, as
it seems to move at just the right rate of speed. We'll take a
short strip of film, Joe, I guess."

The tug did not occupy a whole section of the lock, for they are
built to accommodate vessels a thousand feet long. To economize
time in filling up such a great tank as that would be the locks
are subdivided by gates into small tanks for small vessels.

"It takes just forty-six gates for all the locks," explained
Captain Watson, while Blake and Joe were getting their camera in
position, and the men at the locks were closing certain water
valves and opening others. "Each lock has two leaves, or gates,
and their weight runs anywhere from three hundred to six hundred
tons, according to its position. Some of the gates are forty-seven
feet high, and others nearly twice that, and each leaf is
sixty-five feet wide, and seven feet thick."

"Think of being crushed between two steel gates, of six hundred
tons each, eighty feet high, sixty-five feet wide and seven feet
thick," observed Joe.

"I don't want to think of it!" laughed Blake. "We are well out of
that," and he glanced back toward the closed and water-tight lock
gates which had so nearly nipped the tug.

"Here comes the water!" cried the captain. There was a hissing and
gurgling sound, and millions of bubbles began to show on the
surface of the limpid fluid in which floated the _Nama_. The water
came in from below, through the seventy openings in the floor of
each lock, being admitted by means of pipes and culverts from the
upper level.

As the water hissed, boiled and bubbled while it flowed in Blake
took moving pictures of it. Slowly the _Nama_ rose. Higher and
higher she went until finally she was raised as high as that
section of the lock would lift her. She went up at the rate of two
feet a minute, though Captain Watson explained that when there was
need of hurry the rate could be three feet a minute.

"And we have two more locks to go through?" asked Joe.

"Yes, two more here at Gatun, and three at Miraflores; or, rather,
there is one lock at Pedro Miguel, where we go down thirty and a
third feet, and then we go a mile to reach the locks at
Miraflores.

"There we shall have to go through two locks, with a total drop of
fifty-four and two-thirds feet," Captain Watson explained. "The
system is the same at each place."

The tug was now resting easily in the basin, but some feet above
the sea level. Blake and Joe had taken enough moving pictures of
th