same right line and even through an embankment, and are connected with a drain sufficiently deep to prevent any lodgment of water at the centre of the base of the embankment or near the foot of a slope. With regard to covering a slope of a cutting or embankment, its principal use is to lessen deterioration from meteorological action, to keep the ground underneath in an equable condition, to reduce percolation and make it uniform, to diminish the danger arising from cracks and fissures caused by heat, evaporation, or drought, to prevent the erosion of the surface by a flow of water or the production of unctuous surfaces, and yet not interfere with effectual drainage. It is known that percolation is decreased by vegetation, and that it is less through turf than bare ground, but varies greatly according to the kind of covering, the season of the year, the regular or irregular distribution of the rainfall, and other causes. If the surface has to be covered with vegetation it should be close, uniform, and vigorous throughout the whole year, and nothing fulfils these conditions as well as grass or turf. The protecting value of turfing earthwork may be judged from an inspection of fortifications in which steep slopes, deep ditches, and perfect maintenance are a necessity. As a consequence of the binding and shielding of the earth by the roots of grasses and plants, and their protection of the surface, the slopes stand at a steeper inclination than they otherwise would, and the system of clinching the exposed faces of the parapets of earthwork with a layer of sods laid header and stretcher is found to be a great support. In earth possessing considerable cohesion, such as the clays, provided the covering is uniform, grass having comparatively deep roots is not a particular advantage, but the closeness of the growth of the plant and the unimpaired maintenance of a complete cover is of importance, and the earth should be disturbed as little as possible so as to prevent any particles comprising the soil becoming disintegrated and dissolved. When it is considered advisable to adopt a covering of grass, plants, shrubs, or trees, it should be remembered that some grasses, such as the couch-grass, are injurious to other plants. To equally cover a slope with sods of turf they should be cut to a regular form and depth of about 6 inches, and be firmly pressed into their places so as to produce an even smooth surface. A steep slope or any less than 1 to 1, if of considerable depth, will not give a sufficiently flat surface for grass to properly grow upon it.