Ear, 272. Wireless telegraphy, 137; advance of, 145; receiver, 140, 141; syntonic, 143; transmitter, 138, _139_. Yale lock, _436_, _437_. Yellow spot, in eye, 251. Spring balance 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 fine insulated wire cord having a.