easily, and it is therefore advisable to make them according to the nature of the soil, situation, and requirements not less than 1 foot 6 inches to 3 feet in width at the top and 1 foot at bottom; they may be from 1 foot to 3 feet in depth. Care should be taken that the bends are not too abrupt or the water may make its own course. A gentle curve considerably increases the flow. The angle of a bend should be as easy as possible, and not exceed 26° or 2 to 1. In sandy and loose soils, if unprotected, open drains may be difficult to maintain even when filled with broken stone, and covered or pipe drains be necessary, and those loosely filled with stones or faggots may not succeed; in any case no run of the sand must be allowed, and it is advisable to rapidly construct them. In peaty soils, from subsidence of the ground consequent upon draining, the drains often become choked. The depth of a drain in the formation may require to be deeper than elsewhere, as at the toe of the slope, the weakest part, the water will generally be most abundant. Upon railways, the advantage of thorough drainage of the formation as regards the stability of the permanent way and reduction of the cost of repairs is proverbial, but here is only named in its relation to the prevention and the reparation of slips. When field drains are intercepted in the slopes, drain pipes or timber ducts should be joined to them and be connected with the general drainage of a cutting. Draining the slopes, providing outlets for the water, and also support to the earth can be effected by means of a counterfort of permeable material at the toe of the slope, with its foundation a few feet below formation level, with open drains at right angles or obliquely to it extending from the foe to the top of the slope.[1] These open drains and trenches can be filled with stones, gravel, hard chalk, ashes, brushwood and gravel, broken bricks, burnt clay or other suitable material; and a simple covering of picked ashes, &c., over a moist place in a clay cutting of little depth may be sufficient. The distance apart of such trenches in clay cuttings generally ranges between 10 and 33 feet; their location must be governed by the consideration that they exist in order to prevent a localization of water in the slopes: their width is usually from 2 feet to 8 feet, and most frequently 4 to 6 feet, and the depth from 1 foot 6 inches to 3 feet and upwards, below the surface of the slope, but in very wet embankments a width from 6 to 10 feet and of such a depth as the soil will allow without extensive support. If the earth has not slipped, and it should be found that the ground is wet for from 6 to 8 feet or so beneath the surface, and the depth of the trench is made about half that of the wetted soil, it is sufficient to collect the water, but if it has slipped most probably such drains will not be effectual until carried down below the seat of movement. At the foot of a slope these drains