194t Mr. H. Spencer on the Form of the Earth. 



during the season of thunder-storms; and no other method 

 presents itself to my mind at this time for obviating the effect, 

 but that of increasing the size of the battery, and diminishing 

 the sensibility of the magnet, so that at least the smaller in- 

 duced currents may not be felt by the machine. It must be>;;( 

 recollected that the inductive influence takes place at a distance 

 through all bodies, conductors and non-conductors; and hence 

 no coating that can be put upon the wire vk^ill prevent the forma- 

 tion of induced currents. 



I think il not improbable, since the earth has been made to 

 act the part of the return conductor, that some means will be 

 discovered for insulating the single wire beneath the surface 

 of the earth; the difficulty in effecting this is by no means as 

 great as that of insulating two wires, and preventing the cur- 

 rent striking across from one to the other. A wire buried in 

 the earth would be protected in most cases from the effect 

 of a direct discharge; but the inductive influence would still 

 be exerted, though perhaps in a less degree. 



The wires of the telegraph are too small and too few in 

 number to affect, as some have supposed, the electrical con- 

 dition of the atmosphere, by equalizing the quantity of the 

 fluid in different places, and thus producing a less changeable 

 state of the weather. The feeble currents of electricity which 

 must be constantly passing along the wires of a long line, may, 

 however, with proper study, be the means of discovering many 

 interesting facts relative to the electrical state of the air over 

 different regions. 



XXXV. The Form of the Earth no proof of Original Fluidity, 

 By Herbert Spencer*. 



TT has been generally considered that the spheroidal form 



-■■ of the earth — indicating as it does obedience to centrifugal 

 force — implies a primary state of fluidity. If however it can 

 be shown that, notwithstanding its apparent solidity, the earth 

 must be at the present moment entirely subject to the influ- 

 ences affecting its general figure, and that so far as the gra- 

 vitative and] centrifugal forces are concerned it is plastic still, 

 the theory of original fluidity, however probable on other 

 grounds, can no longer be inferred from the earth's oblate- 

 ness. 



The facts indicative of a varying relationship between the 



bulk and tenacity of matter are of every-day observation. We 



constantly see a drop of water maintain its sphericity in spite 



of opposing forces — increase the mass, and it flows out in com- 



* Communicated by the Author. 



