He looked at his map to make sure.  It was one that he had specially plotted out himself from observations he had made when flying in the vicinity.  Having verified their whereabouts he found that they had flown about fifty miles, possibly a fraction more.

But at this juncture he noticed that the voice of his father pulsing through space began to grow thin and weak.  Obviously the limit of the radio ’phone’s capacity had been reached.

“Better turn back,” said Mr. Chadwick.

Jack turned to Tom and gave him the necessary instructions.  Then he set over his guiding wheel, turning the big rudder at the stern of the Wondership and she acted as obediently as a sea-going craft answering her helm.  Never had she behaved better.

They flew swiftly back toward High Towers and were soon in sight of Rayburn.  In order to test what effect the magnetism of the earth had upon the radio messages, Jack brought the great flying craft close to the ground.  They almost grazed the treetops as they flew along.

Skimming a patch of trees they roared above a farmhouse with a great red barn adjoining it.  The barn attracted Jack’s attention because of the fact that it had a flat roof, an almost unique feature in that part of the country.  He supposed it was used to dry some sort of produce on and noted that there were several hop-fields near at hand.  Undoubtedly the roof was used for exposing them to the sun and thus drying the moisture from them without the expense of wood for the drying fires usually used for the purpose.

He had hardly noted all this when there came a sudden tug at the Wondership as if a titanic hand had reached up from below and grasped her.  She pitched wildly and, but for Jack’s skill as an airman, there might have been a serious accident.  But he brought the big craft under control by skillful manipulation.

The next instant he discovered what had occurred.  The grapple of the aircraft had, in some way, dropped from its fastenings and, trailing behind the Wondership, had caught in the roof of the farmer’s barn.

A great section of it was torn away and as Jack brought the Wondership to rest on the roof, the only available place, for the rope was in danger of fouling the propellers if he descended to the ground, the farmer and a number of his men came running from the farmhouse.

In the hands of the farmer was a formidable looking shotgun.  As the Wondership settled on the roof of the barn the man began shouting angrily.

CHAPTER IX.

The boys face trouble.

“Phew! looks as if we are in for trouble,” exclaimed Tom, as he saw the warlike expression on the farmer’s face.

“It does that,” agreed Jack.  “Hop out, will you, Tom, and get that grapple clear?  Confound it, I don’t see how it came loose.”

“Wore through the lashing,” said Tom, who had been examining the place where the big hooked steel anchor was usually tied.