A moment of maneuvering, then Jon reported, "Ship level at twenty-four hundred, traveling parallel to ground surface." "Check rocket balance." "All tubes on balance." "Switch on auto-pilot." "Auto on, but keeping ready to switch back to manual if necessary." Jak loosened his straps and went to look out of the port, but Jon kept his gaze fastened on the lookout plate before him, his hands resting lightly on the controls, although they were not connected now. Beneath them the land was sliding by, as the ship cruised at the slow speed, for it, of just under a thousand miles an hour. The boys saw the same sort of jungle forests, the same occasional clearings. From time to time the glint of water revealed rivers or lakes, the latter seldom more than a mile or so in width or length. After nearly an hour, they were flying above a huge plain, covered with some sort of grass or grain. They had been above this for some minutes when Jon uttered an exclamation and Jak came up quickly to see what his brother had spotted in the magnifier-screen. "Look down there, Owl," the younger brother was excited. "Thousands of cattle!" "Whew! Most like those old buffalo-herds we read the old pioneers saw on the western plains of Noramer. Hey, those things are tripeds, too, like the big one we shot, and the rabbits." "Yes, I see. Must be the usual thing here. But those down there are smaller, like cows. Wonder if they're good to eat, or give milk?" "Don't know, but we sure want to report this." He took several pictures with the recording camera, then made notations in the data book. The two continued watching until the tremendous herd was out of sight behind them, and they were flying once more above a great forest. They had gone almost two thousand miles when they saw ahead and downward the beginnings of what was either an ocean or a great sea. As they drew closer, they still could not see its further shore. "I don't remember this from before, do you?" Jon looked perplexed. "Yes, I think this must be the one we saw part of from the north--that is, I assume it was north, as we were near the icecap. But I didn't realize it was so...." "Hey, look down there! That proves I was right." Jon pointed triumphantly toward his visiplate. "See those high-water marks along the shore? That means this moon is big enough to cause tides, same as Luna does to Terra." "What good, really, are tides?" "Why," superciliously, "they're one of the most useful things God has given man. They ... they...." Jon stopped, flushed, then laughed. "Darned if I know what they're good for. Of course, if they're high enough, men can make tide-motors and produce power, but now that we've got atomics, we don't need those." "I suppose we should record them, though." Jak was tactful enough not to laugh. "Yes, write it down."