least for some time, neither Tom nor Ned mentioned the
matters they had been discussing--Tom's failure to enlist, his
exemption, and what was being built in the closely guarded shop.

Tom's business in Sackett did not take him long, and then he and Ned
went for a little ride in the air.

"It's like old times!" exclaimed Ned, his eyes shining, though Tom
could not see them for two reasons. One was that Ned was sitting behind
him, and the other was that Ned wore heavy goggles, as did the young
pilot. Also, they had to carry on their talk through the speaking tube
arrangement.

"Yes, it is a bit like old times," agreed Tom. "We've had some great
old experiences together, Ned, haven't we?"

"We surely have! I wonder if we'll have any more? When we were in the
submarine, and in your big airship Say, that big one is the one I
always liked! I like big things."

"Do you?" asked Tom. "Well, maybe, when I get--"

But Tom did not finish, for the Hawk unexpectedly poked her nose into
an empty pocket in the air just then, and needed a firm hand on the
controls. Furthermore, Tom decided against making the confidence that
was on the tip of his tongue.

At last the aircraft was straightened out and the pilot guided her on
toward the army encampment.

"That's the place I'd like to be," called Ned through the tube as the
faint, sweet notes of a bugle floated up from the parade ground.

"Yes, it would be great," admitted Tom. "But there are other things to
do for Uncle Sam besides wearing khaki."

"Tom's up to some game," mused Ned. "I mustn't judge him too hastily,
or I might make a mistake. And Mary mustn't, either. I'll tell her so."

For Mary Nestor had spoken to Ned concerning Tom, and the curiously
secretive air about certain of his activities. And the girl, moreover,
had spoken rather coldly of her friend. Ned did not like this. It was
not like Mary and Tom to be at odds.

Once more the Hawk came to the ground, this time near the airship sheds
adjoining the Swift works. Just as Tom and Ned alighted, one of the
workmen summoned the young inventor toward the shop, which was so
closely guarded by Koku and Eradicate on the outside.

"I'll have to leave you, Ned," remarked Tom, as he turned away from his
chum. "There's a conference on about a new invention."

"Oh, that's all right. Business is business, you know. I've got some
bond calls to make myself. I'll see you later."

"Oh, by the way, Ned!" exclaimed Tom, turn