"And their curiosity, too!" put in Tom. "I'll stake my last cent they're just as much in the dark about us and the Sky-Bird II as we are about their outfit."

"We'll hope so, anyhow," remarked Bob; "but ever since we had those blue-prints stolen, and found we had a stranger sneaking around the hangar, I've been uneasy."

At this reference, all the young men felt a strange oppression. They had talked over it more than once, and each time it had left them with a sense of peril to their interests, why they could not tell. As before, they now tried to laugh it off, and began to talk about other subjects.

There was still considerable to do in the way of preparing the Sky-Bird and themselves for the long trip, and for weeks all four boys were kept hustling to make the final installations of accessories and equipment. Bob rigged up a wireless telegraph in connection with his telephone set, and for protection, four good repeating rifles and an automatic shotgun were put in racks in the after-cabin, while each fellow provided himself with an automatic revolver which he would carry in a holster attached to a belt. Medium-weight flying suits, with a heavy, wool-lined coat to slip on in case they flew very high, and trim flying boots and soft gloves, made up the personal toggery.

Whenever the boys found a chance they went to the public library and absorbed all the knowledge they could about the countries over which they would pass and the places at which they were destined to stop. By writing to the authorities in these localities, Mr. Giddings also secured much valuable information for them as to present weather conditions and landing-fields—information which was further supplemented by numerous special airway maps supplied by the Aero Club of America and similar aviation organizations in foreign countries. From these maps Paul worked out a very clear chart of their own course from beginning to end. A copy was given to each of the newspaper publishers concerned, to reproduce on their large electric street boards, and another was framed and placed immediately in front of the pilot's seat in the cabin of the Sky-Bird II.

All this time the columns of the Daily Independent and the Clarion contained frequent vivid references to features of the trip calculated to awaken the interest of the public, and as the time slipped along into July, the attention of people all over the land was centered upon the forthcoming contest, and it became the principal subject for comment. The secrecy maintained by both principals as to the kind of aircraft to be used, and the mystery as to identity of the members of the respective crews, only whetted curiosity and interest the more, as the sharp newspaper men knew it would. Every man, woman, and child in the wide world seemed to be eagerly waiting for the moment to come when he or she would see the promised pictures of the bold aviators and their machines in the big newspapers, and hear that they had made their first jump eastward from Panama.

All being in readiness, at daybreak on the morning of July 16th the Ross boys and Tom Meeks appeared at the Sky-Bird's hangar, and pushed the airplane outside. As they were doing so, Mr. Giddings and Bob joined them. The publisher had planned to accompany his crew to Panama in the machine, to see them officially off, while his reporters made the journey by train, in company with the writing force of the rival paper.

"We'll keep the time of our going secret, leaving before people are generally up," Mr. Giddings had said to the boys; "and by going on the 16th we'll not only be ahead of their smart calculations, but we shall have about half a week to rest up and see the country down there before you begin your strenuous journey. I need a little vacation anyway, so I will accompany you. We will stop off at Miami on the way, and enjoy some big-game fishing in the Florida waters with some of my friends."

So the young men were very much excited and eager to be off this morning of the 16th, you may be sure. The Sky-Bird was tuned up a little to make certain she was in first-class condition, then they all climbed in and the big glistening creature of wood, metal, and silk shot up into the air. It would probably be close to three weeks before they would see that familiar field and hangar again, and in that time if all went well they would circle the huge globe upon which they and their fellow-men lived. It was truly a most inspiring thought—one to have filled less phlegmatic blood than theirs with the wildest pulsations!

The weather was not at all promising, masses of gray nimbus-cloud threatening to shut out the sun as it arose, with a promise of uncertain winds, if not rain; but John and Tom declared the conditions all the better for giving the machine a good test-out.