About nine o'clock Lord Percy, one of the British officers, crossed the Common, and in doing so noticed a group of persons in eager chat. He joined these, curious to learn the subject of their conversation. The first words he heard filled him with alarm. "The British troops will miss their aim," said a garrulous talker. "What aim?" asked Percy. "The cannon at Concord," was the reply. Percy, who was in Gage's confidence, hastened to the head-quarters of the commanding general and informed him of what he had overheard. Gage, startled to learn that his guarded secret was already town's talk, at once set guards on all the avenues leading from the town, with orders to arrest every person who should attempt to leave, while the squad of officers of whom we have spoken were sent forward to patrol the roads. But the patriots were too keen-witted to be so easily checked in their plans. Samuel Adams and John Hancock, the patriot leaders, fearing arrest, had left town, and were then at Lexington at the house of the Rev. Jonas Clarke. Paul Revere had been sent to Charlestown by the patriotic Dr. Warren, with orders to take to the road the moment the signal lights in the belfry of the old North Church should appear. These lights would indicate that the troops were on the road. We have seen how promptly he obeyed, and how narrowly he escaped capture by General Gages' guards. On he went, mile by mile, rattling down the Medford Road. At every wayside house he stopped, knocked furiously at the door, and, as the startled inmates came hastily to the windows, shouted, "Up! up! the regulars are coming!" and before his sleepy auditors could fairly grasp his meaning, was away again. It was about midnight when the British troops left Boston, on their supposed secret march. At a little after the same hour the rattling sound of hoofs broke the quiet of the dusky streets of Lexington, thirteen miles away. Around the house of the Rev. Mr. Clarke eight minute-men had been stationed as a guard, to protect the patriot leaders within. They started hastily to their feet as the messenger rode up at headlong speed. "Rouse the house!" cried Revere. "That we will not," answered the guards. "Orders have been given not to disturb the people within by noise." "Noise!" exclaimed Revere; "you'll have noise enough before long; the regulars are coming!" At these startling tidings the guards suffered him to approach and knock at the door. The next minute a window was thrown up and Mr. Clarke looked out. "Who is there?" he demanded. "I wish to see Mr. Hancock," was the reply. "I cannot admit strangers to my house at night without knowing who they are." Another window opened as he spoke. It was that of John Hancock, who had heard and recognized the messenger's voice. He knew him well. "Come in, Revere," he cried; "we are not afraid of you."