I was silent, for I knew that it was so, and broodingly I considered that light, whose white illumination filled all the great chasm outside, beating faintly even into the cavern, yet seeming to have no visible source whatever. And then, even as I gazed upon it, that light died! It seemed to gray, to darken, and then had vanished altogether, within a moment, while at the same moment there beat faintly through the air from far away a great clanging note like that of a giant gong. The chasm outside, the world and worlds about us, lay now in dusk, their only illumination the lurid, dark crimson light of the comet's glowing coma, a red disk that gave to the barren rocky world about us an inconceivably weird appearance. "That gong!" Jurt Tul was saying. "You heard it? It sounded when the light died--it means that these comet-creatures maintain and regulate their own day and night!" "That white light," I said; "you mean that it's made by them, turned off for their night?" He nodded quickly. "It must be. They can use the coma's great electrical energy to produce that light at will, just as they use that energy for their crimson bolts. They must turn it off and on at regular intervals, to produce their day and night, their activity-periods and rest-periods." "But then we can venture back to the comet-city--back to the central world for Gor Han and Najus Nar!" I exclaimed, and he nodded. "Yes, but we'd best wait longer, since now the cube-ships' search will be going on, even in this dusk, and we'd have small chance of escaping them." * * * * * For all my impatience I saw the wisdom of Jurt Tul's suggestion and so composed myself to a longer period of waiting. So hour followed hour while we crouched there in the great crack in the chasm's wall. Far above we could see the crimson coma, against which there came and went now and then divisions of cube-ships, still searching, searching for the fugitives who had escaped them. My thoughts turned to Gor Han and to Najus Nar, prisoned in the comet-city, and then to our own predicament. But hours remained now in which the comet might be turned aside, and unless we could escape from it, could meet the five thousand cruisers that were racing toward it from the galaxy and lead them inside, no power in all space and time could turn the comet aside from the galaxy. And I could not, would not, attempt to escape from the comet without having first learned the fate, at least, of Gor Han and Najus Nar. At last I stood upright, turned to Jurt Tul. "The cube-ships above seem to have slackened their search," I told him, "and now's the time for our venture. We've had hours now of this dusk, and the light of their day may be turned on at any time."