——, stations, position of, 10 ——, trestles or solid embankment, 12 ——, tunnels or cuttings, 11 ——, valley or hill-side line, 11 ——, valley, stable side of, 10 ——, valley, sunny or wooded side, 11 ——, wetter side of a hill, 12 Loose chalk, 27 Loose rock, 24 M. Maintenance, soft ground, 151 Marly chalk, slopes, 27 Marly soils, characteristics of, 44–46 ——, difficulty of draining, 46 ——, safe load upon, 89 ——, slopes, 100 Marsh earth, slope, 100 Marsh land, safe load upon, 88 Metalling, slope, 101 Mica-schist, hardness of, etc., 24 ——, quantity of quartz in it, 24 Mixtures of earth, troublesome, 20 Moraine, treacherous soil, 18 Morass, safe load upon, 88 Mud, consolidated, slope, 100 Mutability, of the created elements, 1 N. Normal load, influence of, 89–91 Normal pressure, consideration of, 91 Number of drains, 75 O. Object of, drainage, 72, 73, 74, 81 Obstruction, of drainage by embankment, 9, 10, 11 Open trestle work _versus_ embankments, 180 Overflow, drainage by, 75 P. Peat moss, safe load upon, 88 Peat soil, consolidation of, 153, 154 ——, drainage of, 149–151 ——, nature of, 152, 153 ——, necessary test, 151, 152 ——, sustaining power of, 151, 152 Peat turf, slope, 100 Percolation of water, overflow and requisite pumping, 69, 70 ——, chalk, 70, 71 ——, clay soils, 70 ——, cuttings and embankments, 65–67 ——, effect of, 66–69 ——, excavated earth, 70 Percolation of water, fissures, 69–71 ——, loamy soils, 70–72 ——, marly clays, 70 Percolation of water, maximum, 66, 68 ——, principles of, 67–72 ——, regulation of, 65, 66 ——, sand, 71 ——, top soil, 70 Piers, foundations of, 181, 182 Pitching, on unequally consolidated soil, 131 ——, precautions respecting, 130–131 ——, protection of slope by, 129, 130 ——, when necessary, 129, 130 Porphyry, slope, 23 Pressure, normal, on earth, 91 Probability of a slip, 13–18 Protective works, burning the slipped earth, 62, 63 ——, cover shed and catch trenches, 59, 60 ——, different methods necessary, 52–60 ——, earth counterforts, 57, 58, 61, 121 ——, enumeration of, 53–55 ——, exceptional, 55, 57, 58 ——, flexible _v._ rigid drains, 56 ——, flood waters, 57 ——, general principles, 55–58 ——, object of, 52 ——, salifiable earth, 59 ——, slopes, general considerations, 115–117 ——, trickling of surface soil, 58 ——, turf and plant, 122–124 ——, weighting the foot of, 119 ——, when drainage alone required, 56 ——, when required, 52 ——, where to commence drainage operations, 56 Q. Quartz, slope, 23 Quicksand, safe load upon, 88 R. Rainfall, influence of, 15, 16 Rammed earth counterforts, 61, 121 ——, thickness of layers, 120