"Did you roll off when you were learning?" asked Marco.
"Yes," said the man. "I've been off the log into the water many a time."
"And how did you get out again?" said Marco.
"Oh, I could swim," he replied; "and as soon as I came up, I would paddle back to the log, and climb up upon it. Once, however, I came very near being drowned."
"How was it?" said Marco.
"Why, I was on the upper side of a boom"——
"A boom?" said Marco, "what is that?"
"A boom!" repeated the millman; "don't you know what a boom is? It is a place to catch logs. They go to some cove or eddy, where the water is pretty still, and chain logs together, end to end, so as to form a long line on the lower side of the eddy, and then along up the middle of the river a little way, so as to enclose a space to catch the logs."
"What do they fasten the boom to?" asked Marco.
"Why, the lower end," said the millman, "is fastened to the shore, by means of a very strong post, or an iron staple set into the rocks. The other end, which is out in the middle of the stream, is fastened to some island, if there is one, or, if not, to a pier built up from the bottom."