864 THE COMPLETE GRAZIER. BOOK ix. 



increasing greatly the productive powers of land which had been long 

 under cultivation. 



As no one system of drainage can be regarded as universally ap- 

 plicable to all soils, the method to be adopted in any particular case 

 must be largely determined by local considerations. 



If the land is not marked by any great inequality of surface, and 

 the wetness proceeds from the texture of the soil, particularly of the 

 substratum, the system of thorough under- draining applied to the 

 whole field is, perhaps, the best cure of which the evil will admit. 

 On the contrary, where the land is situated on a declivity, and springs 

 break out on the slope, causing great damage to the land below, the 

 first object must be to intercept these at their head, and divert them 

 before they saturate the soil with their moisture. Their site may be 

 ascertained by means of an auger or borer, and the subsequent measures 

 taken accordingly. 



Where there is much irregularity of surface, it will often be found 

 that the clayey and impervious strata do not extend far up the rising 

 ground, and that more porous strata cover and encircle the top. The 

 moisture received by these upper strata percolates through the open 

 and porous soil until it meets with obstruction from the more im- 

 pervious one ; there it accumulates and forces a passage, either oozing 

 almost imperceptibly, or bursting out in streams. In either case it 

 seriously injures the land, both at this spot and immediately below. 

 The object of draining must be to intercept these streams, and lead 

 them by an artificial channel to some outlet where their waters, if 

 not turned to some useful purpose, may at least cease to operate 

 injuriously. 



The method which was formerly resorted to in the counties of Essex 

 and Herts, and is still used for tolerably level lands, and which 

 has been generally found to answer, was termed hollow-draining, 

 bush-draining , or land- ditching. It consisted in digging main drains 

 and ploughing side drains ; the depth of the main drain varying from 

 22 to 24 inches, and that of the side drains from 20 to 22. The length 

 to which the main drain was continued without a vent depended on 

 the situation of the land. If there was a gentle slope, as much water 

 as possible was carried off by means of side drains ; where, however, 

 the surface of the ground was uneven, it became necessary to form 

 additional main drains. The length of the side drains and their 

 distance apart depended upon the nature of the land. The trenches 

 of a sufficient depth, being cut off, were filled up with stones, or with 

 brushwood, or thorns ; perhaps branches of the alder or willow are 

 preferable, as being less liable to decay, and also, being smooth, they 

 do not disturb the shape of the drain so much. They should, however, 

 be used in a green and never in a dry state. The stones or twigs were 

 then covered over with straw, fern, heather, &c., in order to fill up the 

 interstices and prevent the earth from sinking in, and the surface soil 

 was laid on archwise. In making drains of this kind, the chief object 

 was, not the durability of the materials, but the proper arching of the 

 earth, which, when of a tenacious nature, remains perfect after the 



