628 PRACTICE OF AGRICULTURE. Part III. 



S923. Where the uppermost stratum is so extremely thick as not to be easily penetrated, 

 or where the springs, formed by the water passing from the higher grounds, may be con- 

 fined beneath the third or fourth strata of the materials that form the declivities of hills 

 or elevated grounds, and by this means lie too deep to be penetrated to by the cutting of 

 a ditch, or even by boring {Darwin s Phytologia, p. 263.) ; the common mode of cut- 

 ting a great number of drains to the depth of five, six, or more feet, across the wet 

 morassy grounds, and afterwards covering them in such a manner as that the water may 

 suffer no interruption in passing away through them, may be practised with advantage, 

 as much of the prejudicial excess of moisture may by this means be collected and carried 

 away, though not so completely as by fully cutting off the spring. 



3924. As water is sometimes found upon thin layers of clay, which have underneath 

 them sand, stone, or other porous or fissured strata, to a considerable depth ; by perfor- 

 ating these thin layers of clay in different places, the water which flows along them may 

 frequently be let down into the open porous materials that lie below them, and the sur- 

 face land be thus completely drained. 



3925. Where morasses and other kinds of wetnesses are formed in such low places and 

 hollows as are considerably below the beds of the neighboring rivers, they may, proba- 

 bly, in many instances, be effectually drained by arresting the water as it passes down 

 into them from the higher grounds, by means of deep drains cut into the sides of such 

 hills and rising grounds, and, after collecting it into them, conveying it away by pipes, 

 or other contrivances, at such high levels above the wet lands as may be necessary : or 

 where the water that produces the mischief can by means of drains, cut in the wet 

 ground itself, be so collected as to be capable of being raised by means of machinery, it 

 may in that way be removed from the land. 



3926. The drainage of lands that lie below the level of the sea, can only be effected by 

 the public, and by means of locks erected for the purpose of preventing the entrance 

 of the tides, and by wind-mills and other expensive kinds of machinery constructed for 

 tlie purpose of raising the stagnant water. 



3927. Tfie superficial wetness of lands, which arises from the stiff retentive nature of 

 the materials that constitute the soils and the particular circumstances of their situations, 

 is to be removed in most cases by means of hollow surface drains, judiciously formed, 

 either by the spade or plough, and filled up with suita))le materials where the lands are 

 xmder the grass system ; and by these means and the proper construction of ridges and 

 furrows where they are in a state of arable cultivation. 



3928. Having thus exjdained the manner in which soils are rendered too wet for the 

 jmrposes of agriculture, and shown the principles on which the over-proportions of 

 moisture may, under different circumstances, be the most effectually removed, we 

 shall proceed to the practical methods which are to be made use of in accomplishing the 

 business in each case. 



Sect. II. Of the Methods of Draining Boggy Land. 



3929. In the drainage of wet or boggy grounds, arising from springs of water beneath 

 them, a great variety of circumstances are necessary to be kept in view. Lands of this de- 

 scription, or such as are of a marshy and boggy nature, from the detention of water beneath 

 the spongy surface materials of which they are composed, and its being absorbed and 

 forced up into them, are constantly kept in such states of wetness as are highly improper 

 for the purpose of producing advantageous crops of any kind. They are, therefore, on 

 this account, as well as those of their occupying very extensive tracts in many districts, 

 and being, when properly reclaimed, of considerable value, objects of great interest and 

 importance to the attentive agricultor. Wet grounds of these kinds may be arranged 

 under three distinct heads : first, such as may be readily known by the springs rising out 

 of the adjacent more elevated ground, in an exact or regular line along the higher side 

 of the wet surface ; second, those in which the numerous springs that show themselves 

 are not kept to any exact or regular line of direction along the higher or more elevated 

 parts of the land, but break forth promiscuously throughout the whole surface, and 

 particularly towards the inferior parts (Jig. 484 a), constituting shaking quags in every 

 direction, that have an elastic feel under the feet, on which the lightest animals can 

 scarcely tread without danger, and which, for the most part, show themselves by the 

 luxuriance and verdure of the grass about them ; that sort of wet land, from the oozing 

 of springs, which is neither of such great extent, nor in the nature of the soil so peaty 

 as the other two, and to which the term bog cannot be strictly applied, but which in 

 respect to the modes of draining is the same. {Johnstons Account of Elkington's Mode 

 of Draining Land, p. 19.) 



3930. In order to direct the proper mode of cutting the drains or trenches in draining 

 lands of this sort, it will be necessary for the draining engineer to make himself perfectly 

 acquainted with the nature and disposition of the strata composing the higher grounds, 

 and the connection which they have with that which is to be rendered dry. This may in 



