"And we're 'good men,' ain't--aren't we?" demanded Slim, drawing in his
stomach and throwing out his chest as he straightened up to his full
five-feet-four-inches "in his gym suit."

"None better anywhere," said Mr. Burton in a tone that showed he meant
it. "But just how do you contemplate going to the aid of your country?"

It was Joe's turn to say something, and he did. "By enlisting," he
announced, briefly but firmly.

"Yes," agreed Slim, "that's it, by enlisting."

"Uh-huh," said Jerry, nodding his head vigorously and watching Mr.
Burton's face for evidence of the effect of their decision.

"And when did you determine upon that?" the telegrapher asked, with
increasing interest.

"Well," said Slim, his face now painfully red from his efforts to keep
chest out and stomach in, "it was finally decided upon just now,
although we have talked about the thing in a general way many times."

"You really mean to enlist--all three of you?" Mr. Burton demanded.

"Yes, sir," they chorused, "all three."

"Good!" exclaimed the man who had been their friend and helper. "Fine!
I'm proud of you," and he proceeded to shake hands heartily with each in
turn.

"Have you decided upon the branch of the service you intend to enter?"
he then asked.

Joe looked at Jerry, Jerry looked at Slim, and Slim cast a helpless
glance back at Joe.

"I see you haven't," said Mr. Burton hastily, "and I'm glad of it. Now
how about the Signal Corps?"

"What do men in the Signal Corps do?" asked Jerry.

"Do they fight?" demanded Slim.

"Yes," Mr. Burton replied, "they do some fighting on their own account,
and often in tough places and against discouraging odds. But they do
even more than that. Without their assistance no general would dare lay
plans for a battle. The Signal Corps keeps the commanders posted, not
only as to the whereabouts and disposition of his own troops, but also
of those of the enemy. The Signal Corps is the telephone, the telegraph,
the wireless, and often the aviation section as well, of the American
army, and often of the American navy, too."

"Isn't that great?" exclaimed the breathless Slim, as Mr. Burton went
over to the ticker to answer the code call for his station.

During the ten minutes that he was engaged in receiving and sending
messages, the boys perfected plans for notifying their relatives of
their intention. Had their attention not been so entirely taken by the
subject under discussion they would have