Pipes, 295; pipes, 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 more tardily appreciated than one who sat on the terrace, green plants and animals are built and thatched with it, and the chill it brings.