you ever forget that,” Pat grinned.

“Oh, I’ll be game, all right,” was the reply.

Before leaving the beach for the camp the boys walked to the point around which the boat had gone and scanned the lake and its shores through the field-glass. There was no sign of life anywhere, except where the birds swung from forest limbs back from the rim of the lake and called each other through the sultry air.

Reaching the camp after a weary climb, they did full justice to the meal which Pat had prepared, though the bacon and the hoecakes were stone cold, or at least as cold as anything could be in that glare of sunlight. Then, the dishes washed and the beds prepared for the night, they sat down to watch the lake and the sky to the south, for it was now the general belief that Ned would make his appearance with the aeroplane which had been promised by the government officials.

The point they had last visited, as well as the location of the fire, was in full view of the plateau, so the boys made no efforts to conceal their presence there. The men who had been observed in the boat must have noted their presence on the plateau before taking their leave. Perhaps, they reasoned, they had taken their departure because of this invasion.

The sun sank lower and lower in the sky, turning the plateau and the smooth waters of the lake to gold, still there were no signs of Ned, no indications of the return of the boat to the place from which it had been launched. Half an hour after dark, Frank, who was looking through the field-glass, caught sight of light in the south which did not appear to come from any star.

“Here he comes!” he cried. “That’s an aeroplane, all right!”

As the light drew nearer, traveling rapidly, the sharp explosions of the gasoline engine became audible. Then a light flickered over the upper plane, passed off, and swept the white surface again.

“How does he make that?” demanded Pat. “Looks like a great question mark.”

“That’s what it is,” Frank exclaimed. “Now, what does he mean by it?”

Chapter III.—JUST A TYPEWRITER RIBBON.

“I don’t understand what question he is asking,” Jack said, “but I know how he makes the signal. He has an electric flashlight, and he tips the plane—the upper plane—forward, like he was plunging to the earth, and writes the interrogation mark on the under side with the flame of the flashlight. See? Then it shines through the canvas and we read it! Great idea!”

“That must be the way of it,” Frank said, “but what does he want? And how does he expect us to answer?”

“If I was up there in the dark on a contraption like that,” Pat said, “I’d be asking how I was going to find a landing place.”

“Sure!” Frank cried. “Ned wants to know where we are, and whether it is safe for him to make a landing. Dunderheads! Why didn’t we think of that before? He is passing now, and may not come back again.”

The light flashed by at swift speed, whirled, ascended several hundred feet, and came over the plateau, repeating the signal. Then it settled down into a steady circling of the camp.

“He knows where we are, all right,” Pat said. “What he wants to know is if it is safe for him to make a landing. If I ever go up in one of those things I’ll drag a rope so I can climb down it.”

“I’ll tell him what he wants to know,” Frank said, “if you’ll get me a long stick on fire most of its length.”

“Wigwag?” asked Jack.

“Sure!” was the reply. “Now,” Frank continued, “build four fires, one on each edge of the plateau. That will show him how large the place is. Then I’ll take the flaming stick and wigwag o.k. Ned’ll understand that.”

Pat watched the wigwag signal with interest.

“I saw foolish signs like those in the Philippines,” he said, with a grin. “The natives use them to talk treason to each other. I’ve heard that the same method is used by the East Indians who talk from one mountain top to another faster than words on a wire. How does he make the o.k. signal?”

“O is one left, followed by one right,” Jack replied, “and k is left, right, left, right. You won’t think the signs are foolish when you see how quickly Ned reads them. See! He’s shooting away now.”

“Perhaps he thinks the signals are being made by savages,” Pat said.

The aeroplane darted off to the west for half a minute, then whirled and came back. The boys could not see the great ’plane distinctly, but the lights which burned on the front were bright and clear, so they saw that the ’plane was sweeping toward the earth as it advanced in their direction.

“I don’t believe many professionals would care to make a landing like this,” Frank said, as the machine dipped and slid to the ground, exactly in the center of the plateau.

“Hello, Ned!” he yelled, as the aeroplane rolled over the smooth surface for an instant and stopped.

In a second the three boys were gathered about the machine, pulling at the hands and feet of the daring riders. Jimmie McGraw bounded to the ground as soon as he could cast off the lines which had held him to his quivering seat.

“Say,” he cried, “you got a fire here? I’m most froze.”

Indeed the little fellow’s teeth were chattering.

“Cold?” echoed Pat. “We’re melting down here. You’re scared, that’s what’s the matter with you. You’re scared stiff.”

Jimmie made a run for the speaker but brought up at the fire where the supper had been cooked.

“Here’s comfort!” he cried, extending his hands out over what was left of the small blaze. “The next time you get me up in the air I don’t go! I’ve been freezing for an hour.”

In the meantime Ned Nestor was caring for the aeroplane, looking after the delicate machinery and covering it carefully with a huge oil-cloth. Pat stood watching the work with a grin on his face.

“Are you thinking of giving me a ride in that thing?” he asked.

“Not to-night!” laughed Ned.

“Well, when you get ready for me to ride the air,” Pat said, “just tell me the night before, and I’ll shoo myself into the hills. If I’m going to fall off anything, I’ll take the drop from something solid, like a mountain top.”

“No danger at all, when you know how to operate the machine,” Ned replied. “There’s danger in running anything if you don’t know how, even a sewing machine.”

“Where did you pick it up?” asked Frank.

“He didn’t pick it up at all,” interposed Pat. “It picked him up.”

“I found it at Missoula,” was the reply, “all packed and stored away in a freight warehouse. I had to get it out at night, and so lost time. The people would have kept me there until now giving exhibitions if I had shown up during the day.”

“But you did leave there in the daytime,” urged Jack. “You were never in the air since last night.”

“We left early this morning,” was the reply, “and I was well up in the sky before many of the people saw me.”

“I never knew you could run one,” Frank said.

“Oh, I had some instructions from the Wrights,” was the modest reply, “and, besides, there was an expert at Missoula who helped me get the machine together and contributed a few parting instructions.”

“Then you’ve been in the air all day?” asked Pat.

“No, we stopped several times, of course, once on the right of way of the Great Northern railroad and filled our gasoline tanks,” was the