The first time that a French reader opens Maxwell's book, a feeling of malaise and even distrust at first mingles with his admiration. Only after long acquaintance and much work does this feeling vanish. For some eminent minds, the feeling never disappears.
"The English scientist does not try to construct a single, definite, well-ordered structure: he seems rather to raise a great number of provisional and independenl houses, among which communication is difficult and sometimes impossible."
H. Poincar~ ;~
"To a mathematician of the school of Laplace and Amp8re, it would be absurd to give two distinct theoretical explanations of the same phenomenon, and to mai~tai~ that these two explanations are simultaneously valid. "Io a physicist of the school of Thomson or Maxwell, there is no contradiction in representing the same phenomenon by two different models. Moreover, the complication thus introduced into science never shocks the Englishman: for him it adds the charm of variety .... Thus in English theories we find those inconsistencies, those incoherencies, those contradictions which we are forced to judge severely because we seek a rational system, whereas the author has sought to present only a work of imagination."
P. Duhem ~
"We have still in front of us the important task of deriving Maxwell's equations in such a way as will not contradict the atomic theory of electricity . . . when it Ethe task] is completed we shall find that, by one of those ironies of history, we shall have to a large extent returned to the views of Maxwell's predecessors and contemporaries, which he unwisely rejected." A. O'Rahilly ~ 1. INTRODUCTION A few definitions, chosen more or less at random from the literature of electromagnetism, are as follows : (a) The electric field strength E at a given point P is equal to the force per unit charge which acts on a charged particle placed at P. (b) The voltage V between two points a and b in an electric circuit is equal to the difference in potential between the two points: