“That’s so,” observed the other, scurrying around in search of things. “I’ve heard a high school teacher say it was not over seven hundred feet, as distance was so deceptive. And on the other hand, a surveyor who was used to judging distance told me he felt sure it would go much beyond a thousand feet. Now we’ll get a line on it, and the day of the race the facts will be known to a dead certainty.”

In a short time both air boys were ready for the flight.

“Put on your coat, Andy,” advised Frank, on seeing that his chum was about to take his place in his shirt sleeves. “While it’s oppressively hot down here, don’t you know that five hundred feet up the air will be chilly. And if we are moving at the rate of a mile a minute, you’ll be wishing you had your sweater on, mark my words.”

Andy smiled, but all the same he donned his coat. Frank knew, for there was precious little that escaped him. And Andy, as a rule, was quite satisfied to take pattern by his wide-awake cousin.

There were a few fellows hanging around. It was holiday time and on such a hot day they cared precious little for baseball or any other sport requiring exertion. In their minds it was much finer watching what the Bird boys would do next, for by now all of juvenile Bloomsbury had been seized with a severe attack of what Andy called “aviatus,” and numerous projects for building aircraft were being discussed in homes and on the commons.

As usual there was a whoop of pure delight from the gathered boys when the little monoplane started upward. None of them had been taken into the secret of what new stunts were to be undertaken, but they anticipated that Frank and Andy must have something up their sleeves—they looked so mysterious after that conference.

The aeroplane rose with not the slightest hitch. They were getting so accustomed to handling the machine by now that it seemed second nature to accomplish a successful rise. Indeed, as yet there had not been the slightest serious accident to alarm them, since the engine was cut off so suddenly on that first day.

After circling the field a few times at furious speed, “just to get his hand in,” as Frank said, the pilot turned the nose of the little flier straightaway in an easterly direction.

To their ears was borne the faint whoops from the cluster of envious boys left on the aviation field, as they realized what sort of new program the young aviators had on tap.

“How high are we now?” asked Andy, as he craned his neck and looked down upon the country that lay far below, and which was spread out for miles in all directions around them.