vals by a regulator clock which is kept at absolutely correct time by daily comparison with the observations made with a transit instrument. Many so-called chronometer watches made by American watch companies, though none of them have the chronometer escapement, have proved as accurate as any timepieces ever made. Repeating watches were very popular in the early part of this century, but very few are now made. They require a separate train and main-spring, as well as a spring or bell on which to strike, and are too bulky and inconvenient to be in demand at the present day. The horse-timers or racing watches were also very complicated in their construction, and liable to derangement of their action. The latter were taken up by the Waltham Company in 1876, and are now made by them, simply adding to their regular movements a double bevel-gearing pinion connecting two wheels, without causing any complication of the timekeeping parts of the watch. By the same attachment, split seconds, and even split minutes, are made, the mechanism in all cases being distinctly detached from the timekeeping parts of the watch without any complication whatsoever.. L. P. BROCKETT.

Watch Hill Point, the south-westernmost point of the State of Rhode Island, is in the town of Westerly. It is a favorite place of summer resort.

Wa'ter [Sax. water; Ger. Wasser; Fr. eau; Lat. aqua; Gr. Sp], hydrogen oxide or protoxide, H2O.

Occurrence. In the liquid form it constitutes the ocean, seas, lakes, rivers, springs, etc., covering three-fourths of the earth's surface. It also occurs disseminated throughout the rocky strata which constitute the earth's crust. In the solid state it covers the polar regions and high mountainous districts permanently, and the temperate regions periodieally, appearing as snow, ice, glacier, and iceberg. In the state of vapor it is always contained in the atmosphere, and gives rise to clouds, fog, mist, rain, dew, snow, hail, etc. It is a constituent of many minerals, as water of crystallization; gypsum contains 20 per cent., alum 45. It occurs in all plants in quantities reaching sometimes 99 per cent. Air-dried wood contains 20 per cent. mals it is always present in considerable quantities. An average man weighing 154 pounds contains about 116 pounds of water, or three-fourths his weight.

In ani

Composition.-The Hindoos and the Egyptians considered water the element from which all other bodies were formed. Among the Greeks the idea was maintained that water was the first or fontal element; that from it all other substances were produced; that even plants and animals owed their origin to it. Aristotle regarded water as one of four elements, and this idea was maintained for more than 1000 years, though the old idea that water was the primal element seems to have been mingled with this idea; for it was supposed that these four elements, fire, earth, air, and water, were mutually convertible. Heat converted water into invisible air; repeated evaporation, they said, converted water into earth, so that there seems to have been an original idea that water was the only sole element. Lavoisier in 1770 tested experimentally the question of the conversion of water into earth. It had long been known that when water was placed in a glass retort or alembic, and distilled, there remained behind a small quantity of earthy matter, and if the water was returned to the alembic and distilled again, the quantity of earthy matter increased, and it continued to increase as often as the water was distilled from it. It was supposed, therefore, that the water was gradually converted into earth. Lavoisier distilled 3 pounds of water again and again in an alembic provided with a condenser, the whole apparatus being hermetically sealed, that not a particle of water should be lost. At the close of the experiment he found that while the quantity of water had not diminished in the least, he had a residue of 20 grains of earthy matter in the alembic. As the water had not diminished, he justly concluded that it had not come from the water; it must then have been derived from the alembic itself. On cleansing the alembic and condenser, and weighing them, it was found that they had lost 17 grains; 17 grains of the earthy matter had therefore been produced by the action of the boiling water on the glass. The remaining 3 grains were attributed by Lavoisier to the natural impurities of the water. Scheele tested the same question, and not only proved that the earthy matter was derived from the glass, but analyzed it and found it to consist of the same constituents, potash, lime, and silica. Dalberg repeated the experiment in a silver vessel and obtained no earthy matter. So the conversion of water into earth was proved to be a fallacy due to the action of the water upon the glass vessel. In 1781, Cavendish and Watt proved its composition by synthesis. In 1805, Humboldt and Gay-Lussac determined the ratio of its constituents, hydrogen and oxygen, to be as 2: 1, and Berzelius and Dulong proved the ratio by weight to be as 1 : 8.

