MOMENTS, in the new doctrine of infinites, denote the indefinitely small parts of quantity; or they are the same with what are otherwise called infinitesimals and differences, or increments and decrements: being the momentary increments or decrements of quantity considered as in a continual flux.
Moments are the generative principles of magnitude; they have no determined magnitude of their own, but are only inceptive of magnitude.
Hence, as it is the same thing if, instead of these moments, the velocities of their increases and decreases be made use of, or the finite quantities that are proportional to such velocities; the method of proceeding which considers the motions, changes, or fluxions of quantities, is denominated by Sir Isaac Newton, the method of fluxions.
Leibnitz, and most foreigners, considering these infinitely small parts, or infinitesimals, as the differences of two quantities, and thence endeavouring to find the differences of quantities, i. e. some moments, or quantities indefinitely small, which taken an infinite number of times shall equal given quantities, call these moments differences; and the method of procedure, the differential calculus.