roar of many propellers and the steady hum of a score of engines
combined to make a deafening noise. Nevertheless, when Tom felt a tug at
his sleeve, such as had been agreed upon with his chum, he took hold of
his little receiver and was delighted to hear Jack's voice as plainly as
though there had been no interference.

Plainly then Jack's idea was bearing fruit, and properly cultivated
there might be something worth while in the scheme.

"Tom, do you get me?" demanded the agitated inventor, the first thing.

"Yes, and plainly, too," came the reply that greatly pleased Jack; for
up to then they had found no occasion to test the wireless telephone
under severe conditions.

If it "made good" with all that noise about them, Jack felt that he
ought to call it a success.

"That's right!" he told Tom, exultantly. "I never missed a syllable that
time. Oh, boy! it seems as if it's O K, doesn't it?"

"Splendid thing for talking when you're rushing along; and without
cracking your voice, either," Tom told him.

"Did my bomb explode exactly at the same second as the other one?" next
asked Jack, more to continue the conversation and thrill with his
triumph than for information, because he had already made up his mind on
that score.

"Just what it did, Jack. But let up on this now. I've got to keep my
whole attention pinned to my work."

That often different minds run in the same channel is proved every day;
and in Jack's case it really turned out that while he was testing his
crude invention another much more eminent person in far-away America had
just succeeded in accomplishing the idea he had in mind, and was almost
ready to offer it to the Washington Signal Corps authorities.

After rejoining the squadron of battleplanes the old formation had been
resumed. A cordon of fighters moved on either side, one to each bombing
unit in the fleet. Just as transports were convoyed across the dread
submarine danger-zone of the Atlantic by destroyers and cruisers, so
these working planes were protected by those better equipped for holding
off intending offenders, and striking with all the strength of Uncle
Sam's good right arm.

It would not be for long, Tom believed. Straight as the honey bee heads
toward the hive when laden with sweets extracted from blossom and
flower, they were now aiming for their main objective, the last powerful
stronghold of the Hun in that sector, perhaps in all the extended battle
front.

Doubtless