and in the bow and stern."

"You speak as though you, yourself, were going into a battle of
the air," said Ned.

"No, I don't believe I'll go that far," Tom replied. "Though,
if the government wants my craft, I may have to go aloft and fire
shots at targets for them to show them how things work.

"Please don't think that I am in favor of war, Ned," went on
Tom earnestly. "I hate it, and I wish the time would come when
all nations would disarm. But if the other countries are laying
themselves out to have aerial battleships, it is time the United
States did also. We must not be left behind, especially in view
of what is taking place in Europe."

"I suppose that's right," agreed Ned. "Have you any of your
guns ready?"

"Yes, all but the mounting of them on the supports aboard the
Mars. I haven't dared do that yet, and fire them, until I
provided some means of taking up the recoil. Now I'm going to get
right to work on that problem."

There was considerable detailed figuring and computation work
ahead of Tom Swift, and I will not weary you by going into the
details of higher mathematics. Even Ned lost interest after the
start of the problem, though he was interested when Tom took down
the door-check and began measuring the amount of force it would
take up, computing it on scales and spring balances.