Then again it swelled up much louder than before and with a different note. At first it sounded like the wind blowing in a telegraph wire; but this time it was a much deeper tone, rather resembling the after reverberation of a great bell.

I stepped out of the tent to try and discover the cause. It was at once clear that it could not be due to the wind in the tent ropes, for it was a perfectly calm night. The thunder still growled occasionally in the distance and the lightning flickered in the sky to the north. After the hot scorching weather we had experienced, the air felt damp and chilly enough to make one shiver.

The sound was not quite so distinctly audible outside the tent as inside it, presumably owing to the fact that the rain had so tightened the ropes and canvas that the tent acted as a sounding board. At times it died away altogether, then it would swell up again into a weird musical note.

Thinking that possibly it might be due to a singing in my ears, I called out to my men to ask if they could hear anything.

Abd er Rahman, whose hearing was not so keen as his eyesight, declared that he could hear nothing at all. But Khalil and Qway both said they could hear the sound, Qway adding that it was only the wind in the mountain. It then flashed across me that I must be listening to the “song of the sands,” that, though I had often read of, I had never actually heard.

This “song of the sands” was singularly difficult to locate. It appeared to come from about half a mile away to the west, where the sand came over a cliff. It was a rather eerie experience altogether.

Musical sands are not very uncommon. The sound they emit is sometimes attributed, by the natives, to the beating of drums by a class of subterranean spirits that inhabit the dunes. In addition to those sands that give out a sound of their own accord, there is another kind that rings like a bell when struck. A patch of sand of this kind is said to exist on the plateau to the north of Dakhla Oasis. I never personally came across any sand of this description, but much of the Nubian sandstone we found on the plateau to the south-west of Dakhla Oasis gave out a distinctly musical sound when kicked, and in the gully that leads up to the plateau at the Dakhla end of the ’Ain Amur road, I passed a shoulder of rock that emitted a slight humming sound as a strong south wind blew round it.

The following day we reached Mut without any further incident. We, however, only just got in in time as our water-tanks were completely empty, after our journey of eleven days in the desert.

Knowing that many of the natives in Dakhla suspected me of being engaged on a treasure hunt, and of looking for the oasis of Zerzura, I had played up to the theory by continually asking for information on the subject. On our return from such a long journey into the desert several natives, assuming that we must have found something, came round to enquire whether I had actually found the oasis.

Khalil, who had heard the account in the “Book of Treasure,” called my attention to the fact that the road we had followed on our return journey, until it lost itself in the sand dunes on the outskirts of Dakhla, at that time was leading straight for the Der el Seba’a Banat, and gave it as his opinion that, if we only followed the road far enough in the opposite direction, it would be bound to lead us to Zerzura. For the benefit of any treasure seekers who wish to look for that oasis, to embark on a treasure hunt, I will mention another and still more significant fact—that road exactly follows the line of the great bird immigration in the spring—showing that it leads to a fertile district, and moreover—most significant fact of all—many of those birds are wild geese!