But, try as I would, I never could get anything from the outer world, and after a while I gave up trying, convinced that the earth's crust was impervious to radio.

In fact we used our stations but seldom, for, after all, Pellucidar is only commencing to emerge from the stone age, and in the economy of the stone age there seems to be no crying need for radio.

But sometimes I played with it and upon several occasions I thought that I heard voices and other sounds that were not of Pellucidar. They were too faint to be more than vague suggestions of intriguing possibilities, but yet they did suggest something most alluring, and so I set myself to making changes and adjustments until this wonderful thing that has happened but now was made possible.

And my delight in being able to talk with you is second only to my relief in being able to appeal to you for help. David is in trouble. He is a captive in the north, or what he and I call north, for there are no points of compass known to Pellucidarians.

I have heard from him, however. He has sent me a message and in it he suggests a startling theory that would make aid from the outer crust possible if—but first let me tell you the whole story; the story of the disaster that befell David Innes and what led up to it and then you will be in a better position to judge as to the practicability of sending succor to David from the outer crust.

The whole thing dates from our victories over the Mahars, the once dominant race of Pellucidar. When, with our well-organized armies, equipped with firearms and other weapons unknown to the Mahars or their gorilla-like mercenaries, the Sagoths, we defeated the reptilian monsters and drove their slimy hordes from the confines of The Empire, the human race of the inner world for the first time in its history took its rightful place among the orders of creation.