CONTENTS.
USES OF WATER
IN HEALTH AND DISEASE.
IN HEALTH AND DISEASE.
IN HEALTH AND DISEASE.
PHYSICAL PROPERTIES.
Water is one of the most abundant elements in nature. As rivers, lakes, seas, and oceans, it covers three-fourths of the earth’s surface. It even enters largely into the formation of the solid rocks. The clearest and purest air contains it in large quantities as an invisible gas; while in clouds, fogs, and mists, it appears in the form of minute drops.
Water also forms a very considerable part of all vegetable productions, and constitutes aboutthree-fourthsof the human body, as well as other animal tissues. The blood and the brain are each about four-fifths water, while the fluid secretions and excretions contain more than nine-tenths of their weight of this limpid fluid.
Chemical Composition.—The chemist designates water as hydrogen oxide, and represents it by the chemical formula, H2O, which signifies that it is composed of the two gases, hydrogenand oxygen, in the proportion of two volumes of the former to one of the latter. Both of these gases are colorless, transparent, tasteless, and odorless. Hydrogen is the lightest gas known; oxygen is the great supporter of combustion and animal life and heat. Water is produced by the burning, or oxidation, of hydrogen, a process attended with very little light, but most intense heat. The two gases are explosive when mixed.
Physical Properties.—Water exists in three states; viz., as a solid, in the form of ice; as a liquid, its most common form; and as a vapor, in the form of steam. When in the last condition, the gaseous, it is invisible. That to which the term steam is very commonly applied, is not steam, but water in a state of fine division, or mist.
Below 32° F., pure water exists in the form of ice. Between 32° and 212°, it is a liquid. At 212°, it is converted into vapor. Water also slowly evaporates at all temperatures below 212°, being absorbed and held in solution by the air.
Water possesses the greatest specific heat of any substance. By specific heat is meant the actual amount of heat required to elevate its temperature a given number of degrees. For example, it requires ten times as much heat to raise a pound of water 1° in temperature as to elevate a pound of copper 1° in temperature. To raise the temperature of a pound of lead 1°, requiresonly one-thirtieth as much heat as to produce the same effect upon a pound of water. Water absorbs more heat by elevation of temperature than any other substance. In passing from the solid to the liquid state, it absorbs a vast amount of heat without any elevation of temperature. The same thing occurs in the conversion of water into steam or vapor by evaporation. In the evaporation of one pound of water, as much heat is absorbed, or rendered latent, as would suffice to raise nearly a thousand pounds of water one degree in temperature. This heat is abstracted from surrounding objects; and, hence, evaporation is one of the most powerful means of producing cold. The effect is the same, no matter what the temperature at which evaporation occurs.
Water is not the best conductor of heat, but it conducts much more readily than air, and readily communicates its heat to bodies with which it comes in contact, also abstracting heat when of a lower temperature, when changing from a solid to a liquid state, or from the liquid to the gaseous condition.
One of the most useful properties of water is its power to dissolve numerous substances, its solvent properties being nearly universal. To this property it owes its value as a cleansing agent.
Pure Water.—Absolutely pure water is not found in nature. Rain water is the nearest approachto it; but even this gathers impurities of various sorts as it falls through the air, and often becomes very unwholesome by the absorption of foul gases and the collection of dust in this way. For any use connected with the human body, the purest water is always preferable to any other. Filtered rain water and distilled water are the purest forms of water attainable.
Hard Water.—Water is said to be hard when it will not produce a good lather with soap, but forms curds instead. Hardness is due to the presence of earthy salts in the water; salts of lime—chalk and gypsum—are the most common. Ten grains per gallon of any of these salts is sufficient to render water hard and unfit for use, though some waters furnished to cities for general use contain from 70 to 160 grains per gallon of solid matter. Hard water is unfit for cleansing purposes because its mineral ingredients form insoluble compounds with fatty substances. When mixed with soap, the lime or other mineral takes the place of the soda or potash in the soap, and forms an insoluble curd, instead of a lather.
Mineral Water.—Water containing in solution salts of iron, magnesia, or other metallic elements, as well as sulphur, arsenic, iodine, or any compound of these or other elements which are capable of imparting a nauseous or saline taste, an unpleasant odor, or medicinal properties, hasbeen much employed for the cure of all sorts of chronic ailments. Such waters are totally unfit for general use for drinking or cooking purposes, and certainly possess no particular advantages as cleansing agents. Whether they are useful as medicines is a medical question which we do not purpose to consider here; but one would naturally suppose that water which is unfit to cleanse the outside of the body could not be of very great utility as an internal application.
Magnetic Water.—Within the last few years, the scientific world has been startled with the alleged discovery of “magnetic wells” and “magnetic springs” in various parts of the country. The claim has been made and stoutly defended by interested parties that the water furnished from these sources is magnetic in character, and possesses wonderful healing virtues on that account. The truth in the matter, when viewed in the light of science, seems to be that the water of these much-lauded wells is no more magnetic than any other water; the magnetic phenomena are all explicable by well-known laws of physics, without attaching to the water any magnetic properties. A close examination shows that the iron pipe through which the water passes is the only magnetic object. The supposition that the pipe derives its magnetism from the water is both unnecessary and illogical. In the first place, any iron pipe or rod placed vertical in the ground—or,better, placed parallel to the earth’s axis—will spontaneously become magnetic. The production of magnetism is greatly favored by the friction of flowing water, and by jarring, as beating with a hammer. In the second place, the water possesses no magnetism to impart. In view of these facts, the conclusion is inevitable that so-called magnetic water has no existence except in the minds of certain persons whose credulity greatly exceeds their scientific knowledge.
“Magnetic” wells and springs are ingenious humbugs. Thousands of people are duped by them. Hundreds are benefited by getting well washed, and by enjoying recreation and pleasant social surroundings. The curative effects are attributed to the imaginary magnetism, while other more tangible agents are the real means of cure.