Dead Reckoning, v, 65-6 Dead Sea, formation of basin, iii, 151, xiv, 118, 120-1; level and level changes, iii, 151-2, xiv, 121, 205, 362; salinity, iii, 152, viii, 139, xiv, 207 Deaf and Dumb, sign language of, xv, 148, 150 Deafness, ix, 103-4; from brain disease, 146 Death, correlative of life, xii, 13; "irritability" theory of, x, 86, 87; James on phenomena of approaching, 242; physiological meaning, ix, 17; primitive conceptions of, xv, 327-9, 331-8; vital knot in relation to, ix, 257 Death Adders, xii, 229 Debtors, treatment of, in African tribes, xv, 370 De Candolle, plant classification, xvi, 165-6; vegetable table, xiii, 221 Decay, air and, xiii, 312-18; carbon dioxide from, viii, 49, 61; humus produced by, 340; nitrogen from, 73, 346; phosphorescence from, i, 346, 349, xii, 20 Deccan of India, lava fields, iii, 105, 228, xiv, 103 Deciduous Trees, xiii, 175, 269, 271-2; of temperate forests, xiv, 370, 371, 372, 373, 374 Decimal System, xv, 181 Declination, of compass needle, iv, 247 Declination of Stars, ii, 299 Decomposition, (chemical), viii, 12, 101; contrasted with dissociation, 121; double, 104-5; of salts, 117 Decrement, of oscillating currents, vii, 286, 287-8 Deeps, ocean, iii, 52, xiv, 9, 23, 286; volcanoes and, 316 Deep Sea, animal life in, xii, 21-4; animals, luminosity of, 139; conditions of life in, 21-2; darkness of, 22, xiv, 298; density of, xii, 21; deposits, iii, 54-5, xiv, 285, 286; fish of, xi, 53, xii, 20, 23-4, 136, 138-9, 163, xvi, 146; ground sharks of, xii, 143, 147; movement of water in, xiv, 284, 298-9; never over present continents, iii, 55; ooze, xii, 18, 19; plants of, 16-17; seaweeds not found in, xiii, 72; soundings of, xiv, 284; temperature, 297, 298, 299; topographical features, 284, 286-7, 288-90; unknown to us, v, 202 Deer, xii, 317-20; evolution of hoofs, iii, 300; fear in, xi, 136; heart in, x, 332 Deer Family, xii, 315-20 Deer-hunting, in India, xv, 223 Defectives, human, increase in, xv, 27 De Forest, audion detector, xvi, 191 Degrees, electrical, vi, 204 De Haen, x, 77 Dejection, emotion of, xi, 146; posture and, 337, 338-40 (see also Despondency) DeLaval Steam Turbine, v, 148-50, 382 Delaware Indians, prayer song of, xv, 346-7 Delaware River, estuary of, xiv, 40; geological history, 40, 60, 168-9, 171; heterogeneous course, 155; rapids of, 159; shad season in, xii, 155; superimposed stream, iii, 233; transverse characters, xiv, 99, 154, 167; valley and gap, 50-1, 52, 169 Delaware Water Gap, iii, 233, xiv, 50-1, 167, 169; rock weathering at, 76 Delco Automobile System, vii, 137 Delco Power Sets, vii, 232 De Lesseps, Ferdinand, Saharan proposal, xiv, 205