I figured for a few minutes on a scrap of paper and decided that the moon and the earth were at that moment ninety thousand miles apart. It seems that I was ten thousand miles out of the way, but as my result was based on a purely mathematical calculation, without any help from observation other than the moon's time of revolution around the earth, my error was excusable. * * * * * Waiting for the End There was no slackening of the wind after the moon had disappeared beneath the western cliff which was our horizon. It was then eleven o'clock in the morning. The sky kept its burnished copper tint and the sun was not visible. In fact, we did not see the sun during this entire period. Day was a little brighter than night, but there was nothing that corresponded to ordinary daylight. "Now if the moon doesn't come up for fifteen hours," I said to Jim, "we'll know that the worst is not going to happen." "Why?" "It will mean that the force that flung it in the direction of the earth has been neutralized in some way, and that it will continue to revolve around the earth about 90,000 miles away instead of 240,000." Jim looked cheerful for the first time in two days. "We'll know by two o'clock tomorrow morning, then?" "If the news is bad, we'll know it before that." There was no possibility of our venturing out of the depression between the two sandstone cliffs where we were sheltered from the wind. There was nothing to do except wait. As the half light, that we called day, faded, Jim and I began to watch the eastern cliff. Six o'clock, seven o'clock, eight o'clock passed. Jim turned to me with a half grin. "Seems funny to be watching for the moon and frightened to death for fear we'll see it." "Well, I guess we're safe if we don't see it for the next six hours." I climbed into the cabin of the plane and began going over the engine. Suddenly I heard a shout from Jim. I jumped out of the door to the ground and saw him pointing to the eastern cliff. There was a line of molten gold above it, too dazzling to look at. It was at that moment that we had our first earthquake. There had been many earlier ones in other parts of the world. I was thrown violently to the ground and the sideways motion was so strong that I tried to find something on the bare rocky surface to hang on to. By the time I was able to raise myself to a sitting posture, a great blinding segment of a sphere had appeared in the sky. [Illustration: A great blinding segment of a sphere appeared in the sky. I realized that it was the moon travelling toward the earth at a terrific velocity.]