After Faraday's discovery that electric currents could be developed in a wire by causing it to cut across the lines of force of a magnet, it was to be expected that attempts would be made to construct machines to avail of this fact in the development of voltaic currents. The first machine of this kind was due to Hippolyte Pixii, 1832. It consisted of two bobbins of iron wire, opposite which the poles of a horseshoe magnet were caused to rotate. As this produced in the coils of the wire an alternating current, Pixii arranged a commutating device (commutator) that converted the alternating current of the coils or armature into a direct current in the external circuit. This machine was followed by improved forms of magneto-electric machines due to Edward Samuel Ritchie, Joseph Saxton, Edward M. Clarke 1834, Emil Stohrer 1843, Floris Nollet 1849, Shepperd 1856, Van Maldern, Werner von Siemens, Henry Wilde and others.