Washington chose for his decisive movement the night of the 4th of March. Eight hundred men led the way, escorting the wagons laden with spades and crowbars, hatchets, hammers, and nails; and after them followed twelve hundred men, with three hundred ox-carts, carrying timbers and bales of hay; while the rear was brought up by the heavy siege-guns. From Somerville, East Cambridge, and Roxbury, a furious cannonade was begun soon after sunset and kept up through the night, completely absorbing the attention of the British, who kept up a lively fire in return. The roar of the cannon drowned every other sound for miles around, while all night long the two thousand Americans, having done their short march in perfect secrecy, were busily digging and building on Dorchester Heights, and dragging their siege-guns into position. Early next morning, Howe saw with astonishment what had been done, and began to realize his perilous situation. The commander of the fleet sent word that unless the Americans could be forthwith dislodged, he could not venture to keep his ships in the harbour. Most of the day was consumed in deciding what should be done, until at last Lord Percy was told to take three thousand men and storm the works. But the slaughter of Bunker Hill had taught its lesson so well that neither Percy nor his men had any stomach for such an enterprise. A violent storm, coming up toward nightfall, persuaded them to delay the attack till next day, and by that time it had become apparent to all that the American works, continually growing, had become impregnable. Percy's orders were accordingly countermanded, and it was decided to abandon the town immediately. It was the sixth anniversary of the day on which Hutchinson had yielded to the demand of the town meeting and withdrawn the two British regiments from Boston. The work then begun was now consummated by Washington, and from that time forth the deliverance of Massachusetts was complete. Howe caused it at once to be known among the citizens that he was about to evacuate Boston, but he threatened to lay the town in ashes if his troops should be fired on. The selectmen conveyed due information of all this to Washington, who accordingly, secure in the achievement of his purpose, allowed the enemy to depart in peace. By the 17th, the eight thousand troops were all on board their ships, and, taking with them all the Tory citizens, some nine hundred in number, they sailed away for Halifax. Their space did not permit them to carry away their heavy arms, and their retreat, slow as it was, bore marks of hurry and confusion. In taking possession of the town, Washington captured more than two hundred serviceable cannon, ten times more powder and ball than his army had ever seen before, and an immense quantity of muskets, gun-carriages, and military stores of every sort. Thus was New England set free by a single brilliant stroke, with very slight injury to private property, and with a total loss of not more