Page:Tom Swift and His Airship.djvu/59

Rh persons who go into a thin air for the first time; just as if you had climbed a high mountain. Breathe as slowly as you can, and swallow frequently. That will relieve the pressure on your ear drums. I'll send the ship lower."

Tom did as he was advised, and the aeronaut, deflecting the rudder, sent the Red Cloud on a downward slant. Tom at once felt relieved, both because the action of swallowing equalized the pressure on the ear drums, and because the airship was soon in a more dense atmosphere, more like that of the earth.

"How are you now?" asked the man of the lad, as the craft was again on an even keel.

"All right," replied Tom, briskly. "I didn't know what ailed me at first."

"I was troubled the same way when I first went up in a balloon," commented Mr. Sharp. "We'll run along for a few miles, at an elevation of about five hundred feet, and then we'll go to within a hundred feet of the earth, and see how the Red Cloud behaves under different conditions. Take a look below and see what you think of it."

Tom looked low, through one of several plate-glass windows in the floor of the car. He gave a gasp of astonishment.

"Why! We're right over Lake Carlopa!" he gasped.