M. Seetzen, the first European traveller who visited this extraordinary

mountain, set out from Wodyel Nackel on the 17th of June, at five o’clock in the morning. He was accompanied by a Greek Christian and some Bedouin Arabs, and after a quarter of an hour’s walk they reached the foot of a majestic rock of hard sand-stone. The mountain itself was quite bare and entirely composed of it. He found inscribed upon the rock several Greek and Arab names, and also some Koptic characters, which proved that it had been resorted to for centuries. About noon the party reached the foot of the mountains called _Nakous_, where at the foot of a ridge they beheld an insulated peaked rock. This mountain presented upon two of its sides two sandy declivities about 150 feet high, and so inclined that the white and slightly adhering sand which rests upon its surface is scarcely able to support itself; and when the scorching heat of the sun destroys its feeble cohesion, or when it is agitated by the smallest motions, it slides down the two declivities. These declivities unite behind the insulated rock, forming an acute angle, and like the adjacent surfaces, they are covered with steep rocks which consist chiefly of a white and friable free-stone. The first sound which greeted the ears of the travellers took place at an hour and a quarter after noon. They had climbed with great difficulty as far as the sandy declivity, a height of seventy or eighty feet, and had rested beneath the rocks where the pilgrims are accustomed to listen to the sounds. While in the act of climbing, M. Seetzen heard the sound from beneath his knees, and hence he was led to think that the sliding of the sand was the cause of the sound, and not the effect of the vibration which it occasioned. At three o’clock the sound became louder and continued six minutes, and after having ceased for ten minutes, it was again heard. The sound appeared to have the greatest resemblance to that of the humming-top, rising and falling like that of an Æolian harp. Believing that he had discovered the true origin of the sound, M. Seetzen was anxious to repeat the experiment, and with this view he climbed with the utmost difficulty to the highest rocks, and sliding down as fast as he could, he endeavoured, with the help of his hands and feet, to set the sand in motion. The effect thus produced far exceeded his expectations, and the sand in rolling beneath him made so loud a noise, that the earth seemed to tremble to such a degree that he states he should certainly have been afraid if he had been ignorant of the cause.