5PRING. 



of either boring, orliaving recourfe to the making or finking 

 of pits in the land, for removing and taking away the wetnefs. 

 It has been found that fields or grounds of confiderable ex- 

 tent, wliich lie upon irregular banks, hills or knolls, have 

 been readily drained in this manner ; though the water 

 which rofe and illued out from the fprings in particular parts 

 of them, rendered them before of but very little value : and 

 though many drains, in improper diredlions, and not pro- 

 perly cut, had been before formed in them, at great ex- 

 pence, for draining off the wetnefs without efTeft. This 

 has been nccomplifhed by cutting drains to fuitable depths 

 through the porous fubitrata, and in fuch direftions as to 

 cut off the fprings commg from the higher grounds ; or to 

 take the water of them away, which lodged in the hollow 

 parts of the land. Such drains have often fpeedily removed 

 the wetntfs, without colling a tenth part ot what was paid 

 for the others, or taking into the account the difference 

 of keeping them in order, which mult be a mere trifle, when 

 compared with that of the others, as they were moftly on a 

 loofe bottom, and made lo lma!l, as to be readily choaked up 

 and dellroved. The nature of the fituation, and the lie of 

 the (Irata of which fuch lands are formed and compofed, 

 readily explain the realon why the moi'.ture in fuch cafes is 

 fo quickly removed by properly cut and direfted drains, as 

 it ariles, in molt inftanccs, from the inclination of the ftrata, 

 which is commonly towards the hollow part? of the grounds, 

 and from their frequently terminating on the lides of Inch 

 banks, hills, or knolls, under the impervious, clayey, marly, 

 or lliff loamy ftrata, though for the moll part upon them. 



Millakes in the modes of cutting the drains, and in the 

 direftions they ihould have for properly intercepting and 

 taking away the water of the fprings, are almott every 

 where in Inch cafes committed, and valt expeuee thereby not 

 unfrequently incurred ; it is confequcntly of much import- 

 ance, in all fuch inltauces, to have a proper plan laid down 

 before any part of fuch works be undertaken. 



There are fometimes fprings and wetned'es found on the 

 tops of bai;ks and hills, where the ground which is conti- 

 guous is much lower on all fides ; but in fuch cafes they are, 

 in many inllances, fupplied with the water from higher 

 ground at a diftance, by means of metaUic, mineral, or 

 other fubftrata, lying in a particular curving direftion, be- 

 tween impervious ftrata, from the higher parts of the land 

 to the lower. The fprings, in thefe cafes, ifl'ue forth at the 

 points where the metals crop out. 



The drainage, in fuch cafes, is to be accomplifhed by 

 forming fuitable outlets for the water, and by boring or 

 finking piis through the porous or metallic ftrata, fo that 

 the water flowing through them may be intercepted, and re- 

 duced to fuch a level, that the fource of the fprings may be 

 cut off, and the ground on the top and on both fides of the 

 declivity become dry. By this means the metals, to that 

 depth, may be rendered capable of being wrought, with- 

 out any inconvenience from the water. 



In the above method, the continuation of the ftrata is fup- 

 pofed to keep on the fame rife, in the high ground on the 

 north fide of the rivulet, to a much higher level than the line 

 of fprings, by which means, the fprings iffuiug from the 

 crop of the metals are fupplied. 



By bringing up a cut from the rivulet into the bank an 

 outlet will be obtained for the water, free from that of the 

 rivulet ; and by boring or finking a pit, the water flowing 

 through the porous ftrata will be reduced to a level, and of 

 courfe the fource of the fprings will be intercepted, and the 

 ground on the top, and on both fides of the declivity, be- 

 come dry ; and the metals, to that depth, may be wrought 

 free of water. 



This could not be effeAed by boring from the bottom of 

 the rivulet, or any run of water, for the prefture of the run- 

 ning water above would prevent that below from rifing 

 freely, and fmall ftones or fand would be lodged in the hole. 

 If the ftrata crop out to the furface, and caule wetnefs, the 

 pit or bore may be contmued till it reach it ; but lying at 

 inch a depth, and covered with lo much clay on the furface, 

 the water contained in it may do no injury to the ground 

 above it. 



Drainage in Lands compofed of alternate Beds of Clay and 

 Sand ; and other mixed Soils. — In diftrifls where the foil is 

 compofed of an intermixed variety, and where clay forms 

 the molt predominant part, draining is, according to the 

 firlt writer above noticed, a work attended with much 

 greater difficulty and expence, than in thofe V\here both the 

 furface and internal ftrata are more regularly difpofed. In 

 thefe kinds of ioils, where every refervoir of water is un- 

 connedtcd with another, being feparated by intervening beds 

 of clay, the partial coUcftions of water that thefe refer- 

 voirs contain are fo much augmented in time of great rains, 

 that, bemg full to the level of the furface of the furrounding 

 clay, the water having then a free ifiue, as over the edges 

 of a difh, fo overflows and furcharges the furface of that 

 clay, and renders it fo wet and four, that its produce be- 

 comes every year m.ore fcanty, and the nature ot the foil 

 itfelf more barren. As thefe fand-beds have no communi- 

 cation with each other, it requires as many drains as they 

 are in number to extract the water from each of them. From 

 tlicnearcil and loweft part of the field to be drained, a trench 

 mull be cut up to the higheil or moll diftant fand-bank, in 

 fuch a direftion, as, if polfible, to hit on fome of the inter- 

 mediate fand-beds, and fave the making a longer fide-cut, 

 otherwife neeeflary ; but where this would give many auk- 

 ward turnings to theraain trench, it would necellarily lengthen 

 it ; and where, by croffing the beds in places higher than the 

 furface of the furrounding clay, it would confiderably in- 

 creafe the depth of it, and be difficult to work, efpecially if 

 rock or running-fand ; drains in form of the letter Y mult 

 branch off to fuch beds, to draw off the water they 

 contain, and convey it into tho leading one. Although the 

 fand-beds throw out the water they contain on all fides, fo 

 as to inj'ire the clay-furface immediately round them, a 

 drain on the o-e fide will completely extraft the water from 

 the whole, and prevent it from breaking out at either fide, 

 provided that where it is cut be the loweft. It may be ob- 

 ferved, that unlefs the drain is fo cut, it cannot be fuppofed 

 to have this effett, while the water can find an outlet on 

 the oppofite fide of the bank, lower than the bottom of the 

 drain. This ought, therefore, to be previcufly confidered ; 

 and by carefully examining the ground, and applying the 

 fpirit-level, the proper fide for the drain may eafily be 

 found : or, if the water burfting out round the bank has 

 been obferved in dry feafons to run at ore place, and not 

 at others, it is a proof that this is the loweft point ; and by 

 cutting the drain in the direftion of this level, the water will 

 afterwards be prevented from rifing to the height of the 

 upper outlets, or above the level of the bottom of the drain, 

 even in the wettell feafons. In many cales, the whole water 

 that caufes the wetnefs, and fupplies the ether land-beds be- 

 low, may arife from the upper fprings, paffmg over the 

 upper foil, and through the difi'trent fand-beds ; by being 

 prevented from defccnding deeper than the retan-ir.g bed of 

 clay. In this cafe, the drainage of the whole field may be 

 accomplifhed with much lets difficulty and expence than in- 

 the former. After the m.am condudting drain from the out- 

 let has been cut, a drain on the upper or higher top part, quite 

 acrofs, muft next be made, which will intercept and cut ofE 

 12 the 



