It was a year since I had left medical college in America to begin practise in Perth, Australia. There I had an uncle who was my sole surviving relative. My companion on the voyage had been Dr. Horace Austen, the well-known radiologist, archeologist, and explorer. He had been my dearest friend. That he was thirty years my senior, had never interfered with our comradeship. It was he who had paid most of my expenses in school. He had left me at Perth, and went on to investigate some curious ruined columns that a traveler had reported in the western part of the Great Victoria Desert. There Austen had simply vanished. He had left Kanowna, and the desert had swallowed him up. But it was his way, when working on a problem, to go into utter seclusion for months at a time. My uncle was an ardent radio enthusiast, and it was over one of his experimental short wave sets that we picked up the remarkable message from my lost friend that led me to abandon my practise, and, heeding the call of adventure that has always been strong in those of my blood, to seek the half mythical Mountain of the Moon, in the heart of the unexplored region of the Great Victoria Desert of Western Australia. The message was tantalizingly brief and hard to interpret. We picked it up five times, over a period of two weeks, always just after sunset. Evidently it was sent by one who had not recently practised his knowledge of code, and it seemed that the sender was always in a great hurry, or under a considerable nervous tension, for minor errors and omissions were frequent. The words were invariably the same. I copy them from an old notebook. "To Winfield Fowler, physician, Perth, Australia: I, Horace Austen, am lost in an unknown new world, where alien terrors reign, that lies in a crater in the Mountain of the Moon. I implore you to come to my aid, for the sake of mankind. Bring arms, and my equipment--the Rontgen tubes and coils, and the spectrometer. Ascend ladder at west pinnacle. Find my friend Melvar, maiden of the crystal city, whom I left beyond the Silver Lake. Come, for the sake of civilization, and may whoever hears this forward it with all dispatch." My uncle was inclined to suspect a hoax. But after the message had come over twice I received telegrams from several other radio amateurs who had heard it, and were forwarding it to me. We took the direction of the third call and had amateurs in Adelaide do the same. The lines intersected in the Great Victoria Desert, at a point very near that at which Wellington located the Mountain of the Moon, when he sighted it and named it in 1887.