Heron’s Artillery Construction chapters 10—12.

| English Translation (from Greek) |

| English Translation (from German) |
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| p. 86 ...when [the axle] is turned in the opposite direction, the lines original: "hopla", literally "tools" or "tackle" of the pulley system original: "polyspaston" are wound up; for as they are wound up, they draw up the slider original: "diostra". 5 But instead of the pulley system, a drum original: "tympanon" can be made as one with the axle and turned by hand-spokes original: "skytalon", performing the drawing back by means of a single line. It is also necessary for the whole engine 12 10 to be placed elevated upon a base, so that the drawing down the process of tensioning the bow-arms becomes easier, and so that it may be rotated as one chooses, . | ...turned in the opposite direction, the ropes of the pulley system are wound up, whereby the slider the sliding trough that holds the bolt is brought forward¹. Instead of the pulley system, one can also attach a wheel to the shaft, which is turned with hand-grips and effects the tensioning by a simple rope². The whole artillery piece must, however, rest on a base, so that the tensioning is facilitated and one can take the vertical and horizontal aim literally: "height and side direction", so that after the... |

¹ In the manner described by Heron, the forward movement is only possible with the simple use of a shaft for tensioning.

The ropes for bringing [the slider] forward look like a single rope on the drawing. However, there must actually be two ropes, because a single one, even if looped several times around the shaft, would gradually stretch out and then no longer have sufficient friction on the shaft. In engines with pulley systems, the slower movement of the tensioning shaft must be converted into the necessary faster movement of the forward-propelling shaft by means of gearing or belt transmission.

² In the drawing in Manuscript M folio 49, the letter Z on the left arm is cut away, and the upper locking pin on the right arm is missing.

On both sides of the ladder the main stock of the catapult, the half-frames of the Palintonon a "v-shaped" torsion catapult that shot stones are depicted, drawn disproportionately small, with the bow-arms and the string.

The frame, tensioning cords, and tensioning bolts are clearly recognizable, as are the arms with the locking pins and the string.

The middle section shows, seen from above: the ladder, the slider with the arrow groove, the claw the trigger mechanism with its supports, the trigger, the widening of the slider at the rear end, the axle 3 A, the hand-spokes, and the ropes, without the pulley system.