Dawson’s steamer, London-Gravesend, 70 Day Line, 49, 51 Day, Summers & Co., 114 Decks for passengers, 42 Delaware River, early steamboats on the, 25, 29 Dempster, John, 299 Denny Bros., Dumbarton, ships by, 96, 105, 281, 310 Dent & Co., 203 Destroyers, 336 Dewey floating dock, 362 Dicey, Capt., 377 Dickenson, Robert, and iron ships, 195 Dieppe-Honfleur route, 108 Displacement, theory of, 30, 193 Ditchburn and Mare, Blackwall, ships by, 233, 234, 260, 313, 371, 372 Dixon, Sir Raylton, & Co., Ltd., 346 Docks, dry, difficulties of, 353; floating, 352-363 Dod, Daniel, 123 Dodd, Capt., of the _Thames_, 67 Dominion Line, 243, 288 Donaldson Line, 255 Dover-Calais service, 72, 105; designs to prevent sea-sickness, 377-379; race, paddle _v._ screw, 259; proposed railway ferry, 366 Doxford, Messrs., and the rolling of ships’ plates, 345; and shifting cargo in bulk, 346, 351 Dramatic Line, 155 Dublin and Liverpool Steam Navigation Co., 73, 74 Dublin and London Steam Packet Co., 176 Dublin, City of, Steam Packet Co., 72, 74, 89; service to London, 97; Irish mail service, 102-104; and transatlantic service, 144 Dublin-London service, 97 Dublin-Wexford service, 98 Duck-foot paddles, 7, 27, 207 Dudgeon, Messrs. J. & W., ships and engines by, 108, 184, 186, 234, 264, 265, 322; expansion engines and screw propellers, 256; first apply twin-screws, 325 Duncan, R. (shipbuilder), 151 Dundas, Lord, 28, 57, 59 Dundee, Perth, and London Shipping Co., 87 Dundonald, Lord, 127, 129 Dundrum Bay, _Great Britain_ ashore, 225 Dupuy de Lome, M., 320 Durham, Capt., 264 Dutch steamers, 76 Dynamite gun, 339 East, communication between England and the, 164 East India Co. and steamers to India, 166; inefficiency of service, 176; services, 180, 181; iron ships for, 317 East Indiamen with auxiliary steam, 167 Eastern Archipelago Co., 235 Eastern Navigation Co., and the _Great Eastern_, 270 _et seq._ Eckford, Henry, naval architect, 42 Edinburgh and Leith Shipping Co., 84 Edinburgh-London service, 81; by sea, 84 Edward VII., yachts of, 371 Egyptian royal yachts (Khedive’s), 372, 374 Elbing-Schichau Works, 303 Elder, Alexander, 299 Elder, Dempster & Co., 262, 298, 299 Elder, John, 229 Elder, John, & Co., Govan, 108, 109, 249, 250, 251, 282, 306 Electric lighting on steamers, 242; incandescent lamps, 281 Ellerman Line, 291 Ellice, Mr. Edward, and Chilian independence, 128 Emigrant traffic to America, 238 Engines: compound, 185, 187, 261; of earliest boats, 199 _et seq._; gas vacuum, 211; Ogden’s, 219; multiple-expansion, 229, 256, 306; reciprocating, 286; triple-expansion, 296; high-pressure, 306; turbine, 307; reciprocating and turbine, 310; hot-air, 384; piston engine development, 387 English Channel Steamship Co., 377 English river steamers, construction of, 46