‹‹‹ Vitr. 1.5.4 | Table of Contents | Vitr. 1.5.6 ›››
5The towers should be made either round or polygonal. A square is a bad form, on account of its being easily fractured at the quoins by the battering-ram; whereas the circular tower has this advantage, that, when battered, the pieces of masonry whereof it is composed being cuneiform, they cannot be driven in towards their centre without displacing the whole mass. Nothing tends more to the security of walls and towers, than backing them with walls or terraces: it counteracts the effects of rams as well as of undermining.
5The towers themselves must be either round or polygonal. Square towers are sooner shattered by military engines, for the battering rams pound their angles to pieces; but in the case of round towers they can do no harm, being engaged, as it were, in driving wedges to their centre. The system of fortification by wall and towers may be made safest by the addition of earthen ramparts, for neither rams, nor mining, nor other engineering devices can do them any harm.