The Reasons of Motive Forces

Of Motive Forces.

A decorative woodcut headpiece consisting of a horizontal band with symmetrical scrolling foliage, floral patterns, and central ornamental motifs.

THEOREM VII.

A woodcut illustration depicts an Archimedean screw, an early hydraulic machine. It consists of a pipe wound like a helix around a central wooden cylinder. The device is set at an angle, supported by a wooden frame and a wall. The lower end, submerged in a basin of water, is marked 'A'.

The variety of machines suitable for raising water is great, and among all those invented in antiquity, there is one of Archimedes’ invention, of which Diodorus Siculus speaks; he says that Egypt was drained Refers to the drainage of the Nile's floodwaters for agriculture. by Archimedes' screw. Vitruvius also makes mention of it, as does Cardano, who says that a certain De Rubeis of Milan, thinking he was the first inventor of this machine, went mad with joy. To tell the truth, those who are ignorant of the proportions of motive forcesThe physical principles or mechanics that cause an object to move. will judge this machine to be a means of achieving perpetual motionA machine that could work indefinitely without an external energy source, a common but impossible quest for early engineers., for they will think that the water rising through the said machine will be capable of making it turn itself. Its construction shall be thus: one must have a pipe of lead or copper and turn it in the fashion of a screw, as the figure demonstrates; then it must be placed on an incline like the diagonal of a square, with one of the ends inside [the water], turning on a pivot, and the other end leaning against a wall or piece of wood, so that it can be turned by the force of a man or any other means. Then, when the lower end marked A is raised by turning, the water inside the screw will always descend within the said pipe, and finally find itself at the top. Thus, while the water is descending through this instrument, it is always rising until it exits. The consideration of this machine is wonderful, for its premise contradicts itself, in that the water descending through it rises to the top.

THEOREM VIII.

It is a well-known thing that if there is a hole at the bottom of a vessel full of water, the water will empty faster at the beginning than at the end; the reason is that the water, being at a greater height, weighs more and forces that at the bottom to exit faster. The same applies to a pipe at the bottom of a vessel, for the vessel will be emptied much sooner if the pipe is long than when it is short. The same reason is further proven in ordinary pumps; for if the water is 24 feet down, it will be much harder to pull up than water that is only 12 feet down, even if the 12-foot pipe were much thicker than the 24-foot one and contained more water. For the quantity of the water will not make the machine heavier to pull, but rather the length In modern terms, this refers to hydrostatic head or pressure, where vertical height determines the weight felt by the pump mechanism regardless of the pipe's diameter..