BEFORE entering upon the investigation of retaining walls and their design, the author devotes two chapters to the consideration of earthwork slopes and the lateral pressure of earth. Owing to the changeable condition of earth under the influence of moisture, and the variable nature of any stratum, it is impossible to obtain strictly exact expressions for the forms of slopes of cuttings and embankments, or definitely accurate values for the lateral pressure of earth; but, nevertheless, the formulæ deduced by the author from general principles are useful in serving as a guide to correctness of design. It is indicated that theoretically an earthwork slope should be curved, becoming flatter towards the base; and though a straight slope is always adopted for cuttings and embankments, the curved form left by slips is somewhat in accord with this theory. The inclination of slopes must indeed depend on the nature of the soil, and must be flatter in made ground than in cuttings; whilst efficient drainage and protection of the surface of the slopes from the weather are equally important for ensuring stability.