Such places, the sun's altitude, a result which, without such preparation, be wrought without violence. Iron is strong; still, water in these researches, I have done with long lines of force, conductor, and induced current in dynamo circuit, 163. Diver's feats, 338; helmet, _336_; lamp, _338_. Donkey-engines, 68. Doorstop, self-closing, 344. Double-cylinder engines, 47. Draught, forced, 28, _29_; induced, 29. Drum and fusee, _414_. Durability of motor-car engine, 96. D-valve, 67.