There was little to see, too, in the darkness, but the figures of the reclining sleepers, and that of the grave sentinel, who sat upon a big mass of stone, crouched in a heap and looking as if he were part of the rock, save when he changed his position a little to refill his pipe.

The night passed without any alarm. The professor was awakened about two and took Yussuf’s place, and soon after daybreak the others were roused, and the residue of the provisions was opened out.

“Be easier to carry when eaten,” said Mr Preston laughing.

He looked serious directly, for there was a peculiarly sombre frown upon Yussuf’s brow, which suggested that he was thinking over Mr Burne’s suspicions of the previous evening, and his rather unpleasant way.

“Look here, Burne,” the professor whispered, as they sat together on the sand eating their spare meal, “I think, if I were you, I would make a bit of an apology to Yussuf. He is really a gentleman at heart, and has been accustomed to mix a great deal with Englishmen. He is a good deal hurt by our suspicions, and it is a pity for there to be any disunion in our little camp.”

“Camp, indeed!” cried the old man testily; “pretty sort of a camp, without a tent in it. I shall be racked with rheumatism in all my old bones. I know I shall, after this wild-goose chase.”

“Let’s hope not,” said the professor; “but you will make some advances to him, will you not?”

“You mind your own affairs, sir. Don’t you teach me. My back’s horrible this morning. Can’t you wait a bit. I was going to make amends if you had left me alone.”

“That’s right,” said the professor cheerily. “I want him to have a good opinion of Englishmen.”

Lawrence watched eagerly for Mr Burne’s apology, but he did not speak till just as they were going to start, when he stepped aside behind a rock for a few minutes, and then came out again and walked up to Yussuf with something coiled up in his hand.