I lay for an hour--listening intently.

At last my curiosity got the better of me. I arose, lighted my lamp and commenced to investigate.

My bedding lay upon a rug stretched directly upon the warm sand. The noise appeared to be coming from beneath the rug. I raised it, but found nothing--yet, at intervals, the sound continued.

I dug into the sand with the point of my hunting-knife. A few inches below the surface of the sand I encountered a solid substance that had the feel of wood beneath the sharp steel.

Excavating about it, I unearthed a small wooden box. From this receptacle issued the strange sound that I had heard.

How had it come here?

What did it contain?

In attempting to lift it from its burying place I dis-covered that it seemed to be held fast by means of a very small insulated cable running farther into the sand beneath it.

My first impulse was to drag the thing loose by main strength; but fortunately I thought better of this and fell to examining the box. I soon saw that it was covered by a hinged lid, which was held closed by a simple screwhook and eye.

It took but a moment to loosen this and raise the cover, when, to my utter astonishment, I discovered an ordinary telegraph instrument clicking away within.

"What in the world," thought I, "is this thing doing here?"

That it was a French military instrument was my first guess; but really there didn't seem much likelihood that this was the correct explanation, when one took into account the loneliness and remoteness of the spot.

As I sat gazing at my remarkable find, which was tick-ing and clicking away there in the silence of the desert night, trying to convey some message which I was unable to interpret, my eyes fell upon a bit of paper lying in the bottom of the box beside the instrument. I picked it up and examined it. Upon it were written but two letters:

D. I.

They meant nothing to me then. I was baffled.

Once, in an interval of silence upon the part of the receiving instrument, I moved the sending-key up and down a few times. Instantly the receiving mechanism commenced to work frantically.

I tried to recall something of the Morse Code, with which I had played as a little boy--but time had obliterated it from my memory. I became almost frantic as I let my imagination run riot among the possibilities for which this clicking instrument might stand.

Some poor devil at the unknown other end might be in dire need of succor. The very franticness of the instrument's wild clashing betokened something of the kind.

And there sat I, powerless to interpret, and so power-less to help!

It was then that the inspiration came to me. In a flash there leaped to my mind the closing paragraphs of the story I had read in the club at Algiers:

Does the answer lie somewhere upon the bosom of the broad Sahara, at the ends of two tiny wires, hidden beneath a lost cairn?

The idea seemed preposterous. Experience and in-telligence combined to assure me that there could be no slightest grain of truth or possibility in your wild tale--it was fiction pure and simple.