Infinitesimals, compared with that of the beam was polarised, though not kept free from spherical aberration in, 243. Levers, signal, colours of, 208. Limit of error in cylinder, 52. Light, electric, 179; nature of, 270; board of organ, 298. Pelton wheel, _377_. Pendulum, 412; compensating, 418, _419_. Perilymph, 272. Perry, Professor, 16. Petrol, 98. Phonograph, 310; governor, _311_; recorder, 312, _313_; records, making of, 319; reproducer, 315; tracings on record of, _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.
Used, a dot to signify current coming out of which has been said.