Coke, 395. Combinations in Chubb lock, 436; Yale lock, 436. Combustion, 26, 393; perfect, 28. Compensating gear, 107, _108_. Gear-box of motor car, 110; railway, 187; vacuum, 189, _190_, _191_; Westinghouse, 194, _195_, _197_; George, 194. Wheatstone needle instrument.] Probably the best-known needle instrument is.