405

The

Their method of investigation consisted in passing pure and dry hydrogen gas over red-hot oxide of copper. oxide gives up its oxygen to form water with the hydrogen. This water is collected in a receiver and chloride-of-calcium tubes. By comparing the weight of the water produced with the weight of the oxygen given up by the oxide of copper, its loss in weight, the composition of the water is determined. It is

Berzelius and

Dulong.

2

16

18

11.111 + 88.888 + 100.

11.1

88.9

100.

Dumas.

11.11

88.89

100.

1 U. S. gallon (231 cu. in.) of water contains about 620 gallons of oxygen and 1240 of hydrogen.

Decomposition.-Water may be decomposed (1) with liberation of both constituents (disassociation) by (a) heat, tricity, as when the poles of a galvanic battery are placed first noticed by Grove (see Am. Chemist, vi. 126); (b) by elecin water slightly acidulated with sulphuric acid to increase its conducting power. (2) With liberation of one constituent only: (a) by the metals of the alkalies and alkaline earths at ordinary temperatures, H2O + Na = NaOH + H; by iron and some other metals at high temperatures; by zine and some other metals in the presence of an alkali; the oxygen is always taken into combination by the metal, while the hydrogen is liberated; (b) carbon decomposes steam at a red heat, yielding hydrogen and carbonic oxide, with a little carburetted hydrogen (see WATER-GAS); (c) evolution of hydrogen, as hydrated silicious oxide, carsome lower oxides decompose water or water-vapor, with bonic oxide, etc.; (d) chlorine decomposes water with the vapor at a red heat. Bromine vapor produces the same deliberation of oxygen under the influence of light, or watery bination of both constituents: (a) phosphorus in the prescomposition at a red heat; iodine does not. (3) With comence of an alkali forms phosphuretted hydrogen and an hyposphite; (b) Schönbein says that when boiled in contact with nitrogen (air) water is converted into ammonic nitrite, 2H2O + 2N = NH,NO2; (c) many chlorides decompose water, PCl5 + 4H20= H3PO4 + 5HC1; (d) arsenious and sulphurous oxides decompose water in the presence of chlorine, SO2 + 2H2O + 2C1 = H2SO4 + 2HC1; (e) certain oxides decompose water, or at least combine both its constituents in a new state:

SO3 + H2O = H2SO4
CaO + H2O = Ca(OH)2.

(See HYDRATES and HYDROXYL.)

Formation.-Water is formed whenever hydrogen or combustible bodies containing hydrogen are burned in oxygen, atmospheric air, or any gas capable of supplying oxygen. It is one of the products of most forms of combustion for heating and lighting purposes, also of the combustion which occurs in animal life, fermentation, etc. It is also produced in many cases when bodies containing hydrogen are heated with easily-reducible metallic oxides or salts capable of yielding oxygen under these conditions.

Properties. Between 32° and 212° F., under the ordinary atmospheric pressure, water is a limpid liquid. When pure, it is entirely free from smell and taste, and has neither an acid nor an alkaline reaction. It is colorless in small

