Andy remained on guard at the door with his gun. He said he was going to take no more chances with the crazy machinist.
Nothing further had been seen or heard of the mysterious thief who had stolen the plates, and it was supposed that he was unable to make any use of them.
One afternoon, about three days before the time set to start for Mars, Mr. Roumann was working alone in the machine shop. The boys and Professor Henderson had done all there was for them to do, and the Annihilator was practically finished.
"Are you going to take along any extra–sized bullets, Andy?" asked Jack of the old hunter, who was on guard, as usual, at the door.
"I don't see why I should. I guess the regular ones will do when I get to Mars."
"I don't know about that," went on Jack. "We may find bigger game than elephants or sea lions there."
"If we do, I'll use a new kind of explosive electric bullet Mr. Roumann told me about," declared Andy. "It has a charge of electricity in it, and he says it will kill the biggest animal that ever lived, with one shot."
"Then you're all right," said Mark. "Well we'll soon be on our way now."
"I suppose Washington will want to take some of his chickens along?" ventured Jack.
"Well, I don't see why he can't," said Andy. "They take pigeons up in balloons, and I guess chickens would live in the Annihilator—at least, until we ate them."