Lord Dartmouth alone had the military sagacity to give sound advice to the British cabinet. He maintained that by the occupation of New York, and the presence of a strong naval force at Newport, Rhode Island (within striking distance of Boston), and the control of the Hudson River, the New England Colonies would be so isolated, as neither to be able to protect themselves, nor to furnish aid to the central Colonies beyond the Hudson River. For the same reason, an adequate garrison at New York might detach troops to seize the region lying on the waters of the Delaware and Chesapeake, and thereby separate the South from the centre. When General Howe, in 1775, formally urged the evacuation of Boston and the occupation of New York and Newport, he also advised the seizure of "some respectable seaport at the southward, from which to attack seacoast towns, in the winter." Washington never lost sight of the fact, that, while an important issue had been joined at Boston, its solution must be so worked out as to conserve the general interests of the Colonies as a Nation, and that the delay which was incident to scarcity of powder, and the resulting inability to assault the city, was to be employed, to the utmost, in preparing the troops for an ultimate march to New York, there to face the British in the field. The reinforcement of General Howe, at midwinter, when an attack upon the American lines would be without hope of success, quickened Washington's preparations for crowding the siege, while constantly on the watch for some manifestation of British activity in other directions. Within a week after the garrison of the city had been thus strengthened, Washington learned that Clinton had been detached, to make some expedition by sea. General Lee, then in Connecticut on recruiting service, was ordered to New York to put the city in a condition for defence, and arrived on the very day that Clinton anchored at Sandy Hook. Clinton, however, neglected his opportunity, and sailed southward to attack Charleston. Lee also went South, to co-operate with Governor Rutledge, in the defense of that city. The repulse of that expedition at Fort Sullivan (afterwards called Fort Moultrie) could not be known to Washington; but the knowledge that the British had enlarged their theatre of active war was a new stimulus to exertion. The strain upon the American Commander-in-Chief, in view of this rapid development of hostilities beyond the reach of his army, was intense. Clinton had been authorized to burn all cities that refused submission. In a letter to Congress, Washington wrote: "There has been one single freeze, and some pretty good ice," but a council of war opposed an assault. At last he conceived an alternative plan, in the event that he would not have sufficient powder to risk a direct assault, and the two plans were balanced and matured in his own mind with the determination to act promptly, and solely, at his own independent will.