De Westermolen, Kollumerpomp of the upright shaft. At the bottom of the upright shaft is the "crown wheel", which has 41 cogs, drives a gearwheel with 42 cogs on the axle of the Archimedes' screw. The axle of the Archimedes' screw is diameter. The screw is diameter . It is inclined at 16.7°. Each revolution of the screw lifts of water. The Archimedes' screw that pumped water into the polder has been removed. "De Westermolen" is open on Friday mornings. It is also open on Saturday mornings if there is enough wind to work the mill. De Westermolen, Kollumerpomp De Westermolen is a
Archimedes and the Cylinder I, II", "On Spirals", "On Conoids and Spheroids", "On Floating Bodies I, II", "On the Measurement of a Circle", "The Sand Reckoner". c. Boyer, Carl Benjamin "A History of Mathematics" (1991) "Arabic scholars inform us that the familiar area formula for a triangle in terms of its three sides, usually known as Heron's formula — "k" = , where "s" is the semiperimeter — was known to Archimedes several centuries before Heron lived. Arabic scholars also attribute to Archimedes the 'theorem on the broken chord' ... Archimedes is reported by the Arabs to have given several proofs