Richard Preston, Esq. of lilac k more, prefers, on twen ty years experience, black thorns to every other mate rial for filling drains. Wood is sometimes used with this view, in the following manner Two billets arc placed at opposite sides of the drain, and each is made to rest upon the opposite side to that on NV hiCil its lower part stands, so as to form with each other a St Andrew's cross. The upper part of the cross is filled with brushwood, laid longitudinally, above which straw is placed cross-ways and the mould is thrown in over all. This kind of drain is said to have continued running in Berwickshire for thirty years ; and it is recommended by the author of the Agricultural Report of the county of Caermarthen, in Wales. He says, " The completest method I have yet known, is to cut the strongest w or other aquatic brushwood, into lengths of about 20 incites, and place them alternately in the drain, with one end against one side of the bottom, and the other lean ing against the opposite side. Having placed the strong wood in this manner, 1 fill the space left between them, on the upper side, with the small brushwood, upon which a few rushes or straw being laid, as before men tioned, the work is done. Willow, alder, asp, or beech boughs, arc exceedingly durable if put into the drain green, or before the sap is dried ; but if they are suffer ed to become dry, and then laid under ground, a rapid decay is the consequence. I have seen willow taken out of a bog, after lying there thirty years, and its bark was as fresh and sappy as if it had been recently cut from the hedge ; and it is well known, that beech laid green in the water will continue sound for any length of time." Another method of using wood consists of fixing at every foot distance in the drain, a stick in the forma a semicircular arch, and of laying upon these, longer branches or twigs longitudinally. Thus is a curved ca vity, or arch, formed beneath, capable of supporting any weight of earth. For this purpose young wood is re commended, and, in particular, the prunings of larch.
Instead of wood or stone, in many places it has of late become customary to fill the lowest part of drains with straw, and with that view to make use of wheat-stubble as the cheapest. On this subject, Mr Vancouver, in his Report of the Essex husbandry, remarks, that when the soil is a very close and retentive clay, the drains should be made proportionally near to each other, shallow, and filled with straw only ; it being totally unnecessary to use wood, or any more durable material, upon land where the sides of the drains are not likely to crumble in. Ile asserts, that drains formed in this mn.nncr through the tough and retentive clays, will be found in a shot t time after the work is finished, to form over the straw, witi. which the drain was filled, an arch of sufficient strengt't to support the incumbent weight of the soil, and the casual traffic of the field. " In twelve or eighteei, months, it may be observed, that the str)w being of one uniform substance, is all rotted, and carried away, lea\ ing a clear pipe through the land in every drain, into which the passage of the water may have been much facilitated, by a due attention to the filling or the drain. with the most friable and porous parts of the surfac,• the field might have afforded." As in sonic situations it is an object of great impor tance to save the expense of materials commonly used in filling drains, a variety of have with th.tt view•
been adopted. One of these is of the following nature : A drain is first dug to the necessary depth, narrow at bottom. Into the trench is laid a smooth tree, or cylin drical piece of wood, 12 feet long, 6 inches diameter at the one end, and 5 at the other, having a ring fastened into the thickest end. Alter strewing a little sand upon the upper side of the tree, the clay, ur toughest part of the contents ol the trench, is first thrown in upon it, and alter that the remainder of the earth is luby trodden down. By means of a rope through the ring, the tree is then drawn out to within a foot or two of tile smaller or hinder end ; and the same operation is repeated till the whole drain is complete. Such a drain is said to have conducted a small run of water a considerable way under ground, for more than 20 years, without any sign of failure.
What is called the sod or pipe drain consists of a trench dug to a proper depth ; alter which a last spade ful is taken out in such a way as to leave a narrow channel, which can be covered by a sod or turf dug in grass land, and laid over it, the grass side downwards. Such drains are said to continue hollow, and to discharge well for a great number of years. Mosses are said to he drained in Lancashire nearly in the same manner, by leaving shoulders about a foot and a half from the bot tom of the trench, and laying across these pieces of dried peat or turf, cut into lengths of 16 inches, and 8 or 9 inches in breadth.
In Buckinghamshire, in grass lands, the sod drain 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 12 to 13 inches in length. The chain 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 press ed 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 water course; and the space above is filled with the earth thrown out.
Another invention for chaining land is described in the Agricultural Report of the County of Essex. It consists of a draining wheel of cast iron, that weighs about cwt. It is 4 feet in diameter, the cutting edge or extremity of the circumference of the wheel is half an inch thick, and it increases in thickness towards the centre. At 15 inches deep it will cut a drain half an inch wide at the bottom, and 4 inches wide at the top. The wheel is so placed in a frame, that it may be loaded at pleasure, and made to operate to a greater or less depth, according to the resistance made by the ground. It is used in winter when the soil is soft ; and the wheel tracks are either immediately filled with straw ropes, and lightly covered over with earth, or they are left to crack wider and deeper till the ensuing summer ; after which the fissures are filled with ropes of straw or of twisted twigs, and lightly covered with the most porous earth that is at hand. Thus, upon grass or ley lands, hollow drains, which answer extremely well, are formed at a trifling expense. It is said that 12 acres may be fully gone over with this draining wheel in one day, so as to make cuts at all necessary distances.