_420_; lever, 421, _422_. Ether, 270. Eustachian tube, 276. Eye, human, 246, _247_; self-accommodation of, 248. Expansive working of steam, 56. Faraday, Michael, 159. Field, magnetic, 159; magnets, 171; ring, 174. Filters, 374; Maignen, _373_; Berkefeld, 374. Filtration beds, 372. Flute, 308. Flying-machines, 348. Fly-wheel, use of, 244. Sun-dial of.