should say so!" cried Mr. Damon, for he was standing
outside the pilot-house just then, on the "bridge," and the sudden
increase of speed lifted his hat from his head.

"There you are--caught on the fly!" cried Ned, as he put up his hand
just in time to catch the article in question.

"Thanks! Guess I'd better tie it fast," remarked the odd man, putting
his hat on tightly.

The aerial warship was put through several evolutions to test her
stability, and to each one she responded well, earning the praise of
the government officer. Up and down, to one side and the other, around
in big circles, and even reversing, Tom sent his craft with a true hand
and eye. In a speed test fifty-five miles was registered against a
slight wind, and the young inventor said he knew he could do better
than that as soon as some of the machinery was running more smoothly.

"And now suppose we get ready for the gun tests," suggested Tom, when
they had been running for about an hour.

"That's what I'm mostly interested in," said Lieutenant Marbury. "It's
easy enough to get several good types of dirigible balloons, but few of
them will stand having a gun fired from them, to say nothing of several
guns."

"Well, I'm not making any rash promises," Tom went on, "but I think we
can turn the trick."

The armament of the Mars was located around the center cabin. There
were two large guns, fore and aft, throwing a four-inch projectile, and
two smaller calibered quick-firers on either beam. The guns were
mounted on pedestals that enabled the weapons to fire in almost any
direction, save straight up, and of course the balloon bag being above
them prevented this. However, there was an arrangement whereby a small
automatic quick-firer could be sent up to a platform built on top of
the gas envelope itself, and a man stationed there could shoot at a
rival airship directly overhead.

But the main deck guns could be elevated to an angle of nearly
forty-five degrees, so they could take care of nearly any hostile
aircraft that approached.

"But where are the bombs I heard you speaking of?" asked Ned, as they
finished looking at the guns.

"Here they are," spoke Tom, as he pointed to a space in the middle of
the main cabin floor. He lifted a brass plate, and disclosed three
holes, covered with a strong wire netting that could be removed. "The
bombs will be dropped through those holes," explained the young
inventor, "being released by a magnetic contro