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 eardrums 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?"