Races, and by inheritance into us, must necessarily be more remarkable than their enterprise in constructing artificial 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. Dynamo, alternating, 164, 174; brushes, _172_; compound, 174; continuous-current, 165; multipolar, 169; series wound, _173_; shunt wound, _173.