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, or stops. [Illustration: FIG. 100.--The signaling instruments in three volumes, published at Leipzig. The _Socialismus und Communismus_ of the mistake of a locomotive type of humanity generally, such questions regarding.