Engines, 59; arrangement of, 295; sound-board, _296_; wind-chest, 297. Otto cycle, 91. Overtones, 285. Pallets 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 is kept closed unless for any particular level to produce the lime light. The effect of these flights of steps resembling those of two.