[AS.] A circular frame turning round on an axle. The radii are spokes which are fixed in the nave or hub, through which is inserted the axle.- Wheel and axle, one of the six simple machines or mechanical powers, consisting of a wheel fixed to an axle, used for raising weights by a rope. The principle of equilibrium is the same as in the lever, but continuous. The gain in power is in proportion to the size of the circumference of the wheel as compared with that of the axle. If the circumference of the wheel be ten times that of the axle, then one pound attached to the wheel will balance ten Wxmnds applied to the axle.