It was impossible to foretell, of course, what obstacles to the carrying out of this daring proposal would arise.  Both boys felt certain, however, that so far they were not suspected, and that first Jack and then Frank had successfully thwarted the attempt of Morales to send a warning to the ranch by radio.

Neither was aware, of course, that the jumble of sounds through the air, when Jack from the airplane had interfered with Morales’ attempt to warn the ranch, and later the code conversation between Jack and Frank, after the latter had obtained possession of the radio plant in the cave and had overcome Morales, had aroused the curiosity and then the suspicions of the young German, Muller, who operated the radio plant at the Calomares ranch.

A few moments before the beat of its engine in the sky signalized the approach of the airplane, Muller had decided to go to the ranch and report to Calomares.  He had crossed the landing field afoot and had just reached the belt of trees when the machine volplaned to the field behind him.

Although, as has been said, his suspicions were aroused, Muller was far from suspecting the truth.  He had no idea the airplane had been recovered by its rightful owners and that these latter were about to make a daring attempt to rescue Mr. Hampton.  His thought on the contrary, was that something—­he could not make a more definite surmise—­had gone wrong at the cave.

Therefore, when, after standing several minutes at the belt of trees, gazing back toward the airplane, he saw a figure start from it for the ranch house, he believed it was either Von Arnheim or Morales coming to report.

Muller was a sycophant, the type of man eager to curry favor with those in authority.  He decided he would gain the ear of the great Calomares first.  That would detract somewhat from the glory of the other when he arrived.  Turning he darted for the ranch.

Meantime, Jack was making his way ahead more slowly.  While not attempting to hide, he was on unfamiliar ground and felt that it behooved him to follow implicitly the directions given by Roy Stone and make no mistakes.

Passing through the grove, Jack came in sight of the ranch.  He paused in astonishment.  Roy Stone’s description of the great house had prepared him in a measure.  Yet he was astounded.  Here, indeed, was a palace in the wilderness.

The mansion stood on a slight elevation with a lawn in front sloping down to the trees from which Jack had emerged.  In design it was like a country house of the ancient Roman aristocracy.  The walls were of vari-colored brick with inlaid designs representing formal flowers.  Two stories in height, with towers at the corners rising another two stories higher, the building was in two wings or sections, joined in front by a marble-tiled walk, roofed and pillared, but with the sides open.  Inside, between these two wings, Roy Stone had told Jack, was an open court.