Wind instruments we employ, instead of on kites, 345; on sails, 346. Windmills, 375. Window, oval, in ear, 272. Wireless telegraphy, 137; advance of, 145; receiver, 140, 141; syntonic, 143; transmitter, 138, _139_. Yale lock, 436. Combustion, 26, 393; perfect, 28. Compensating gear, 107, _108_. Compound 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.