“And it is substantiated by many seemingly irrefutable scientific facts,” I reminded him—“open polar sea, warmer water farthest north, tropical vegetation floating southward from the polar regions, the northern lights, the magnetic pole, the persistent stories of the Eskimos that they are descended from a race that came from a warm country far to the north.” “I’d like to make a try for one of the polar openings,” mused Jason as he replaced the ear phones. Again there was a long silence, broken at last by a sharp exclamation from Jason. He pushed an extra headpiece toward me. “Listen!” he exclaimed. As I adjusted the ear phones I heard that which we had never before received on the Gridley wave—code! No wonder that Jason Gridley was excited, since there was no station on earth, other than his own, attuned to the Gridley wave. Code! What could it mean? I was torn by conflicting emotions—to tear off the ear phones and discuss this amazing thing with Jason, and to keep them on and listen. I am not what one might call an expert in the intricacies of code, but I had no difficulty in understanding the simple signal of two letters, repeated in groups of three, with a pause after each group: “D.I., D.I., D.I.,” pause; “D.I., D.I., D.I.,” pause. I glanced up at Jason. His eyes, filled with puzzled questioning, met mine, as though to ask, what does it mean? The signals ceased and Jason touched his own key, sending his initials, “J.G., J.G., J.G.” in the same grouping that we had received the D.I. signal. Almost instantly he was interrupted—you could feel the excitement of the sender. “D.I., D.I., D.I., Pellucidar,” rattled against our ear-drums like machine gun fire. Jason and I sat in dumb amazement, staring at one another. “It is a hoax!” I exclaimed, and Jason, reading my lips, shook his head. “How can it be a hoax?” he asked. “There is no other station on earth equipped to send or to receive over the Gridley wave, so there can be no means of perpetrating such a hoax.” Our mysterious station was on the air again! “If you get this, repeat my signal,” and he signed off with “D.I., D.I., D.I.” “That would be David Innes,” mused Jason. “Emperor of Pellucidar,” I added. Jason sent the message, “D.I., D.I., D.I.,” followed by, “what station is this,” and “who is sending?” “This is the Imperial Observatory at Greenwich, Pellucidar; Abner Perry sending. Who are you?” “This is the private experimental laboratory of Jason Gridley, Tarzana, California; Gridley sending,” replied Jason. “I want to get into communication with Edgar Rice Burroughs; do you know him?” “He is sitting here, listening in with me,” replied Jason. “Thank God, if that is true, but how am I to know that it is true?” demanded Perry. I hastily scribbled a note to Jason: “Ask him if he recalls the fire in his first gunpowder factory and that the building would have been destroyed had they not extinguished the fire by shoveling his gunpowder onto it?”