Page:The New International Encyclopædia 1st ed. v. 20.djvu/416

* WATER METERS. 346 WATER POWER. and some of the disk meters cease registering without any effect upon the flow of water. CuRREXT Meters (q.v.) are employed to meas- ure the velocity of water in rivers and large aqueducts and also to determine the flow of sewers. See Water-Works. WATER-MOCCASIN. A snake. See Moc- CASIX-Sx,KE. WATER-NET. The common name of the Hydrodictyon, a genus of green algfe. See C'ULOROPIIYCE-E. WATER-PLANTS. See Hydbophttes. WATER POET, The. A name used of John Taylor (1580-1C53). He was apprenticed to a waterman in youth, was pressed into the navy, and called his first volume The HcuUer and its second edition Tnylor's WaterAYorks. WATER POWER. A term used by en- gineers to define the power obtained or capable of being obtained from water by its fall from a higher to a lower level; also, more specifically, the term applied to a fall in a stream which is used or is capable of being employed to develop power. Water power is, perhaps, after wind power, the most natural and at the same time the most truly economic source of energy. The terra water power is something of a misnomer. Tlie real agent is gravity, the fluid itself being the medium through which the action of gravity is transmitted to the prime motor. In order that water may be available for the purpose of doing work, it must be in such a position that it can fall from a higher to a lower level, or must be under pressure produced liy some ex- ternal force, such as that of a weight or spring acting on the surface of the fluid through a pis- ton or plunger. Under the former condition its utmost capacity for doing work — potential energy or energv- of position — is the product of the height through which it can fall into the weight of the water falling, so that if li denote the avail- able height of the fall and G denote the weight of the water falling per second, then h X G equals the energy' or power available per second. If the fluid is allowed to fall without resistance under the action of gravity, either free or confined in pipes, the power available is expended in impart- ing velocity to the water, and the ])otential energy of position is converted into kinetic energy or energy of motion, and in this form is available for jjerforming work. It is, however, not neces- sary' that the potential energy of water should first be transformed into kinetic energy in order that it may be employed for motive power. The weight of the fluid can also be allowed to act directly on the prime motor in a manner similar to that in which the weight of a body attached to one end of a rope, passed over a ])ulley for in- stance, may be made to raise another body sus- pended at the opposite end. A third way of using water power for doing work is Ijy means of its pressure, but the difference between this method and the preceding method is more ap- parent than real. The so-called pressure of water is the result of weight or its equivalent. For practical purposes it may. nevertheless, he said that there are three ways in which water power can be aj)|)licd to the performance nf work: (1) As kinetic energy, or through the velocity of the fluid; (2) by weight; and (3) by pressure. Kach of these three methods requires a different type of motor for its application, denoted respectively as (1) turbine (q.v.), (2) water wheel (q.v.), and (3) lydraulic pressure engine (q.v.). The most usual source of water power in nature is a river or stream, but to make this available for practical purposes some form of work such as dams (q.v.), canals (q.v.), and aqueducts (q.v.) is almost invariably neces- sary. A river has always a certain fall or gradient, but to be able to take advantage of this fall for doing work, the portion of it utilized must be applied in one or several nearl,v perpen- dicular steps. One common way of accomplish- ing this object is to build a dam across the stream. The eft'ect of this dam is to raise the level of the water above it a height equal to the difference between tlie original level and the level of the top of the dam, while the level of the stream below the dam remains as it was. To illustrate, let us assume that the stream had originally a fall of 1 foot in 100 feet, and that a dam 6 feet high is built across it. The head which was previously expended almost entirely in overcoming the resistance of the river bed over a distance of (500 feet, while the water grad- ually descended feet down a gentle incline, will now be available for doing a corresponding amount of useful work by a sudden drop through the same height as Ijefore. In other words, the energy originally wasted in useless friction in the gradual descent of the stream is accumulated in the form of head immediately behind the dam Min. H.P, Lowell, Mass Nashua, N. H Coboee. N. Y Norwich. Conn Augrusta, Me Manchester. N. H Hooksett. N. H Lawrence, Mass Aiiprusta, Ga Hoi,yoke, Mass Lewiston, Me Columbus, Ga Rochester, N. Y St. Antlion,v Falls, Minn,... Niagara, N. Y. (Hy. Canal) Turner's Falls, Conn ...> Fox River, Wis nirmingham, Conn Bangor, Me .ugU8ta, Ga Palmer's Falls, N. Y Mechanicsville, N. Y St. Cloud, Minn Little Fal», Minn Spokane, Wash Howlaod, Me Great Falls, Mont Austin. Tex ;.... Sault Ste. Marie, Ont P^olsom, Cal Concord, N. H Niagara. N. . (tunnel) Ogden, Utah Helena, Mont Minneapolis. Minn Mechanicsville, N. Y Year Fall, feet 1822 35 1823 36 1826 104 18'28 16 1834 17 1835 S4 1841 10 1845 30 1847 60 1848 BO 1849 55 1850 26 1856 230 1857 60 18G1 95 1866 35 1866 182 1870 29 1876

1876 50 1882 30 1882 24 1885 14 1887 10 1888 72 1888 22 1890 40 1891 68 1891 16 1891 53 1894 10 1894 176 1896 442 1897 38 1897 18 1898 18 11,845 1,200 9.450 700 3,500 12,000 1,800 11,000 8,500 14,000 11,900 10,000 8,000 15,500 15.000 10.000 "i,'oo6 1,767 8,5(X) 1,125 3,636 4,500 4,000 18,000 6,000 16,000 10,000 10,000 6,200 6,000 60,000 2,940 10.000 6.000 3,270 before the plunge of the water. To apply this energv' the water flowing over the <lam is taken into the chamber or reservoir containing the motor through which it passes to the tail race. In other cases, where it is not admissible or pos- sible to construct a dam. or where onl.y a por- tion of the water of a stream is required, the necessary quantity is drawn off by a separate channel at a sufljcient distance above the point