Professor Galileo Ferraris, of Turin, had already in 1885, arrived at the same fundamental ideas as those of Baily and of Deprez. But the result was more fruitful, inasmuch as he, without knowing of the work of either, united both sets of ideas. Like Baily he proposed to produce rotation of a copper conductor by means of eddy-currents induced in it by a progressively shifted magnetic field ; and this progressively shifted magnetic field he proposed to generate as a true rotating field by combining at right angles to one another two alternate currents which differed by a quarter-period from one another.