698 



PRACTICE OF AGRICULTURE. 



III. 



be saved. In these cases, when drains are made, they should always be cut as narrow as it is possible to 



make them, and, alter the holes have been formed 



6-jy 



•;•'*; 



6:iO 





I 





in them by boring, filled up with loose stones to within 

 about a loot and a half of the surface, which space 

 may be made up by a portion of the earth that had 

 been taken out, putting in turf with the green side 

 to the stones before the earth is thrown in By this 

 means the water and prejudicial moisture of the peat, 

 or upper soil, may be taken away by the drains, and 

 pass off through the holes that have been formed in 

 their bottoms. But where pits are employed, these 

 should only be filled with small stones to the level of 

 the bottom of the drain, the filling being performed 

 as soon as possible after they are formed. (Ander- 

 son's Treatite on Draining, p. 8s.) Where there is a 

 chalky stratum below, alter taking it out, the flints 

 contained in it may be made use of in this way with 

 much advantage ; and where the drains can be carried 

 into quarries, where the stone is much fissured no- 

 thing more will be necessary. Where land of this 

 sort is afterwards to be ploughed, great attention 

 should be given to the forming of the ridges and 

 giving them a regular descent towards the main 

 drain, which will contribute greatly to the assistance of the others in conveying off heavy falls of rain, 

 water when they occur. 



4244. But a necessary precaution previously to any attempt to drain lands of this kind in the way that 

 has been described, is to ascertain whether the porous stratum under the clay be dry, and capable of 

 receiving the water when let down into it ; or already so loaded with moisture itself, as, instead of receiving 



more from above, to force up a large quantity to the 

 surface, and thus increase the evil it was intended to 

 remove. This may be the case in many instances, and 

 the substratum contain water which affords no appear- 

 ances of wetness on the surface, at the place, on 

 account of the compact body of clay that is placed over 

 it, but which, from its being connected with some 

 spring that is higher, may flow up when an opening oi 

 passage is given it, either by means of a pit or the 

 auger. In this way a greater quantity of water might 

 be brought to the surface, which, from its being con- 

 fined by the surrounding banks, would render the 

 ground much more wet than before, and in particular 

 situations produce very great degrees of wetness. 

 When the surrounding high ground declines lower 

 than the bog, though it may be at a considerable dis- 

 tance, by the aid of the level, and the appearance of 

 the surface, the nature of the stratum underneath 

 may, in some degree, be ascertained ; and, notwith- 

 standing it may already contain water, a drain may be 

 „ formed into it to carry off that water, and what may 

 3 a|i§8 likewise be let down into it from the retentive stratum 

 that lies above it. It must be confessed, however, 

 that cases where surface water can be let down through 

 a retentive stratum to a porous one that will actually 

 carry it off, are very rare. When these occur, it is 

 chiefly in limestone or coal districts, where the surface 

 is hilly or rugged (Jig. 630.), and more calculated for 

 the pursuits of the mineralogist than those of the agricultor. 



Sect. III. Braining Hill'/ Lands. 



4245. Braining hilly lands is not in general attended with great expense, as the chains 

 need seldom be covered or filled up, only in such places as maybe sufficient for passages 

 for the animals to cross by : and though, where the depth of the trench does not come 

 to the water confined below, it may be necessary to perforate lower, there need not be 

 any fear that the holes will fill up, even where the drain is left open ; as the impetuosity 

 of the water itself will remove any sand or mud that may fall into them, where much 

 flood or surface water does not get in. Small openings may, however, be made along 

 the upper side of the trench, in order the more effectually to secure them against any 

 obstructions ; and in these the perforations may be made, leaving the mouth of the holes 

 about six inches higher than the bottom of the drain, which will be without the reach of 

 the water that may be collected during the time of heavy rains. 



4246. One of the greatest improvements of the hilly sheep-pastures of Holland has been effected by 

 drainage, while the expense is comparatively small. The depth and width of the small ones are only 

 those of the spade. They are usually carried across the face of the hills in a slightly inclined direction, 

 so as to avoid the injury "of too rapid' a descent after heavy rains; and these small cuts open into a lew 

 larger, formed with due regard to the same principle ; the whole at last, for an extent of several hundred 

 acres, being led into one still larger, which discharges itself into the nearest rivulet. Improvements of 

 this kind arc, perhaps, of greater benefit to the individual proprietors of land who undertake them than 

 any other. 



4247. The sides or declivities of man;/ hills, from the irregularity of the disposition of 

 the strata that compose them, are often covered with alternate portions or patches of wet 

 and dry ground. By the general appearance of the surface and the vegetable products 

 that are grown upon it, the nature and direction of the internal strata may frequently 

 be ascertained with so much certainty as to determine the line or direction of a drain 

 without tlie necessity of examining below the surface of the land. As the ease or difficulty 



