"Well, all I can say then, is, that you jumped to the occasion mighty well. Some fellows would have been scared just stiff, and couldn't have thrown out a hand to save a chum. But look here, Frank, you don't imagine that thing was done on purpose, do you?"
Frank looked at his companion, with a wrinkle on his forehead.
"I don't want to think anybody could be so mean and low as to want to hurt boys who'd never done them any harm," he said; "but all the same I seem to have an idea that I got a glimpse of a man's arm when that rock started to drop."
"Whew! you give me a cold chill, Frank," muttered Bob, gazing helplessly upward toward the spot from which the descending rock had started on its riotous tumble.
"Yes, and I hope I was mistaken," Frank went on. "I don't see anything up there now; and perhaps it was only a delusion. All these bright colors affect the eyes, you see. Then, again, it might have been some goat jumping, that started that rock on its downward plunge."
"But you didn't see any goat, Frank, did you?" Bob asked, anxiously.
"No, I didn't," admitted the other; "but then there may be a shelf up there, and any animal on it would be hidden from the eyes of those right below."
They passed on; but more than once Bob craned his neck in the endeavor to look up to that spot, from whence the loose rock had plunged. He could not get it out of his head that foes were hovering about, who thought so little of human life that they would conspire to accomplish a death if possible.
The day passed without any further peril confronting them. Charley Moi seemed to fill the bill as a guide, very well. He also knew the different points of interest, and chattered away like a magpie or a monkey as they kept pushing on.
Bob became curious to know just how the Chinaman could tell about so many things when they were now above the trails used ordinarily by tourists, who gave two or three days to seeing the Grand Canyon, and then rushed away, thinking they had exhausted its wonders, when in fact they had barely seen them.