"I understand," Tom answered. "And I am going to begin work on mounting the guns at once. I am going to use the Newton recoil check," he added. "Ned, here, is responsible for that."
"Is that so?" asked the lieutenant, as Tom clapped his chum on the back.
"Yes, that's his invention."
"Oh, it isn't anything of the sort," Ned objected. "I just—"
"Yes, he just happened to solve the problem for me!" interrupted Tom, as he told the story of the door-spring.
"A good idea!" commented Lieutenant Marbury.
Tom then briefly described the principle on which his aerial warship would work, explaining how the lifting gas would raise it, with its load of crew, guns and explosives, high into the air; how it could then be sent ahead, backward, to either side, or around in a circle, by means of the propellers and the rudders, and how it could be raised or lowered, either by rudders or by forcing more gas into the lifting bags, or by letting some of the vapor out.
And, while this was being done by the pilot or captain in charge, the crew could be manning the guns with which hostile airships would be attacked, and bombs dropped on the forts or battleships of the enemy.
"It seems very complete," observed the lieutenant. "I shall be glad when I can give it an official test."
"Which ought to be in about a week," Tom said. "Meanwhile I shall be glad if you will be my guest here."