The _number_ of such engines employed was sometimes very great. We have seen that St. Lewis captured 24 at once, and these had been employed in the field. Villehardouin says that the fleet which went from Venice to the attack of Constantinople carried more than 300 perriers and mangonels, besides quantities of other engines required for a siege (ch. xxxviii). At the siege of Acre in 1291, just referred to, the Saracens, according to Makrizi, set 92 engines in battery against the city, whilst Abulfaraj says 300, and a Frank account, of great and small, 666. The larger ones are said to have shot stones of “a kantar and even more.” (_Makrizi_, III. 125; _Reinaud, Chroniques Arabes, etc._, p. 570; _De Excidio Urbis Acconis_, in _Martène and Durand_, V. 769.) How heavy a _mangonade_ was sometimes kept up may be understood from the account of the operations on the Nile, already alluded to. The King was trying to run a dam across a branch of the river, and had protected the head of his work by “cat-castles” or towers of timber, occupied by archers, and these again supported by trebuchets, etc., in battery. “And,” says Jean Pierre Sarrasin, the King’s Chamberlain, “when the Saracens saw what was going on, they planted a great number of engines against ours, and to destroy our towers and our causeway they shot such vast quantities of stones, great and small, that all men stood amazed. They slung stones, and discharged arrows, and shot quarrels from winch-arblasts, and pelted us with Turkish darts and Greek fire, and kept up such a harassment of every kind against our engines and our men working at the causeway, that it was horrid either to see or to hear. Stones, darts, arrows, quarrels, and Greek fire came down on them like rain.” The Emperor Napoleon observes that the direct or grazing fire of the great arblasts may be compared to that of guns in more modern war, whilst the mangonels represent mortar-fire. And this vertical fire was by no means contemptible, at least against buildings of ordinary construction. At the sieges of Thin l’Evêque in 1340, and Auberoche in 1344, already cited, Froissart says the French cast stones in, night and day, so as in a few days to demolish all the roofs of the towers, and none within durst venture out of the vaulted basement. The Emperor’s experiments showed that these machines were capable of surprisingly accurate direction. And the mediæval histories present some remarkable feats of this kind. Thus, in the attack of Mortagne by the men of Hainault and Valenciennes (1340), the latter had an engine which was a great annoyance to the garrison; there was a clever engineer in the garrison who set up another machine against it, and adjusted it so well that the first shot fell within 12 paces of the enemy’s engine, the second fell near the box, and the third struck the shaft and split it in two.