Book III. 



KINDS OF DRAINS. 



641 



does not suffer them to go to the bottom, a cavity is left which serves as a watercourse ; 

 and the space above is filled with the earth thrown out. 



3973. The hollow farrow drain is only used in sheep-pastures. Wherever the water is 

 apt to stagnate, a deep furrow is turned up with a stout plough {^Jig. 506 a). After 

 this, a man with a spade pares off the loose 

 soil from the inverted sod, and scatters it over 

 the field, or casts it into hollow places. The 

 sod thus pared, and brought to the thickness 

 of about three inches, is restored to its original 

 situation, with the grassy side uppermost, as if 

 no furrow had been made (b). A pipe or 

 opening is thus formed beneath it, two or three 

 inches deep in the bottom of the furrow, which 

 is sufficient to discharge a considerable quan- 

 tity of surface water, which readily sinks into 

 it. These furrows, indeed, are easily choaked 

 up by any pressure, or by the growth of the roots of the grass ; but they are also easily 

 restored, and no surface is lost by means of them. 



3974. The earth drain, called also the clay pipe drain, is better calculated for the pur- 

 pose of an aqueduct, or conveyance of water, than for drying the soil. A drain is dug 

 to the necessary depth, narrow at bottom, in which is laid a sihooth tree or cylindrical 

 piece of wood, ten or twelve feet long, six inches in diameter at the one end, and five at 

 the other, having a ring fastened in the thickest end. After strewing a little sand upon 

 the upper side of the tree, the clay or toughest part of the contents of the trench is first 

 thrown in upon it, and then the remainder, which is trod firmly down. By means of 

 the ring and a rope through it, the tree is drawn out to within a foot or two of the small 

 or hinder end, and the same operation repeated. A gentleman who has tried this experi- 

 ment says, this clay pipe has conducted a small rill of water a considerable way under 

 ground for more than twenty years, without any sign of failing. 



3975. Pipe drains of turf Bxe sometimes 

 507 formed where the surface soil is a strong 



clay, as it is only turves from such a surface 

 that are sufficiently durable. A semicylin- 

 drical spade [fg. 507 a), is used to dig the 

 turves, the ground-plan of which (A) pre- 

 sents a series of semicircles or half pipes. 

 The drain (c), being dug out to the proper 

 depth, one turf is laid in the bottom (d), 

 and another being placed over it (e), com- 

 pletes the pipe. The same sort of pipe drain 

 has been formed out of solid beds of clay, 

 and has served for a time to convey water. 

 As collecting drains, of course, they can be 

 of little or no use. This mode of draining 

 appears to have been first practised by 

 Hannah, an ingenious farmer in Wigton- 

 shire. He adopted it for the purpose of 

 onveying water through running sand, in which only a pipe drain will last for a mo- 



derate time. After a 

 number of years the 

 clay turves were found 

 effective in conveying 

 away the water, and 

 preventing the run- 

 ning away of the sandy 

 sides of the drain. 



3976. A mode of 

 turf draining in use 

 in Cheshire, is done in 

 the following man- 

 ner : The surface of 

 the ground where the 

 drain is intended to be 

 cut, is marked out in 

 parallelograms about 

 the size of bricks on 



one h\dQ{fg.lQia 



508 



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