"After dinner, the weather being warm, we went into the garden, & drank tea under the shade of some apple trees; only he & myself. Amidst other discourse, he told me, he was just in the same situation, as when formerly, the notion of gravitation came into his mind. "Why should that apple always descend perpendicularly to the ground," thought he to him self; occasion'd by the fall of an apple, as he sat in a contemplative mood. "Why should it not go sideways, or upwards? but constantly to the earths centre? Assuredly, the reason is, that the earth draws it. There must be a drawing power in matter. The sum of the drawing power in the matter must be in the earth's center, not in any side of the earth. Therefore does this apple fall perpendicularly or toward the center. If matter thus draws matter; it must be in proportion to its quantity. Therefore the apple draws the earth, as well as the earth draws the apple.""