"Yes," replied Dave, "it's the lake."

"Lake Superior! Dave, are we going to cross it?"

"A good many times in the future probably, but not tonight. I am looking for a revolving light west of the city, right along the coast."

"I'll keep a lookout, too."

The lake was here and there dotted with the signal lights of steamers. Along the sh.o.r.e, which Dave skirted closely, various lights their met view. Both boys strained their gaze. Finally Hiram called out sharply: "I see it, Dave."

"See what?"

"A revolving light."

"Where?"

"See, just beyond that little cl.u.s.ter of town lights--quite high up."

"Yes," answered Dave in a tone of satisfaction. "That is Rocky Point lighthouse. I know my bearings, now."

"Are you going to land, Dave?"

"Presently."

"But you're driving out further over the lake."

"Just for a short distance, Hiram," advised Dave. "There's an island down sh.o.r.e where they run a smelter--ah, I think I locate it."

Dave was not mistaken. He came within range of some tall, stacks sending out sparks and flames. Now he changed his course. He kept his glance fixed below him and to the right as steadily as his duties at the lever would permit.

The Monarch II pa.s.sed over two small islands. Half a mile beyond them arose a third larger one. It was quite prominent, for the reason, that it presented a range of great cliffs. Dave navigated the air in narrowing circles. Then, timing and calculating a volplane glide, he let the machine down easily to the ground.

"Well!" e.j.a.c.u.l.a.t.ed Hiram, "you've hit on a pretty dark spot for a camp, Dave."

"And a safe one," replied the young aviator. "Mr. Alden described this place to me. It is called Desert Island, and has no inhabitants on it. It seems dark because we are so shut in, but your eyes will soon become used to that."

It was a singular place into which the Monarch II had descended.

High declivitous, ma.s.ses of rock formed a sort of immense cairn.

They seemed shut in on every side, fully one hundred feet below the level of the cliffs.

The farther north they had run the cooler air currents had become.

Both boys felt somewhat chilly.

"See here," spoke Hiram, after they had seen that the machine was all right and a rubber sheet thrown over the machinery to protect it from the heavy night dews, "a warm cup coffee wouldn't hurt us."

"That's right, Hiram," agreed Dave. "We are all shut in here, and even a big fire wouldn't show from the land or the deck of a pa.s.senger steamer. You can try your hand at coffee making, if you like."

"The coffee is all made, but cold, in these bottles," explained Hiram, fishing out two from the accommodation basket.

There were both trees and bushes near by. Hiram gathered some dry branches and roots and soon had a comfortable little campfire going. He poured out the coffee from the bottles into a tin water pail, and soon had it steaming hot. Sandwiches and some bakery stuff Dave had bought at Ironton made a very satisfactory meal.

Then they spread some wraps over a heap of dried gra.s.s, which they gathered up without much trouble. They rested in luxurious ease, watching the bright, snapping fire glow and feeling its genial warmth.

"Well, this is just like Robinson Crusoe, isn't it, Dave?" asked Hiram, with an air of great comfort.

"If you are a man Friday, then," rejoined the young aviator with a smile, "you scout around in the morning and see if there are any breaks in these great walls of rock shutting us in."

"Oh, then you're not counting an leaving here again by the air route?" inquired Hiram in some surprise.

"Not in daylight. I want to find some other way out for that. You see," explained Dave, "this is just an ideal spot as a rendezvous.

I want to get over to the city tomorrow, though, to attend to some important business."

"How are you going to get there?"

"Why, I'll have to trust to my swimming skill, I guess," replied Dave.

"Um-m," observed Hiram thoughtfully, and, if the young aviator had been more watchful, he would have noticed that for the rest of the evening his willing a.s.sistant seemed to have something on his mind.

CHAPTER XIX

THE SEARCHLIGHT

"Hallo! Hallo!"

Dave made the echoes ring with the loud call as he moved up and down and across the queer basin, or cairn, where they had landed in the Monarch II the night previous.

He had awakened just at daylight to find Hiram Dobbs mysteriously missing. Dave was not worried at the first, but as he looked around and then explored the immediate neighborhood, he began to get mystified, if not alarmed.

Neither did his vigorous shouting bring any response. Dave came back to the camp spot to make a new discovery that puzzled him. On the ground near where they had slept were Hiram's coat, vest, shoes and cap.

"Why, I can't understand this at all," mused the young aviator.

"Hiram couldn't have done much in the way of climbing up, he appears to be nowhere within hail, and he is not given to play tricks."

Dave did not wait to eat anything. He was really concerned about his comrade. He got a long tree branch, stripped it, and went along the side of the cairn, poking in and out among the dense dumps of shrubbery.

"h.e.l.lo," he exclaimed suddenly, as disturbing some vines he saw an opening, and not twenty feet away a natural rocky tunnel, "daylight, and the waves of the lake. I think I understand now."

Dave penetrated the pa.s.sage. As he came out at the other end, he found he faced a rock-strewn stretch of sand. The waves of the lake lapped this. In the distance he could make out Anseton, and nearer still, about a mile distant, the main sh.o.r.e.

The sh.o.r.e he was on terminated in a ridge of rocks that ran far out into the water. Dave wondered if the exploring spirit had moved Hiram to attempt an entire circle about the island.

"He went away in swimming trim," thought Dave, "so that may be so.

I'll go out on that ledge of rocks and explore a little myself."

"h.e.l.lo, Dave Dashaway!" sang out an exultant voice, just as Dave was about to remove his shoes.