Great progress was made with the work under cover of the night, but when morning came the besieged, whose fire had been at haphazard during the night, could see the works and commenced to shoot more accurately. A curious _contretemps_ was discovered at dawn. By some miscalculation the locality of the left-hand battery had been laid out a little too far to the east, so that half its front was blocked by the ruins of the Redout Renaud. This, of course, was the effect of working in pitch darkness, when the outline of that work was invisible even from a score or so of yards away. Possibly the error may have originated from the fact that, early in the night, the directing engineer officer, Captain Ross, was killed by a flanking shot from the convent of San Francisco. Thus the men constructing the battery had been deprived of all superior direction. In the morning Colonel Fletcher directed that the east end of the battery should have no guns; the five which should have been placed there were to be transferred to the right-hand battery, which thus became designed for sixteen guns instead of eleven[181]. [181] This mistake is acknowledged in Jones’s _Sieges_, i. p. 120, and much commented on by Burgoyne [_Life and Correspondence_, i. p. 161], who complains that an immense amount of work was wasted, two nights’ digging put in, the _terre-plain_ levelled, and even some platforms laid, before the error was detected. On the 10th-11th January, when the 4th Division had charge of the trenches the first parallel was nearly completed, the batteries continued to be built up, magazine emplacements were constructed in them, and a trench of communication between them was laid out. When daylight revealed to the French the exact situation of the three batteries, which were now showing quite clearly, a very fierce fire was opened on them, the rest of the works being neglected. The losses, which had hitherto been insignificant, began to grow heavy, and so many men were hit in the exterior trenches, which were being dug in front of each battery, that Wellington and Colonel Fletcher gave orders that they should be discontinued. Heavy damage was done to the batteries themselves--the French adopted a system of firing simultaneous flights of shells with long fuses at given points, ‘of which several falling together upon the parapets blew away in an instant the work of whole hours.’