That these holes and this jet of air had some connection with the bridge I felt sure, but rack my brains and puzzle my mind as I might, I could not see what the connection was or how a stream of light--even if it issued from the holes--could provide a firm span over which human beings could walk in safety. Indeed, it seemed so utterly preposterous, so contrary to all laws of physics and of common sense, that at times I almost believed it was a figment of my imagination, that I had dreamed of it and actually had entered the valley by some other route. Yet Itza, the prince, Nohul Voh and everyone else knew of the Bridge of Light; with the exception of the sorcerer all regarded it as quite to be expected, as a supernatural manifestation, and no one, not even Nohul Voh, seemed to think it so very remarkable. In fact he and the others looked upon things that were everyday matters to me as far greater marvels than the Bridge of Light. Indeed, my own amazement, my own wonder that such an inexplicable thing as that span of light could exist was far less than their astonishment at such a simple matter as the wheel. CHAPTER XIV Innovations AS I had agreed to do, I told Nohul Voh and taught him much in exchange for what he told me. And I have no doubt that he felt he had much the best of the bargain. He was fascinated, intensely interested in my descriptions of other lands upon the earth, of the great oceans, of other races and of our civilizations. Of course there was much of this that he could not grasp, because so many of our everyday affairs are based upon principles, mechanics and forces of which he was entirely ignorant. Not until I tried to explain matters to him did I fully realize this fact. I could not of course make him understand steam, electricity, the simplest forms of chemistry. I could not describe anything that depended upon iron or steel, for there were no words in his language for these common substances unknown to the Mayas. And I could not describe or make him understand our means of travel, our industries, our daily life, because all depended upon the principle of the wheel, and the wheel was unknown to him and his race. I drew sketches of various things--at which he was immensely delighted, for he, like all his race, was an excellent artist and could grasp the meaning, could visualize the reality of an object by means of a drawing. But though he thus acquired a perfect idea of the appearance of our houses, our people, our dress; our trains, boats, aircraft, motor cars and innumerable other objects, yet to him they were more than incomprehensible, more than impossible, because of the ever-present wheel.