356 ETHEREAL MEDIUM MAGNETIC. SECT. XXXIV. 



Professor William Thomson of Glasgow lias computed that in the 

 space traversed by the earth in its annual revolution, a cube 

 whose side is 1000 miles would contain not less than a pound 

 weight of the ethereal medium, and that the earth, in moving 

 through it, would not displace the *250th part of that pound of 

 matter. Yet that is enormously more dense than the con- 

 tinuation of the earth's atmosphere would be in interplanetary 

 space, if rarefied according to Bayle's law. But whatever be 

 the density or nature of the ether, there is every reason to be- 

 lieve that it is the medium which transmits the gravitating force 

 from one celestial object to another, or possibly it may possess 

 a higher attribute with regard to gravity than its mere trans- 

 mission. 



Dr. Faraday, who discovered the magnetism of the atmosphere, 

 is led to believe that the ethereal medium too is magnetic by the 

 following experiment. Three solutions of the protosulphate of 

 iron, I, m, n, the first of which contained 4 grains of the salt 

 dissolved in a cubic inch of water, the second 8 grains, and the 

 third 16 grains these were respectively enclosed in three glass 

 globules, all of which were attracted by the pole of a magnet. 

 A quantity of the mean solution m was then put into a vessel, 

 and the globule containing the strongest solution n was immersed 

 in it, which was attracted as before, but the globule Z, containing 

 the weakest solution, was repelled when plunged into the same 

 liquid. Here there was a diamagnetic phenomenon, although 

 the glass globules and the liquid in which they were immersed 

 contained iron. The effect was evidently differential, for when 

 the liquid was less attracted than the globule, the globule ap- 

 proached the pole, and when the liquid was more attracted than 

 the globule, the latter appeared to recede from the pole. In 

 fact, the effect is the same as that of gravity on a body immersed 

 in water ; if it be more forcibly attracted than the water, it 

 sinks ; if less forcibly attracted, it rises, the effect being the same 

 as if it were repelled by the earth. Hence the question, are all 

 magnetic phenomena the result of a differential action of this 

 kind, and is the ethereal medium less strongly attracted than 

 soft iron, and more strongly attracted than bismuth, thus per- 

 mitting the approach of the iron, but causing the bismuth to 

 recede from the pole of a magnet ? If such a medium exist, that 

 is, if the ethereal medium be magnetic, then diamagnetism is 



