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WELL

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Originally appearing in Volume V28, Page 506 of the 1911 Encyclopedia Britannica.
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WELL , the name given to an artificial See also:

boring in the eartl through which See also:water can be obtained. Two classes may bi distinguished: shallow or See also:ordinary See also:wells, sunk through a per became a leading authority on the subject, but none of his later I meable stratum until an impermeable stratum is reached; an, proposals—not even the See also:Weldon-Pechiney See also:magnesia See also:process, deep and Artesian wells (q.v.), the latter named from Artoi; in See also:France, which are sunk through an impermeable stratum down into a water-bearing stratum which overlies an impermeable st See also:rat um. Obviously ordinary wells can See also:supply water very cheaply, but, since impurities readily reach them, there is See also:great See also:risk of contamination. The same does not apply to deep wells, such water being usually See also:free from organic impurities. In ordinary wells, and in deep wells, the water requires pumping to the See also:surface; in artesian wells, on the other See also:hand, the water usually spouts up to a greater or less height above it. The Secondary and See also:Tertiary See also:geological formations, such as those underneath See also:London and See also:Paris, often See also:present the See also:appearance of immense basins, the boundary or rim of the See also:basin having been formed by an upheaval of the subjacent strata. In these formations it often happens that a porous stratum is included between two impermeable layers of See also:clay, so as to See also:form a See also:flat porous U See also:tube, continuous from See also:side to side of the valley, the outcrop on the surrounding hills forming the mouth of the tube. The See also:rain filtering down through the porous layer to the bottom of the basin forms there a subterranean See also:pool, which with the liquid or semi-liquid See also:column pressing upon it constitutes a sort of huge natural hydrostatic See also:bellows. It is obvious then, that when a hole is bored down through the upper impermeable layer to the surface of the See also:lake, the water will be forced up by this pressure to a height above the surface of the valley greater or less according to the See also:elevation of the level in the feeding column, thus forming a natural See also:fountain. In the Tertiary formations, the porous layers are not so thick as in the Secondary, and consequently the occurrence of underground lakes is not on so See also:grand a See also:scale; but there being a more frequent See also:alternation of these sandy beds, we find a greater number of them, and often a See also:series of natural fountains may be obtained in the same valley, proceeding from water-bearing strata at different depths, and rising to different heights. It does not follow that all the essentials for an artesian well are present, though two impermeable strata with a porous one between may See also:crop out See also:round a basin. There must also be continuity of the permeable See also:bed for the uninterrupted passage of the water, and no See also:breach in either of the confining layers by which the water might See also:escape.

It has occasionally happened that on, deepening the See also:

bore, with the See also:hope of increasing the flow of water, it has ceased altogether, doubtless from the See also:lower confining layer being pierced, and the water allowed to escape by another outlet. The subterranean pool is frequently of small extent, and of the nature of a channel rather than of a broad See also:sheet of water; and the existence of one See also:spring is no See also:guarantee that another will be found by merely boring to the same See also:depth in its neighbourhood. Faults also have an effect on the supply, which in many cases has been found to increase by cutting headings or adits. The most suitable strata in See also:England are the See also:Chalk, Oolite, New Red See also:Sandstone and Lower See also:Greensand; London is in See also:part supplied by the Chalk, whilst See also:Liverpool utilizes the New Red. The theoretical determination of the existence of artesian conditions can be arrived at only by a thorough acquaintance with the See also:geology of the See also:district. Although water from deep wells is free from organic See also:matter, it usually contains salts such as See also:calcium bicarbonate, &c., which make the water unsuitable for washing and certain manufacturing purposes although it is See also:fit for drinking. The See also:mechanical appliances employed in boring for water are practically the same as in boring for See also:petroleum (q.v.). The upper part of a deep well may be of See also:brick, the continuation being lined with See also:steel pipes, or, better, it may be lined with See also:metal for its entire length. One of the most remarkable artesian wells is at Grenelle, near Paris. The operation of boring extended from 1834 to 1841; after a depth of 12J4 ft. had been reached (May 1837), a length of 270 ft. of the boring rods See also:broke and See also:fell to the bottom of the hole, and nearly fifteen months' See also:constant labour was required to pick it up again. Discouraged by the delay, the See also:French See also:government was to have abandoned the project after a depth of 1500 ft. had been reached without any satisfactory result; but See also:Arago prevailed on them, to prosecute the See also:work, and an additional depth of about 300 ft. proved the correctness of Arago's theory. On the 26th See also:February 1841, at a depth of 1798 ft., the boring rods suddenly sank a few yards, and within a few See also:hours a vast column of water spouted up at the See also:rate of 6ao gallons per See also:minute, and at a temperature of nearly 82° F.

