‹‹‹ Vitr. 10.3.7 | Table of Contents | Vitr. 10.3.9 ›››
8Thus also oxen have an equal draft when the piece which suspends the pole hangs exactly from the middle of the yoke. But when oxen are not equally strong, the method of apportioning to each his due labour is by shifting the suspending piece so that one side of the yoke shall be longer than the other, and thus relieve the weaker animal. It is the same in the porters’ levers as in yokes, when the suspending tackle is not in the centre, and one arm of the lever is longer than the other, namely that towards which the tackle has shifted; for in this case if the lever turn upon the points to which the tackle has slid, which now becomes its centre, the longer arm will describe a portion of a larger circle, and the shorter a smaller circle.
8In the same way, oxen have an equal draught when their yoke is adjusted at its middle by the yokestrap to the pole. But when their strength is not the same, and the stronger outdoes the other, the strap is shifted so as to make one side of the yoke longer, which helps the weaker ox. Thus, in the case of both poles and yokes, when the straps are not fastened at the middle, but at one side, the farther the strap moves from the middle, the shorter it makes one side, and the longer the other. So, if both ends are carried round in circles, using as a centre the point to which the strap has been brought, the longer end will describe a larger, and the shorter end a smaller circle.