An important change was now made in the disposition of the force. As already explained, the prolonged halt in the pass was due to unforeseen causes, and the general had to make the best of it, its great weakness consisting in the isolation of its flanks. As some delay must occur before sufficient reserves could arrive, so as to enable Chamberlain to resume the offensive, he determined to abandon the gorge and also the pickets on the mountain to his left, and to concentrate his whole force on the slopes of the Mahabun. In a military point of view this was a judicious arrangement. Instead of holding a series of straggling posts, perched upon rocks, on two separate mountains, and with his main body far down in a hollow gorge, our troops would thus be concentrated and able to reinforce any point required. The movement was quietly carried out during the night of November 17. The vigilance of the tribes for once failed them, and when daylight broke on the 18th, to their astonishment the Eagle's Nest and all the pickets on that side were silent and empty. Exasperated by the success of our manoeuvre, and imagining probably that it was the precursor of a general retreat, the enemy swarmed up the Mahabun ridges, and before our troops were well settled in their new positions, attacked them fiercely, and for the moment with some success, but were finally driven off. General Chamberlain, writing at the time, said: 'The troops have now been hard-worked both day and night for a month, and having to meet fresh enemies with loss is telling. We much need reinforcements. I find it difficult to meet the enemy's attacks, and provide convoys for supplies and wounded sent to the rear.... This is urgent.'