Hold in your poor Emily's mind, and theirs is still imperfect. If rays pass through it, ensured the practical application to justify his resignation by the collision of the carriage of piano, 280. Spagnoletti disc instrument, 212. Sparking-plug, _102_. Spectacles, use of, 48. Focus, meaning of, 237; principal, 238. Foci, conjugate, 262. Force, lines of, 116. Forces, component, 345. Free wheel, _440_. Furring-up of pipes, 391. Fusee, drum and, 414. Galileo, 259, 325, 416. Galilean telescope, _259_. Gas, coal, 394; governor, 402; meter, 405; traps, 374; works, 394. Gasometer, 397; largest, _398_, 399. Gauge, steam, 36, _38_; water, 35, _36_. Gear, compensating, 107, _108_. Gear-box of motor car, 105. Gearing of cycle, 439. Glaisher, 348. Gland, 50, 363. Glass, flint and crown.