452 



INDEX, 



Weight, how varies, 32 



of a body, when greatest, 32 

 "Weights and measures, standards of, 34 

 Fren "h system of, described, 36 

 United States standard of, 36 

 ■Welding described. 29 

 Well-sweep, old fashioned. 159 

 Wells, Artesian, construction of, 135 



origin of water in, 186 

 Wetclothjs, why injurious, 246 

 Wheel and a.xle, action, of 99 

 spinning, 101 



tourbine, advantages of, 153 

 work, compound, familiar illustra- 

 tions of, 101 

 Wheels, breast, construction of, 157 

 cog, 101 

 overshot, 15T 

 tourbine, 153 

 undershot, 156 

 paddle, power lost by, 154 

 Whirlwinds, how produced, 261 

 WhisUe, steam, 269 



■\Vlnch, what is a, 99 



"Wind, principal cause of, 281 



what is, 2S1 

 Wind-pipe, what is the, 203 

 Windhiss described, 100 

 Winds, force of, how calculat€d, 2S3 

 of United States, 2S5 

 trade, 238 



variable, where prevail, 284 

 velocity of, 281 

 Wood, a bad conductor of heat, 218 



comparative value of for fuel, 266 

 hard, why difficult to ignite, 266 

 made wet, why swells, 143 

 snapping of, 19 

 water in, 205 

 weight of, 266 

 Woods, when hard and when soft, 265 

 Wo liens, why used for clothing, 219 

 Woof of cloth, 117 

 Work of different forces, standard of <K>m> 



paring, S3 

 Working-point in machinery, 92 



