sometimes when an elevator descends quickly from a great height.
There is too much outside air pressure on the ear drums. By
opening your mouth and swallowing rapidly, the pressure is nearly
equaled, and you feel no discomfort."

The boys tried this when the next big gun was fired, and they
found it true. They noticed quite a crowd of officers and men
about a certain large barbette, and Captain Badger led them in
that direction.

"Is that General Wailer's gun?" asked Tom.

"That's where they are going to test it," was the answer.

Eagerly Tom and Ned pressed forward. No one of the many
officers and soldiers grouped about the new cannon seemed to
notice them. A tall man, who seemed very nervous and excited, was
hurrying here and there, giving orders rapidly.

"How is that range now?" he asked. "Let me take a look! Are you
sure the patrol vessels are far enough out? I think this
projectile is going farther than any of you gentlemen have
calculated."

"I believe we have correctly estimated the distance," answered
someone, and the two entered into a discussion.

"That excited officer is General Wailer," explained Captain
Badger, in a low voice, to Tom and Ned.