The Spanish wheel is a very light framework disc having a series of pots secured to the periphery. Its most remarkable feature is that motion is given to the wheel by a system of spokes on its axle working into other spokes on a vertical shaft - one of the earliest forms of cog-wheel.
The fault common to all the wheels hitherto described is that they begin to discharge before reaching the channel provided for the reception of the water, and waste power in carrying much of the water higher than it is required. These two detects are well remedied in the Persian wheel, by suspending the buckets so that they are free to swing, thus hanging perpendicularly throughout their course, until they reach the receiving trough, when they are made to tilt and discharge their contents at once by coming into contact with a stop on the trough. Fig. 33 illustrates another form of Persian wheel having both scoops and buckets. it has .1 hollow shaft and curved Hosts, at the extremities of which are suspended buckets or tubs. The wheel is partly convex surface of its floats; and as it is thus caused to revolve, a quantity of water will be elevated by each float at each revolution, and conducted to the hollow shaft, at the same time that one of the buckets carries its till of water to a higher level, where it is emptied by coming into contact with a stationary pin placed in a convenient position for tilling it.
In Fig. 39 is represented a machine of ancient origin, still employed on the river Eisach, in the Tyrol, for raising water from the stream. The current on its periphery are successively immersed, filled, and emptied into a trough.
The bucket wheel being incapable of reaching water at any considerable depth, led to the adoption of a modified form, called a chain of pots, the buckets being attached to chains working over the wheel instead of to the wheel itself. In Egypt, under the name of sukia, this machine is in common use, and its employment extends throughout Spain and the East generally, power being applied by a vertical shaft and cog-wheels, moved by bullocks. It is nothing less than a modern "elevator" worked by animal power instead of steam.
Another form of elevator or chain pump is illustrated in Fig. 40, lifting water by continuous circular motion. Wooden or metallic dises, carried by an endless chain, are adapted to a water-tight cylinder, and form with it a succession of buckets filled with water. Power is applied at the upper wheel.
The chain pump known as the Chinese or Californian pump, represented in Fig. it, is in common use in alluvial gold diggings in America and Australia. A rectangular box, about 10 in. by 3 in. inside measurement, and varying from 10 to 30 ft. long, according to need, is traversed by an endless flexible band or belt of canvas, on one side of which arc securely fixed at intervals wooden discs nearly as large as the inside of the box. The lower end of the box is furnished with a roller, around which the belt passes, and is immersed in the water to be raised from the pit, while the upper end delivers the water into a trough or launder, by which it is carried away. At the upper end the belt passes round a second roller or drum, which is made to revolve by either hand- or water-power. In Fig. 41 is shown one driven by a water wheel: a is a Hat wooden pipe or box, open at both ends, forming the pump; b, the pump-belt, carrying the wooden stops, faced with leather, called the buckets or suckers d; c, the ends of the belts joined together by lacing; A, the drum fixed on the axle of the water wheel to and turning with it; t, entrance of water to be pumped up; e, exit of same; f, launder or race to convey the water from the pump and wheel clear of the working; g, sluice-box set in a head-race to bring the water necessary for driving the wheel.
The Chinese diggers make even the belt of wood, hinging short sections together by wooden pins.
An application of the Archimedes screw to the raising of water Is shown in Fig. 42, the supply stream being the motive power. The oblique shaft of the wheel has extending through it a spiral passage, the lower end of which is immersed in water, and the stream, acting upon the wheel at its lower end, produces its revolution, by which the water is conveyed upward continuously through the spiral passage, and discharged at the top.
A reciprocating lift for wells is indicated in Fig. 43. The top part represents a horizontal wind-wheel on a ■haft which carries a spiral thread. The coupling of the later allows a small vibration, that it may act on one worm-wheel at a time. Behind the worm-wheels are pulleya, over which passes a rope which carries a backet at each extremity. In the centre la a vibrating tappet, against which the bucket strikes in its ascent, and which, by means of an arm in a step wherein the spiral and shaft are supported, traverses the spiral from one wheel to the other, so that the bucket which has delivered its water is lowered, and the other is raised.
Fair bairn's baling scoop for elevating water short distances is illustrated in Fig. 44. The scoop is connected by a pitman with the end of a lever or of a beam of a single-acting engine. The distance of the lift may be altered by placing the end of the rod in the notches Briar's bilge ejector, for discharging bilge-water from ships, or for raising and forcing water under various circumstance!, is represented in Fig. 45; D is a chamber having attached a suction-pipe B and discharge-pipe C, and having a steam-pipe entering at one side, with a nozzle directed towards the discharge-pipe. A jet of steam entering through A expels the air from D and C, produces through B and pass through D and C in a regular and constant stream. Compressed air may be used as a sub-Fig. 46 is another apparatus operating.