quantities-blue when viewed in mass. The impurities in large bodies of water often produce decided colors, as the mud in rivers, the red microscopic plants seen at times in the Red Sea, etc. The density of water in the liquid state is about 770 times that of the atmosphere, and is greatest at about 4° C. (39.2° F.). Taking the density of water at 4° C. as unity, it is 0.999877 at 0° C. (32° F.) and 0.999107 at 15.5° C. (60° F.). The density of water is always taken as the standard unit for comparing the densities of all other liquids and of solids-on the Continent at 4° C., in Great Britain and the U. S. at 60° F. (15.5° C.). Its density or specific gravity is therefore 1.000. (See GRAVITY, SPECIFIC.) A cubic centimètre of water at 4° C., under a barometric column of 760 millimètres of mercury (29.922 inches), weighs 15.432349 grains, or 1 gramme, which is the unit of weight in the metric system. As 1000 grammes make a kilogramme, and 1000 cubic centimètres a litre, the litre of water at 4° C. weighs 1 kilogramme. A cubic inch of water at 62° F. weighs 252.458 grains, equivalent to 16.386 grammes. A cubic foot of water weighs 62.355 pounds avoirdupois, 436.495 grains, 28,315 grammes. Our U. S. or wine gallon (231 cu. in.) of water at 60° F. weighs 58,318 grains or 8.331 pounds avoirdupois. The imperial gallon, used only in Great Britain, weighs 70,000 grains or 10 pounds avoirdupois. (See GALLON; also Am. Chemist, i. 318, 398.) Water is slightly elastic; an increased pressure of 1 atmosphere reduces its volume.000045 (Oersted) or .000047 (Regnault); 200 atmospheres reduces its volume th (Perkins). Taking the volume of water at 0° C. as 100, it expands to 104.2986 when heated to 212° F.: 100° C. (Kopp), and to

FIG. 3.

is dissolved by the water from the air. The quantity is very small: 25 cubic feet of water take up only 1 cubic foot of oxygen. But this quantity is sufficient for the maintenance of life in the fishes; their gills enable them to absorb it, and they die without it.

Water which is collected from roofs in the city is never pure. It contains gases which are only developed in cities, sulphur compounds, products of the combustion of coal. After thunderstorms the rain-water is always found to contain minute quantities of nitric acid, produced by the electric sparks, which cause the oxygen and nitrogen of the air to unite. Rain-water almost always contains a little organic matter, causing it to become putrid when kept for some time." Boussingault found .004 grm. per litre in rainwater collected in Paris, and in that collected in the country only .00079 grm. per litre. Dew he found to contain from .001 to .006 grm. per litre. In water condensed from fog he found .0497 grm., and on another occasion in Paris .1378 grm. per litre. Barral found from .002 to .003 grm. per litre in rain-water collected in Paris." (Ann. Ch. Phys. [3], xxxix. 257; xl. 129.) In rain-water collected at Lyons, Bineau found as much as .03 grm. per litre. The amount of ammonia in rain is also much larger in summer than in winter.

Nitric acid is commonly present in rain-water, chiefly in combination with ammonia. The amount varies considerably, and is greater in rain falling during thunderstorms. Boussingault estimated the average amount at .0002 grm. per litre. In rain-water, collected during a hailstorm in Paris, he found .055 grm. per litre, and in the melted hail .083 grm. per litre; on other occasions from .0001 to .0021 grm. per litre in rain-water, from .0003 to .004 grm. per litre in snow-water collected in Paris, and in water condensed from fog .0101 grm. per litre. In the country (Alsace) he found in rain-water from .00004 to .00028 grm. per litre; in that collected during a thunderstorm .0021 grm. per litre; and in water condensed from fog, from .0004 to .0018 grm. per litre. Barral found from .002 to .036 grm. per litre in rain-water collected in Paris. The amount is less after rain has continued for some time, and it is generally greater in summer than in winter. (Compt. rend., xxxiv. 283, 824; xxxv. 427; xlvi. 1123, 1175.)

Nitrous acid is also present in rain-water, and, according to Schönbein, ammonia-nitrite is formed by the direct combination of nitrogen with water. Lawes, Gilbert, and Way estimate the average amount of nitrogen contained in rain-water, as ammonia, nitrous and nitric acid, at about .985 grm. per litre. (See Report of the Brit. Assoc. for 1854.)

Rain water perhaps always contains a small amount of organic substance, in consequence of which it readily becomes putrid when kept some time. Angus Smith found .01 grm., Marchand .024 grm., and Chatin .05 grm. per litre.

Sulphuric acid is often found in the rain-water falling in towns, and near factories where sulphurous gas is generated and discharged into the atmosphere. A. Smith found .1 grm. per litre in rain water collected at Manchester.

