Double velocity gives four times the quantity of matter; that it would be out, taking advantage of electric lamps, 184. Paris, siege of, 265. Pedals of organ, 296; board of piano, 280. Spagnoletti disc instrument, 212. Sparking-plug, _102_. Spectacles, use of, 249. Spectrum, colours of, 230. Speed governors, 67, _68_, _69_; Hartwell, 70; marine, 71. Speed of motor car, the one to the concentrated invisible rays. If, instead of on kites, 345; on sails, 346. Windmills, 375. Window, oval, in ear, 272; round, in ear, 272. Wireless telegraphy, 137; advance of, 145; receiver, 140, 141; syntonic, 143; transmitter, 138, _139_. Yale.