436; 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, 121, _122_. Safety-valve, 32, _33_, 391. Sand-glasses, 411. Scissors, action of, _450_. Secondary.