Then, from the Arabs concealed a few hundred yards in their front, there broke a sudden volley which emptied many saddles and took the Turks aback. The officer shouted an order, the men wheeled round, suffering losses from a second volley, and dashed back to the shelter of the belt of vegetation from which they had emerged, causing some confusion in the rear part of the column. Burnet estimated that the number of those who had come in sight was about two hundred; how many more there were it was impossible to guess. But Rejeb perceived that his little force was not strong enough to hold the position long when the Turks should have taken its measure, and he instantly sent a rider to the stronghold to bring back another hundred men on foot, and to order a hundred and fifty horsemen to post themselves near the outer end of the causeway. Before the reinforcements arrived the enemy started a dropping fire from their sheltered position, with the intention, no doubt, of drawing the Arabs' fire and causing them to disclose their strength. This proving ineffectual, they made another attempt to carry the position with a rush, losing even more heavily than before. Again they fell back, and for a while there was no further move. Rejeb sent a scout out on each flank to worm his way towards the enemy and discover what he was about. They returned with the not unexpected news that the Turks, now dismounted, were deploying; it could only be with the object of outflanking the defenders. They reported also that behind the Turks there was a large force of mounted Arabs. Burnet's suspicion that this was the expedition organised by the Turks and Halil's tribe jointly was confirmed; he wondered where Major Burckhardt was. By this time the reinforcements had come up stealthily from the rear. Rejeb threw them out on the wings, so that the defending force, its main strength in the centre, covered a rough semi-circle nearly half a mile in extent. Within a very few minutes the enemy's intentions were disclosed. Advancing on a wide front, taking cover wherever it was possible, they came on in short rushes. It was seen now that the majority of them were Arabs, and the total force could hardly have been less than a thousand men. Rejeb ordered his men to fall back slowly, holding on as long as they could without the risk of being cut off, and inflicting as much loss as possible on the enemy whenever they crossed stretches of open ground. It was clear to the chief, as to Burnet and Ellingford, that Major Burckhardt's profession of knowledge of the stronghold's position had not been vain. Clearly they had to look forward to a siege. They were not strong enough to defeat the enemy in the open, and as soon as the safety of the aeroplane was assured, they must retreat along the causeway and make the best use of their natural advantages.