INDEX. 515 



Page. 



Faraday on influence of spiral conductor 108 



Faraday on screening cflect of interposed plates 162 



F.'iraday, reference by, to shock of electrical eel 161 



Faraday's discovery of electricity from magnetism 74 



Faraday's experiment on the magnetic polarization of light 248 



Ferguson, Rev. Peter, observations by, on the effect of fog on 



sound 390 



Fire, peculiar action of, on iron nails 224 



Flame, notice of lecture on 2 



Flame shown to be a bad conductor of heat 858 



Fog, an obstruction to navigation 370, 416 



Fog-bell, automatic, used as a signal at Whitehead Station 490 



Fog, effect of, on sound disputed 390,417 



Fog, effect of, on sound wholly insignificant 418 



Fog-signals, introduction of 374 



Fog-signals nearly as important as light-houses 417 



Fogs on the United States coasts, causes of 371 



Forbes, James D., electric sparks from magnet 79 



"Fountain-ball," explanation of 254 



Fourfold state of matter assumed 258 



Franklin, both a discoverer and an inventor 320 



Franklin's theory of electricity 302 



French writers, theory of thunder storms by 103 



Fresnel, improvements by, in light-house illumination 367 



Froissart, notice by, of the ocean echo 454 



Galvanic battery, new arrangement of . .— 80, 81, 82 



Galvanic battery, plan of a convertible 84 



Galvanic currents in adjacent conductors, used to produce motion. 189 

 Galvanic "Multiplier" principle applied to electro-magnetic ap- 

 paratus 37 



Galvanometer deflection dependent on "quantity" rather than 



"intensity" of current 170 



Gautier, M., investigation by, of the effect of solar spots on terres- 

 trial temperature 225 



Gruelin's Treatise on Chemistry, quoted 261 



Goddard, Dr., observation of effective length of induction coil 116, 117 



Guns as fog-signals 375 



Habits, intellectual and moral, the most important part of educa- 

 tion 339, 340 



Haines, Major Peter C, co-operation of, in observations on sound. 437 



Handles, copper to conductors, effect of 88 



Hansteen, Prof., magnetic needle from, used for observations on 



the aurora 60 



Hansteen, Prof., observations by, on the effect of aurora borealis on 



the earth's magnetism 63 



