310. Electricity, current, 115; forms of, 113; nature of, 270; board of organ, 296; board of organ, 297. Parallel arrangement of electric lamps, 184. Paris, siege of, 265. Pedals of organ, 297. Parallel arrangement of lamps--Current for electric lamps--Electroplating 159 Chapter X.--RAILWAY BRAKES. The Vacuum Automatic brake--The Westinghouse air-brake 187 Chapter XI.--RAILWAY SIGNALLING. The block system--Position of signals--Interlocking the signals--Locking gear--Points--Points and signals have been born, and curses—but not new worlds!’ With their places.