Most of this labor had to be done at night, and the utmost possible silence observed. As the transports lay a mile off shore, while the only wharf was an open beach, and a norther blew violently from the twelfth to the sixteenth, the work of landing ordnance and ordnance stores proceeded slowly. Fortunately the work on the batteries was not discovered; but the fire of Paixhan guns and heavy mortars from the city and castle, though irregular and singularly unfruitful despite the undeniable skill of the gunners,[22.19] compelled the Americans to adopt extreme precautions. Nor were these embarrassments the only ones. Notwithstanding seasonable orders, only fifteen carts and about a hundred draught horses had arrived. Not more than one fifth of the ordnance requisitioned by Scott about the middle of November and due at the Brazos--he now reminded Marcy--by January 15, had yet appeared. A great many artillery and cavalry horses had been drowned, injured or delayed; and there was a shortage of almost every requisite for siege operations.[22.20] But the army and the navy coöperated zealously; soldiers took the places of draught animals; and in spite of every difficulty three batteries, mounting seven 10-inch mortars, were in readiness by two o'clock on the afternoon of the twenty-second, and the soldiers felt eager to hear what they called the "sweet music" of these "faithful bull-dogs."[22.21] [THE BOMBARDMENT] At this hour, therefore, Scott formally summoned the town, intimating that both assault and bombardment were to be apprehended. The reply was a refusal to surrender; and at a quarter past four, accompanied by a deafening chorus of joyous, frantic shouts and yells, the American batteries opened, while the "mosquito fleet" of two small steamers and five gunboats,[22.22] each armed with a single heavy cannon, stationed themselves behind Point Hornos, and fired briskly.[22.24] Like "hungry lions in search of prey," a soldier thought, the shells from the mortars flew "howling" to their mark. With heavier metal and vastly more of it, Vera Cruz and the castle replied. The city wall blazed like a sheet of fire. Shot, shell and rockets came forth in a deluge, it seemed to the men; and the two columns of smoke, rolling and whirling, mounted high and collided as if striving to outflank and conquer each other. Still more terrible was the scene at night. A spurt of red fire; a fierce roar; a shell with an ignited fuse mounting high, pausing, turning, and then--more and more swiftly--dropping; the crash of a roof; a terrific explosion that shook the earth; screams, wailing and yells--all this could be distinctly seen or heard from the American lines. During the twenty-third and the following night the fire still raged, but on the American side more slowly, for although ten mortars were now at work, a norther interrupted the supply of ammunition.[22.24]