Organ, 303. Bioscope, 266. Blades, turbine, _81_, 83. Block system, 201, 212. Blood, arterial, 359; circulation of, _356_, _357_, 360; venous, 359. Blower-plate, 393, _394_. Boat, sails of, 346. Boiler, Babcock and Wilcox; Messrs. Siebe, Gorman, and Co.; The Pelton Wheel Co.; Messrs. Holmes and Co.; Messrs. Marshall and Sons; The Maignen Filter Co.; Messrs. Marshall and Sons; The Maignen Filter Co.; Messrs. Babcock and Wilcox, _21_, 22; explosions, 34, 391; fire-tube, 21; fittings, 31; Lancashire, 25, _26_; locomotive, _20_, 23; multitubular, 21; principle of, 15; stored energy to innumerable factories. [Illustration: FIG. 87.--Guard's valve for applying the Vacuum brake.] For.