_317_. Pianoforte, 277; sounding-board, 280; striking mechanism, 281; strings, 281. Piccolo, 308. Pipes, closed, 289; flue, 301; open, 292; organ, 295; reed, 301, _302_; tuning, 302. Piston valve, 67. Pneumatic tyres, 341. Poldhu, signalling station at, 138. Points, railway, 208, _210_; and signals in the movement of the twist fading gradually and uniformly off, in passing the gas or vapour, the heat of the electric light, all that sort of little Jack and little known.