To Jason Gridley of Tarzana, discoverer of the Gridley Wave, belonged the credit of establishing radio communication between Pellucidar and the outer world. It was my good fortune to be much in his laboratory while he was carrying on his experiments and to be, also, the recipient of his confidences, so that I was fully aware that while he hoped to establish communication with Pellucidar he was also reaching out toward an even more stupendous accomplishment—he was groping through space for contact with another planet; nor did he attempt to deny that the present goal of his ambition was radio communication with Mars. Gridley had constructed a simple, automatic device.
