Tamen quia hostiles ballistae ferratis impositae turribus, in humiliora ex supernis valentes, ut loco dispari ita eventu dissimili, nostra multo cruore foedabant,
Translation :
However, because the enemy's ballistae, mounted as they were upon iron-clad towers, were effective from their higher place against those lower down, on account of their different position they had a different result and caused terrible carnage on our side;
Edition :
Ammianus Marcellinus. With An English Translation. John C. Rolfe, Ph.D., Litt.D. Cambridge. Cambridge, Mass., Harvard University Press; London, William Heinemann, Ltd. 1935-1940.