Before they went to sleep that night all preparations had been concluded looking to getting out of the trap in the morning.  Frank had made his estimations and knew to a nicety just what his engine could do.  Once free from the valley he believed they could head direct for the distant Magdalena, carrying two passengers and making short flights.  It was true that as yet he had never taken up any second passenger and it entailed an additional tax upon the motor, but he had great faith in the little Kinkaid engine and felt that it would respond nobly to any additional demand made upon it.

But it would be advisable that he carry the professor out of the valley and land him on that plateau where they had made their last halt, ere going back for Andy.  Then, from that elevated place they could start on the return trip, with everything favorable for a successful flight.

The night passed at length, though it must have seemed interminable to Andy.  Frank knew that often his chum would rise up on his elbow and put out a hand gently, just to touch the form of his sleeping father close to him.  And Frank did not wonder at it, for there were times when even he found it difficult to realize that their remarkable mission had actually proven successful.

At length the day came.

They were early astir, for much remained to be done.  And there would needs be deft manipulation of the gallant little monoplane by its clever pilot, if two separate flights out of the enclosed valley were to be undertaken.

Finally all was ready.

The professor had really next to nothing he wished to bring away.  The valley had grown hateful to him because of his enforced stay and he never wanted to see it again.

He took his place in the seat usually occupied by Andy.  His face was grave, for he knew what risks they were running.  But surely the lad who had piloted the frail craft through so many perils would not fail now!

“Good-bye, both of you!” said Andy, beaming upon them, as he prepared to assist in the launching.  “Please don’t forget me down here and let me root, hog, or die for months.  Birds of a feather flock together, you know, so come back again, Frank.”

Then came the start.  It was anything but an easy job to get going in the small space allowed by the character of the valley, but Frank had figured it all out, measured the ground, removed such obstructions as promised to give trouble and had perfect confidence in his ability to make it.

And he did.

After that other ascent in the heart of the tropical forest he declared he did not mean to let anything appal him henceforth.

Once they started circling the valley, low down and just missing the tops of the trees growing there, Andy, sent vigorous whoops after them, and his father answered by waving his hand, for hat he had none.

So, guided by the master hand of Frank Bird, the aeroplane rose above the line of those hateful and cruel cliffs and for the first time since his captivity the man of science saw the blessed outside world again.