“Oh, no,” she said, “the wings we use simply for propelling ourselves through the air. In a bag, upon our backs, we carry a gas that is lighter than air. It is this gas which supports us, and we carry it in such quantities as to maintain a perfect equilibrium, so that we may float at any altitude, or with our wings rise or fall gently; but as I hovered over Laythe, came the air that runs, and seizing me with its strong arms bore me off across the surface of Va-nah. Futilely I fought against it until I was spent and weak, and then it dropped me into the clutches of the Va-gas, for the gas in my bag had become depleted. It was not intended to carry me aloft for any great length of time.” She had used a word which, when I questioned her, she explained so that I understood that it meant time, and I asked her what she meant by it and how she could measure it, since I had seen no indication of the Va-gas having any conception of a measurable aspect of duration. Nah-ee-lah explained to me that the Va-gas, who were a lower order, had no means of measuring time, but that the U-ga, the race to which she belonged, had always been able to compute time through their observation of the fact that during certain periods the bottoms of the hoos, or craters, were illuminated, and for another period they were dark, and so they took as a unit of measure the total period from the beginning of this light in a certain crater to its beginning again, and this they called a _ula_, which corresponds with a sidereal month. By mechanical means they divide this into a hundred parts, called _ola_, the duration of each of which is about six hours and thirty-two minutes earth time. Ten _ulas_ make a _keld_, which one might call the lunar year of about two hundred and seventy-two days earth time. I asked her many questions and took great pleasure in her answers, for she was a bright, intelligent girl, and although I saw many evidences of regal dignity about her, yet her manner toward me was most natural and unaffected, and I could not help but feel that she occupied a position of importance among her own people. Our conversation was suddenly interrupted, however, by a messenger from the point, who came racing back at tremendous speed, carrying word from Ga-va-go that the scouts were signaling that they had discovered a large village, and that the warriors were to prepare to fight. Immediately we moved up rapidly to Ga-va-go, and then we all advanced toward the scout who could be seen upon a knoll far ahead. We were cautioned to silence, and as we moved at a brisk canter over the soft, pale lavender vegetation of the inner Moon, the feet of the Va-gas giving forth no sound, the picture presented to my earthly eyes was weird and mysterious in the extreme.