The result was unexpected. Von Holtz could not unravel the secret of the catapult he himself had operated. He could not sell the secret for which he had committed a crime. In desperation he called in Tommy Reames--rather more than an amateur in mathematical physics--showed him Evelyn and her father marooned in a tree-fern jungle, and hypocritically asked for aid. Tommy's enthusiastic efforts soon became more than merely enthusiastic. The men of the Golden City remained invisible, but there were strange, half-mad outlaws of the jungles who hated the city. Tommy Reames had watched helplessly as they hunted for the occupants of the steel globe. He had worked frenziedly to achieve a rescue. In the course of his labor he discovered the treachery of Von Holtz as well as the secret of the catapult, and with the aid of Smithers--who had helped to build the original catapult--he made a new small device to achieve the original end. * * * * * The whole affair came to an end on one mad afternoon when the Ragged Men captured first an inhabitant of the Golden City, and then Denham and Evelyn in a forlorn attempt at rescue. Tommy Reames went mad. He used a tiny sub-machine gun upon the Ragged Men through the model magnetic catapult he had made, and contrived communication with Denham afterward. Instructed by Denham, he brought about the return of father and daughter to Earth just before Ragged Men and Earthling alike would have perished in a vengeful gas cloud from the Golden City. Even then, though, his triumph was incomplete because Von Holtz had gotten word to Jacaro, and nattily-dressed gunmen raided the laboratory and made off with the model catapult, leaving three bullets in Tommy and one in Smithers as souvenirs. Now, using the principle developed in the catapult, Tommy and Denham had built a large Tube, and as Tommy climbed along its corrugated interior he knew a good part of what he should expect at the other end. A steady current of air blew past him. It was laden with a myriad unfamiliar scents. The Tube was a tunnel from one set of dimensions to another, a permanent way from Earth to a strange, carboniferous-period planet on which a monstrous dull-red sun shone hotly. Tommy should come out into a tree-fern forest whose lush vegetation would hide the sky, and which furnished a lurking place not only for strange reptilian monsters akin to those of the long-dead past of Earth, but for the bands of ragged, half-mad human beings who were outlaws from the civilization of which Denham and Evelyn had seen proofs. * * * * *