And weather, 331; Fortin's, _326_; 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 cars, 109. Siphon, _351_. Slide-valve, 49, 50, 51; setting of, 53. Sliders, 297. Sound, nature of, 230; propagation of, 231. Li Hung Chang, 157. Lindsay, James Bowman, 145. Lines of Force.' It is inscribed.