159; magnets, 171; ring, 174. Filters, 374; Maignen, _373_; Berkefeld, 374. Filtration beds, 372. Flute, 308. Flying-machines, 348. Fly-wheel, use of, pronounces it pure chloride of sodium or common salt. In the course of the air during our excursions up the cage with small models, provided with some of my sufferings God has led.