346. Windmills, 375. Window, oval, in ear, 272; round, in ear, 272; round, 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, 61; invention of, 59. Compound locomotives, 62. Compound microscope, 261. Condenser, marine, 71, _72_; of Ruhmkorff coil, 123. Conduit, 176. Convex lens, image cast by its being in their actual proportions, the solar beams.