An account of Sir Isaac Newton's philosophical discoveries : in four books / By Colin Maclaurin ... Published from the author's manuscript papers, by Patrick Murdoch.

  • MacLaurin, Colin, 1698-1746
Date:
M.DCC.XLVIII. [1748]
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Licence: Public Domain Mark

Credit: An account of Sir Isaac Newton's philosophical discoveries : in four books / By Colin Maclaurin ... Published from the author's manuscript papers, by Patrick Murdoch. Source: Wellcome Collection.

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    afcend from it, as fhe moves from the conjunction to the next quarter. The adion which difturbs her motion will have a like, and almoft equal, effed upon her, while (he moves in the other half of her orbit, I mean, that half of it which is farthelt from the fun : fhe will proceed from the quarter that follows the conjunction with an accelerated motion to the oppofition, approaching a little towards the earth, becaufe of the addition made to her gravity, at that quarter, from the aCtion of the fun; and receding from it again, as fhe goes on from the oppofition to the quarter from which we fuppofed her to let out. The areas defcribed in equal times by a ray drawn from the moon to the earth will not be equal, but will be accelerated by tne confpiring adion of the fun, as fhe moves towards the con¬ junction or oppofition from the quarters that precede them ; ^nd will be retarded by the fame aCtion, as ihe moves from the conjunction or oppofition to the quarters that fucceed them. 7. Our author has computed the quantities of thefe irregula¬ rities from their caufes. He finds, that the force added to the gravity of the moon in her quarters, is to the gravity with which fhe would revolve in a circle about the eaitn, at her prefent mean diftance, if the fun had no erred on her, at 1 to 178^. He finds the force fubduded from her gravity, in the conjundions and oppofitions, to be double of this quantity, and the area defcribed in a given time in the quarters, to be to the area defcribed in the fame time in the conjundions and oppofitions, as 10973 to 11073. He finds, that, in fuch an orbit, her diftance from the earth in her quarters, would be to her diftance in the conjundions and oppofitions, as 70 to 69. 8. The'