When they had drunk their fill the guide took them to a place where a boulder as round as a football and about five times the size, lay upon the ground. This he rolled away, not without difficulty, and underneath it was a hole about three feet across, like one of those "blowholes"
which can be seen in some of the caves of Cornwall or South Wales.
Fernando let himself down through the hole until he was hanging by his hands; then he dropped, and they heard him alight upon the ground about ten feet beneath. Braid followed next, and then Klein; Harry was the last to descend into the darkness.
Below, they found themselves in what was evidently a pocket in the side of the crater, a great rent caused by some volcanic disturbance in bygone times. The place was a kind of low and narrow gallery. The moonlight was admitted through several cracks in the walls.
At the farthermost end of the gallery a fire burnt, and at this a man was seated, whom they found to be Cortes, the younger of the two guides.
When he saw them he rose to his feet without a word, walked deliberately to the wall, and thrust his head into one of the fissures.
The two boys watched him in amazement. The man--who, it will be remembered, was extremely slim and agile--wriggled like a snake.
Gradually, it became manifest that he was squeezing himself through with the greatest difficulty. First his head, then his shoulders, then his body, and finally his legs and feet disappeared through the wall.
"Where is he going?" asked Harry, turning to Fernando.
"He has gone to replace the stone upon the hole through which we came.
My brother is no fool. Life in the bush has taught us many things."
After a while the younger brother returned, squeezing himself again through the narrow opening. When he came to the firelight there were places upon his back and shoulders where his clothes had been torn, and where the rents were stained with blood. He did not seem to mind these wounds in the least, but laughed when Harry pointed them out.
"Here," said Fernando, "we are safe, and here we must stay for some days, until the Germans have left the district. They will never find us; no one could ever find us."
"We have food?" asked Harry.
Cortes pointed to a corner where lay the dead body of an antelope.
"I killed that this morning," said he. "Cooked, and in this cool climate, it will keep for days. Besides, my brother and I can hunt upon the mountain; but you and your two friends must remain here until the Germans have left the district. Then we can continue our march towards Maziriland."
In his heart Harry Urquhart felt more than grat.i.tude towards these strange, gallant men. They were loyal, faithful, courageous, and full of infinite resource. They seemed to love adventure for its own sake, after the manner of the old Spanish explorers--the followers of Columbus--whose blood ran in their veins.
For three days the party remained in this singular hiding-place. Every morning the brothers went out to hunt. Harry and Braid did not mind the monotony of their temporary imprisonment, first, because they knew that this was their only place of safety, and, secondly, because they were glad enough of a few days" rest after all the exertions and privations they had undergone in the wilderness of the bush.
At midnight on the third night, something that was well-nigh miraculous occurred. All were asleep except Harry Urquhart, who was doing his turn on watch. He was walking to and fro along the gallery, and had reached a spot immediately underneath the hole which was covered by the stone, when suddenly a great shaft of moonlight shot down into the cave.
It was a moment before the boy realized what had happened--that the stone had been rolled away. Before he had time to give the alarm, to cry out, or bring his rifle to his shoulder, the stone was rolled back again, and all was dim and silent as before.
He ran to the fire and woke up his companions. All sprang to their feet. In a few breathless words Harry told them what had happened. Jim Braid seized a lighted brand from the fire, which was burning brightly, and carried this to the end of the gallery. Sure enough the stone was back in its place.
"Are you sure," he asked, "you were not dreaming?"
"I can swear to it," said Harry.
"What"s that?" cried Braid, pointing to something white that lay upon the floor.
Harry Urquhart stooped, and to his amazement picked up a letter, written in German, which was addressed to:
"_Peter Klein, Coward_"
Here was a greater mystery than ever.
"This is apparently for you," said Harry, giving the letter to Klein.
The whole thing was amazing.
Klein opened the envelope with shaking hands. Then he took it to the other end of the gallery, and, kneeling down, read it by the light of the fire.
Presently he returned and handed the letter to Fernando, who had a fair knowledge of the German language.
"Read that," said he. "How did it come here?" The man was as white as a ghost.
The writer had evidently been at some pains to disguise his handwriting.
The letter was written in capital letters with a violet indelible pencil. The message, when translated, was as follows:--
"I have something of importance to say to you. Leave your hiding-place at once and alone."
"It is from von Hardenberg," said Klein. "He orders me to return to him--at once."
"Orders you! And you will go?"
"I have no option. I dare not refuse."
"Dare not!"
At that a groan escaped from the man"s lips, and he threw out his hands with a gesture of despair.
"You do not understand," he cried. "In London that man was in my power, but in this wild country I am at his mercy; for there is one with him who is pitiless and terrible, who carries his crimes as a jester jangles his bells."
"Whom do you mean?" asked Harry.
"I mean the Arab sheikh. That man is a demon. There is nothing he would not do for money. There were times when I travelled with them when I thought that they meant to kill me. When I fell asleep at the camp-fire, I could see in my dreams the cruel, piercing eyes of the sheikh fixed upon me; they were like coals of living fire. Fool that I was to come here!" he broke out in despair. "Why did I not stay where I was safe?"
Fernando, turning to Harry, cut short the man"s whining words.
"I must know the truth," said he. "How did that letter come here? Who wrote it?"
"It was written by my cousin," said Harry, "the man whom we follow; but whether he himself brought it here or the rascal who serves him, I am quite unable to say. At any rate," he added, with a smile, "your hiding-place has been discovered."
The half-caste returned to the fire, where he sat down, holding out his hands to warm them. He remained thus for some time, seemingly deep in thought; then he returned to Harry.
"Just now," said he, "I heard mention of a sheikh. Is the man"s name by any chance Bayram; for he is a devil, in truth."
"That is the name of the man who is with von Hardenberg."
"I did not know," said the other, and remained silent for a long time.
"You did not know?" repeated Harry.
"When I agreed to come with you I did not know that the Black Dog of the Cameroons--as I and my brother call him--was to be our enemy. In all the hills and plains and forests of this huge, amazing continent, from the Sahara to Kilima-Njaro, from the Niger to the Nile, there is no man more greatly to be feared than the Black Dog of the Cameroons. He knows neither pity nor fear. There is hardly a valley in these mountains with which he is not acquainted. Small wonder he discovered our hiding-place! He is a foe who cannot be despised. Single-handed he could keep an army of natives at bay. Almost every cartridge in his bandolier, almost every bullet in the chamber of his rifle, means the life"s blood of a human being. At one time he was the richest slave-trader in Africa. But I heard the English hunted him down, and that he was starving and penniless in London."
"It was he!" cried Harry, turning sharply to Braid. "He was the man we saw that morning on the mountain-side, who fired into the German bivouac at dawn."