INDEX 



367 



Tuning coil, 260 

 Tuning in, 251, 259, 260 

 Turbine, 124 

 Turquoise, 51 

 Twins, the, 34, 35 



Uranium, 168, 171, 173 

 Uranus, 2, 7, n; discovery of, 2 

 Ursa Major, 19, 20, 21, 22, 38 

 Ursa Minor, 22 



Vacuum cleaner, 239 



Vacuum tubes, 174, 268, 270, 271 



Vacuum valve, 268 



Valence, 65, 168, 169, 172, 176 



Vega, 29, 39 



Veins in rocks, 52 



Vibrating column of air, 325, 330; laws 



of, 33i 



Vibrating strings, laws of, 329 

 Violin, 328, 329, 334 

 Virgin, 38 

 Virgo, 38 

 Vocal cords, 335 

 Voice modulations, 335 

 Voisin, 94 

 Volt, 227 



Volta, Alessandro, 206 

 Voltage, 227, 244 

 Voltaic pile, 206 

 Voltammeter, 228 

 Volta's crown of cups, 206 

 Voltmeter, 228 



Water-Bearer, 39, 40, 41 

 "Water, displacement of, 114, 155 

 Water power, 125; in the United States, 



125-27 



Water pressure, 113, 124, 125 

 Water wheel, 125 

 Watt, 228 

 Watt, James, 181 

 Watt's engine, 181, 182 

 Wave: compensating, 274; formation 



of, 305 



Wave-length, 255, 279 

 Wave motion, 250 



Wave- train, 255 



Waves, damped, 255, 256 



Wealth, increase of, 186 



Weapons, early, 131 



Weather, prediction of, 157 



Weather bureau, 157, 158 



Weather map, 158 



Weathering, 63 



Week, 12 



Weight arm, 341 



Well, the deepest, 45 



Wenham, Herbert, 90 



Westerlies, 156 



Whale, the, 40 



Wheatstone and Cook's Telegraph, 211 



Wheel and axle, 343, 344, 345 



Wheelbarrow, 343 



Wheel, sprocket, 346 



Wheels, gear, 345 



Williams, J. A., 96 



Wind instruments, 330 



Windlass, 343, 345 



Windmill, 78, 121; directions for mak- 

 ing, 121, 122; paper, 121; wooden, 

 122 



Windmills with sails, 123 



Winds, 155; cause of, 155; local, 157; 

 trade, 156; westerlies, 156 



Winter, n 



Wireless, 250, 252, 254; making, 261; 

 receiving outfit, 256, 258; secondary 

 circuit, 260; transmission, 252, 254 



Wiring of house, 247, 248 



Woodsmen of Arden, 136 



Wrench, 350 



Wright brothers, 88, 92, 93, 95 



Wringer, centrifugal, 133 



Xenon, 167, 171, 239 

 X-ray, 173, 175 



Zeppelin, Count von, 107 



Zeppelins, see Balloon 



Zero, absolute, 164 



Zinc mine, 51 



Zodiac, 35 



Zodiacal constellations, 35, 37, 39 



PRINTED IN THE U.S.A. 



