Gas making, 394; gas plant, _396_; gas, purification of, 397. Cochlea, 273. Coherer, 140. Coil, Ruhmkorff, 121. Coke, 395. Combinations in Chubb lock, 436; Yale lock, 436. Combustion, 26, 393; perfect, 28. Compensating gear, 107, _108_. Compound engines, 59; arrangement of, 295; sound-board, _296_; wind-chest.