The object of this hardy enterprise was to compel Carleton, either to draw his troops from the upper country and leave the passage open to the army invading the province by the way of the river Sorel, or, if he should maintain that position, to take possession of Quebec. All his accounts assured him that this place was unable to hold out against the force which would appear before it; and, if attacked by an American army before the return of Carleton, would surrender without firing a shot. This arduous enterprise was committed to Colonel Arnold. About a thousand men, consisting of New England infantry, some volunteers,[20] a company of artillery under Captain Lamb, and three companies of riflemen, were selected for the service. [Footnote 20: Colonel Burr, since Vice President of the United States, was of this number.] [Sidenote: Arnold's expedition by the way of the Kennebec.] Such delays in expediting this detachment were occasioned by the derangements of the army, that Arnold could not commence his march until the middle of September. The success of the expedition depending in a great measure on the friendly temper of the province against which it was directed, the instructions given to Arnold earnestly inculcated the cultivation of a good understanding with the Canadians; and even enjoined an abandonment of the enterprise, should this sudden invasion of their country threaten to irritate them, and induce them to take up arms against the United Colonies. He was furnished with about one thousand pounds in specie to defray contingent expenses, and with a cargo of manifestoes to be dispersed through Canada. The opinion which had been formed of the favourable disposition of the Canadians was not disproved by the event. They gave essential aid to the Americans, and cheerfully facilitated their march through that province. But the previous difficulties to be surmounted were much greater than had been apprehended. The intermediate country, which had never been well explored, opposed obstacles to the march, which only perseverance like that of Arnold and of his brave and hardy followers, could have conquered. Colonel Enos, who commanded the rear division, consisting of one third of the detachment, returned from the Dead River, a branch of the Kennebec. At first, his appearance excited the utmost indignation in the army; yet, on being arrested, he was acquitted by a court martial, on the principle that it was absolutely impracticable to obtain provisions on the route to preserve the troops from perishing with famine.