"Both might have been manufactured by the intelligences we have come to investigate. More likely, however, the gas comes from the disintegration of the radium in the earth, and has been rising out of fissures in the ocean floor and collecting here for ages. The oxygen of the air may have come from the decomposition of rocks--the earth's crust is nearly fifty per cent oxygen. This place may be as old as the sea. That alien power may have been growing up in here through all the ages that man has been developing outside!" "You think there may be living things here?" "No reason why not. In fact, this is the logical habitat for your Green Girl. Red and green are complementary colors. If there are people here, green would be the natural color for the protective pigmentation against this red light!" CHAPTER XII The Second Sea Leaving to me the visions and the flights of wild hope that his last words induced, Sam went below. In a few minutes he called me to eat. Suddenly I realized that I was very hungry. I looked at my watch. It was eight o'clock. "Why, is it just two hours since we left the surface?" "No. It's fourteen!" Forgetting the intense red sky, the strange, smooth sea, and the damp, hot wind, I went below to meet Sam's wonderful biscuit, with fresh steak and fruit from the refrigerator. A very mild and colorless beginning for adventurers newly fallen into an unknown world, but a very sensible one! After the meal, each of us took a turn on guard in the conning-tower, while the other slept. Nothing happened. The soft hot wind blew steadily out of the south, the bloody glare of the weird sky was changeless, and the sea lay about in a motionless desert. The thermometer outside registered 115°, but on account of the automatic temperature control, the machine was comfortable enough, though the heat and humidity on deck were stifling. When we had rested, we turned the bow of the Omnimobile toward the north and cruised along at a speed of four or five knots. I stood in the conning-tower at the wheel, while Sam busied himself with making an analysis of the air, and of a sample of water from the sea. Presently he came up out of the little laboratory, with his report. "The air shows to be 31% oxygen," he said, "and 64% helium, with the remainder a mixture of various other gases. The barometer pressure is only eleven pounds, which compensates for the excess of oxygen. The helium is a good indication of the radioactivity which must have produced the gas overhead, since helium is one of the ultimate products of radium disintegration. The oxygen must have come largely from the breaking up of carbon dioxide by plant life." "Then there is life?" "There were microscopic organisms, both animal and vegetable, in the sample of water I took. The water, by the way, carries only 1.23% solid matter, mostly sodium chloride. Less than half as much as the sea above, which has 2.7%."