Book 23
4.7
And the machine is called tormentum as all the released tension is caused by twisting (torquetur); and scorpion, because it has an upraised sting; modern times have given it the new name onager, because when wild asses are pursued by hunters, by kicking they hurl back stones to a distance, either crushing the breasts of their pursuers, or breaking the bones of their skulls and shattering them.
4.8
Now we shall come to the ram. A tall fir or mountain ash is selected, to the end of which is fastened a long, hard iron; this has the appearance of a projecting ram’s head, and it is this shape which has given the machine its name. This is suspended between ironbound beams running across on both sides, so that it hangs from a third beam like the pan of a balance. Then a number of men, as great as the length of the pole permits, draw it back and then shove it forward again with powerful blows, just as a ram charges and retreats, to break everything in its way. As this is renewed with the force of a repeated stroke of lightning,The ancients believed that a stroke of lightning returned to the sky, doing damage as it came and as it went. Cf. Lucan, i, 156. buildings are cracked and shattered as the structure of their walls is destroyed.
4.9
If this kind of engine is worked with full vigour, the strongest cities, after their walls have been stripped of defenders, are laid open, and the siege is thus brought to an end.
