but they had all sorts of opinions as to the causes. Maxwell himself in his text on Electricity and Magnetism, published in 1873, recognizes, in the chapter on “Electrolysis,”[3] the significance of Faraday’s laws, and even goes so far as to say that “for convenience in description we may call this constant molecular charge (revealed by Faraday’s experiments) one molecule of electricity.” Nevertheless, a little farther on he repudiates the idea that this term can have any physical significance by saying that “it is extremely improbable that when we come to understand the true nature of electrolysis we shall retain in any form the theory of molecular charges, for then we shall have obtained a secure basis on which to form a true theory of electric currents and so become independent of these provisional hypotheses.” [Pg 20] And as a matter of fact, Faraday’s experiments had not shown at all that electrical charges on metallic conductors consist of specks of electricity, even though they had shown that the charges on ions in solutions have definite values which are always the same for univalent ions. It was entirely logical to assume, as Maxwell did, that an ion took into solution a definite quantity of electricity because of some property which it had of always charging up to the same amount from a charged plate. There was no reason for assuming the charge on the electrode to be made up of some exact number of electrical atoms. On the other hand, Wilhelm Weber, in papers written in 1871,[4] built up his whole theory of electromagnetism on a basis which was practically identical with the modified Franklin theory and explained all the electrical phenomena exhibited by conductors, including thermo-electric and Peltier effects, on the assumption of two types of electrical constituents of atoms, one of which was very much more mobile than the other. Thus the hypothetical molecular current, which Ampere had imagined fifty years earlier to be continually flowing inside of molecules and thereby rendering these molecules little electromagnets, Weber definitely pictures to himself as the rotation of light, positive charges about heavy negative ones. His words are: The relation of the two particles as regards their motions is determined by the ratio of their masses and , on the assumption that in and are included the masses of the ponderable atoms which are attached to the electrical atoms. Let be the positive electrical particle. Let the negative be exactly equal and opposite and therefore denoted by (instead of ). [Pg 21] But let a ponderable atom be attracted to the latter so that its mass is thereby so greatly increased as to make the mass of the positive particle vanishingly small in comparison. The particle may then be thought of as at rest and the particle as in motion about the particle . The two unlike particles in the condition described constitute then an Amperian molecular current.