The Theater of Hydraulic Machines, Volume II

...to apply the rods, shall be shown below in Table XVII, Fig. I. Such a pressure-work force pump will provide a much larger quantity of water than such a scoop-wheel. The reason is: because it is of immense weight and therefore has much friction, whether it goes too shallow or too deep in the water; and, most importantly, because it spills almost half of the water in vain, whereas with the pressure-work not a drop of water nor a pound of force can be in vain.

According to this figure, it will be quite easy for everyone to hang other types of water-wheels or scoop-wheels. However, because such wheels often must be placed where one cannot catch the water or force it through a sluice-way, especially in very large streams, it will be necessary—if the current is too dead—to make a hanging float-bed that becomes somewhat wide at the top toward the incidence of the current and narrower at the bottom. Therefore, they are also good under bridges, where the water can be made lively by the piers if they are covered with posts on both sides.

Driving water-screws by means of a water-wheel.

It often happens that one only has to lift a reasonable quantity of water a few feet high, and does not want to do this with cylinders pumps because of the costs caused by leather, pistons, and valves, and yet wants to have a constant mechanism. If a river with sufficient power is present, one can accomplish this with several water-screws. For if these are made well and diligently once, and covered with sufficient iron hoops, they can last constantly for many years, and little will be necessary except the repair of the journals, specifically as much as wears off, and what the various wheels with their teeth and gears cost to maintain. However, some advantage that one gains from the screws might be lost somewhat by the many wheels.

How the screw is to be made was shown in Part I, Table XV. Here it only appears, according to Ramelli's instructions, how different screws are to be applied side by side to a water-wheel.

A Tab. II. is the water-wheel, on whose shaft a cam-wheel B is fastened, which engages in a large gear C, which then [turns] the shaft C, on which are again as many spur-wheels as there are to be screws. Each of the spur-wheels engages in a similar star-wheel a type of gear wheel that is fixed to the water-screw. Thus, when the star-wheels E are turned by the gear C, they also turn the four screws G H I K at the same time. Furthermore, the scaffolding is arranged so that one should be able to set the wheels high and low by means of the screws L M. However, it has the same condition here as with the previous machine and is therefore likewise useless. It would be easier to adjust by means of an iron lever, as was likewise indicated for the previous machine.