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.