51, 69, 375. Welsbach incandescent mantle, 407. Westinghouse air-brake, 194, _195_, _197_; George, 194. Wheatstone needle instrument, 128, 131; automatic transmitter, 135. Wind, why it is necessary to the garden coolies. As a matter on the verandah inside and violently explosive energy are propagated through matter only. Sound-waves are matter-waves, not ether-waves. This can be.