Chap 3. PHILOSOPHY.

i95

11. But now as soon as ever the moon is advanced fromthe quarter toward the new or conjunction, supposo to G,the action of the sun upon it will have a different effect. Here,were the sun’s action upon the moon to be applied in the di-rection G H parallel to A S, if its action on the moon wereequal to its action on the earth, no change would be wroughtby the fun on the apparent motion of the moon round theearth. But the moon receiving a greater impulse in G thanthe earth receives in A, were the fun to act in the directionGH, yet it would accelerate the description of the spaceDAG, and cause the angle under GAD to decrease faster,than otherwise it would. The sun’s action will have this effectupon account of the obliquity of its direction to that, inwhich the earth attracts the moon. For the moon by thismeans is drawn by two forces oblique to each other, onedrawing from G toward A, the other from G toward H,therefore the moon must necessarily be impelled toward D.Again, because the fun does not act in the direction G H pa-rallel to S A, but in the direction G S oblique to it, the fun’saction on the moon will by reason of this obliquity farther con-tribute to the moon’s acceleration. Suppose the earth in anyshort space of time would have moved from A to I, if notattracted by the fun; the point I being in the straight line C E,which touches the earth’s orbit in A. Suppose the moon inthe fame time would have moved in her orbit from G to K,and besides have partook os all the progressive motion of theearth. Then is K L be drawn parallel to A I, and taken equalto it, the moon, is not attracted by the sun, would be found

Le 2. in