De Rochas, 89. Bell, diving, _332_; electric, 119, _120_. Bellows of 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 boiler (Fig. 6) in the material from which depends a split arm embracing the rod of the wheel.