But the lock canal was decided on, and, had it not been, it is probable that the Canal would be in process of making for many years yet to come, instead of being finished now.
"Whew!" whistled Joe, as they came in sight of the dam. "That sure is going some!"
"That's what it is!" cried Captain Watson, proudly, for he had had a small part in the work. "It's a mile and a half long, half a mile thick at the base, three hundred feet through at the waterline, and on top a third of that."
"How high is it?" asked Joe, who always liked to know just how big or how little an object was. He had a great head for figures.
"It's one hundred and five feet high," the captain informed him, "and it contains enough concrete so that if it were loaded into two-horse wagons it would make a procession over three times around the earth."
"Catch me! I'm going to faint!" cried Blake, staggered at the immensity of the figure.
"That dam is indeed the key to the whole lock," murmured Mr. Alcando, as he looked at the wonderful piece of engineering. "If it were to break—the Canal would be ruined."
"Yes, ruined, or at least destroyed for many years," said Captain Watson solemnly. "But it is impossible for the dam to break of itself. No waters that could come into the lake could tear it away, for every provision has been made for floods. They would be harmless."
"What about an earthquake?" asked Joe. "I've read that the engineers feared them."
"They don't now," said the captain. "There was some talk, at first, of an earthquake, or a volcanic eruption, destroying the dam, but Panama has not been visited by a destructive earthquake in so long that the danger need not be considered. And there are no volcanoes near enough to do any harm. It is true, there might be a slight earthquake shock, but the dam would stand that. The only thing that might endanger it would be a blast of dynamite."