effected as with gravel ballast; the sleepers are frequently not uniformly supported throughout their length, the pressure upon the formation is localized, depressions are formed and water collected, and slips and subsidences in soils of a treacherous nature may be induced from this cause, as the equilibrium is soon disturbed. The formation should be so drained and constructed that water cannot percolate to or cause the surface to become soft and work up into or through the ballast, or a state of unsettlement will be produced by water soaking through the ballast to an embankment, and so saturating part of it and forcing out the upper portion of a slope. In all close granular ballast cross channels should be made to lead away the surface water. Transverse open tile-drains may be required leading to an impervious channel. Water has been known to percolate through a considerable depth of ballast when added to restore a sunken embankment, even through as much as 7 to 10 feet when two falling gradients induced a flow of the surface waters to one place. In certain situations it may be necessary should an embankment be of clay or treacherous soil when wet, to cover the formation with an impervious stratum to prevent percolation to the embankment, and to thoroughly and separately drain the ballast placed upon it. At the base of an embankment a ditch should be cut upon the higher side, or both sides, as near as convenient to the fence. When in addition to the interception of any surface waters by an embankment the ground is very retentive of moisture, it may be necessary to drain the seat; with this object trenches can be excavated at intervals at right angles or obliquely to the centre line of the embankment, and be filled with some hard filtering substance, such as stone or gravel, so as to effect and control the discharge of the waters. Should this be too expensive a method to adopt, and always provided the surface waters are prevented from flowing or trickling into the base of an embankment, the ground might be excavated so as to equally incline downwards towards the centre, the level at that point being 1 foot to 2 feet below the toe of the slope on each side, according to the width of the base of the embankment; a small trench being cut in the centre and filled with stones, and covered at the top with brushwood or hurdles or other provision necessary to ensure it being permanently an effectual water channel, with occasional or other drains to lead the water to the nearest culvert or side ditch. When it is found that water passes over the surface of firm soil upon which an embankment is deposited, the water must be intercepted and led away; and should an embankment be of retentive earth, in order to tap the water that has flowed and percolated into it, and to restore the earth to its normal condition and prevent slips and subsidences, it may be necessary to sink shafts to a depth of a few feet below the seat of an embankment until the mass is