1. THE EARTHEN WALL, (fig. 1. Plate LXXIX.) is the simplest description of embankment, and is fre quently erected by temporary occupiers of lands on the general principle of enclosing and subdividing, which is sometimes made a condition of tenure be tween the landlord and tenant. This wall applies to lands occasionally, but rarely overflown, or inundat ed ; and is set out in a direction generally parallel to the river or shore. Its base is commenced on the surface from two to five feet wide, regularly built of turf on the outsides, with the grassy sides underneath. The middle of the wall is filled up with loose earth. The wall is carried up with the sides bevelled towards the centre, so as to finish in a width of one foot or eighteen inches at five or six feet in height. In the inside of such walls, and at the distance of three or four feet, a small open drain is formed, as well to collect the sur face water of the grounds within, as that which, in time of floods, will necessarily nose through a wall of this construction. The water so collected
is let through the wall by tubes, or tunnels of boards, with a valve opening outwards on their exterior ex tremity. Such a tube and valve is represented by fig. 2. When the flow of water from without ap proaches, it shuts the valve, which remains in this state till the flood subsides, when the height of the ter within being greater than that without, it presses open the valve and escapes. Walls and valves of this kind were erected about the year 1800, on the estate of the Earl of Galloway near Wigton, by Mr Hannah, tenant for life of Cue farm; and by Mr Hutchinson, tenant for thirty years of Merse head farm, on the Solway Frith. (Farmer's Maga zine.) They are common enough in the drier parts of the fenny districts of Lincolnshire and Cambridge shire ; and in Caernarvonshire 1800 acres were, in 1804, completely protected in this way on the estate of Tre Madoc by the proprietor, who has since made greater efforts in embanking, to be afterwards de scribed.