"Now, Jim," whispered the colonel, "we're in your hands, for you are the senior officer at present."

"Then hold your fire till I give the word," was the calm response, "and then you can blaze into them for all you are worth."

Standing on the stone pavement at the bottom of their trench, each of the defenders carefully adjusted his weapon, Jim and Ali taking care to throw open the catch of their magazines, while John Margetson placed the spare revolver close at hand, so that, when his gun was discharged, he would still have something to fall back upon. Then, in absolute silence, and without allowing any portion of their figures to be observed, they waited with fast-beating hearts for the attack of the enemy. It came even sooner than they had expected, for, spurred on by the Mullah's words of encouragement, and by their own fanatical hatred of the infidel, the mass of Somali warriors came bounding towards the mine, those on the outer edge crushing towards the centre in their desire to take a part in the battle. As a result, they became closely jammed together, and arrived at the arched entrance in this formation.

"Fire!" cried Jim, when they were only a few yards away.

Instantly the guns of the defenders rang out and poured a perfect hail of missiles into the enemy. At such a close range it was impossible to miss one's aim, and therefore the losses sustained by the Somalis were very great. Indeed, so unexpected was the volley, and so disconcerted were they at the fall of their comrades, that all at once stopped their mad rush at the mine, and stood there aghast at the slaughter, and hesitating how to act. The breathing-space thus afforded was taken full advantage of by Jim and his friends, for, instantly reloading, they sent a second volley into the attackers. Its effect was excellent, for, finding that more of their fellow-warriors were falling, and that as yet not one of them had caught sight of the enemy, the Somalis gave vent to a howl of dismay, and retreated at the top of their speed. Nor did they pause until they had clambered from the ravine to the top of the slope outside.

"That will make them think twice about the matter," said the colonel, with a chuckle. "And just look at their leader! He took particular care not to join in the attack, and was the very first to scramble away to a safe distance. However, a humbug, such as he is, will soon stir up the tribesmen again by reminding them that we are few in numbers, and that the score against us is a heavy one. Then, no doubt, we can expect a second attack, and, if I know their wily commander at all, he will adopt different tactics."

How true the prophecy of the colonel was destined to be was soon found out, for, after retiring out of sight for a short period, the Somalis again appeared on the surrounding heights. Then they dropped silently into the ravine, and, lying down in the long grass at the foot of the hills, began to pour a hot fire into the mine. Soon, indeed, the air was alive with their slugs and bullets, which came whistling in through the opening. But, thanks to the trench which John Margetson had suggested, the defenders ran no danger of being hit, but sat down at the bottom, placidly listening to the uproar. For half an hour the fusillade continued without cessation, and, indeed, at the end of that time, became even louder and fiercer.

"It sounds as though they had been strongly reinforced," remarked Jim, whose coolness had never for a moment deserted him. "I'll just take a look through one of our peep-holes and see what is happening, for it would never do to make the sudden discovery that they were rushing upon us again."

Accordingly, taking every precaution not to expose himself to the bullets, he cautiously raised an eye to one of the embrasures, and closely inspected the ravine. He found that what he had thought had just occurred, for even then scores of men were climbing over the hill-tops, to slide at once into the valley beneath. Down below a large force of Somalis was gathered, and these, it was easy to perceive, were filled with excitement, and eager for the attack. They were shouting to one another, and brandishing their weapons.

"We can expect a second rush in a few moments," said Jim, sinking into the trench again; "there are scores of the enemy, and it seems to me that we shall be wise if we at once take steps to arrange for a retreat. I cannot think that our four weapons will be sufficient to keep them out. No doubt we shall kill a number of them, but all are in such desperate earnest that those who survive will come on, in spite of their losses, and once they get to close quarters with us, we shall be done for. I suggest, therefore, that a couple of us go and investigate those passages, while the others keep watch here. Then, as soon as the advance begins, a shout will bring us together again."