7. Thus for instance, one of the early _Divisions_ established by electrical philosophers was that of _Electrics_ and _Conductors_. But this division Dr. Faraday has overturned as an essential opposition. He takes[42\3] a _Gradation_ which carries him from Conductors to Non-conductors. Sulphur, or Lac, he says, are held to be non-conductors, but are not rigorously so. Spermaceti is a bad conductor: ice or water better than spermaceti: metals so much better that they are put in a different class. But even in metals the transit of the electricity is not instantaneous: we have in them proof of a retardation of the electric current: 'and what {225} reason," Mr. Faraday asks, "why this retardation should not be of the same kind as that in spermaceti, or in lac, or sulphur? But as, in them, retardation is insulation, [and insulation is induction[43\3]] why should we refuse the same relation to the same exhibitions of force in the metals?" [Note 42\3: _Researches_, 12th series, art. 1328.] [Note 43\3: These words refer to another proposition, also established by the Method of Gradation.] The process employed by the same sagacious philosopher to show the _identity_ of Voltaic and Franklinic electricity, is another example of the same kind[44\3]. Machine [Franklinic] electricity was made to exhibit the same phenomena as Voltaic electricity, by causing the discharge to pass through a bad conductor, into a very extensive discharging train: and thus it was clearly shown that Franklinic electricity, not so conducted, differs from the other kinds, only in being in a state of successive tension and explosion instead of a state of continued current. [Note 44\3: _Hist. Ind. Sc._ b. xiv. c. ix. sect. 2.] Again; to show that the decomposition of bodies in the Voltaic circuit was not due to the _Attraction_ of the Poles[45\3], Mr. Faraday devised a beautiful series of experiments, in which these supposed _Poles_ were made to assume all possible electrical conditions:--in some cases the decomposition took place against air, which according to common language is not a conductor, nor is decomposed;--in others, against the metallic poles, which are excellent conductors but undecomposable;--and so on: and hence he infers that the decomposition cannot justly be considered as due to the Attraction, or Attractive Powers, of the Poles. [Note 45\3: _Ibid. Researches_, art. 497.]