INDEX. 



Page. 



Electricitj-, Miillei's report — Continued. 



§ 173. Accumulation of ihiid at the negative pole - 380 



§ 174. Electrolysis of polybiisic salts - 381 



§ 175. Electrolysis of arscnites and sulphites — ....- 384 



§ 176. Transfer of bases 384 



§ 177. Becquerel's researches on the laws of electro-chemical decomposition. 385 



§ 178. Formation of cloride of nitrogen by electrolysis 387 



§ 179. Oxydizing effects of the oxygen evolved at the positive pole of the 



battery . 388 



§ 180. Electrolysis of valerianic and ascetic acid - 390 



§ 181. Electrotype , 392 



§ 182. Gilding, silvering, &c., by means of galvanism 398 



§ 183. Etching by galvanism 407 



§ 184. Nobili's rings - - 407 



§ 185. Obtaining metals from their ores by means of galvanism - 409 



Electrotype operations of the United States Coast Survey -- 412 



Mathiot's improvements -- 412 



Electricity of the air, by M. F. Duprez - 290 



Means used to judge of the electrical phenomena which take place in the 



atmosphere 290 



Electro-Atmospheric Apparatus -- 200 



Stationary A pparatus - 290 



Electric Kite •• 291 



Electroscopes 293 



Electrometers - .- 293 



Rheometers ._ - 293 



Use of Electro-atmospheric apparatus ' 302 



State of our knowledge of the electricity of the air 312 



Origin of atmospheric electricity 312 



Variations of atmospheric electricity in clear weather 322 



Influence of local causes and of height on atmospheric electticity in 



clear weather — 322 



Diurnal and annual variations of atmospheric electricity in clear weather. 326 



Observations, by Schiibler 327 



Observations, by De Saussure - 328 



Observations, by M. Arago 329 



Probable causes of the periodical variations of atmospheric electricity in 



clear weather 332 



Atmospheric electricity in overcast, foggy, and cloudy weather 337 



Electricity in cloudy weather and fogs - 337 



Electricity of the clouds - -- 339 



Formation of electric clouds 340 



Distribution of electricity in the clou,ds 347 



Atmospheric electricity during rain and snow 349 



During storms 354 



Lightning, Summary of our knowledge of 358 



Flashes of 358 



Thunder, Cause of 363 



Lightning, Effects of, at the surface of the earth 368 



