A French engineer, Chevalier d'Arcon, had invented some enormous floating batteries, fire-proof, as he believed; a hundred and fifty pieces of cannon were to batter the place all at once, near enough to facilitate the assault.

On the 13th of September, at 9 A.M., the Spaniards opened fire: all the artillery in the fort replied at once; the surrounding mountains repeated the cannonade; the whole army covered the shore awaiting with anxiety the result of the enterprise.

Already the fortifications seemed to be beginning to totter; the batteries had been firing for five hours; all at once the Prince of Nassau, who commanded a detachment, thought he perceived flames mastering his heavy vessel; the fire spread rapidly; one after another, the floating batteries found themselves disarmed.

"At seven o'clock we had lost all hope," said an Italian officer who had taken part in the assault; "we fired no more, and our signals of distress remained unnoticed.

The red-hot shot of the besieged rained down upon us; the crews were threatened from every point." Timidly and by weak detachments, the boats of the two fleets crept up under cover of the batteries in hopes of saving some of the poor creatures that were like to perish; the flames which burst out on board the doomed ships served to guide the fire of the English as surely as in broad daylight.