A treatise of the system of the world ... / By Sir Isaac Newton. Translated into English [by A. Motte].

  • Isaac Newton
Date:
1728
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Licence: Public Domain Mark

Credit: A treatise of the system of the world ... / By Sir Isaac Newton. Translated into English [by A. Motte]. Source: Wellcome Collection.

    55/196 page 23
    tion raifed thereon, Mr. Huygens has demonftrated that bodies -falling by all that centripetal force, with which (of whatever nature it is) they are impelled near the furface of the Earth, do, in one fecond of time, deicribe 15:2, Paris feet. Bur if the Earth is fuppofed to move, the Earth and Moon together a4 And the Moon will in the fame perio- dic time 27 4%. 74. 43’, with the fame cir- cum-terreftrial force, diminifhed in the duplicate proportion of the diftance, de- {cribe an orbit, whofe femi-diameter is to the femi-diameter of the former orbit, that is, to 60 femi-diameters of the Earth, the fum of both the bodies of the Earth and Moon to the firft of two mean pro- portionals between this fum and the body of the Earth ; that is, if we fuppofe the Moon (on account of its mean appa- rent diameter 31 /) to be about 4, of the Earth, as 43 to Wc. 42 X 43], OF aS a- bout 128 to 127. And therefore the femi-diameter of the orbit, that is, the diftance between the centers of the Moon and Earth, will inthis cafe be 60 £ femidiameters of the Earth,.almoft the fame with that affigned by Coperuicus, 4 which
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