Rain-water sometimes contains a very small amount of hydrochloric acid, sodic or calcic chlorides, and other saline substances. Barral found the rain-water collected in Paris gave, on evaporation to dryness, a residue amounting to .022 grm. per litre, and that collected in the neighborhood of Paris .0078 grm. per litre. A. Smith also found a minute quantity of coal-ash in rain-water collected in Man

chester.

Rain-water is stated by some observers to contain iodine. (Chatin, Compt. rend., xlvi. 399; 1. 420; li. 496; Marehand, ibid., xlvi. 806; De Luca, ibid., xlvii. 644; xlix. 170; li. 177.)- Watts's Diet.

The accompanying engravings, showing the residues obFIG. 2.

Newcastle Rain.

tained by evaporating rain-water, are taken from R. Angus Smith's Air and Rain.

II. SPRING WATERS.-Terrestrial waters are always impure. Rain falling upon the earth's surface is absorbed by the porous soil, and the materials of which the soil is composed, being to a greater or less extent soluble, the water becomes contaminated with mineral matter. The character of spring water, therefore, depends upon the character of the soil through which it has passed before it issues as a spring. In New England, where the rocks are granitic, and the minerals chiefly quartz, feldspar, and mica, water is nearly pure. But in limestone countries, where carbonate of lime and magnesia abound, we find the spring waters largely contaminated with these substances. These carbonates are rendered much more soluble in water by the carbonic acid present, which forms bicarbonates with them. To such solutions of bicarbonate of lime are due many curious phenomena in nature. Where they trickle down from the roofs of caves, the evaporation of a portion of the carbonic acid causes the separation of an equivalent quantity of carbonate of lime. Each drop, as it hangs for a moment and then falls, leaves behind a thin pellicle of solid spar, and finally, in years of dripping, a stalactite is formed. Where the drops strike the floor of the cave, corresponding stalagmites gradually spring up, often meeting the stalactites at last, and forming columns of glistening stone. Sometimes where the water falls from a crevice, a series or row of columns is produced, which finally becomes a solid wall or partition of calcareous spar. On boiling solutions of bicarbonate of lime and magnesia, the excess of carbonic acid is expelled, and the carbonates, having no longer a solvent, are precipitated. In this way incrustations are formed in tea-kettles and steamboilers.

Spring water is generally very clear, although it may be quite impure. It holds its impurities in solution. The soil through which it has passed, although it has conferred upon it its impurities, has at the same time filtered it, and thus rendered it clear and sparkling. As it comes from below the surface, it is generally cool. For these reasons spring water has always been highly prized.

Ordinary open wells are supplied partly by springs and partly by surface-drainage. The water usually contains the alkaline and alkaline earthy salts of spring water, the total quantity of mineral matter and the relative proportions of the various salts depending upon the nature of the soil. In the neighborhood of dwellings the proportion of chloride of sodium or common salt is generally increased by the drainage of house-refuse, which also leads to the contamination of the water with the products of the decomposition of animal matters, such as salts of ammonia, nitrites, and nitrates. In many cases, from the proximity of cesspools and privy-vaults, the water becomes contaminated with filtered sewage-matters, which, while they hardly affect the taste or smell of the water, have nevertheless the power to create the most deadly disturbances in the persons who use the waters. In the neighborhood of graveyards the water of wells is often impregnated with animal matters from the recently-filled graves. As long ago as 1808 it was decreed in France that no one should dig a well within 100 mètres of any cemetery. (See article by Jules Lefort in American Chemist, vol. ii. p. 448.) The water of driven wells does not differ in any respect from that of open wells in the same localities, except in cases where there is near the surface a bed of clay or "hard pan" impervious to water. When such a stratum is penetrated by the tube, and the water is drawn from beneath it, the well is somewhat protected from surface-drainage. Well- Waters.

