With regard to earthworks in or upon sidelong ground, the configuration of the surface conduces to a movement of the hill-slope of a cutting, and the centre of gravity of an embankment is not in the middle, and in a narrow embankment may be outside the central portion, the tendency, therefore, is for the slope of an embankment on the upper or hill-side to assume a steeper inclination than that on the lower, as the earth is tipped against the inclined ground until the point is reached where a perpendicular erected upon the surface of the ground cuts the top of the inside slope. This slope, if protected from weathering, might be allowed to stand at the inclination at which it remains when tipped, and be simply trimmed and covered; but the toe of the slope on the lower or valley side is especially likely to slip, and therefore, every precaution should be taken to prevent movement. A retaining wall is a certain protection, benching the ground, weighting the foot of the slope, dividing it into benches about 10 to 15 feet apart, varying in width from 5 feet and increasing according to the depth; the benches having sufficient inclination to prevent an accumulation of water; counterforting the slopes in dry and mild weather with simple earth counterforts 5 to 12 feet in width at intervals, and in length about twice their height with a reasonable slope, the height being about half that of the embankment; a dry retaining wall may also be erected in temperate climates and in a comparatively unexposed situation: are all precautionary measures that can be adopted. But in the case of a cutting in drift or permeable soil upon rock or an impermeable surface liable to become wet, which not infrequently occurs, the conditions of equilibrium may easily be destroyed, and the slope upon the higher side may not stand at a less inclination than that of the hill. Obviously this slope cannot be obtained either in cuttings or embankments, therefore, provided the drift is of considerable depth and treacherous, means must be taken to prevent movement, and drains should be inserted so as to make the earth capable of standing at a steeper inclination than it naturally assumes; and in order to drain the ground at the seat of an embankment, a trench on the valley side filled with stones or supported by other means acting as a wall and drain can be made. Every precaution should be taken to prevent any accumulation of water in earthworks in sidelong ground, and to gently control them, and to promote this object it is well that lateral outlets be opposite to each other so as to afford through drainage and an unobstructed flow.