438 



INDEX, 



Torricelli, 103. 



Transmutation of force chemically illus- 

 trated, 372. 

 Tyndall, xxx., 57. 



U 



Units of heat produced in combustion, 261. 



Vacuum, not yet obtained, 134. 

 Vital and physical forces, correlation of, 

 xxxii. 



effects, crude explanations of, 401. 



activity, characteristics of, 407. 

 of plants, purpose of, 41& 



principle, 402, 420. 

 Vis viva, 218, 263. 

 Volcanoes, loss of heat by, 310. 

 Volta, 153. 



Voltaic arc, cause of light of, 88. 



W 



Wartmann, Mr., 146. 



"Water, expansion of, as it approaches 



freezing, 50. 



Water-power, force produced by, 215. 

 Watt, James. 75. 

 Wortheim, 96, 150. 

 Whewell, Dr., xxvi., 136. 

 Wollaston, Dr., 136. 

 Wilson, Dr., 136. 



Words, misguiding influence of, 94. 

 their social import, 180. 

 Work performed by chemical force, 226. 

 Wood, Dr., 54, 160. 



Young, Dr. Thomas, xxvii., 124, 125, 128, 

 129, 138. 



Zodiacal light, 272. 



THE END. 



