He hastened back to the governor’s headquarters, and informed him that he had been betrayed. An order was instantly issued to prevent any American from leaving town, but it came a few minutes too late to produce effect. Dr. Warren, who had returned in the evening from the meeting of the Committee of Public Safety, at West Cambridge, was already informed of the movement of the British army, and had taken the necessary measures for spreading the intelligence through the country. At about nine o’clock on the evening of the 18th the British troops intended for the expedition were embarked, under the command of Colonel Small, in boats at the bottom of the Common. Dr. Warren inspected the embarkation in person, and having returned home immediately after, sent for Colonel Revere, who reached his house about ten o’clock. He had already dispatched Mr. Dawes overland as a special messenger to Lexington, and he now requested Colonel Revere to proceed through Charlestown on the same errand. The colonel made arrangements, in the first place, for displaying the two lights on the steeple of the North Church, agreeably to the understanding with his friends in Charlestown, and then repaired to a wharf, at the north part of the town, where he kept his boat. He was rowed over by two friends, a little to the eastward of the British ship of war _Somerset_, which lay at anchor in this part of the channel, and was landed on the Charlestown side. He pursued his way through Charlestown and West Cambridge, not without several perilous encounters with British officers, who were patroling the neighborhood, and finally arrived safely at Lexington, where he met the other messenger, Mr. Dawes, whom he had, however, anticipated.