When Donop retreated from Bordentown to Princeton after the battle of Trenton, he threw up an arrow-head breastwork at the point not far from where Mercer and Stockton Streets now join; on this still lay a cannon of the size known as a thirty-two pounder, the carriage of which was dismantled. It was early morning when Cornwallis became aware that his expected battle would not be fought at Trenton; the roar of artillery gave him the terrible assurance that the blow had been struck on his weakened flank,—that his precious stores at New Brunswick were in danger. Swiftly he issued the necessary orders and appeared at the west end of the town on the King’s Highway, just as Washington was leaving Princeton, his van having been delayed in crossing Stony Brook. The citizens had loaded the gun in the breastwork and on the approach of the intruders they fired it. This utterly deceived the English generals, for they thought themselves facing a well-manned battery. It was some time, tradition says an hour, before they were undeceived and in that precious interval Washington collected his army and marched away. His forces were too weak to risk the venture of seizing New Brunswick, even temporarily; accordingly he turned northwestward and reached Morristown in safety. There and at Middlebrook his headquarters practically remained for the rest of the war. The English were content to secure New Brunswick. In the battle of Princeton there were engaged somewhat under two thousand men on each side. The actual fighting lasted less than half an hour. We lost very few men—so few that the number cannot be accurately reckoned—possibly thirty; but we lost a brave general, Hugh Mercer, a colonel, a major, and three captains. The English soldiers fought with unsurpassed gallantry. They lost two hundred killed and two hundred and fifty captured, but no officers of distinction. It was not, therefore, a big fight, but it was none the less a great and decisive battle. How important Washington felt it to be, is attested by his personal exposure of himself. How decisive the great military critics have considered it, is shown by the fact that the campaign of which it was the finishing stroke is held by them to have been typical of his genius as a strategist. The two affairs of Trenton and Princeton are in the short histories of the Revolution generally reckoned together. And naturally so, since they occurred so near to one another in time and place. But, strategically and tactically examined, the battle of Trenton made good Washington’s position behind the Delaware; the battle of Princeton secured New Jersey and the Middle States.