eight o'clock
In a few hours the cannon were all mounted in position on the ramparts , adding very much to the defensive power of the town , which was now safe for a time from any attempt at a siege by Las Torres , whose plans would be entirely frustrated by the capture of the artillery intended for the siege . But Peterborough was not yet contented . The junction of the four thousand Castilians , of whose approach he had heard , with Las Torres would raise the force under that general to a point which would enable him to blockade the town pending the arrival of artillery for siege works ; and no sooner had the earl returned to his quarters , after seeing the cannon placed upon the walls , than he began his preparations for another expedition . He ordered Colonel Zinzendorf to march quietly out of the city at eight o'clock with four hundred of his dragoons , and four hundred British and as many Spanish infantry were to join him outside the walls . The colonels of these three bodies were ordered to say nothing of their intended movement , and to issue no orders until within half an hour of the time named . At the same hour the rest of the troops were to march to the walls and form a close cordon round them , so as to prevent any one from letting himself down by a rope and taking the news that an expedition was afoot to Las Torres . At a few minutes past eight , eight hundred foot and four hundred horse assembled outside the gates , and Peterborough took the command .