omatic, and as nearly "error proof" as anything controlled by
human beings can be. That is to say it was planned that no vessel
could proceed into a lock until the fender chain was lowered, and
that an upper gate could not be opened until a lower one was
closed. But in this case something went wrong, and the two gates
were opened at once, letting out the flood.

This, however, had been foreseen, and the emergency dam provided,
and it was this solid steel wall that had saved the lock from
serious damage, and the _Bohio_ from being overwhelmed.

As it was no harm had been done and, when the excitement had
calmed down, and an inspection made to ascertain that the gates
would now work perfectly, the tug was allowed to proceed.

"Well, what are your plans now, boys?" asked Mr. Alcando on the
day after the lock accident.

"Back to Culebra Cut," answered Blake. "We have orders to get a
picture of a big slide there, and we're going to do it."

"Even if you have to make the slide yourself?" asked the Spaniard
with a short laugh.

"Not much!" exclaimed Blake. "I'd do a good deal to get the kind
of moving pictures they want, but nothing like that. There have
been some rains of late, however, and if things happen as they
often have before in the Cut there may be a slide."

"Yes, they do follow rains, so I am told," went on the Spaniard.
"Well, I do not wish your Canal any bad luck, but if a slide does
occur I hope it will come when you can get views of it."

"In the daytime, and not at night," suggested Joe.

For several days nothing of interest occurred. Blake and Joe sent
back to New York the films of the mad rush of waters through the
lock, and also dispatched other views they had taken. They had
gone to Culebra Cut and there tied up, waiting for a slide that
might come at any time, and yet which might never occur. Naturally
if the canal engineers could have had their way they would have
preferred never to see another avalanche of earth descend.

Mr. Alcando had by this time proved that he could take moving
pictures almost as well as could the boys. Of course this filming
of nature was not all there was to the business. It was quite
another matter to make views of theatrical scenes, or to film the
scene of an indoor and outdoor drama.

"But I do not need any of that for my purpose," explained Mr.
Alcando. "I just want to know how to get pictures that will help
develope our railroad business."

"You know that pret