CENTRIFUGAL Machine, a curious ma chine for raising water by means of a centrifugal force, combined with the pres sure of the atmosphere. This machine consists of a large tube of copper, &c. in the form of a cross, placed perpendicu larly in the water, and resting at the bot tom on a pivot. At the upper part of the tube is an horizontal cog-wheel, which touches the cogs of another in a vertical position ; so that by the aid of a double winch, the whole machine is moved round with very great velocity. Near the bot tom of the perpendicular part of the tube is a valve opening upwards ; and near the two extremities, but on the contrary sides of the arms, or cross part of the tube, are two other valves opening outwards. These two valves are kept shut, by means of springs, till the machine is put in motion, when the centrifugal velocity of the wa ter forces them open, and discharges it self into a cistern or reservoir placed there for that purpose. On the upper part of the arm are two holes, which are closed by pieces that screw into the metal of the tube. Before the machine can work, these holes must be opened, and water poured in through them, till the whole tube be full : by these means all the air will be forced out of the machine, and the water supported in the tube by means of the valve at the bottom. The tube
being thus filled with water, and the holes closed by their screw-caps, it is turned round by the winch, when the water in the arms of the tube acquires a centrifugal force, opens the valves near the extremities of the arms, and flies out with a velocity nearly equal to that of the extremities of the said arms.
If the men who work the machine be supposed to turn the winch round in three seconds, the machine will move round its axis in one second ; and, consequently, each extremity of the arms will move with a velocity of 18.8 feet in a second. A column of water, therefore, of three inches will issue through each of the valves with a velocity of 18.8 feet in a second ; but the area of the aperture of each of the valves is 7.14 inches; which, being multiplied by the velocity in inches = 125.6, gives 1610.784 cubic inches, the quantity of water discharged through one of the apertures in one second ; so that the whole quantity discharged in that space of time through both the apertures is = 3221.568 inches ; or 193294.08 cubic perpendicular tube by the pressure of the atmosphere, it is evident that this machine cannot raise water above thirty two feet high.