See also:

Prior to this no artesian boring had reached even woo ft.; and that of Grenelle was the deepest executed till the completion (12th See also:August 1853) of the See also:salt-spring at See also:Kissingen, in See also:Bavaria, which throws up a column of water to the height of 58 ft. from a depth of 18781 ft. The most remarkable feature of this spring is that the projecting force is due, not to hydrostatic pressure, but to that of carbonic See also:acid See also:gas generated at the junction of the See also:gypsum with the magnesian See also:limestone, about 168o ft. down. See also:Modern mechanical improvements have enabled See also:engineers to exceed these Artesian dimensions considerably, and at a greatly diminished cost. The well at Passy, near Paris, which is supplied from the same water-bearing stratum as that of Grenelle, was bored by See also:Kind in a very See also:short See also:time, having been begun on 15th See also:September 1855, and carried to a depth of 1732ft. by See also:March 1857. Its See also:total depth is now about 1923 ft. with the See also:diameter of 2 ft. 4 in. at the bottom; and it throws up a continuous stream of water at the rate of five and a See also:half million gallons per See also:day to a height of 54 ft. above the ground. Among other deep wells sunk in the Paris basin subsequently to those of Grenelle and Passy, the following may be mentioned. A gigantic bore, 5 ft. 7 in. in diameter, was begun in See also:January 1866 at La Chapelle, and by See also:November 1869 had reached a depth of 1811 ft., the intention being to extend it to a depth of 2950 ft. A bore of 19 in. diameter was carried down to a depth of 1570 ft. in about two and a half years (1864-1867), for the purpose of obtaining a water-supply for the See also:sugar refinery of Say in Paris; and the same engineer who executed this work (Dru) began in 1866 an artesian boring of the huge diameter of 61 ft. at the part of Paris named See also:Butte aux Cailles, to be carried down to a depth of 260o to 2900 ft. In the Paris basin there are a great many other wells, varying from 300 to 400 ft. in depth, and from 2 to 8 in. in the diameter of the bore-hole. The Tertiary chalk strata over which London stands have been riddled with artesian borings for the See also:sake of pure water supply.

Many of the large London, factories, See also:

