Book III. 



FORMATION OF DRAINS. 



709 



653 



h 



may be much facilitated by a due attention to filling them with the most friable and porous parts of the 

 surface the field may afford. 

 4292, The turf drain {Jigs. 650. and 651.), may be made of any convenient depth, but it must be at least 



rrjji. the breadth of a turf at bottom. The drain being 

 ij j/! dug out as if it were to be filled with stones or any 

 i/Ill ordinary material ; the operator next, with a spade 

 three inches wide, digs a narrow channel along its 

 centre (a), clearing it out with the draining scoop ; 

 and over this the turves {b) are laid without any 

 other preparation, or any thing put over them but 

 the earth that was excavated. This is found to 

 be a very cheap, and, considering the materials, a 

 surprisingly durable method of draining ; answer, 

 ing, in pasture-fields especially, all the purposes 

 that the farmer can expect to derive from drains 

 constructed with more labour, and at a much 

 greater expense. They are said to last frequently 

 twenty years and upwards : but the period which 

 it can be supposed they will continue to prove 

 effectual, must depend on the nature of the soil and 

 the current of water. 



4293. The wedge or triangular sod drain [fi^. 

 652.) is thus made : When the line of drain is 

 marked out, a sod is cut in the form of a wedge, 

 the grass side being the narrowest, and the sods 

 being from twelve to eighteen inches in length. 

 The drain is then cut to the depth required, but is contracted to a very narrow bottom. The sods are 



then set in with the grass side downwards, and pressed as far 

 as they will go. As the figure of the drain 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. The work is performed by means of three 

 spades of different sizes. The first may be a common spade 

 of moderate breadth, with which the surface clay may be 

 taken off to the depth of eight or ten inches, or not quite so 

 much, if the clay be very strong. The breadth of the drain, 

 at top, may be from a foot to fifteen inches ; but it never 

 should be less than a foot, as it is an advantage that the sides 

 should have a considerable slope ; and the two sides should 

 slope as equally as possible. Another workman follows the 

 first, with a spade six inches broad at the top, and becoming 

 narrower towards the point, where it should not exceed four 

 inches, {fig. QSS.a.) The length of the plate of this second 

 spade should be fourteen inches, and with it a foot or four- 

 teen inches in depth can easily be gained. A third workman, 

 and he should be the most expert, succeeds the second, and 

 his spade should be four inches broad at top, only two inches 

 broad at the point, and fourteen or fifteen inches in 

 length {b). With this spade a good workman can take out 

 at least fifteen inches of clay. A sort of hoe or scoop, made 

 of a plate of iron, formed nearly into the shape of a half 

 cylinder of two inches diameter, and a foot or fourteen inches 

 long, and fastened, at an acute angle of perhaps 70, to a 

 long wooden handle (c), is now employed to scrape out the 

 bottom of the drain, and remove any small pieces of clay 

 that may have fallen into it. The grassy side of the turf 

 being turned undermost, they are put down into the drain, 

 the workman standing upon them after they are put in, and 

 pressing them down with his whole weight till they are 

 firmly wedged between the sloping sides of the drain. The 

 ends of the turfs being cut somewhat obliquely, they overlap 

 each other a little ; and by this means, although there is 

 sufficient opening for the surface water to get down, nothing 

 else can. The open space, below the turf, ought to be five 

 or six inches in depth, three inches wide at top, and an inch 

 and a half or two inches at bottom. {Trans. Highl. Soc. 

 vol. vi. p. 571.) 



4294. The hollow furrow drain is only used in sheep-pastures. WTierever the water is apt to stagnate, 

 a deep furrow is turned up with a stout plough {fig. 654.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 



Wlll'llllllllllilllflWl '^stored to its original situation, with the grassy side 



IlllllllililiWmlilllll. uppermost, as if no furrow had been made {b). A pipe 



or opening two or three inches deep is thus formed 



beneath it, in the bottom of the furrow, sufficient to 



discharge a considerable quantity of surface water, which 



readily sinks into it. These furrows, indeed, are easily 



choaked up by any pressure, or by the growth of the 



I'ljl roots of the grass ; but they are also easily restored, and 



'"' no surface is lost by means of them. 



4295. The earth drain, called also the clay-pipe drain, 

 is better calculated for the purpose 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 smooth 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 experiment 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. 



Z z 3 



