INDEX. 



599 



U 



Underground heat, 53-64, 98- 

 102, 104, 238-243, 297, 300 



-302,307-315 



Underground currents, 222-227 

 Uniformity in geology, 6-9, 44 



Vacuum tubes, 221 



Variation of earth's magnetism, 



220 



Varley, 449 



Vincent, Dr., 530 



Volcanoes, result of local action, 



300 



Voltaire, 535 

 Vortex motion, 164, 217, 245 



W 



Waterston, 128 

 Watt, 460, 473, 569 

 Weber, 159, 160, 213, 214 

 Wells, I, 2, 290 

 Welsh, 143 



Wheatstone, Sir C., 449 

 Willoughby, 531-2 

 Wind, energy of, 440-444 

 Wollaston, 168 

 Work and heat, 420, 421 



light, 430 

 indestructibility of, 418, 419 



Young, 137, 433 



END OF VOL. II. 



RICHARD CI.AY AND SONS, LIMITED, LONDON AND BUNGAY. 



