Half an hour passed. There had been no sound from up stream; no sign of activity among the enemy. Bob began to feel more hopeful. They had apparently met with great obstacles to the passage of the guns. He was momentarily expecting to hear the hum of the returning aeroplane when, with a suddenness that took him all aback, there was a tremendous roar, followed in a second or two by a terrific crash just beyond the Pathan compound. Turning in consternation to discover the cause of it, he saw a great mass of the cliff falling amid a cloud of dust and smoke upon the wooden pathway, and plunging into the river beneath. Such destruction could only be the effect of a shell. Beyond doubt one at least of the field guns had been brought into position behind the enemy's breastwork at the bend.

This fact filled him with as much dismay as amazement. It was not surprising that the enemy had placed their gun without his knowledge. They would, of course, have been careful to mask it until they were ready to open fire. But why had Lawrence or the Gurkha not seen it? Could it be that the aeroplane had been damaged and brought down after all?

While he was in a painful state of anxiety, there was another roar, and a second shell burst on the cliff, just beyond the Pathan gallery. He ran to the northern wall and peered through one of the loopholes. Smoke hung above the enemy's breastwork, but there was not a man to be seen, so that rifle fire was useless. He ordered Gur Buksh to fire the machine gun. The havildar's aim was good; chips of rock flew from the breastwork; and Bob thought he saw the muzzle of a gun disappear. His attention was immediately drawn from it by the sight of the aeroplane flying round the bend, and with the thrill of relief at his brother's safety came the expectation of hearing an explosion and seeing signs of havoc about the breastwork. But the aeroplane flew high over the scene, passed it, and disappeared up the river. There had been no explosion. Why had not Lawrence dropped a bomb?

Hardly had he asked himself this question when a third shell burst from the breastwork. It was better aimed than the other two. Instead of striking the cliff, it hit the northern wall of the compound, carrying away several yards of the metal parapet, scattering jagged fragments of iron and stone in every direction, then flew over the heads of the garrison and plunged into the earthwork at the southern boundary of the compound, within a few yards of the spot where the sortie party were gathered. Bob was almost at his wits' end. No defences could withstand a bombardment at such close quarters. None of the garrison had as yet been wounded, but he could see by their cowering attitude and the terror written upon their faces that their courage had been shocked out of them. Only Gur Buksh and the other Sikhs stood immovable at their posts.

A few minutes after the report of the gun, the aeroplane again came flying down stream. Lawrence, then, had not landed. Bob was in a maze of bewilderment. But he was suddenly aroused from his stupor by a sharp detonation. It was not the report of a gun. Then there were loud cries and yells from the direction of the enemy, and looking through the loophole he saw a smother of dust above the breastwork. Lawrence had dropped a bomb at last, and again was out of sight.

This was to have been the signal for the sortie; but after what had happened Bob felt that it would be sheer madness to lead his men along a stretch of the track commanded by the field guns. He doubted, indeed, whether their courage would face the task. It was only common prudence to wait for a second signal. He could not see what damage the bomb had done; whether it had only temporarily frightened the enemy. But Lawrence would not hesitate to hurl another bomb among them; and believing that, guns or no guns, they must be demoralized if attacked a second time from the air, Bob hastened across the compound, ordered the bridge to be lowered, and went to the twenty men huddling under cover of the wall.

LAWRENCE DROPS A BOMB

He allowed no trace of mental perturbation to show itself in his bearing.

"The time has come!" he said quietly to the men. "Lawrence Sahib is driving the enemy away. There are no more shots from their gun, you see. We shall soon hear another explosion; then you will follow me, and in five minutes we shall be masters of our breastwork."