railways, institutions are supplied by artesian wells over 300 ft. deep. At Merton in See also:Surrey, at See also:Brighton, at See also:Southampton, all along the See also:east See also:coast of See also:Lincolnshire, and in the See also:low district between the chalk wolds near See also:Louth and the See also:Wash, artesian borings have See also:long been known, and go by the name of See also:blow-wells among the See also:people of the district. The See also:general level to which the water rises in the London district has been very sensibly lowered by the immense number of perforations that have been made; and in several wells where the water formerly See also:rose to the surface, it now requires to be pumped up. None of the artesian borings in England approach the depths frequent on the See also:Continent and in See also:America. The See also:average depth of the water-bearing stratum around Paris is six times that of the London chalk beds; and in some parts of See also:Germany and of America, wells have been sunk to even See also:double the depth of the Parisian wells of Grenelle and Passy. In See also:Chicago there are several wells more than 2000 ft. deep; and at See also:West Chicago in Dupage See also:county, See also:Illinois, there is one 3081 ft. deep. In the See also:city of St See also:Louis, See also:Missouri, there is an artesian well 3843; ft. deep, yielding a few gallons of salty water (temperature, 105° F.), a minute; boring was stopped in September 1868. Among the deepest borings in the See also:world are: a well in See also:Putnam Heights, See also:Windham county, See also:Connecticut, 6004 ft. deep and 6 in. in diameter, yielding 2 gallons per minute with water rising to 4 ft. from the surface; one at Schladenbach (5735 ft.), near See also:Leipzig; one 12 M. See also:south-east of See also:Pittsburg, which is 5575 ft• deep and 61 in. in diameter; one in See also:Lawrence county, See also:Alabama, 5120 ft. deep and 6 in. in diameter, yielding gas, oil and salt water; and one (about 4200 ft.) at Sperenberg 20 M. from See also:Berlin, sunk for the purpose of obtaining a supply of See also:rock salt,—the salt See also:deposit here is 3907 ft. thick. The following are some of the other most important artesian sinkings that have been made. At See also:Louisville, See also:Kentucky, a bore of 3 in. was carried to a depth of 2086 ft. between See also:April 1857 and the summer of 1858; it yields 264 gallons a minute and its fountain rises 170 ft. high. At See also:Charleston, South Carolina, there are: one well 2050 ft. deep and 4 in. in diameter, yielding 450 gallons a minute; another 1945 ft. deep and 5 in. in diameter, yielding 695 gallons a minute; and three more each exceeding 1900 ft. in depth. In 1858 a well at Neusalwerk,near See also:Minden, had reached the depth of 2288 ft.

At See also:

Bourne, Lincolnshire, there is a well 95 ft. deep, which yields over half a million gallons of water per day, the pressurebeing sufficient to supply the See also:town and force the water to the tops of the highest houses. There is one in See also:Philadelphia (See also:Mount See also:Vernon and 13th sts.), 3031 ft. deep and 8 in. in diameter, yielding 2600 gallons a minute. There are several deep wells in South Dakota: in See also:Aberdeen City there are two 1300 ft. deep with flows of 1350 and woo gallons, respectively, per minute. Two artesian wells at See also:Croydon supply a million gallons of water per day; and Brighton draws over a million gallons from artesian sinkings. There is a well at Bages, near See also:Perpignan, which gives 330 gallons per minute; and one at See also:Tours, which jets about 6 ft. above ground, and gives 237 gallons per minute. The boring of wells in the great See also:desert of See also:Sahara is a very See also:ancient See also:industry; and some oases are supplied with water wholly from artesian wells. The average depth of these is from 16o to 200 ft., and the upper strata have only to be pierced to give a constant stream. With their See also:primitive methods of boring, the See also:Arabs often labour for years before they reach the wished-for pool; and with only See also:palm See also:wood as a casing, they have great difficulty in keeping the bore-hole from closing up by the drifting of the See also:sand, and they require to scour them out periodically. Since 1858 an immense number of perforations have been made by French engineers, and the fertilising effect upon the sandy desert plains has already made itself apparent. The importance of deep wells in such cases cannot be over-estimated. Artesian wells have been made to supply warm water, for keeping hospitals, &c., at a constant temperature. Invariably the temperature of water from great depths is higher than that at the surface.

The temperature of the water in the well at Grenelle is 82° F., and that of Passy the same, showing that they have a See also:

common source. Kissingen well has a temperature of 66° F., that of St Louis one of 730.4 F. that of Louisville 762° F., and that of Charleston 87° F. The average rate of increase of temperature is 1° for a descent of from 40 to 55 ft. In See also:Wurttemberg the water of artesian wells is employed to maintain in large manufactories a constant temperature of 47° when it is freezing outside. Artesian See also:waters have also been employed to reduce the extreme See also:variations of temperature in See also:fish-ponds.

End of Article: WELL

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