546 • INDEX. 



Page. 

 Elastic force of vapor proportional to its density 224 



Elastic force of vapor, table of, at diflFerent temperatures 217 



Elasticity, an ultimate property of matter 94, 95 



Electrical absorption and induction, instruments for observing 358, 359 



Electrical condition of an insulated long vertical rod 352 



Electrical induction illustrated 328, 333 



Electrical kite, observations with 358, 359, 389 



Electric discharge accompanied by a transfer of matter from con- 

 ductor 336 



Electric discharge tending mainly to surface of conductors 342 



Electricity by Franklin's theory, the postulated conditions of 312 



Electricity from steam explained by Faraday 347 



Electricity, mechanical, more self-repellant than galvanism 336, 342 



Electricity, positive and negative, method of distinguishing 818, 329 



Electricity referred to an action of the ether 105, 313, 346 



Electricity, simple method of developing 315 



Electric tension increased by diminished surface in cloud condensa- 

 tion 360 



Electro-magnetic bell signal devised at Albany in 1831 434 



Electro-magnetic telegraph first made operative by the " intensity " 



magnet 427, 436 



Electro-magnetic telegraph, two systems of 427 



Electro-magnet with numerous close coils illustrated 429 



Electrometer devised by Pettier, for measuring the force of elec- 

 trical induction of the earth 354, 355 



Electroscope, simple forms of, illustrated 317, 322, 328 



Energy developed by the running down of organic compounds 118, 120 



Energy developed from matter in a potential state 457 



Energy of de-composition exactly equal to that of composition 131 



Epinus, theory by, of electric fluid 311, 313 



Espy, Mr. James P., investigation by, on conditions of vapor 



Espy, Mr. James P., investigation of tornadoes by 292, 293, 306 



Espy, Mr. James P., meteorological labors of, highly commended- 442 

 Espy, Mr. James P., observations by, on the warming eflfect of at- 

 mospheric vapor 55, 57 



Espy, Mr. James P., theory of storms by, not sufficiently appre- 



Espy, Mr. James P., views of, as to the compensation of wind cur- 

 rents 83, 84 



Equatorial belt of calms and rains illustrated 276, 277, 278 



Equatorial rain-belt, oscillation of, with the seasons 58 



Equivalents, chemical, determining series of chemical compounds. 110, 111 



Evaporation greatly promoted by wind.__ 238 



Evaporation not a probable cause of atmospheric electricit}' 346 



Evaporation of water, method of estimating 236, 239 



