WELL. 



M. Blondel informs the Royal Academy of Sciences of 

 a device they ufe, in the Lower Auftria, which is encom- 

 paiTed with the mountains of Stiria, to fill their wells with 

 water; viz. that they dig in the earth, to the depth of 

 twenty or twenty-five feet, till they come to a clammy 

 earth, which they bore into, continuing the operation 

 till the water breaks forcibly out ; which water, in all 

 probability, comes from the neighbouring mountains, in 

 fubterraneous channels. Caffini obferves, that in many 

 places of Modena and Bologna, they make themfelves 

 wells by the fame artifice. Dr. Derham adds, that the 

 like has been fometimes found in England, particularly 

 in Effex. 



In the Philofophica Tranfaftions we are informed, by 

 Mr. Norwood, that, in Bermudas, wells of frefh water 

 are dug within twenty yards of the fea, and even lefs, 

 wh-^h rife and fall with the tides, as the fea itfelf does. 

 He adds, that, in digging wells in that idand, they dig 

 till they come almofl to a level with the furface of the fea ; 

 and then they certainly find either frefh water, or fait : if it 

 prove freih, yet, by digging two or three feet deeper, they 

 always come at fait water. If it be fandy ground, they 

 ufually find frefh water ; but if hard lime-ftone rock, the 

 water is commonly fait, or brackifh. 



Lay-iuell, near Torbay, ebbs and flows very often every 

 hour ; though fomewhat oftener in winter than in fummer. 

 Dr. Oliver obfervts, iits flux and reflux fometimes return 

 every minute ; though, at other times, not above twenty- 

 fix or twenty-eight times in an hour. Philof. Tranf. 

 No. 104. 



In Scotland they have a well, which Sibbald has men- 

 tioned as foretelling florms. It is a deep and large well 

 near Edinburgh, and from the noifes heard in it at cer- 

 tain times is called by the people the routing well. They 

 go to this to liften after the prefagcs of weather, and it is 

 faid that ftorms are particularly foretold by it ; and that 

 noifes are not only heard in it before florms happen, but 

 that they are always heard determinately and diftinftly on 

 that fide whence the itorm will come. 



In the Philofophical Tranfaftions we have an account of 

 a boiling-well, &c. See Spring. 



Well, in Rural Economy, a deep circular opening, pit, 

 or fort of fliaft, funk by digging down through the differ- 

 ent ftrata or beds of earthy and other materials of the foil, 

 fo as to form an excavation for the purpofe of containing 

 the water of fome fpring or internal refervoir by which it 

 may be fupplied, for domeftic or other ufes of different 

 kinds. 



It is ufiial to have wells bricked round from the bottom 

 to the top, and frequently to have pumps fixed in them. 

 The width is moftly from three to four feet, which, where 

 the fprings are ftrong, may afford and contain a fufBcient 

 quantity of water. 



As wells are fupplied from fprings, and thefe are formed 

 in the bowels of the earth, by water percolating through the 

 upper itrata, and defcending downwards until it meets with a 

 ftratum of clay or other impervious material that intercepts 

 it in its courfe, it may naturally be concluded, that an 

 abundant fpring for this ufe need never be expefted in any 

 diftrift or place that is covered to a great depth with fand, 

 without an,y ftratum of clay to force it upwards, as is the 

 cafe in the fandy deferts of Arabia, and the immeafurable 

 plains of Lybia. Neither are we to expeft abundant fprings 

 for wells in any foil that confills of an uniform bed of clay 

 from the furface to a great depth ; for it muft always be in 

 fome porous ftratum that the water flows in abundance, and 

 it can be made to flow horizontally in that only, when it is 



fupported by a ftratum of clay, or other fubilance tliat is 

 equally impermeable by water. By this means is ex- 

 plained the rationale of that rule fo univerfally eftablifhed in 

 digging for wells, that if begun with fand, gravel, or other 

 fuch matters, it need feldom be hoped to find water until 

 clay is come to ; and that if clay be begun with, none can 

 be hoped for in abundance till fand, gravel, or porous rock 

 is met with. 



Hence, as the doftrine of wells is fo much and fo inti- 

 mately connefted with the nature of the ftrata and the 

 fprings afforded by them, it may not be unneceffary to ob- 

 ferve, that in cafes where differently formed ftrata of fand, 

 to a confiderable depth, reft upon beds of clay, and have a 

 free ifliie at the loweft ends of them, if wells were funk into 

 the fand-beds higher up no water could be there perma- 

 nently found until they penetrated quite through the ftrata 

 of fand, and went to fome depth into the beds of clay that 

 lie below them. In fuch cafes, the water could never rife 

 in the wells much higher than a certain point ; becaufe, 

 whenever it rofe as high as the porous fand, it would flow 

 along through it until it made its efcape below ; and if the 

 beds of clay fhould extend backwards under the ground a 

 great way, and at a great depth below the furface, fo as to 

 form an abundant and never-ccafing ftream under the beds 

 of fand, it muft neceffarily follow, that the wells will con- 

 tinue conftantly at the fame height, exaftly as in the cafe of 

 a ftrong bafon at a fountain, into which a pipe of water a 

 conftantly flows, fo as to keep it running over. 



If, however, the ftreams that run below the beds of fand 

 be fmall, and the draught of water from the wells, at par- 

 ticular times, be uncommonly large, the furface of the water 

 in the wells will of courfe be made to fink : they may be, 

 indeed, quite drained of water at times, fo as to require to 

 be left for a while till they fhall fill again. This may be 

 occafionally a very ferious inconvenience, and ought to be 

 guarded againft by enlarging the refervoir, which may be 

 effedled either by widening the diameter of the wells, or by 

 finking them to a greater depth in the clay, or by both 

 thefe means. Hence it appears, it is faid, that in cafes of 

 this fort, very wide wells ought always to be made. 

 Other cafes, however, will come to be noticed in the courfe 

 of this article, in which the ftraiteft well that can be 

 made, would fupply a quantity of water as abundant as 

 thofe that are wider. In thefe cafes, pipes as above will be 

 found very ufeful. 



Nor would the phenomena here defcribed, it is faid, be 

 in the leaft varied if the wells, inftead of being dug in the 

 fand immediately below the vegetable mould, fhould be firft 

 funk through a confiderable thicknefs of fome other ftrata. 

 The depth of the well only would be greater, and all other 

 circumftances the fame. 



It may be here noticed, that quickfand, when it comes in 

 the way of well-digging, affords impediments which can only 

 be furmounted with great labour and difficulty. The beft 

 and moft obvious remedy in fuch cafes when they occur, is 

 probably to endeavour to find the means of opening an outlet 

 by which the water may be fuffered to run off or difcharge 

 itfelf. This, where the quickfand is fituated above the level 

 of the fea,or fome adjoining plain, may in many cafes be effeft- 

 ed at very little expence,if due attention be beftowed upon the 

 pofition and natural dip of the ftrata, which may be dif- 

 covered bv various means befides boring. But there are 

 cafes, particularly where the quickfand is produced by a 

 cavity like a bafon fcooped out of the entire bottom, fo as 

 to contain water to a confiderable depth, which in fome par- 

 ticular lituations may be deemed incurable. 



It deferves alfo to be remarked, as a circumftance ne- 

 ceffarily 



