14The tortoise contrived for filling up ditches, which also affords an access to the walls, is thus made. A base, called by the Greeks εσχάρα, is prepared twenty-five feet square, with four cross pieces. These are tied in by two other pieces, one twelfth high, and one half wide, distant from each other about a foot and a half, and under each of their intervals are placed the naves of wheels, called in Greek ἁμαξόποδες, within which the axles of the wheels turn in iron hoops. The naves are so made that they have holes in their heads, in which the handspikes being received, are made to turn them. The naves thus revolving, it may be moved forward or backward, to the right or left, or diagonally, as wanted.
14A tortoise intended for the filling of ditches, and thereby to make it possible to reach the wall, is to be made as follows. Let a base, termed in Greek ἑσχἁρα, be constructed, with each of its sides twenty-one feet long, and with four crosspieces. Let these be held together by two others, two thirds of a foot thick and half a foot broad; let the crosspieces be about three feet and a half apart, and beneath and in the spaces between them set the trees, termed in Greek ἁμαξὁποδες, in which the axles of the wheels turn in iron hoops. Let the trees be provided with pivots, and also with holes through which levers are passed to make them turn, so that the tortoise can move forward or back or towards its right or left side, or if necessary obliquely, all by the turning of the trees.