Knox was one of those providential characters which spring up in emergencies, as if they were formed by and for the occasion. A thriving bookseller in Boston, he had thrown up business to take up arms for the liberties of his country. He was one of the patriots who had fought on Bunker’s Hill, since when he had aided in planning the defences of the camp before Boston. The aptness and talent here displayed by him as an artillerist, had recently induced Washington to recommend him to Congress for the command of the regiment of artillery in place of the veteran Gridley, who was considered by all the officers of the camp, too old for active employment. Congress had not yet acted on that recommendation; in the mean time Washington availed himself of the offered services of Knox in the present instance. He was, accordingly, instructed to examine into the state of the artillery in camp, and take an account of the cannon, mortars, shells, lead and ammunition that were wanting. He was then to hasten to New York, procure and forward all that could be had there; and thence proceed to the head-quarters of General Schuyler, who was requested by letter to aid him in obtaining what further supplies of the kind were wanting from the forts at Ticonderoga, Crown Point, St. Johns, and even Quebec, should it be in the hands of the Americans. Knox set off on his errand with promptness and alacrity, and shortly afterwards the commission of colonel of the regiment of artillery which Washington had advised, was forwarded to him by Congress. The re-enlistment of troops actually in service was now attempted, and proved a fruitful source of perplexity. In a letter to the President of Congress, Washington observes that half of the officers of the rank of captain were inclined to retire; and it was probable their example would influence their men. Of those who were disposed to remain, the officers of one colony were unwilling to mix in the same regiment with those of another. Many sent in their names, to serve in expectation of promotion; others stood aloof, to see what advantages they could make for themselves; while those who had declined sent in their names again to serve.[26] The difficulties were greater, if possible, with the soldiers than with the officers. They would not enlist unless they knew their colonel, lieutenant-colonel and captain; Connecticut men being unwilling to serve under officers from Massachusetts, and Massachusetts men under officers from Rhode Island; so that it was necessary to appoint the officers first.