ull of pity for them. For himself, Jack Benson
appeared to have no especial feeling. Then the young commanding
officer went back into the engine room, closing the door after him.

"What did he shut the door for?" asked Jetson.

"Probably they're going to do something, in there, that will call
for a good deal of physical exertion."

"Well, what of that?" demanded Jetson, not seeing the point.

"Why," Dave explained, "a man at laborious physical work uses up
more air than a man who is keeping quiet. If the three officers
are going to work hard in there then they've closed the door in
order not to deprive us of air."

"We called them kids, at first," spoke Dan

Dalzell ruefully, "but they're a mighty fine lot of real men, those
three acting Naval officers."

Dave Darrin rose and walked over to the engine room, opening the
door and looking in. Hal and Eph were hard at work over the motor,
while Lieutenant Jack Benson, with his hand in his pockets, stood
watching their efforts.

"I beg your pardon, sir," said Darrin, saluting, "but did you close
this door in order to leave more air to us?"

"Yes," answered Jack Benson. "Go back and sit down."

"I hope you won't think us mutinous, sir," Darrin returned steadily,
"but we don't want any more than our share of whatever air is left
on board this craft. We belong to the Navy, too."

From the after end of the cabin came an approving grunt. It was
here that the cook and the four seamen had gathered.

With the door open the midshipmen could see what was going on
forward, and they watched with intense fascination.

Eph Somers had taken 'the too-thin copper' plate to the work-bench,
and had worked hard over it, trying to devise some way of making
it fit so that it would perform its function in the motor. Now,
he and Hal Hastings struggled and contrived with it. Every time
that the pair of submarine boys thought they had the motor possibly
ready to run Hal tried to start the motor. Yet he just as often
failed to get a single movement from the mechanism.

"I reckon you might about as well give it up," remarked Lieutenant
Jack Benson coolly.

"What's the use of giving up," Eph demanded, "as long as there's
any life left in us?"

"I mean," the young lieutenant explained, "that you'd better give
up this particular attempt and make a try at something else."

"All right, if you see anything else that we can do," proposed
Eph dryly. "Say, here's a quarter to pa