other effectual powers, deflected and bent into a motion describing a circle, ellipsis, or some other more compounded curve line. The third supposition is that these attractive powers are so much the more powerful in operating, by how much the nearer the body wrought upon is to their own centers.
Page 50 - ... this power is not found sensibly diminished at the remotest distance from the centre of the earth to which we can rise, neither at the tops of the loftiest buildings, nor even on the summits of the highest mountains, it appeared to him reasonable to conclude that this power must extend much farther than was usually thought : Why not as high as the Moon ? said he to himself ; and, if so, her motion must be influenced by it ; perhaps she is retained in her orbit thereby.
Page 70 - For nature is a perpetual circulatory worker, generating fluids out of solids, and solids out of fluids, fixed things out of volatile, and volatile out of fixed, subtile out of gross, and gross out of subtile ; some things to ascend and make the upper terrestrial juices, rivers, and the atmosphere, and by consequence others to descend for a requital to the former. And as the earth, so perhaps may the sun imbibe this spirit copiously, to conserve his shining...