306; pipes, 301, _302_. Reflecting telescope, 260. Relays, telegraphic, 133, 141. Retina, 247. Retorts, 395. Reversing gear, 62; Allan, 65; Gooch, 65; radial, 66. Rocking bar mechanism for watches, 425. Rods of Corti, 274. Ruhmkorff coil, 121, _122_. Safety-valve, 32, _33_, 391. Sand-glasses, 411. Scissors, action of, _450_. Secondary winding of induction coil, 122. Pump, air, 340; bucket, 352, _353_; force, 354; most marvellous, 355; Westinghouse air, 199. Railway brakes, 187.