From James Walker
Hardware Mills July 21st 1811.
I have taken a second consideration on the calculation of the running gears intended for your saw Mill. both for a 10.½ feet water-wheel &. a 15 feet wheel—&. am most in favour of the latter. more particularly as you intend using the small branch the 15 feet wheel will with the same quantity of water drawn on it produce the greatest effect as there will be so many more1 buckets to act at the same time. should you have a 15 foot wheel it may work by the side of the saw Mill and if the top of the wheel projects above the floore of the mill house it will not be in the way of any thing. the water from the river may act on the same perpendicular descent & more buckets than on the 10.½ foot wheel=&. the water from the branch will act on a much greater perpendicular descent consiquently the wheel of 15 feet damr2 with the same quantity of water must act with most power—as you can obtain sufficient fall in the branch—I should clearly recommend the 15 feet wheel=we can also give the saw 10 or 12 strokes in a minute more than with the 10.½ foot wheel, as it will bear gearing reather higher—but in either case it will be difficult with only single gearing to give the saw sufficient motion without having the cogwheel too large & wallower too3 small=in case you should have a 15 foot water wheel I have added at the bottom of the former Bill=a little to the length and sizes of some of the timbers—
RC (DLC); at foot of text: “mr. Thos Jefferson”; endorsed by TJ as received 25 Aug. 1811 and so recorded in SJL.
wallower: trundle, or lantern-wheel (OED description begins James A. H. Murray, J. A. Simpson, E. S. C. Weiner, and others, eds., The Oxford English Dictionary, 2d ed., 1989, 20 vols. description ends ).
1. Word interlined.
2. Abbreviation for “diameter.”
3. Manuscript: “to.”