Barlennan was thoughtful for a little while. “That seems silly; I should think you’d want a level that stayed put to measure from. Our seas go up and down hundreds of feet each year — and I’ve never noticed any particular change in the air.”
“I don’t suppose you would, for several reasons; the principal one is that you would be at sea level as long as you were aboard the Bree, and therefore at the bottom of the atmosphere in any case. Perhaps it would help you to think of this as a question of what weight of air is above you and what weight below.”
“Then there is still a catch,” the captain replied. “Our cities do not follow the seas down; they are usually on the seacoast in spring and anywhere from two hundred miles to two thousand inland by fall. The slope of the land is very gentle, of course, but I am sure they are fully three hundred feet above sea level at that time.” Lackland and Rosten stared silently at each other for a moment; then the latter spoke. “But you’re a lot farther from — the pole in your country — but no, that’s quibbling. Even if gravity were only a third as great you’d be experiencing tremendous pressure changes. Maybe we’ve been taking nova precautions for a red dwarf.” He paused for a moment, but the Mesklinite made no answer. “Would you be willing, then, Barlennan, to make at least an attempt to get up to the plateau? We certainly will not insist on your going on if it proves too hard on your physical make-up, but you already know its importance to us.” “Of course I will; we’ve come this far, and have no real reason to suppose what’s coming will be any worse than what’s past. Also, I want…” He paused briefly, and went on in another vein. “Have you yet found any way of getting up there, or is your question still hypothetical?” Lackland resumed the human end of the conversation.
“We have found what looks like a way, about eight hundred miles upstream from your present position. We can’t be sure you can climb it; it resembles a rock fall of very moderate slope, but we can’t tell from our distance how big the rocks may be. If you can’t get up there, though, I’m afraid you just can’t get up at all. The cliff seems to be vertical all around the plateau except for that one point.”
“Very well, we will head upstream. I don’t like the idea of climbing even small rocks here, but well do our best. Perhaps you will be able to give suggestions when you can see the way through the vision sets.”
“It will take you a long time to get there, I’m afraid.” “Not too long; for some reason there is a wind along the cliff in the direction we wish to go. It has not changed in direction or strength since we arrived several score days ago. It is not as strong as the usual sea wind, but it will certainly pull the Bree against the current — if the river does not grow too much swifter.”
“This one does not grow too much narrower, at any rate, as far as you will be going. If it speeds up, it must be because it grows shallower. All we can say to that is that (there was no sign of rapids on any of the pictures.”
“Very well, Charles. We will start when the hunting parties are all in.”
One by one the parties came back to the ship, all with some food but none with anything interesting to report. The rolling country extended as far iri all directions as anyone had gone; animals were small, streams scarce, and vegetation sparse except around the few springy. Morale was a trifle low, but it improved with the news that the Bree was about to travel again. The few articles of equipment that had been disembarked were quickly reloaded on the rafts, and the ship pushed out into the stream. For a moment she drifted seaward, while the sails were being set; then they filled with the strangely steady wind and she bore up against the current, forging slowly but steadily into unknown areas of the hugest planet man had yet attempted to explore.