The only way in which I could make matters clear was to give him a demonstration of this simple but most important of man’s inventions, and I set about doing so. It sounds like a simple matter to make a wheel; but let my readers try to do so without the aid of a steel or iron tool--aside from a pocket knife--and see how simple it is! Here however, I must digress to call attention to the wonder that my knife had excited. My pistol, of course had been regarded with awe and terror; to the minds of the people it was the abode of a caged or captive god of thunder and lightning, and realizing fully the power it gave me and the fear it inspired, I had kept it hidden from sight in its holster. But my knife was a necessity. I used it constantly, and the people never tired of watching me use it, gazing with fascinated eyes as I cut a stick or pared my nails with the keen blade. Hence it had been a fairly simple matter to demonstrate the properties of steel to Nohul Voh. But the wheel was a very different affair. Had I possessed a watch, I could have done so easily, but my watch had been lost somewhere in my wanderings--probably in my tumble down the crater as I fled from the man-eating dinosaur--and my entire possessions consisted of my knife, my pistol, my cartridges, my pipe and a lead pencil. Why I had not discarded my pipe, I cannot say. My tobacco had been exhausted weeks before I reached the valley, but still I had retained it. And I had been very glad that I had done so. The people of Mictolan were inveterate users of tobacco; they smoked both cigars and pipes, and only an old pipe smoker can appreciate the satisfaction, the enjoyment that I felt when, after weeks of forced abstinence, I again puffed away at my seasoned old briar.