at them, and said 'Contract!' It was like a fellow saying 'Baa!' to
sheep. Why, those fellows just sneaked away. We've beaten them at
every angle, Dave, and I reckon they'll give up their meanness now,
and quickly fade away."

"It would be a good thing for honest aeronautics if they would,"
growled old Grimshaw.

"We'll hasten them with a little help, if they try any more tricks,"
announced Mr. King.

The hydroplane had been run into a boat house after the practice of
the day previous, and was all ready for use. It was equipped to
carry two or more passengers, and was driven by a fifty horse power
motor. It had two propellers, and these were controlled by chain
transmission.

Old Grimshaw had not much use for hydroplanes, he had told Dave.
His hobby was air machines. However, because his favorite pupil was
going to run the machine, he allowed Dave to explain about the
hydroplane, and was quite interested.

The machine had a bulkhead fore and aft, with an upward slope in
front and a downward slope to the rear.

"It's safe, comfortable, and quick to rise to control," declared
Dave. "See, Mr. Grimshaw, there's a new wrinkle."

Dave touched a little device attached to the flywheel. The latter
was made with teeth to fit into another gear, operated from a shaft.