"Then it looks as though the openings from the entrance-hall ran on into the hill, diverging slightly, and connected at this point by a cross-cut. Evidently our path lies right ahead."

"You've hit the right nail this time, without a doubt," answered John Margetson. "Forward is the word."

When they had advanced some two or three hundred yards farther, the explorers suddenly came to a spot where the workings converged, and here they found a chamber which was larger even than that at the entrance. From it again there were many exits, into which they dared not venture. However, they had already gone far enough to learn that, should the enemy prove too strong for them, they had a way of retreat which would enable them to elude pursuit for some time.

"I doubt even whether these Somali beggars would dare to follow us as far as this," said John Margetson; "and if they do, I think we can guarantee that they shall be thoroughly scared. But I am firmly of belief that by pushing on we should come to an exit on the other side of this enormous hill, for the air here is perfectly pure and good, which is wonderful, when you come to consider the age of these workings. It looks, in fact, as though there was a perfect system of ventilation, a precaution which the ancients were too wise to neglect. Hullo! That was a shout."

At that moment a loud cry reached their ears, the sound, indeed, seeming to be collected together and enlarged by the solid walls of the mine. There was no doubt that it came from the two defenders who were watching the Mullah's followers, and at once Jim and his companion took to their heels, and raced back at their fastest pace. Arrived at the entrance-hall, they flung their brands into the fire and darted across the floor to the trench, in which they at once took their places.

"You have returned in the nick of time," remarked the colonel, in unruffled tones, "for those fellows outside are on the point of attacking. You can hear for yourself that the firing has ceased. But tell me, what luck have you had?"

"Splendid, father. We've explored the central tunnel, and find that it runs on for a considerable distance before coming to a meeting-place in the centre of the hill, from which a second series of workings emerge. If we have to fly, there will be plenty of room in which to play hide-and-seek, and always a chance of turning upon our followers and punishing them."

"Then we put the command in your hands as before, my boy, and leave it to you to give the word to retire. But, remember, all of you, that ammunition is valuable, and that you must not forget to carry every cartridge away with you."

His last words were interrupted by a perfect babel of sounds which came from the ravine, and each of the defenders at once sprang to his position, and, looking through the embrasure, saw that the enemy had begun to advance. This time they had taken the precaution to observe some order, and collecting together into a long, tongue-like band, came rushing up the central road towards the entrance of the mine. As before, Jim waited calmly until they were within easy range, and then gave the word to fire. Immediately a volley flashed from the sandbank, and a number of the natives fell. Then the defenders emptied their magazines into the closely packed ranks, and set to work with all haste to load again. For the second time they repeated the process, causing great loss to the enemy. But, in spite of that fact, the latter still rushed forward with marvellous pluck, and with loud shouts. Leaping over the bodies of the fallen, shrieking with pain, and tumbling headlong to the ground in their haste, they struggled fiercely to get at the infidels. Arriving at the deep cutting which the stream had made through the pathway, the foremost leapt it successfully; but those behind were not able to see it till right upon its edge, and, pushed by those who followed them, fell into the abyss with wild shrieks. Soon some thirty of them had met with this fate, and the gulley was full to overflowing. But their comrades never paused, never even hesitated, but, roused to fury by the loss of their friends, and by the stinging hail of bullets which still swept amongst them, came on with fierce determination, and in such huge numbers that it quickly became clear that there was no stopping them.

"Give them a last volley!" shouted Jim, raising his voice above the din. "Now, all together, and afterwards let us bolt."