Drainage Systems, continental, xiv, 189-90; development stages, iii, 33-4, xiv, 48, 49, 155; earthquake effects, 335; Ice Age changes, iii, 243-5, xiv, 60-1, 170-1; joints and, 131 Drake, Daniel, x, 116 Drama, origin and development of, xv, 303-10, 322, 325; sentiment in, xi, 151 Draper, Dr. Henry, astronomical work, ii, 17, 114, 116, 126, 130, 134, 135, 307, 358; reflectors of, 103, 106 Draper Catalogue of Star Spectra, ii, 116-18, 146, 307, 309, 310 Dravidians, of India, xvi, 53 Drawing, development of art of, xv, 296, 298-9 Drawing Rolls, Arkwright's, v, 273-4, 376 Dreams, xi, 292-302; images of, 221; primitive conception of, xv, 328-9, 358; psychoanalysis of, x, 364-5 Dredges, modern, v, 255-9, 381; walking-machine, 216 Dried Foods, viii, 371; antiscurvy vitamines in, x, 262, 266 Drift, Glacial, iii, 378 (see Glacial Debris) Drills, ancient Egyptian, xvi, 67; core, v, 263; diamond, 263, 264, 380; metal-cutting by, 47; multiple, 53 (see Multiple Drills); oil, v, 265-7; pneumatic, i, 27, iv, 129, v, 129-30, 261-2, 263, 380, 381; rock, 129, 261-2; sonic-wave, 108; spiral chisels, 46 Dropsy, polyuria in disappearance of, x, 344; Van Helmont's idea of, 68 Droughts, i, 79, 371; financial panics and, 263; records of, in tree rings, xiii, 25; springs and wells in, xiv, 136, 138 Drowned Valleys, iii, 37, 378, xiv, 40, 164, 255-6; as harbors, 268 Drugs, blood riddance of, ix, 274; coal tar, viii, 253; in mother's blood, effects, ix, 343-4; plant sources, xiii, 249-55; pure food law on, viii, 370; taste deadening by, xi, 72; use of, in medicine, x, 21-2, 22-3, 30, 44, 45, 75-6, 77-8, 380-1, xvi, 109, 186-7 Drumlins, iii, 69, xiv, 60 Drums, xv, 316; African, 313 (fig.) Drupes, xiii, 54, 194 Dry Cells, iv, 297-8, vi, 59, 126, 127, 138, 143-4 Dry Docks, floating of ships in, v, 95 Dry Fogs, i, 96, 371; of 1783, 57, 58-9 Dry Fruits, xiii, 54, 55-6, 57 Drying Machines, iv, 73 Dry Steam, v, 140 Duckbills, xii 272, 273 Ducks, xii, 257-8; darkness effects on, x, 253; primitive methods of hunting, xv, 222 Duckweed, xiii, 31 Ductless Glands, x, 346-53; secretions used in therapy, 382 Dufrausne, x, 181 Duluth, Lake, iii, 149 Dunes, i, 53, iii, 71, 74 Duplex Telegraphy, vii, 112, 114-17, 376 Dupuytren, Guillaume, x, 130 Duralumin, v, 228 Duryea, Charles E., v, 213