第108章 9(1)

It can now be shown plainly that rotation is the primary locomotion.

Every locomotion, as we said before, is either rotatory or rectilinear or a compound of the two: and the two former must be prior to the last, since they are the elements of which the latter consists.

Moreover rotatory locomotion is prior to rectilinear locomotion, because it is more simple and complete, which may be shown as follows.