INDEX. 547 



Evaporation proportional to the difference of tension between the ^^°^' 



water and the vapor in the air _ 939 



Expansion of air by increase of temperature 51 



Expansive effect resulting from the central rarefaction in tornadoes. 299 



Explosion, danger from, in the use of petroleum lamps 500 



Earaday, experiment by, on insulated metallic room 330 



Faraday, explanation by, of the evolution of electricity from steam 347 



Faraday, remark by, on the electricity of chemical decomposition. 389 



Faraday's lectures quoted 112 113 130 



Ferrel, Mr. "W., observations by, of the air being heavier by loss 



of centrifugal rotation 53 



Fish, frozen, retaining vitality 209 



Fitzroy, Admiral, direction by, of system of meteorology in Great 



Britain __. 450^ 453 



Flashing test of the inflammability of petroleum described 502 



Floods on upper rivers, importance of telegraphing, to lower parts 259 



Flourens, assumption by, of the constancy in amount of organic 



life . _-_ 165 



Fluidity of oils, relative, the method of estimating 480, 505 



Fogs in valleys, explanation of 254, 255 



Forests, effect of, on climate 19 



Fossils, meteorological indications derived from 191 



Foucault, M. Leon, apparatus by, for generating heat without con- 

 tact 138 



Fountain lamp employed in light-houses 496 



France, meteorological system established in 451 



Franklin, investigation of tornadoes by 292 



Franklin, observation by, on the travel of storms 452 



Franklin, theory by, of a single electric fluid 311, 312 



Fresnel, polarization of light explained by, through transverse vi- 

 brations of the {ether 103 



Funck, Mr. Joseph, improvement by, in lard-oil lamps 495, 497 



Gages for rain and snow, observations on 1, 3, 261 



Gale, Dr. L. D., application by, of the " intensity " magnet to the 



Morse telegraph 427, 436 



Galvanic electricity less self-repellant than mechanical electricity. 336, 342 

 Gasparin, estimate by, of the annual consumption of carbon from 



the air by vegetation 164 



Gasparin, table by, of relative evaporation from water and earth.. 237 



Gas-pipes and water-pipes good conductors for lightning 375 



Gaudin, illustrations by, of crystalline form? 108 



Gay-Lussac and Biot, electrical observation by, in balloon ascent _ 350 



Germination of plants effected by internal, not external, energy... 121, 124 



" Globular lightning " as described by Arago._._^ 366 



Goodwin, Mr. William, assistance by, in lard-oil investigations..- 485 



