“Oui, monsieur, oui,” answered Dumont, whose knitted brows showed that the worthy blacksmith was at least doing his best to understand me.
“Well, then,” I continued, “you see that we shall have no difficulty as to the dam. Then, as to the wheel, it will be a simple one of not more than four feet diameter, presented vertically to what I may term the water-spout, so that its axle, which will have a crank in it, will work the saw direct; thus, avoiding toothed wheels and cogs, we shall avoid friction, and, if need be, increase the speed easily, d’you see?”
“Bon, monsieur—good, good,” exclaimed Coppet, becoming quite enthusiastic in his appreciation of my plans.
“Of course,” I continued, “the saw can easily be fitted to a frame, and a very simple contrivance can be made to drive along the larger frame that will carry the logs to be sawn; but these are trifling matters of detail which you and I will work out at our leisure, Dumont.”
“Oui, monsieur, oui,” replied the blacksmith, with tighter knitted brows, and with a readiness of assent which I do believe the good fellow would have accorded if I had proposed to fit a new axis to the world.
“There is only one thing that troubles me,” said I: “how are we to gauge or estimate the force of our water-spout so as to regulate our mill when made? Do you understand such matters—the measurement of force—Coppet?”
The carpenter shook his head.
“That’s unfortunate. Do you, Dumont?”
“Non, Monsieur.”
“H’m! I’m sadly ignorant on the point myself,” I continued. “Of course I know that so many cubic feet of water will exert a certain pressure, but then I don’t know what that certain pressure is, nor how to find out how many cubic feet our somewhat irregular dam will contain. Nor do I know precisely the strength of the material required in the dam to resist the water.”