Artesian Wells.-Occasionally wells are sunk to great depths by boring. Such wells are called artesian wells, from the district in France where they were first bored. (See ARTESIAN WELLS.) The earth's crust consists in many localities of strata of gravel, sand, or clay, resting upon sandstones, limestones, or shales. In many cases these strata are in basins, and their edges often come to the surface at the margin of the basins. Some of these strata, which are porous, constitute reservoirs of water, and by boring down to them this water is reached. It may rise above the surface and overflow if the strata rise elsewhere to higher levels; otherwise it must be pumped. Often the pressure of gases forces the water above the surface. At Grenelle, near Paris, an artesian well was bored down 1798 feet, or about one-third of a mile. The water rises 80 feet above the surface, and flows at the rate of 90 cubic feet per minute. Coming from so great a depth, it is very warm, and must be stored in a reservoir to cool. At Rochefort, in France, is a well 2676 feet deep, or more than half a mile. This is the deepest well in Europe. Some of the deepest artesian wells have been put down in this country. At Louisville, Ky., there is one 2086 feet deep, the water of which has a temperature of 82° F. But instead of being suitable for domestic purposes, the water proved to be heavily charged with saline compounds, which gave it a medicinal value.

At Charleston, S. C., there is a well 1250 feet deep, yielding similar mineral water. At Columbus, O., an artesian well at the depth of 180 feet yielded sulphur water, but it proved to be hard water. At the depth of 675 feet salt water was obtained. As fresh water was required, the well was pushed down a half-mile, or 2575 feet, but no water was obtained of a satisfactory quality. At St. Louis a well was bored to the depth of 3881 feet, or two-thirds of a mile, but no water of any consequence was obtained, and the well is a failure. Artesian wells are in some localities of the greatest economic and sanitary importance, yielding water where it could not otherwise be obtained at all, or pure water when the shallow surface-wells are too impure for domestic use. The former case is illustrated in the Libyan desert, where there are no rivers or

springs, and upon which rain never falls; the latter case

in the city of London, where the surface-wells are eontaminated by sewage, while the artesian wells 400 or 500 feet deep bring up from the chalk-beds below a very pure water. In many instances water which rises in artesian wells comes from great distances. At Tours, in France, the well is sometimes obstructed, and when the obstruction is removed, it is found that the leaves which come to the surface, and which caused the obstruction, do not grow within 100 miles of Tours, showing that there is some subterranean communication by which the leaves, as well as the water, are brought from a distance.

Ordinary Spring - Waters (fresh waters, as they are generally called) contain salts of the alkalies and alkaline earths-chlorides, sulphates, and bicarbonates of potassa, soda, lime, and magnesia. The most common salts are the chlorides of potassium and sodium, the sulphates of soda and lime, and the bicarbonates of lime and magnesia. Besides these alkaline and earthy salts, we almost invariably find silica, the substance of quartz, to the amount of a grain or less in a gallon. În wells which receive drainage-waters in the neighborhood of dwellings we generally find nitrates, nitrites, and ammonia salts, derived from decomposing animal matter in the soil. The total quantity of dissolved impurities in ordinary spring waters varies from 1 or 2 grains to 80 or 90 grains in a U. S. gallon of 231 cubic inches.

Hard and Soft Waters.-Lime salts in water are the cause of what is called hardness. They decompose the soap used in washing, forming a flocculent insoluble compound and destroying its detergent properties. In Glasgow the saving to the people in soap, due to the introduction of the pure water of Loch Katrine in place of the hard well waters previously used, is said to amount to $180,000 per annum. Soap is an excellent reagent for testing water-a fact which is well known, though but few persons understand that it indicates the lime compounds only. As bicarbonate of lime is destroyed by boiling, with the formation of insoluble carbonate of lime, which does not act on soap, it is said to produce temporary hardness, while sulphate of lime, which is not affected by boiling, produces permanent hardness.

