. 2,00

Sir I sa a c Newton’s Book II.

the earth and moon would descend with equal pace fo-rward the sun, so as to make no change by that descentin the angle under FAS; but the length of the line F A mustos necessity be shomied. Therefore the moon in moving fromF toward the conjunction with the sun will be impelled moretoward the earth by the sun’s action, than it would have beenby the earth alone, if neither the earth nor moon had beenacted on by the fun ; so that by this additional impulse theorbit is rendred more curve, than it would otherwise be.The same effect will also be produced in the other quarter.

18.Another effect os the luffs action, consequent uponthis we have now explained, is, that though the moon un-disturbed by the fun might move in a circle having the earthfor its center ; by the fun’s action, if the earth were to bein the very middle or center of the moon’s orbit, yet themoon would be nearer the earth at the new and full, thanin the quarters. In this probably will at first appear somedifficulty, that the moon should come nearest to the earth,where it is least attracted to it, and be farthest off when mostattracted. Which yet will appear evidently to follow fromthat very cause, by considering what was last shewn, that theorbit of the moon in the conjunction and opposition is ren-dred less curve ; for the less curve the orbit of the moon is,the less will the moon have descended from the placeit would move into, without the action os the earth. Nowis the moon were to move from any place without fartherdisturbance from that action, since it would proceed inthe line, which would touch its orbit in that place, it would

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