The situation of these forts was far from justifying this confidence of their being defensible. That on Mud Island had been unskillfully constructed and required at least 800 men fully to man the lines. The island is about half a mile long. Fort Mifflin was placed at the lower end, having its principal fortifications in front for the purpose of repelling ships coming up the river. The defenses in the rear consisted only of a ditch and palisade, protected by two blockhouses, the upper story of one of which had been destroyed in the late cannonade. Above the fort were two batteries opposing those constructed by the British on Province and Carpenter's Islands, which were separated from Mud Island only by a narrow passage between 400 and 500 yards wide. The garrison of Fort Mifflin consisted of only 300 Continental troops, who were worn down with fatigue and incessant watching, under the constant apprehension of being attacked from Province Island, from Philadelphia, and from the ships below. Having failed in every attempt to draw the militia of New Jersey to the Delaware, Washington determined to strengthen the garrison by further drafts from his army. Three hundred Pennsylvania militia were detached to be divided between the two forts, and a few days afterward General Varnum was ordered, with his brigade, to take a position above Woodbury, near Red Bank, and to relieve and reinforce the garrisons of both forts as far as his strength would permit. Washington hoped that the appearance of so respectable a Continental force might encourage the militia to assemble in greater numbers. Aware of the advantage to result from a victory over the British army while separated from the fleet, Washington had been uniformly determined to risk much to gain one. He had, therefore, after the battle of Germantown, continued to watch assiduously for an opportunity to attack his enemy once more to advantage. The circumspect caution of General Howe afforded none. After the repulse at Red Bank his measures were slow but certain, and were calculated to insure the possession of the forts without exposing his troops to the hazard of an assault.