Organic matters of various kinds are always present in natural waters. They are derived from the decomposition of plants and animals, chiefly the former. They are both nitrogenous (albuminoid) and non-nitrogenous. Several of them have been identified as crenic and apocrenic acids (see article HUMUS), but most of them are of unknown

water of the river Loka in Sweden, which contains only 2th of a grain of impurities in a gallon. Rivers are more likely to be charged with suspended impurities, for the reason that their waters, which have not been filtered through the soil, carry with them a certain quantity of mud and organic matter. That is what we see in Potomac water; it has had no opportunity to settle, and has not been filtered out. When water flows into lakes and the sediment subsides, it becomes clear; but in streams where the water runs rapidly it has no opportunity to deposit its sediments, and it often appears very turbid. The water of the Mississippi contains 40 grains of mud per gallon, and it is estimated that this river carries 400,000,000 tons of sediment per annum into the Gulf of Mexico; the Ganges is said to carry down 6,368,000,000 cubic feet annually. This transportation of mud in suspension has produced large deposits at the mouths of these rivers. All of the State of Louisiana, and considerable portions of other States which border upon the lower Mississippi, have been formed by the deposition of these sediments brought from higher levels. This mud is rich in plant-food, and the land which it produces is very fertile. The Mohawk Flats are famous for their fertility, and the annual overflow of the Nile is the chief reliance of the poor Egyptians who cultivate the fields enriched by its sediments.

Rivers flowing through populous districts and receiving the drainage of the towns on their banks often become contaminated with sewage to such a degree as to make them positively offensive, and dangerous to those who drink their water.

The waters of ponds are more largely supplied by springs; they are generally clearer than those of rivers, as the suspended impurities subside. They often exhibit more or less color, due to peaty matters held in solution. This is specially the case in the Dismal Swamp and in new reservoirs; such matters are entirely harmless.

Living Organisms in Water.-In addition to the soluble and suspended impurities already mentioned, we find

FIG. 5.

409

The subject was investigated by Dr. John Torrey, who reported the presence of myriads of minute plants (Nostoc), which by their death and decomposition communicated to

FIG. 6.

Organisms in Ridgewood Water.

the water a disagreeable taste and odor. The ora of entozoa (the eggs or embryos of parasitic worms) sometimes enter the body by the water we drink. We have no reason to believe, however, that the animalcula in the Croton, Ridgewood, and other city waters of the U. S. are such embryos, or, in fact, that they are objectionable. Natural waters are never free from bacteria and their germs; they are found even in distilled water. Being ever present in the air and the soil and on the surfaces of rocks, plants, etc., and in all dust, they inevitably find their way into all bodies of water. Unless water has been subjected to a most complete filtration through porous rocks or beds of extremely fine sand, it will continue to carry the germs of bacteria. Much needless alarm has recently been created by the popular discussion of these facts, and methods for the sanitary examination of drinking-water have been founded upon the counting of these germs in measured quantities of water. But, as these bacteria are usually harmless, their presence need not excite alarm. (See WATER ANALYSIS, in APPENDIX.)

III. SEA-WATER.-The ocean is the great and final receptacle of all waters which escape evaporation, and it consequently receives the mineral and other impurities which the rivers and smaller streams carry along in solution or suspension. From the surface of the ocean the water evaporates into the atmosphere, to fall again in the form of rain.

Analysis of Sea- Water, by Von Bibra.

Atlantic Ocean.

1.0275 1671.34

Dead Sea.

1.17205 6702.73 682.63

Organisms in Croton Water.

living organisms in water-animals and plants. Figs. 5 and 6 show some of the most common forms of the Croton and Ridgewood waters. They were prepared by Dr. William B. Lewis for the metropolitan board of health.

These animals when magnified by the microscope are very frightful in their appearance and motions, but they are not really objectionable. The plants even exercise a purifying influence on the water. It is stated by a celebrated English author that the providential spread of the

American weed Anacharis alsinastrum has saved thousands of lives by the purifying influence which it has exerted on the watercourses in certain districts in England. These plants liberate oxygen, which attacks poisonous dead organic matter and destroys it, thus ridding the water of its most dangerous impurities. It occasionally happens, however, owing perhaps to some peculiarity of the season, that microscopie animals or plants multiply to such an unusual extent in the waters of lakes or rivers as to produce serious annoyance. This occurred some years ago in the Croton Lake.

Chloride of manganese

3.35

Bromide of sodium Iodide of sodium....