178 



ELECTRICITY. 



trie conductivity of gases under feeble press- 

 ures, 280 ; passage of the spark of an induc- 

 tion-coil through flame, 281 ; voltaic conduction, 

 281 ; St. Elmo's fire, 281 ; an electrical port- 

 able engine, 281 ; application of electricity to 

 sounding at sea, 282; improved electrotype 

 process, 282 ; new electric fire-alarm, 282 ; 

 cheap electric battery, 282 ; Holtz's electrical 

 machine, 382 ; papers on the subject, 283. 



VII. Conversion of dynamic into electrical 

 force, 287 ; self-augmentation of the power of 

 a magnet, 288 ; another form of the dynamo- 

 magnetic machine, 288 ; the electrical condition 

 of the earth, 289 ; polarization of the electrodes, 

 290; improvements of batteries, 290; new 

 electrical apparatus, 291 ; a new voltaic pile, 

 291 ; self-registering electric thermometer, 

 291 ; electric clocks, 292 ; cost of the electric 

 light, 292 ; electric light-regulator, 293 ; elec- 

 tric light for buoys, 293 ; engraving by elec- 

 tricity, 293; separating silver from lead by 

 electricity, 294; other useful applications of 

 electricity, 294; experiments in electrolysis, 

 295 ; visibility of the electric spark, 295 ; ef- 

 fects of electricity on seeds, 295 ; observations 

 of atmospheric electricity, 295 ; electrical coun- 

 tries, 296. 



VIII. Submerged uninsulated cables, 239 ; 

 electric lights for light-houses and ships, 239 ; 

 light at%)ungeness, 240 ; value for signals, 

 240 ; experiments in electrolysis, 240 ; new 

 batteries, 241 ; electric piano, 242 ; magnetic 

 alphabetical telegraph, 242 ; electric apparatus 

 for blasting purposes, 242 ; electro-capillary 

 paper, 243; an improved voltastat, 243; a 

 new exciting liquid, 244 ; decomposing action 

 of the voltaic arc on certain substances, 244 ; 

 color effects of electric discharges, 244; the 

 electric spark in a vacuum, 245 ; magnetism 

 and molecular changes, 245 ; the aurora bo- 

 realis as a weather prognostic, 245 ; effects of 

 lightning, 246. 



IX. Electro-magnetic induction-machines, 



239 ; new forms of batteries, 239 ; new fric- 

 tional machine, 239 ; new thermo-electric pile, 



240 ; whale-catching by electricity, 240 ; elec- 

 tro-magnetic engines on shipboard, 240 ; elec- 

 tric alarms for variation of temperature, 240 ; 

 electric beacons, 241 ; a phono-electroscope, 

 241 ; electro-deposition of copper and brass, 

 241 ; the electric light for photographing with 

 the microscope, 241 ; vegetable electro-motors, 

 242 ; accumulated magnetic power, 243 ; mag- 



netism and the casting of iron, 243 ; electro- 

 capillary actions, 243; experiments with a 

 great induction-coil, 243 ; duration of an elec- 

 tric discharge, 244; electric conductivity of 

 liquids, 245 ; an explanation of polar auroras 

 and some lightning phenomena, 246. 



X. Cause of molecular motion, 268 ; new 

 electro-dynamic law, 268 ; duration of electric 

 spark, 268; sub-permanent magnetism, 268; 

 depositions of gases in metals, 269 ; electro- 

 metallurgy, 269 ; experiments of Klein, 269 ; 

 improvements in Walenn's invention, 269 ; 

 magnetic changes of iron, 270 ; electrolysis of 

 nitric acid, 270 ; electricity and ozone, 270 ; 

 Sir Charles Wheatstone's paper on " A Cause 

 of Error in Electroscopio Experiments," 270 ; 

 electrification of Island of St. -Pierre Miquelon, 

 271 ; electric light in war, 272 ; use in Paris 

 during siege, 272 ; electro-heating, 272 ; chro- 

 noscope, 272 ; electric buoy, 273 ; electrical 

 resistance pyrometer, 273; electro-magnetic 

 anemometer, 273 ; a magnetic paradox (repul- 

 sion of soft iron by a magnet), 274; Nairn's 

 electrical machine, 274; new thermo-electric 

 pile, 274 ; ingenious electrical experiments of 

 Prof. Tyndall, 275 ; new forms of battery, 

 275 ; curious effects of lightning, 276. 



XL Duration of electric spark, 278 ; mag- 

 netic experiments, 279 ; dynamic-electric lights, 

 279 ; electric railway-signals, 279, 280 ; ther- 

 mo-electric action of metals in liquids, 280, 

 281 ; resistance and temperature, 281 ; mag- 

 netic spectra, 281, 282 ; electric clocks, 282 ; 

 improved telegraph-cables, 282 ; electric tor- 

 pedoes, 282; electric signals in mines, 282, 

 283 ; electric time-guns, 283 ; nature of the 

 luminous arch, 283, 284 ; platinum plates, 284 ; 

 iron electrotypes, 284 ; electrotyped imitations 

 of leather, 284; dynamic condensers, 284; 

 operating a railroad by telegraph, 284, 285 ; 

 improved exciting liquid, 285 ; the Hooper 

 core and Wheatstone apparatus, 285 ; electric 

 novelties, 285, 286 ; nickel-plating by electroly- 

 sis, 286 ; cold galvanization of iron, 286 ; elec- 

 trical properties of aluminium and magnesium, 

 286, 287; electro-deposition of aluminium, 

 287 ; the electrical shadow, 287 ; subterranean 

 electrical disturbances, 287 ; coloring to elec- 

 trical spark, 287, 288. 



XII. Telegraphy without insulation, 279; 

 the aerial telegraph, 279 ; the Alleghany sys- 

 tem of time-signals, 280 ; improved electric 

 clocks, 280 ; automatic registration of earth- 



