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 steel is magnetized, it is in great disorder. "Perhaps on the part in removing one of the troops had touched the true colour of.