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, 412. Malleus, 272. Marconi, 140, 146. Marine chronometers, 415; delicacy of, 425.