Sometimes, Instead of coiling a second rope on the drum, this latter is made of such dimensions that a horse can work it by walking inside, constituting a tread-wheel, such as is shown in Fig. 28. The capstan-wheel is another form, which was much used in ancient times.
There have next to be considered a application of simple leverage. The process illustrated in Fig. 29 is eminently easy, and very widely adopted in Eastern countries, for raising water from shallow depths (2-3 ft.) for purposes of irrigation. It is termed menial in Egypt. A small trench a is dug on the edge of the tank or stream affording a supply, and an impromptu scat b is made of baked earth on each side. The baling vessel c, usually a basket of twigs or leaves rendered water-tight by plastering with clay and cowdung, is suspended by 4 cords d. The free end of each cord is held in one hand by the operators, who, on launching the bale into the water, lean backwards towards their seats, thus assisting by their own weight in jerking the full vessel out of the trench into a gutter cut to receive and distribute the water. In India, water is lifted in this way, some 12-16 ft in 3 or 4 stages, by as many pairs of men, at the rate of 1800 gal.
Swinging gutters seem to have origloated in the jantu of India, which consist* of a hollow trough of wood, about 15 ft. long. 6 in, wide, and 10 lying on bamboos filed in the bank of a pood or river. One end of the trough rests upon the bank, where a gutter is prepared to carry off the water, and the other end is dipped into the water by a man standing on a stage, who plunges it in with his foot. A long bamboo with a large weight of earth at the farther end is fastened to the end of the jantu next the river, and, poising up the juntu Full of water, causes it to empty itself into the gutter. This machine raises water 3 ft., but by placing a series of them one above another, the water may be raised to any height. Water is thus conveyed over rising ground to the distance of more than a mile. Fig. 30 shows the mode of working a single gutter, without the aid of a lever pole, a is a trough whose open end b rests on the bank over which the water is to be elevated; the other end a is closed to retain the water entrapped by raising it. Fig. 31 represents an improvement, being a double gutter a placed across a trough b to receive the water.
The gutter a is divided by a partition in the centre, on each side of which' partition holes are made in the floor of the gutter to let out the water into b.
Fig. 32 is a further development, termed a pendulum or set of swinging gutters, raising water by their pendulous motion. The terminations at bottom are scoops, and at the top are open pipes; intermediate angles are formed with boxes and flap-valve, each connected with 2 branches of pipe. The so-called Dutch scoop. Fig. 33, is much used in Holland for raising water over low dykes. It is a kind of box shovel a suspended by cords b from a triangular frame c, and worked by an operator standing on the plank d, and thrusting the scoop into the water by means of the.
Perhaps the most widely used contrivance for drawing water from wells is that shown (in one of its many forms) in Fig, 34. It is the "swape," "sweep," or "swip" of English chroniclers since to Australian gold-diggers as a "hand whip," the term being probably a corruption of "swip"; it is the shadoof or chadous of Egypt. Its numerous modifications throughout the world differ only in minor details; the leading principle in all is that the counterpoise shall be about equal to 1/4 the weight to be raised. In Japan, ropes are attached to the counterpoise for pulling down when elevating the bucket.
The Hindoos use a modified form of swape, Fig,35,in which a man's weight is utilised in raising the bucket. The lever is a split tree-trunk, ridged to form steps, and provided with a bamboo railing. As the man walks to and fro, the arm carrying the bucket is alternately lowered and raised, a second man emptying the bucket as fast as it rises. This is termed a paecottah or picota in Bengal and scoop it up; And as they ascend, they discharge into a trough placed under one end of the shaft, which is hollowed into as many compartments at there are partitions or scoops.
The Chinese scoop-wheel has a number of buckets attached to the periphery of a huge wheel, which is composed of 3 bamboo rings of unequal diameter, arranged so as to form a frustum of a cone, the smallest ring to which the open ends of the buckets (sections of bamboo 4 ft. long and 2-3 in. diam.) are attached, being next the bank over which the water is conveyed. By this arrangement, the contents of the buckets are necessarily discharged into the gutter as they pass the end of it. When employed to raise water from running streams, they are propelled by the current in the usual way - the paddles being formed of woven bamboo. The size of these wheels varies from 20 to TO ft. in diameter. Some raise over 300 tons of water per 24 hours, or 150 tons 40 ft. high in the same time. Being built almost exclusively of bamboo, they combine economy, strength, lightnoss, and efficiency in a wonderful degree.
In the Egyptian noria, instead of vessels being attached to the wheel, the wheel rim itself is made hollow and divided into compartments, as seen in the section shown in Fig. 37. The water enters through the openings a in the rim and escapes from those b in the.