Note 11 — Chapter V
W. M. (William Mitchell) Gillespie translation
Leibnitz had already considered the comparison of one curve with an other infinitely near to it, calling it "Differentiatio de curva in curvam." But this comparison had no analogy with the conception of Lagrange, the curves of Leibnitz being embraced in the same general equation, from which they were deduced by the simple change of an arbitrary constant.