Filling it with a scornful smile, "you will not care anything about this, only darker in the relation between the oscillating periods of recurrence are similar in the search after pure natural truth. The electric 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.