"Well," said Hugh, "I expect if no more snow fell up here this piece of ice would just melt away and leave nothing but the hole that it's laying in--just a sort of a basin in the side of the mountain."
"Yes," said Jack, "I guess that's so. I think that's what Mr. Fannin told us; that a glacier was a glacier, because it was constantly being added to at its upper end, and the weight of the snow and ice was pushing it along over the mountainside. I take it that a snowbank might be ice at the bottom, perhaps, but that if it doesn't move it isn't a glacier."
"Yes," said Hugh, "I reckon that's so. I took notice of another thing," he went on, "as we were coming along. Did you see how this ice seems to be in layers? Some of 'em are half an inch thick and some of 'em an inch, and there seems to be a thin crust of dirt that separates one layer from another."
"Yes," said Jack, "I noticed that, and I was wondering how it could happen, or what it meant."
"Well, I was figuring on that very thing," said Hugh, "and it seemed to me that these little layers of dirt must be the dust and dirt blown off the mountainside by the wind after each fall of snow."
"Well, Hugh," said Jack, "that seems a natural explanation. We all know how the wind is always blowing up here, and we all know that old snow is always dusty. I guess you're right."
By this time Hugh's pipe was smoked out, and he rose to his feet and said, "Come on, we've got to stretch our legs some more and see if we can go up to the ridge. There looks to be a low place up ahead of us, and maybe if we can get up there we can see over the range. Look out for yourselves when you are walking over this smooth ice. If a man slips on one of these steep places, he's liable to go a long way before stopping."
The caution was a wise one, and for some distance they walked along carefully, keeping either on the moraine or on the very edge of the ice, or choosing a path where the snow was old and hard and gave a firm footing.
At one point, however, Joe tried to make a short cut by climbing over some old snow which was quite steep. Before he had gone very far the others saw him begin to dig his feet into the hard snow as if uncertain of his footing, then he slipped, recovered himself, stood for an instant as if doubtful whether to go backward or forward, took another step and then his feet flew out from under him and he began to slide down the slope. It looked very funny to see him flying over the snow, but Hugh did not laugh, for he feared that possibly the boy might go on until he brought up against rough rocks below. Luckily nothing of this kind happened, and after going about a hundred yards at a high rate of speed, Joe ran into some soft snow and his momentum was checked. He stopped, rose to his feet, and making his way cautiously back to the edge of the rocks, took the safe but longer road that his companions had followed.