"We're going backward!" shouted Joe.
"Yes, the stern locomotives are pulling us back, and the front ones seem to have let go!" Captain Watson said. "We'll be between the lock gates in another minute. Hello, up there!" he yelled, looking toward the top of the lock wall. "What's the matter?"
Slowly the tug approached the closing lock gates. If she once got between them, moving as they were, she would be crushed like an eggshell. And it seemed that no power on earth could stop the movement of those great, steel leaves.
"This is terrible!" cried Mr. Alcando. "I did not count on this in learning to make moving pictures."
"You'll be in tighter places than this," said Blake, as he thought in a flash of the dangers he and Joe had run.
"What'll we do?" asked Joe, with a glance at his chum.
"Looks as though we'd have to swim for it if the boat is smashed," said Blake, who remained calm. "It won't be hard to do that. This is like a big swimming tank, anyhow, but if they let the other water in—"
He did not finish, but they knew what he meant. Slowly and irresistibly the great lock gates were closing and now the tug had almost been pulled back between them. She seemed likely to be crushed to splinters.