Duane was hungry, but he hurried through the ample supper that was set before him, urged on by curiosity and astonishment. The only way he could account for his presence there in a ranger's camp was that MacNelly hoped to get useful information out of him. Still that would hardly have made this captain so eager. There was a mystery here, and Duane could scarcely wait for it to be solved. While eating he had bent keen eyes around him. After a first quiet scrutiny the rangers apparently paid no more attention to him. They were all veterans in service--Duane saw that--and rugged, powerful men of iron constitution. Despite the occasional joke and sally of the more youthful members, and a general conversation of camp-fire nature, Duane was not deceived about the fact that his advent had been an unusual and striking one, which had caused an undercurrent of conjecture and even consternation among them. These rangers were too well trained to appear openly curious about their captain's guest. If they had not deliberately attempted to be oblivious of his presence Duane would have concluded they thought him an ordinary visitor, somehow of use to MacNelly. As it was, Duane felt a suspense that must have been due to a hint of his identity.

Who invited Duane to stay at the camp?

Flowing water causes sediment to move. Flowing water can erode both rocks and soil. You have already learned that materials can dissolve in water. With enough time, even rocks can be dissolved by water. This process happens really slowly. It may take over a million years to dissolve a rock. It doesnt matter how big the rock is. With enough time, flowing water can dissolve it. Moving water also has the ability to move small pieces of rock and soil. How can water move a rock? Doesnt it need energy? Of course, water gets its energy because it is moving. Moving water has kinetic energy. Things that have more energy can do more work. When water stops moving it will have no energy. It will no longer be able to move the rock and soil. When this happens the rock and soil will settle to the bottom of the calm water. Scientists call this process deposition.

What are some things flowing water causes?

We were cornered in a sort of way already. But these butchers up the cavern had been surprised, they were probably scared, and they had no special weapons, only those little hatchets of theirs. And that way lay escape. Their sturdy little forms--ever so much shorter and thicker than the mooncalf herds--were scattered up the slope in a way that was eloquent of indecision. I had the moral advantage of a mad bull in a street. But for all that, there seemed a tremendous crowd of them. Very probably there was. Those Selenites down the cleft had certainly some infernally long spears. It might be they had other surprises for us.... But, confound it! if we charged up the cave we should let them up behind us, and if we didn't those little brutes up the cave would probably get reinforced. Heaven alone knew what tremendous engines of warfare--guns, bombs, terrestrial torpedoes--this unknown world below our feet, this vaster world of which we had only pricked the outer cuticle, might not presently send up to our destruction. It became clear the only thing to do was to charge! It became clearer as the legs of a number of fresh Selenites appeared running down the cavern towards us.
Who was guarding the way to escape?