"It seems to me you don't hit on the easiest and simplest way of doing the job," interposed Mr. Brookbine. "How high will the posts of the boat-house be, Bolly?"
"About thirty feet."
"Very well; rest the posts on the bottom of the pond, where they will have a good foundation," added the master carpenter. "If you take a stick of timber and set it up endways in deep water, one half of it will be below the surface; and in four feet of depth nearly the whole weight of the stick would rest on the bottom. It seems to me this is the simplest way to do it!"
The boys looked at Bolly, and their expression seemed to say, "We have got you now!" But the amateur architect smiled as confidently as ever.
"That plan would do very well in Florida or the West Indies," he replied; whereat the corpulent civil engineer laughed out loud.
"Why not in Vermont?" demanded the carpenter, wondering what Mr. Bridges was laughing at.
"We sometimes have the thermometer twenty degrees below zero, and under the new boat-house the water may freeze to the bottom. When the ice expands, it will be likely to give three corners of the boat-house a lift which the fourth will not get on the solid rock shore. If all the posts were in the water it would be better."
Mr. Brookbine laughed with the civil engineer then, and admitted that he had not thought of the ice.
"But I think it would cost more to stand the posts, thirty feet high, on the ends in the water than it would to build the caissons for coffer-dams," added Mr. Bridges. "I suppose you will raise the building in sections, but you must have something to hold on to in the water, and sink the ends of the posts to the bottom."
"Now, Millweed, you have mentioned several ways of managing the posts in the water, I wish to ask which of these ways you think is the best one," said Captain Gildrock.