Machinery for Drawing Water from a Well
Bucket, rope, pulleys and winch with friction calculations, and a garden of fishponds
The sheet designs an apparatus for drawing water from a well: a bucket on a rope running over a two-groove pulley, a winch-axle (subbio) with a counterweight cylinder, and stairs sized for two men (texts 3-8). A long calculation reckons the friction of the axle poles, reducing 400 pounds on the roller to about four pounds of resistance through the lever ratios of the pole radii, and a double-balance figure sets out the lever and counter-lever of that friction (texts 9-11). At upper left a garden plan lays out little channels and fishponds between which fish can pass from one vessel to another (texts 1-2).
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A garden of channels and fishponds
For each little garden four crossings are set so that small channels connect one to the other, with some fish for the streams. At the bottoms of the vessels fish are to be kept that can go and flee from one vessel into the next.
Bucket, rope and two-groove pulley over the well
The bucket is to be a quarter braccio wide at the mouth, one braccio long and one and a half braccia high; the rope 1/24 thick, so that in the six turns it makes about the roller it occupies no more than a quarter braccio. The rope runs over a two-groove pulley marked 8 1 - 400 50.
Counterweight cylinder and ground-level pulling
A cylinder with pins is labelled the 'true mode of counterweight', and a wheel-and-pulley system places the pulling effort on the ground. Three stairs are provided for two men.
Friction of the axle poles reduced through lever arms
The roller carries 400 pounds, which come to 100 pounds of friction on pole a; since the pole is 1/24 braccio thick, its friction arm is 1/48 against a lever of 24/48, so the 100 pounds reduce to about 4 pounds. The same reasoning is applied to pole b.
Double balance: lever and counter-lever of friction (a b, b c)
a b is the lever of the friction and b c its counter-lever; the lever is 1/50 long and the counter-lever 50, so 100 pounds on the counter-lever balance 2 on the lever. A second joined balance reduces those 2 pounds at d e to one twenty-fifth of a pound at arm e f.
Weighing the rope in the well
A marginal note directs that the weight of the rope entering the well down to the water be included in the calculation.
