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