INDEX. 



Absolute Electrometer, Thomson's, 161-169. 



Accumulators, 72-91. 



Amber, 1. 



Atmosphere, the, as a Leyden jar, 180, 181. 



Atmospheric potential, 177-180. 



strata, difference of potential between, 

 179, 180. 



currents, 181-183. 



Attraction and repulsion, 1-4, 15, 40-42. 

 Aurora, the, 190-206. 



, height of the, 198, 199. 



, geographical position of the, 199-201. 



, causes of the, 201-206. 



, tubes, 146, 147. 



Auroral arches, coronas, and streamers, 191- 

 195. 



movement, curtain formation, 195-197. 



bands, 198. 



Bag experiment, 60. 

 Balanced rod, the, 2. 

 Bath, electric, 142, 143. 

 Battery, the Leyden. 79, 80. 

 Bells, electric, 102, 103, 125, 126. 

 Brush discharge, 117, 118, 134, 137. 



Charge denned, 22. 



, multiplication of, in Topler machine, 

 121, 122. 



, variation of, 67. 



Charged surfaces, formulae for, 167. 

 Chime, electric, for frictional machine, 102, 

 103. 



, for Topler machine. 125. 126. 

 Condensation, surface, 55-58. 

 Condi-users, 74. 



15 



Conductivity for heat and electricity com- 

 pared, 37, 38. 

 Conductors and non-conductors, 4-6. 



, hollow, 58, 59-66. 

 Conservation of energy, the, 23-26. 

 Convection, 66, 67. 

 Cosmic electric influence, 183-186. 

 Coulomb's torsion balance, 156-161. 

 Currents, atmospheric, 181-183. 



, earth, 186-189, 204, 205. 

 Cylinder, electrified, 48, 69. 



Avith points, 70. 



Dielectric denned, 50. 



, required thickness of, 74. 

 Disc, electrified, 71. 

 Discharge, appai-ent time of, 126-128. 



, brush, 117, 118, 134, 137. 



between clouds, 208-211. 



from the clouds to the earth, 214, 215. 



from the earth to the clouds, 125, 126. 



, disruptive, 88. 



, silent, 89. 



, spontaneous, 88. 



through book, 81-84. 

 Discharger, 76. 



, universal, 87, 88. 

 Dual theory, the, 40-42. 



Earth currents, 186-189, 204, 205. 

 Ebonite, 1, 6, 53, 54. 

 Electricity, the nature of, 23-42. 



of the earth and atmosphere, 175-223. 



generated by the friction of metals, 132, 



133. 



Electrics, 4. 

 Electric bath, 142, 143. 



