Jack, of course, was the one who laid out the plan of campaign, he being much better fitted for such essential matters. Perk on the other hand really needed some one above to give him the order and check his impulsiveness on occasion. So they got on together admirably, and worked like a well matched team.

To be sure Jack sometimes knew a bit more than he chose to tell Perk but he always had good and sufficient reasons for holding back such information and his lack of knowledge, until such time as his leader saw fit to take him wholly into his confidence, did Perk no harm whatever.

It did, however, cause him to lie awake nights wondering and speculating as to what would be next on the program. He would try his best to tempt Jack to commit himself but all to no purpose, for the other put him off with one plea or another with Perk returning to the attack time and again.

They had had their wonderfully efficient plane lodged in a hangar out at the flying field where just so often each day an air-mail pilot was scheduled to arrive or depart with the letter sacks of the Post Office Department. This courtesy had been bestowed upon them by a Mr. Spencer Gibbons a private flyer and a man of considerable means who came and went as his fancy dictated.

He had met Jack while the latter, under strict injunctions from the Department, was posing as a young and enthusiastic air-minded millionaire and had given him the use of the single-ship hangar while he, Gibbons, was off on a jaunt that took him down to the Mexican border, but as he was expected back at any time now they had changed the location of their amphibian that same afternoon. It now rested secure in another nearby hangar that happened to be empty and which Jack could hire, being liberally supplied with funds by his generous employer, Uncle Sam.

This was only a minor incident, and yet it was fated to play an important part in the general network of things, and hence to be the cause of many speculations on the part of the two chums.

Perk, acting under the direction of his mate, had taken a vast amount of pleasure in loading up a supply of commodities. These consisted of the ordinary supplies, such as an old and experienced camper would be apt to put down on his list and possibly a few special dainties that particularly appealed to Perk’s appetite and which he meant to spring upon his fellow flyer at some convenient time when both of them happened to be ravenously hungry and there came a chance to build a cooking fire.

Then too, it was always their day by day plan to keep a full stock of fuel and lubricating oil aboard their boat since there never would be much warning given them when the order to hop-off came by telegraph.

They seldom allowed a favorable flying day to pass by without going aloft in order to keep in practice and also be certain the precious ship was in first class condition for immediate service. As they had not had possession of the wonder plane for any great length of time, Jack was always finding out some fresh discovery calculated to increase his admiration for his craft and evoke a volley of expressions from the voluble Perk.

The sun had already set and dusk was beginning to gather, telling them it was about time to descend to the dining room and partake of their customary evening meal. After that Perk would doubtless wander around to the nearest moving-picture palace and allow his feverish soul to have full swing in the excitement depicted on the silver screen.