(3) The continuity of surfaces should always be broken, at the same time avoiding the formation of cavities and lines of cleavage. No excavation to be refilled should have vertical sides, and long continuous horizontal planes should be intercepted by wedge-shaped offsets, enabling the dovetailing of materials together. All loose and seamy rock or other porous material should be removed, and where the refill is not the best for the purpose, mix the good and bad ingredients thoroughly, after which deposit in very thin layers. (4) Make the dimensions and profile of dam with a factor of safety against sliding of not less than ten. The preliminary calculations for designing such a profile have been given on p. 42. (5) Aim at as nearly a homogeneous mass in the body of the embankment as possible, thus avoiding unequal settlement and deformation. This manner of manipulating materials will eliminate many uncertain or unknown factors, but it means rigid inspection of the work and intelligent segregation of materials, no matter what method of transporting them may be adopted. The smaller the unit loads may be, the more easily a homogeneous distribution of materials will be obtained. (6) Select earthy materials in preference to organic soils, with a view of such combination or proportion of different materials as will readily consolidate. _Consolidation is the most important process connected with the building of an earth dam._ The judicious use of soil containing a small percentage of organic matter may be permitted, however, when there is a lack of clayey material for mixing with sandy and porous earth materials. Such a mixture, properly distributed and wetted, will consolidate well under heavy pressure and prove quite satisfactory. (7) Consolidation being the most important process and the only safeguard against permeability and instability of form, use only the amount of water necessary to attain this. Too much or too little are equally bad and to be avoided. It is believed that only by experiment and experience is it possible to determine just the proper quantity of water to use with the different classes of materials and their varying conditions. In rolling and consolidating the bank, all portions that have a tendency to quake must be removed at once and replaced with material that will consolidate; it _must not_ be covered up, no matter how small the area.