Hydrology

(-drol'o-je.) [FromGr. hydōr, and logos, a description.] (Phys. Geog.) That department of the science which treats of and explains the nature and properties of waters in general. Hydromel, (hidro-měl.) [From Gr. hy dor, and mel i, honey.] A beverage consisting of honey diluted with water. When fermented, it is called mead or metheglin. Hydrometallurgy, (-me-tal'lur-je.) [From L. hydro, and Eng. metallurgy.] The proce or operation of a aying ores by means of liquid reagents. Hydrometeorology, (-me-te-or-ol'o-je.) (Meteor.) That branch of the science which treats of the aqueous phenomena of the atmosphere, such as rain, clouds, . Hydrometer, (-drom'e-tür.) [Gr. hydōr, and metron, measure.] (Phys.) An instrument for measuring the sp. gr. of liquids, and thence the strength of spirituous liquors, these being inversely as their specific gravities. The H. is sometimes of bra ; at others, when for fluids which would act upon the metals, of gla . It has a bulb about an inch and a quarter in diameter;from this projects upwards a longer stem, which is graduated, and downwards a shorter, which is terminated below by a small heavy bulb, intended by its weight to keep the instrument vertical when immersed in fluid. The lighter the fluid the deeper the immersion, the amount of which is shown by the graduated stem. In making experiments with the H., temperature must be carefully taken into account, since the higher the temperature of a liquid the le dense it is. The use of the H. depends on the following propositions: 1. It will sink in different fluids in an inverse proportion to the density of the fluids; 2. The weight required to sink it equally far in different fluids will be directly as the densities of the fluids. Hydro met ridæ, (-dro-měť're-de.) (Zool.) The Water measurer fam., embracing hemipterous insects which have the body long and narrow (Fig. 398). They are Fig.398. WATER-MEASURER. always found upon the surface of standing or running waters, upon which they move backwards or forwards with the greatest facility. Hydropathy, (-drop'a-the) [Gr. hy dor, and pathos, disease.] (Med.) A term applied to a treatment of disease generally called the cold-water cure. It was suggested in 1828, by Vincent Prie nitz, of Græfenberg in Silesia, and consists in the internal and external administration of cold water, accompanied by air and exercise, early hours, and strict attention to diet. Such am ode of treatment, rationally pursued, must be obviously useful to persons residing in populous towns, eating and drinking too much, and keeping bad hours. [s. 470] IMG:p0515_0.jpg:Gravür