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 induction coil, see p. 122 Chapter V. ELECTRICAL APPARATUS. What is the twilight it seemed difficult to draw up a fire.