"I provided a trough of planed boards fourteen feet long, six inches wide, and six inches deep in the clear, filled with water within half an inch of the edge, to represent a canal, I had a loose board of nearly the same length and breadth, that being put into the water, might be sunk to any depth, and fixed by little wedges where I would choose to have it stay, in order to make different depths of water, leaving the surface at the same height with regard to the sides of the trough. I had a little boat in form of a lighter or boat of burden, six inches long, two inches and a quarter wide, and one inch and a quarter deep. When swimming it drew one inch of water. To give motion to the boat, I fixed one end of a long silk thread to its bow, just even with the water's edge, the other end passed over a well-made brass pulley, of about an inch in diameter, turning freely upon a small axis; and a shilling was the weight. Then placing the boat at one end of the trough, the weight would draw it through the water to the other. Not having a watch that shows seconds, in order to measure the time taken up by the boat in passing from end to end of the trough, I counted as fast as I could count to ten repeatedly, keeping an account of the number of tens on my fingers. And, as much as possible to correct any little inequalities in my counting, I repeated the experiment a number of times at each depth of water, that I might take the medium." The experiment proved the truth of the boatmen's assertions. Franklin found that five horses would be required to draw a boat in a canal affording little more than enough water to float it, which four horses could draw in a canal of the proper depth.