It was about two o'clock in the afternoon that our march against the enemy began by heads of columns, whilst the eighteen-pounder battery followed slowly along the road. During our advance it was deemed especially important to ascertain with accuracy the number and calibre of the enemy's cannon, and for this hazardous reconnoissance on an open plain, Lieutenant Blake, of the topographical engineers, immediately volunteered. Passing the advanced guard at full speed, he dashed over the long grass that concealed the opposing forces, until he approached within about eighty yards of the line where he had a distinct view of the enemy. The Mexicans gazed with surprise at this daring act, while Blake alighted from his horse, surveyed the whole array with his glass, counting the squadrons and ordnance carefully, and then galloped down their front to the other wing of their extended line.[107] Scarcely had this gallant officer reported to our general when two of the enemy's batteries opened on us vigorously. Taylor immediately ordered our columns to halt, and deploying into line, our artillery returned the fire, whilst the eighth infantry, on our extreme left, was thrown back to secure that flank;--and, thus, with the distance of only seven hundred yards between the opposing lines, the battle began with rattling vollies of ball and grape bounding over our heads. The first fires of the enemy injured us but little, while the heavy metal of our eighteen-pounders, and the smaller shot of Ringgold's battery, quickly dispersed the masses of cavalry on the left. Duncan's battery, supported by May's dragoons, was then thrown forward on that flank, and for more than an hour the incessant thunder of a cannonade raged along both fronts, making sad gaps in the battalions, rending the prairie, filling the air with dust and smoke, killing and wounding a few, yet, producing no decided effect. The Mexicans, unskilled in gunnery, fired without precision; but, at almost every discharge of the American ordnance, the shot told with wonderful precision among the Mexicans. Our artillery was directed not only to masses and groups of the enemy, but often to particular men, so that the officers felt as certain of their aim, as if firing with rifles.