126 On the Constitution of the Electric Fluid. 



noinena of magnetism has been denied ; but when I find it 

 affirmed by such a number of witnesses, comprising Morichini, 

 Carpi, Ridolfi, Gruelin, Davy, Playfair, Barlocci, Zantedeschi, 

 Christie, Somerville, Baumgartner, and the Messrs. Knox, I 

 cannot believe that they were all deceived. The statement of 

 Playfair, as given by Sir David Brewster, is too strong, striking 

 and circumstantial, to admit the suspicion of mistake. 



The advantage to be derived from admitting that the electric 

 fluid is a compound of elementary forces, which, according to 

 the circumstances of its excitation, may vary in its constitution, 

 is that our explanations of phenomena are thereby disentangled 

 from a multiplicity of embarrassments occasioned by the supposed 

 identity of the various forms of electricity ; and the endeavour to 

 reduce irreconcdeable effects under the operation of a single 

 cause is no longer necessaiy. These laboiu'ed efforts to sustain 

 the doctrine of identity, have had their influence in causing the 

 contradictory speculations promulgated concerning electricity iu 

 connexion with matter. Were there as much truth as boldness 

 in them, we should by this time have attained a thorough know- 

 ledge of the internal structure of matter; the very shape of 

 atoms, and their individual constitution and properties, must 

 have been ascertained. By one philosopher we are informed 

 that atoms are spherical ; others find that electricity is an inte- 

 grant part of their composition, and even declare that without it 

 the atoms could not exist. Again, we are informed that each 

 atom has two electrical poles. This is utterly denied by another 

 authority ; the argument adduced is, that polarity is incompatible 

 with sphericity, all the points in the surface of a sphere being 

 symmetrically placed with relation to the centre. The idea of 

 polarity is also denied by others, who have discovered that some 

 atoms are positively and some negatively electrical throughout 

 their mass. To this is also added, that the electricity proper to 

 each atom is disguised by an electrical atmosphere which sur- 

 rounds it. Some philosophers declare that the polar electricities 

 of atoms are not of equal intensity, one always predominating : 

 this is most emphatically denied by others, who conceive that 

 the admission of equality is indispensable. It is not to be for- 

 gotten also, that some will admit but one electric fluid ; others 

 must have two, or they explain nothing J but others, again, ex- 

 plain all the pba?nomena without any electric fluid at all. The 

 list of contradictory speculations should be considered in con- 

 nexion with this very extraordinary fact, that the fundamental 

 principle of one theory of galvanism is, that water is a conductor 

 of electricity ; but in the rival one it is assumed to be an insu- 

 lator ; aud without the admission of one or other of these con- 

 flicting positions neither theory can stand its ground. 



