Bonaparte then advanced upon St. Jean d'Acre, the ancient Ptolemais, situated at the foot of Mount Carmel. It was the only place that could now stop him. If he could make himself master of this fortress, Syria would be his. But the ferocious Djezzar had shut himself up there, with all his wealth and a strong garrison, and he also reckoned upon support from Sir Sidney Smith, then cruising off that coast, who supplied him with engineers, artillerymen, and ammunition. It was probable, moreover, that he would be soon relieved by the Turkish army collected in Syria, which was advancing from Damascus to cross the Jordan. Bonaparte hastened to attack the place, in hopes of taking it, as he had done Jaffa, before it was reinforced with fresh troops, and before the English had time to improve its defences. The trenches were immediately opened. The siege artillery sent by sea from Alexandria had been intercepted by Sir Sidney Smith, who captured seven vessels out of the nine. A breach was effected, and dispositions were made for the assault, but the men were stopped by a counterscarp and a ditch. They immediately set about mining. The operation was carried on under the fire of all the ramparts, and of the fine artillery which Sir Sidney Smith had taken from the French. The mine was exploded on April 17th, and blew up only a portion of the counterscarp. Unluckily for the French, the place had received a reinforcement of several thousand men, a great number of gunners trained after the European fashion, and immense supplies. It was a siege on a large scale to be carried on with thirteen thousand men, almost entirely destitute of artillery. It was necessary to open a new mine to blow up the entire counterscarp, and to commence another covered way.