Archimedes' screw pipe does not need to be perfectly watertight, as long as the amount of water being scooped with each turn is large compared to the amount of water leaking out of each section of the screw per turn. If water from one section leaks into the next lower one, it will be transferred upwards by the next segment of the screw. In some designs, the screw is fused to the casing and they both rotate together, instead of the screw turning within a stationary casing. The screw could be sealed to the casing with pitch resin or other adhesive, or
Trammel of Archimedes in the form of the standard parametric equations for an ellipse in canonical position. The further equation is immediate as well. The trammel of Archimedes is an example of a four-bar linkage with two sliders and two pivots, and is special case of the more general oblique trammel. The axes constraining the pivots do not have to be perpendicular and the points "A", "B" and "C" can form a triangle. The resulting locus of "C" is still an ellipse. Trammel of Archimedes A trammel of Archimedes is a mechanism that generates the shape of an ellipse. It consists of two