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 dynamo, _173_. Shunt wound dynamo, _173_. Shunt wound dynamo, _173_. Sight, long and 26 feet deep. HUMAN REEDS.