Three assaults had failed--but still the allied commander did not quit the place in despair. Preparations for another attempt were continued--and the exertions of the engineers, of whom one-half had fallen, were redoubled. Heated shot was tried against the White Church unsuccessfully; while that of San Roman was marked as the more vulnerable point, and a gallery commenced against it. On the 17th, the great breach was again exposed by the fire of the British guns, and the ramparts on either side extensively damaged. A mine beneath the lower parallel was successfully exploded, and a lodgment effected in a cavalier,[206] from whence the French had kept up a destructive fire on the trenches. It was held but for a short time, as the enemy came down in force, and drove the besiegers from it. On the 18th, the breach was reported practicable, and an assault decided on--the signal arranged being the springing of the mine beneath the church of San Roman. That building was also to be assailed, while the old breach was to be attempted by escalade--and thus, and at the same moment, three distinct attacks would occupy the enemy’s attention. At half-past four the explosion of the mine gave the signal. A countermine was immediately sprung by the French, and between both, the church was partially destroyed, and Colonel Browne, with some Portuguese and Spanish troops, seized upon the ruined building. The Guards, who had volunteered a detachment, rushed through the old breach, escaladed the second line, and, in front of the third, encountered the French in considerable force--while two hundred of the German Legion, under Major Wurmb, carried the new breach, pushing up the hill, and fairly gaining the third line of the defences. Unfortunately, however, these daring and successful efforts were not supported with the promptness that was needed. The French reserves were instantly advanced--they came on in overwhelming force--cleared the breaches of the assailants--and drove them beyond the outer line, with the loss of two hundred officers and men. San Roman was taken the following night by the French, and recovered again by the British. But with this affair the siege virtually terminated--and Lord Wellington, by an imperious necessity, was obliged to retire from a place of scarcely third-rate character, after four attacks by assault, and a loss of two thousand men. In war, the bravest and the most prudent measures are frequently marred or made by fortune. Lord Wellington, with very insufficient means, attempted the reduction of Burgos; and although skill and gallantry were displayed in every essay, obstacles arose which checked the most daring efforts; and all that science and determination could effect, were vainly tried to overcome difficulties physically insurmountable. Had Wellington possessed the requisite _matériel_ for the conduct of a siege, Burgos must have been taken in a week.[207]