Yussuf shook his head as he pointed to the mountains that rose on every side.

“It is only here and there that there is a pass,” he said. “There is no other way for three days’ journey. We must go back to the place where we sheltered and wait till the river flows back to its bed.”

“How long?” asked Mr Burne; “an hour or two?”

“Perhaps longer, effendi,” said Yussuf. “Mind how you turn round; there is very little room.”

They had become so accustomed to ride along shelves worn and cut in the mountain sides that they had paid little heed to this one as they descended, their attention having been taken by the hail that whitened the ledges; but now, as they were turning to ascend the steep slope cut diagonally along the precipitous side of the defile, the dangerous nature of the way became evident.

But no one spoke for fear of calling the attention of his companions to the risky nature of the ride back; so, giving their horses the rein, the docile beasts planted their feet together, and turned as if upon a pivot before beginning to ascend.

So close was the wall of rock in places that the baggage brushed the side, and threatened to thrust off the horses and send them headlong down the slope, that began by being a hundred feet, and gradually increased till it was five, then ten, and then at least fifteen hundred feet above the narrow rift, where the stream rushed foaming along, sending up a dull echoing roar that seemed to quiver in the air.

How it happened no one knew. They had plodded on, reaching the highest part, with Hamed and the baggage-horses in front, for there had been no room to pass them. First Yussuf, then the professor, Mr Burne and Lawrence on Ali Baba, of course counting from the rear. There was a good deal of hail upon the path, but melting so fast in the hot sun that it was forgotten, and all were riding slowly on, when the second baggage horse must have caught its load against the rock, with the result that it nearly fell over the side. The clever beast managed to save itself, and all would have been well had it not startled Ali Baba, who made a plunge, stepped upon a heap of the hail, and slipped, the left fore-hoof gliding off the ledge.

The brave little animal made a desperate effort to recover itself, but it had lost its balance, and in its agony it made a bound, which took it ten feet forward, and along the rapid slope, where it seemed to stand for a moment, and then, to the horror of all, it began to slip and stumble rapidly down the steep side of the ravine towards a part that was nearly perpendicular, and where horse and rider must be hurled down to immediate death.

Everyone remained motionless as if changed to stone, while the clattering of the little horse’s hoofs went on, and great fragments went rattling off beneath it to increase their pace and go plunging down into the abyss as if to show the way for the horse to follow to destruction.