Late in February, various appearances among the British troops indicated an intention to evacuate Boston; but as these appearances might be deceptive, and he had now received a small supply of powder, General Washington determined to prosecute vigorously a plan he had formed, to force General Howe either to come to an action, or to abandon the town. Since the allowance of a bounty, recruiting had been more successful; and the regular force had been augmented to rather more than fourteen thousand men. In addition to these troops, the Commander-in-chief had called to his aid about six thousand of the militia of Massachusetts. Thus reinforced, he determined to take possession of the heights of Dorchester, and to fortify them. As the possession of this post would enable him to annoy the ships in the harbour and the soldiers in the town, he was persuaded that a general action would ensue. But if this hope should be disappointed, his purpose was to make the works on the heights of Dorchester only preparatory to seizing and fortifying Nook's Hill, and the points opposite the south end of Boston, which commanded the harbour, a great part of the town, and the beach from which an embarkation must take place in the event of a retreat. {March.} [Sidenote: Possession taken of the heights of Dorchester.] To facilitate the execution of this plan, a heavy bombardment and cannonade were commenced on the town and on the British lines, which were repeated the two succeeding nights. On the last of them, immediately after the firing had begun, a strong detachment, under the command of General Thomas, took possession of the heights without opposition. Such was their activity and industry through the night that, although the ground was almost impenetrable, the works were sufficiently advanced by the morning, nearly to cover them. When day-light disclosed their operations to the British, a considerable degree of embarrassment appeared, and an ineffectual fire was commenced on the party in possession of the heights, who in turn opened a battery on the besieged; and continued with unremitting labour to strengthen their position. {March 5.} It was necessary to dislodge the Americans from the heights, or to evacuate the town; and General Howe, as had been foreseen, determined to embrace the former part of the alternative. Three thousand chosen men, to be commanded by Lord Percy, were ordered on this service. These troops were embarked, and fell down to the castle, in order to proceed up the river to the intended scene of action; but were scattered by a furious storm, which disabled them from immediately prosecuting the enterprise. Before they could again be in readiness for the attack, the works were made so strong, that the attempt to storm them was thought unadviseable, and the evacuation of the town became inevitable.