Screw propeller, development of, 119; Ericsson’s, 119; Francis Smith’s, 120; effect on ship-designing, 122; “slip” and “pitch” of, 122–3; “racing,” 129; of _Victoria_, 131; spur-gearing for shafts, 135; of _Great Eastern_, 142; twin-screws, 165; “overlapping” of twins, 169; of _Ophir_, 169; of _Campania_, 171; in relation to turbine, 190; of _Mauretania_, 201, 203; of _Laurentic_, 210; adaptation to lifeboats and fire-floats, 256; for yacht, 269 _Sea Serpent_, the, 268 _Servia_, the, 150, 156 Seventeenth century, scientific discoveries of, 20 “Shade-decker” type, 287 Shaft, fractured, 323 Ship architecture, problems of, 319 Side-lever engine, development of, 88; of _Britannia_, 109; improvements of, 127; of _Helen McGregor_, 128; of _Scotia_, 130; first applied to yachts, 268 _Silverlip_, the, 245 _Silvertown_, the, 243 _Sir Francis Drake_, the, 238 _Sirius_, the, 96, 97, 100, 101, 105, 193 _Slavonia_, the, 212 “Slip” of propeller, 122, 310 Smit & Co., Messrs. L., 236 Smith, Assheton, and steam yachts, 266–8 Smith, Francis, screw-propeller of, 120 Somerset, Edward (_see_ Worcester, Marquis of) South America, establishment of Royal Mail service to, 112 South Eastern Railway, 223; boats of, 224 Southampton, as headquarters of Royal Mail Co., 112; -Havre route, 227; dredging at, 239 South of England Steam Navigation Co., 227 South Western Steam Packet Co., 228 “Spar-deck” type, 285 Speed, appreciation of, 181, 213 Sponsons, arrangement of, 261 Spur-gearing, 135 Stability, problems of, 315–6 Stanhope, Earl of, Fulton and, 56; experiments of, 57, 59 Steam power, problems concerning, 3; evolution of, 18; application of by Hero, Archimedes and Mathesius, 19; Solomon de Caus’ and Giovanni Branca’s discoveries, 20; Denis Papin’s invention, 21–4; Savery’s inventions, 24–5; Newcomen’s engine, 25–7; Jonathan Hulls’ tow-boats, 29; Watt’s engine, 34–8; Symington’s engine, 43; Fitch’s development in America, 44–5; improvements on _Charlotte Dundas_, 47; Fulton’s experiments, 49, _et seq._; the Stevens’s boats, 63; development in America, 76; “Grasshopper” type of engine, 79; side-beam engine, 88; American and English engines, 88; improvements in engines, 94; the compound engine, 116; oscillating engine, 132; vertical trunk engine, 134; condenser, 135, 136, 167; steering gear, 144; triple-expansion engines, 166–7; quadruple-expansion engines, 178; turbine engines, 184; beam engines of American river boats, 262; applied to yachts, 268 Steel, first ship of, 150; development of, 156; advantage of, 157 Steeple engines, 269 Steering gear, steam, of _Great Eastern_, 143; principle of, 144 Steering-wheel, development of, 89