Water-lifting screws and pumps for continuous motion
Archimedean screws, a balanced counterweight pump, and a double piston pump
The sheet gathers four hydraulic machines for raising water. At the top right, a flat screw grafted on a rotating shaft forms the base of a truncated cone wound with sixteen spiral coils that carry water from the centre outward and back again; a second, similar screw is meant to work half-immersed in a running stream. The left column shows a pump discharging along a balanced conduit whose water gathers at S to act as a counterweight, and, lower down, a double piston pump that works in alternation like a pair of bellows.
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Spiral screw of sixteen coils on a rotating cone
A flat screw is grafted on a turning shaft as the base of a truncated cone wound with sixteen coils. The water departs from the centre a, runs to b, and from b to c forms an equal lever; from c it rises through the coil of the flat screw and returns to the centre.
Screw device set half-immersed in running water
An analogous instrument is meant to stand half-immersed in a running stream, its central rotating axle formed by a cochlea. As to the cause of the motion it resembles the device above, differing only in the middle screw that carries the water upward.
Balanced conduit with a counterweight pump
Water issuing from the pump runs along the line a c and stops at S, where it acts as a counterweight and descends together with the lever n m, drawing up fresh water. Part of that water goes into the counterweight and part remains raised along the line b f.
Double piston pump working like bellows
The line a b is the plane of the ground; p is the lever of m and q the lever of n. Now one and now the other performs its office in the manner of a pair of bellows, so the two pistons alternate to keep the water rising.