Index 



385 



Direct-current electricity, 211-212. 

 Distilling of liquids, 112-115*. 

 Doorbell, electric battery for ringing, 



204-205. 



"Down," meaning of word, 4. 

 Drainpipe, cleaning of, with lye, 358. 

 Dry-cell battery, 206*. 

 Dust, reason for clinging to walls, 43- 



44. 



Dynamite, 343* ; making of, 347. 

 Dynamo, how electric current is made 



to flow by, 2o7*-2io*. 



Earth, magnetism of, 190-195. 



Easy circuit, a short circuit an, 244 

 245- 



Echoes, explanation of, 183-185. 



Effervescence, process of, 365; gener- 

 ally due to freeing of carbon dioxid, 

 367*-368; helped by stirring or 

 shaking, 368. 



Elasticity, 82-86; of form distin- 

 guished from elasticity of volume, 

 "86-87. 



Electrical apparatus, 216-217*, 222- 

 223*; description of, 370-380. 



Electric arc, the, 233*-24o. 



Electric battery, the, 203-206*. 



Electricity, magnetism and, 1 90 ff. ; 

 static, 196-202 ; negative and posi- 

 tive charges of, i98*-2oo; action 

 of, in thunderstorms, 200-201 ; 

 flowing, 203 ff . ; flowing of, in dy- 

 namo, 207-210; alternating and 

 direct-current, 211-212; conduc- 

 tion of, 2i3*-2i8; chemical change 

 caused by, 335-339- 



Electric lamps, vacuums in, 12*, 

 317; incandescent, 125; gas-filled, 

 317- 



Electric motors, 256*-257*. 



Electrolysis apparatus, 294-295*. 



Electromagnets, 247-257*. 



Electrons, 193; description of, 197; 

 number of, in negative and in posi- 

 tive charges, 198-200. 



Elements, defined, 293; chemists' 

 abbreviations of, 297-299 ; list of 

 common, 299-300; hiding of, in 

 compounds, 300-301. 



Emulsion, defined, 261 ; difference 

 between solution and, 263. 



Energy released by chemical change, 

 340-341. 



Engine, working of cylinder and pis- 

 ton of, 344*. 



Ether, carrying of heat and light by, 

 124-125 ; light as waves of, 163-164. 



Ether waves, 124-125, 163-164. 



Evaporating dish, 101*. 



Evaporation, 100-106*; part taken 

 by, in formation of clouds, rain, 

 and dew, 277. 



Expansion, caused by heat, 8893 j 

 cooling from, 9496*. 



Expansion ball and ring experiment, 

 9i*-92. 



Explosions, use of, 342* ff. ; automo- 

 biles made to go by succession of, 

 344-345; cause of, 345; shooting 

 of guns caused by, 345-346. 



Explosives, manufacture of, 347. 



Extension lights, 238. 



Eye, lens of, 142; section of, 151*; 

 working of, 151*-! 53. 



Fading, process of, 326-327. 

 Filament of incandescent lamp, 125. 

 Fire engines, need of, to force water 



high, 9. 



Fire extinguishers, action of, 317. 

 Fires, caused by electric arcs, 236; 



putting out of, by water, 317. See 



Burning. 



Flames, formation of, 318. 

 Floating, sinking and, 23-28. 

 Focus of light, i42*-i49*. 

 Fogs, cause of, 288. 

 Food, light necessary to production 



of, 332-333- 

 Force, overcoming of extra motion 



by, in lever, 63-64*; reason for, of 



steam, no. 



Forecasters, weather, 282-285. 

 Form, elasticity of, 86-87. 

 Freckles, cause of, 327. 

 Freezing and melting, 96-99. 

 Friction, 49-55*; electricity produced 



by, 197-198*. 

 Frost, 97, 275 ; explanation of, 287. 



