Waves, air, 125. in the ether, 127. length of light, 123. sound, 125. speed of, 126. of water, experiment with, 124. Weather, forecasting, by the barometer, 35. by signs, 37. Weather, and the Moon, 105. Sun and the, 34. Winter, 74. Winter solstice, 181. Wireless, time distributed by, 161. Wireless receiving sets, 165. Zero meridian, 156. Zodiac, as invented by the ancients, 167. as we know it today, 167. constellations of, 168. experiment with a cardboard, 170. how to find the constellations of the, 169. signs of the, 168. stars of the, 166. what it is, 166. Zone system of standard time, 156.