"He took the alarm, it seems," Frank went on, indifferently. "Knew we wanted to find the man who had given him the talking paper; and was afraid we might try to make him tell; or, that failing, stalk him when he went to deliver my note. And on the whole I can't much blame the old Indian. Suspicion is a part of their nature. He believed he was on the safe side in slipping away as he did. Forget it, Bob. We've learned a heap by his just dropping in on us, I think."

"Sure we have," replied the other, being busily employed over the fire just then. "And I was thinking what he could have meant when he pointed off in the direction I calculate the Grand Canyon lies, and said in answer to one of your questions: 'Seek there! When the sun is red it shines in Echo Cave!'"

"I've guessed that riddle, and it was easy," Frank remarked.

"Then let me hear about it, because I'm pretty dull when it comes to understanding all this lovely sign language of the Indians," Bob remarked.

"Listen, then. The sun is said to be red when its setting; that's plain enough; isn't it, Bob?"

"All O.K. so far, Frank. I won't forget that in a hurry, either."

"Then, when he said it looked into the cave at sunset, it was another way of telling us the cave faced the west!" Frank continued.

"Well, what a silly chap I was not to guess that," chuckled the other.

"And from what I know about the bigness of that canyon, Bob, I think that this unknown Echo Cave must be pretty high up on the face of a big cliff to the east of the river."

"Why high up? I don't get on to any reason for your saying that?"

inquired Bob.

"You'll see it just as soon as I mention why," remarked his companion.

"When the sun is going down in the west, far beyond the horizon, don't you see that it can only shine along the very upper part of the cliffs?

The lower part is already lost in the shadows that drop late in the afternoon in all canyons."

"Of course, and it's as plain to me now as the nose on my face," agreed Bob. "Queer, how easy we see these things after they've been explained."

It did not take long to prepare breakfast, and still less time to eat it once the coffee and venison were ready. Just as Frank had said, there was plenty of the meat for the meal.

"That was a mighty juicy little antelope, all right," remarked Bob, as he finished his last bite, and prepared to get up from the ground where he had been enjoying his ease during the meal.

"And for one I don't care how soon you repeat the dose," remarked Frank; "only it will be a long day before you get one of the timid little beasts as easy as that accommodating chap fell to your gun. Why, he was just a gift, that's all you could call it, Bob."

"That's what I've been thinking myself, though of course I don't know as much about them as you do, by a long shot," Bob admitted. "I suppose it's us to hit the saddle again now?"

"We're going to try and make Flagstaff by night," Frank announced, as he picked up his saddle and bridle, and walked toward the spot where Buckskin was staked out.

The horses had been able to drink all they wanted during the night, for the ropes by means of which they were tethered allowed of a range that took them to the little spring hole from which the water gushed, to run away, and, in the end, possibly unite with the wonderful Colorado.

In ten minutes more the boys were off at a round gallop. There was no intention of pushing their mounts so soon in the day. Like most persons who have spent much time on horseback both lads knew the poor policy of urging an animal to its best speed in the early part of a journey, especially one that is to be prolonged for ten or twelve hours.

At noon they were far enough advanced for Frank to declare he had no doubt about being able to make Flagstaff before sunset.

"When we get there, and spend a night at the hotel, we must remember and ask if our friend Mr. Stanwix and his partner arrived in good time, and went on," Bob suggested.

Just as Frank had expected, they made the town on the railroad before the sun had dropped out of sight; and the horses were in fair condition at that.

Flagstaff only boasts of a normal population of between one and two thousand; but there are times, with the influx of tourists bound for the Grand Canyon, when it is a lively little place.

The two boys only desired shelter and rest for themselves and their horses during the night. It was their intention to push on early the following day, keeping along the old wagon trail that at one time was the sole means of reaching the then little known Wonderland along the deeply sunk Colorado.

After a fairly pleasant night, they had an early breakfast. The horses proved to be in fine fettle, and eager for the long gallop. So the two saddle boys once more started forth.

The day promised to be still warmer than the preceding one; and the first part of the journey presented some rather difficult problems. They managed to put the San Francisco Mountains behind them, however, and from that on the dash was for the most part over a fairly level plateau.

Now and then they were threading the trail through great pine forests, and again it was a mesa that opened up before them.

Bob was especially delighted.

"Think we'll make it, Frank?" he asked, about the middle of the afternoon, as they cantered along, side by side, the horses by this time having had pretty much all their "ginger" as Bob called it taken out of them, though still able to respond to a sudden emergency, had one arisen.

"I reckon so," replied the other. "According to my map we're within striking distance right now. Given two more hours, and we'll possibly sight the border of the big hole. That was Red Horse Tank we just pa.s.sed, you know," and he pointed out their position on the little chart to Bob.

It was half an hour to sundown when the well known Grand View Hotel stood out in plain sight before them; and before the shades of night commenced to fall, the tired boys had thrown themselves from their saddles, seen to the comfort of the faithful steeds, and mounted to the porch of the hotel for a flitting view of the amazing spectacle that spread itself before them, ere darkness hid its wonderful and majestic beauty.

CHAPTER XII

HOW THE LITTLE TRAP WORKED

"What do you think of it?" asked Frank, after they had stood there a short time, taking in the picture as seen in the late afternoon.

"It's hard to tell," Bob replied slowly. "It's so terribly big, that a fellow ought to take his time letting the thing soak in. That further wall looks as if you could throw a stone over to it; and yet they say it's more than a mile from here."

"Yes," Frank went on, "and all along in the Grand Canyon there are what seem to be little hills, every one of which is a mountain in itself.

They only look small in comparison with the tremendous size of the biggest gap in the whole world."

"And how far does this thing run--is it fifty miles in length?" Bob asked.

"I understand that the river runs through this canyon over two hundred miles," the other replied. "And all the way there are scores, if not hundreds, of smaller canyons and 'washes,' reaching out like the fingers of a whopping big hand; or the feelers of a centipede."

"That's what I read about it away back; but I had forgotten," Bob remarked. "And they say that it would be a year's trip to try and follow the Grand Canyon all the way down from beginning to end, only on one side."

"I reckon it would, for you'd have to trace every one of these lateral gashes up to its source, so as to cross over. And that would mean thousands of miles to be covered."

"Gee!" exclaimed Bob, throwing up his hands as he spoke; "when you say that, it makes a fellow have some little idea of the size of this hole.

And to think it's come just by the river eating away the soil!"

"They call that erosion," remarked Frank, who had of course posted himself on many of these facts, during his previous visit to the canyons of the Little Colorado. "It's been going on for untold thousands of years; and as the river with its tributaries has gradually eaten away the soil and rocks, it has left the grandest pictured and colored walls ever seen in any part of this old earth."

"When that afternoon sun shines on the red rocks it makes them look almost like blood," declared Bob. "And already I'm glad we came. I think just now I could be happy spending months prowling around here, finding new pictures every day."

"Then you don't blame old Uncle Felix for staying, do you?" laughed Frank.

"Sure I don't," returned the other lad, with vehemence. "And besides, you must remember that he had another string to his bow."

"Meaning his craze to be the fortunate man of science to unravel the mystery that has always hung over the homes of those cliff dwellers?"