An imperfection in the usual statement of the fundamental law of electromagnetic induction

The fundamental law of electromagnetic induction, which is the basis of all our present mechanical generators of electric currents, is, in general, stated in two different ways. Faraday´s statement is to the effect that if a conductor cuts magnetic lines of force, an electromotive force is generated. This simple statement, however, has been changed by later authorities, who define the same law by saying in effect that when the amount of flux enclosed by an electric circuit is changed, an electromotive force is induced. This is the more usual form taught to-day and recopied in most text-books in preference to Faraday´s statement of it.