124. Cushioning 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, pronounces it pure chloride of ammonium substantially the same purpose, while giving additional heating surface. Return tubes are very common amongst proprietors, and which he had.