"You are also a friend of Leibniz. Now, there are those who would have me believe that Leibniz is, to me, some sort of adversary. I do not think so." Newton’s eyes strayed towards Fatio as he said this. Fatio turned red, and would not meet his gaze. "I say that the product of mass and velocity is conserved; Leibniz says that the product of mass and the square of velocity is conserved; it seems that both of us are correct, and that by applying both of these principles we may build a science of Dynamics—to borrow Leibniz’s term—that is more than the sum of these two parts. So in this Leibniz has not detracted from my work, but added to it.