The motion, further, in connection with which we have to consider the quantitative relation of the space traversed to the time elapsed in traversing it, assumes the various determinations of a simply uniform motion, a uniformly accelerated one, and one which is alternatively uniformly accelerated and uniformly retarded (motion that turns back upon itself ); inasmuch as these various species of motion are expressed in accordance with the quantitative relation of their moments, of space and time, we have for them equations of various power determinations, and inasmuch as the need arises to determine one species of motion, or also of spatial magnitudes to which a species of motion is associated, from another species of motion, such an operation likewise entails the transition from one power function to another, whether higher or lower.