WELL. 



ceffarily accompanying fprings of this kind, that the dig- 

 ging wells in a higher pofition, will not fenfibly diminifh 

 the quantity of water that flows over the lower furfaco of 

 the clay ; for, as the well, as foon as it is filled, mull over- 

 flow, that will not intercept one drop more water than what 

 is drawn up out of it. Were it even poflible to pump the 

 water from the well as fait as it falls into it, fo as never to 

 allow one drop to run over, the cafe would not be much al- 

 tered, becauf<? no more water could be thus intercepted than 

 that which would have flowed into the mouth of the well in 

 its defcent ; fo that every drop that would pafs the mouth 

 of the well, on either fide, would flow forward to the lower 

 fituation, as if no well had ever been made. Hence we fee 

 that fprings of this fort can never be intercepted by wells, 

 or fenfibly affefted by other wells placed either higher or 

 lower than them. Wherever this caufe exifts, water will be 

 found nearly in equal abundance, whatever the relative fitua- 

 tion of the well may be in refpeft to others : nothing but 

 an uninterrupted trench, of a fize fufBcient to intercept all 

 the water as it flowed, and to carry it off, could dry up the 

 fprings or wells below it. 



It may alfo be obferved, that if the bed of fand be of 

 great extent, if it be at laft fupported by a bed of clay or 

 other impervious matter, water will undoubtedly be there 

 found, whatever may be the depth of the bed of fand above 

 it, if a well be dug through it ; for, as the water that falls 

 in (howers upon the earth's furface neceffarily finks through 

 that pervious ftratiam, it is foon beyond the reach of the fun, 

 fo as not to be evaporated, and muft; fink downwards till it 

 meets with an impervious ftratum, fo that there can be no 

 doubt but that under the immeafurable deferts of Lybia, 

 there muft be water in abundance to fupply any number of 

 perfons, were wells there funk to the requifite depth ; nor is 

 that depth, perhaps, in many cafes, nearly fo great as has 

 been in general apprehended. 



There are many other cafes of ftrata and fprings, as con- 

 cerned in the opening and forming of wells, that conftitute 

 different claffes of fprings for this ufe, as thofe where the 

 water is eonfined and pent up in retentive beds, fo as to be 

 capable of fupplying wells by fimply boring down into 

 them, or making flight openings in other ways, by which 

 the water may flow up. Some inftances of thefe and other 

 forts will be noticed and confidered below. 



In the execution of the work of digging wells, there is 

 no great difficulty, the perfon employed in the bufinefs 

 chiefly working down by means of a fmall fliort-handled 

 fpade and a fmall implement of the pick-axe kind ; the 

 earthy materials being drawn up in buckets by the hand or 

 a windlafs fixed over the opening for the purpofe. Where 

 perfons converfant with this fort of bufinefs are employed, 

 they ufually manage the whole of the work, bricking round 

 the fides with great facihty and readinefs ; but in other 

 cafes, it will be neceffary to have a bricklayer to execute 

 this part of the bufinefs. As the cxpence and trouble of 

 digging and getting up the materials in thefe cafes are con- 

 fiderable, other means have been had recourfe to, in order to 

 leflen or prevent them. The moft ingenious of thefe is that 

 propofed by a French philofopher, who has advifed that the 

 ground fhould be perforated to a fufficient depth by means 

 of an auger, or borer : a cylindrical wooden pipe being then 

 placed in the hole and driven downward with a mallet, and 

 the boi-ing continued, that the pipe may be forced down to a 

 greater depth, fo as to reach the water or fpring. In pro- 

 portion as the borer becomes filled with earth, it fliould be 

 drawn up and cleared, when by adding frefli portions of 

 pipe, the boring may be carried to much extent under 

 ground, fo that water may in moft cafes be thus reached and 



obtained. It is ftated that wells made in this manner are 

 fuperior to thofe conftrufted in the common method, not 

 only in point of cheapncfs, but alfo by affording a more cer- 

 tain and abundant fupply of water, while no accident can 

 pofTibly happen to the workmen employed. In cafe the 

 water near the furface fliould not be of a good quality, the 

 perforation may be continued to a ftlU greater depth, till a 

 purer fluid can be procured ; and v.-here wells have become 

 injured or tainted from any circumftance or accident, when 

 previoufly emptied, and the bottom perforated in a fimilar 

 manner, fo as to reach the lower flieet of water, it will rife 

 in the cylindrical tube in a pure ftate into the body of the 

 pump fixed for the purpofe of bringing it up. 



This is certainly an ingenious, ready, and fafe method of 

 forming wells ; but it requires a large expenfive boring 

 auger, and which, if carried to any great depth, would 

 ftand in need of an apparatus for being wrought by means 

 of horfe-power. Bcfidcs, other parts would be neceffary, 

 fuch as punches, chifels, and other fuch mouth-pieces, for 

 being fixed on occafionally, in order to work through hard 

 ftrata of m'iny different kinds ; and, in fome inilances, it 

 would be liable to be wholly impeded by the nature of the 

 fubftances thrqugh which it had to get in its paflage to the 

 water or fpring. In fome cafes, it may, however, anfwer in 

 a ready and perfeft manner, and be of great ufe and conve- 

 nience. There would be much difficulty, too, in driving 

 down the wooden pipes in many cafes, efpecially if to any 

 confiderable depth, and great nicety be required in making' 

 them fo as pretty exaftly to fit the aperture formed by the 

 boring auger. And, befides, from their fmallnefs, except 

 they were made from caft-iron, or fome other proper metal, 

 they would not by any means be durable, but fpeedily be- 

 come leaky and out of order. The beft mode would 

 therefore probably be that of having metallic -pipes caft for 

 the purpofe, and fo formed as to fit exaftly upon each 

 other, to any depth that might be neceffary in finking 

 wells. 



In fome cafes and kinds of ftrata, wells formed in this 

 manner could not, however, anfwer perfeftly, as they re- 

 quire much width or fpace at the bottom parts, and fome- 

 times to be dug confiderably into the impervious bed or 

 matter, as feen above. 



It may be neceffary and ufeful to fhew the nature of the 

 different beds or layers of materials which are dug or funk 

 through in forming the openings for wells in different cafes, 

 as well as the manner and heights to whicli the water or 

 fprings rife in them under various circumftances. Some 

 cafes of wells are ftated in the Correfted Report on Agri-- 

 culture, for the diftrift about the metropolis, that explain 

 thefe points in a pretty clear manner. 



It is noted, that in the year 1791, the prefent vicar of 

 Northall, then Mr. archdeacon Eaton, agreed with Mr. 

 White, of Putney, to fink a well in the court adjoining to 

 the vicarage. The workmen firft dug through a bed of 

 folid blue clay 60 feet in depth, under which was a flratum 

 of rough porous ftone about a foot thick. To this fuc- 

 ceeded a fecond ftratum of clay, differing a little from the 

 former in colour, 29 feet in depth ; then a ftratum of fine, 

 grey fand, intermixed with extraneous foffils, as oyfter- 

 ihells, bivalves. Sec. This ftratum continued for twenty- 

 three feet, and was fucceeded by another of clay, of a red 

 or ferruginous colour, Icfs firm in its confiftence than that 

 which occurred before, and intermixed now and then with 

 gravel and ftones of a confiderable fize. After digging 

 through this ftratum for fifty- one feet, at the depth of one 

 hundred and fixty-four feet from the furface, water was 

 found, which, on the removal of the ftone which lay imme- 

 O o 2 diately 



