Some precious minutes had been lost by the British at Lexington, and it soon became clear that the day was to be one in which minutes could ill be spared. By the time they reached Concord, about seven o'clock, the greater part of the stores had been effectually hidden, and minute-men were rapidly gathering from all quarters. After posting small forces to guard the bridges, the troops set fire to the court-house, cut down the liberty-pole, disabled a few cannon, staved in a few barrels of flour, and hunted unsuccessfully for arms and ammunition, until an unexpected incident put a stop to their proceedings. When the force of minute-men, watching events from the hill beyond the river, had become increased to more than 400, they suddenly advanced upon the North Bridge, which was held by 200 regulars. After receiving and returning the British fire, the militia, led by Major Buttrick, charged across the narrow bridge, overcame the regulars by dint of weight and numbers, and drove them back past the Old Manse into the village. They did not follow up the attack, but rested on their arms, wondering, perhaps, at what they had already accomplished, while their numbers were from moment to moment increased by the minute-men from neighbouring villages. A little before noon, though none of the objects of the expedition had been accomplished, Colonel Smith began to realize the danger of his position, and started on his retreat to Boston. His men were in no mood for fight. They had marched eighteen miles, and had eaten little or nothing for fourteen hours. But now, while companies of militia hovered upon both their flanks, every clump of trees and every bit of rising ground by the roadside gave shelter to hostile yeomen, whose aim was true and deadly. Straggling combats ensued from time to time, and the retreating British left nothing undone which brave men could do; but the incessant, galling fire at length threw them into hopeless confusion. Leaving their wounded scattered along the road, they had already passed by the village green of Lexington in disorderly flight, when they were saved by Lord Percy, who had marched out over Boston Neck and through Cambridge to their assistance, with 1,200 men and two field-pieces. Forming his men in a hollow square, Percy inclosed the fugitives, who, in dire exhaustion, threw themselves upon the ground,--"their tongues hanging out of their mouths," says Colonel Stedman, "like those of dogs after a chase." Many had thrown away their muskets, and Pitcairn had lost his horse, with the elegant pistols which fired the first shots of the War of Independence, and which may be seen to-day, along with other trophies, in the town library of Lexington. [Illustration: PITCAIRN'S PISTOLS] [Sidenote: Retreat continued from Lexington to Charlestown]