B. Backing, dock-walls, 214, 215 Ballast, upon soft soil, 82, 151 Basalt, 18 Beach, artificial slope, 180 ——, natural slope, 100, 101 Benching ground, 160, 162 Blue clay, 38, 89 Bog-land, safe load upon, 88 ——, sustaining power, 152 ——, treatment of, 149–151 “Boils” in foundations, ascertaining character of, 218, 219, 224 ——, disturbance of soil, 218, 220, 221 ——, origin and source, 218, 219, 223, 224 ——, treatment of, 216, 218–225 “Boils” in foundations, well system of foundations for, 223 Borings, effect of, 217, 220 Boulders, 22 Breakwaters and piers, foundations of, 181, 182 Brown clay, 13, 42, 43 Bulging of ground, 147, 148 ——, of walls, 207, 213 Burning, slipped earth, 62, 63 C. Canal and similar earthworks. ——, admittance of navigation water, 190 ——, clay and loamy soils, 190 ——, concrete wall, 193 ——, consolidation, 190–192 ——, drawing off water, 188, 196 ——, failure of, 8, 194–196 ——, leakage in, 189 ——, peat and bog, 187 ——, precautions, 190, 193 ——, preparation of foundations, 191 ——, protection of surfaces, 188, 192–194 ——, puddle wall, when objectionable, 192 ——, sand, 187 ——, selection of earth, 191, 192 ——, —— location, 146, 190 ——, time of occurrence of slips, 190 Catchwater drains, 76, 77 Causes of slips and subsidences in earth. ——, principal, 8 Causes of slips and subsidences in earth, universality, 1 ——, variety of, 1 ——, water, the chief cause, 8 Causes of slips in cuttings and embankments, enumeration thereof, 2–8 Chalk, absorption of, 29 ——, affinity for water, 28 ——, angle of friction of water in, 28, 29 ——, characteristics of, 30 ——, classification for earthwork purposes, 31, 32 ——, cohesion of, 31 ——, cuttings in, 33 ——, difficulty of draining, 29 ——, discharge of water in, 29–30 ——, faults, crevices and pot-holes, 28 ——, flints in, 28 ——, magnitude of many slips in, 32 ——, mutability of, 29 ——, non-water bearing, 30–31 ——, pressure on, effects of, 33 ——, safe load upon, argillaceous, 89 ——, —— white, 89 ——, separation, danger of, 28 ——, slopes, 27, 100 ——, treacherous condition, 31 ——, —— soil, 13 ——, treatment of springs in, 29 ——, tunnel entrances in, 32, 33 ——, use as drains in _other_ soils, 28 ——, varieties of, 26, 27 ——, veins and seams in, 29 ——, water-bearing level in, 30 Classification of earths, 23, 36, 46 Clay, beds of, 41, 42 ——, characteristics of, 37, 38, 40–43 ——, classification of, 46 ——, condition of stability, 39 ——, contraction of, 38, 39 ——, expansion of, 37, 38 ——, fissures and cracks in, 38, 39 ——, humid, 41 ——, load upon, blue, 89 ——, —— damp, 89 ——, —— diluvial, 89 ——, —— intermixed beds, 89 Clay, load upon, muddy, 88 ——, —— solid, 89 ——, —— upheaved beds, 89 ——, —— wet, 88 ——, —— yellow, 89 ——, mud mistaken for solid clay, 42, 43