glad to see you."

"Me play you back," said Wab Lee.

"Pay back nothing," responded Bert. "You don't owe us anything. You've
worked your passage, all right."

"Me play you back," he repeated, as calmly as though they had not
protested, and pattered off, after including them all in his irresistible
smile.

"And he will," affirmed Dick, despairingly. "We're just clay in the
hands of the potter, when we come up against that old heathen. If he
says he'll pay you back, paid back you'll be, as surely as my name is
Dick Trent."

Which proved to be true enough, although the payment was made in
different coin and in an other fashion than they dreamed of at the
moment.

Two days later, bright and early they took the train on the little
railroad that runs from Colon to Panama. Their first stop was to be at
the Gatun Dam and Locks, the mightiest structure of its kind in the
world.

As they came in sight of it, the boys gasped in amazement and admiration.
What they had read about it in cold type, had utterly failed to give
them an adequate idea of the reality. Here was a work that might have
been hammered out by Thor. There were the mighty gates, weighing each,
from three hundred to six hundred tons. The locks each had four gates,
seven feet thick and from forty-seven to seventy-nine feet high. The
gates were operated by electricity and open or shut in less than two
minutes, and absolutely without noise.

In these locks were three chambers, lower, middle and upper. Each was a
thousand feet Long, one hundred and ten feet wide and eighty-one feet
deep. As the vessel enters the lower chamber, it finds there a depth of
over forty feet. The gate is closed and the water pours in, lifting the
vessel as it rises. In fifteen minutes, the water rises over
twenty-eight feet. Now the ship has reached the middle chamber, and
again the gates are closed and the process repeated. The upper chamber
is the last stage, and then the vessel reaches the artificial lake of
Gatum. It has climbed eighty-five feet in about ninety minutes.

"Just like climbing a flight of stairs," exclaimed Dick.

"Precisely," said Bert. "Where a train climbs a mountain by a steady
grade, the vessel leaps up to the top in three jumps."

"Think of trying to lift one of those enormous vessels with a derrick or
a crane," murmured Tom; "and yet how gently and easily the water does it
by pushing up from underneath."

"Look at the width of those con