The retrograde of the Spaniards laid open the position of the allied army, and the only good road by which a retreat could be conducted was exposed. To remedy this disaster, the leading brigade of the second division rushed forward; it was speedily under a destructive fire; a heavy rain concealing distant objects; and four regiments of French lancers and hussars having turned the right flank in the obscurity, charged the British battalions in the rear at the moment when they developed their attack, and slew or took prisoners nearly two-thirds of their numbers: one battalion, being in column, maintained its ground, while the French horsemen overthrew all other opposition, and captured six guns. A lancer attacked Marshal Beresford, who pushed the lance aside, and, grappling with the lancer, threw him from his horse. Another British brigade came boldly into the fight, repelling a charge of lancers on its flank; the remaining brigade of the second division arrived; a Spanish corps moved forward, and the enemy's infantry recoiled; but soon recovering, renewed the conflict with greater violence than before. The fighting became vehement, and more than two-thirds of every British corps engaged had fallen, when their ammunition began to fail, and the enemy established a column in advance upon the right flank. The tide of success was evidently flowing in favour of the French, when the fourth division was ordered to the heat of the conflict, and a brigade of the second division, which had only been slightly engaged, rushed forward into the fight. At this moment a number of captured British soldiers were being hurried to the rear of the French army; the enemy's reserves were pushing forward to reinforce their front;--the field was covered with heaps of dead bodies;--the lancers were riding furiously about the upper part of the hill spearing wounded men, and six pieces of artillery were in the hands of the French.