2or

Chap. z. PHILOSOPHY.

recede continually from the earth; and therefore if the powerof the earth upon the moon, be sufficient to retain it atthe fame distance, this diminution of that power will causethe distance to increase, though in a less degree. But on theother hand in the quarters, the moon, being pressed more to-wards the earth than by the earth’s single action, will bemade to approach it; so that in pasting from the conjunctionor opposition to the quarters the moon ascends from theearth, and in pasting from the quarters to the conjunctionand opposition it descends again, becoming nearer in theselast mentioned places than in the other.

19. All these forementioned inequalities are of differentdegrees, according as the fun is more or less distant from theearth ; greater when the earth is nearest the fun, and lesswhen it is farthest off. For in the quarters j the nearer themoon is to the fun, the greater is the addition to the earth’saction upon it by the power of the fun ; and in the conjun-ction and opposition, the difference between the fun’s actionupon the earth and upon the mocn is likewise so much thegreater.

20. This difference in the distance between the earthand the fun produces a farther effect upon the moon’s mo-tion ; causing the orbit to dilate when lest remote from thefun, and become greater, than when at a farther distance.For it is proved by Sir I s a a c Newton, that the action ofthe fun, by which it diminishes the earth’s power over themoon, in the conjunction or opposition, is about twice as

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