"I haven't an idea. But, oh, these mountains!" she exclaimed, stepping in caution to the guard-rail. "Could anything be more awful than this?" They were crawling antlike up a mountain spur that rose dizzily on their right; on the left they overhung a bottomless pit. Their engines churned, panted, and struggled up the curve, and as they talked the dense smoke from the stacks sucked far down into the gap they were skirting.

"The roadbed is chiselled out of the granite all along here. This is the famed Mount Pilot on the left, and this the worst spot on the division for snow. You wouldn't think of extending our truce?"

"To-morrow we leave for the coast."

"But you could leave the truce; and I want it ever so much."

She laughed. "Why should one want a truce after the occasion for it has passed?"

"Sometimes out here in the desert we get away from water. You don't know, of course, what it is to want water? I lost a trail once in the Spanish Sinks and for two days I wanted water."

"Dreadful. I have heard of such things. How did you ever find your way again?"

He hesitated. "Sometimes instinct serves after reason fails. It wasn't very good water when I reached it, but I did not know about that for two weeks. It is a curious thing, too—physiologists, I am told, have some name for the mental condition—but a man that has suffered once for water will at times suffer intensely for it again, even though you saturate him with water, drown him in it."

"How very strange; almost incredible, is it not? Have you ever experienced such a sensation?"

"I have felt it, but never acutely until to-day; that is why I want to get the truce extended. I dread the next two days."