The Bell system, as we have seen, although making use of a battery in the first instance, only obtained the diminution and increase of electric force necessary for the articulation of words by means of induction currents produced by the movements of an armature of soft iron, currents of which the intensity was consequently due to the range and inflections of these movements. The battery only intervened in order to communicate magnetic force to the inducer. This use of induced currents in telephonic transmissions was already of great importance, since various experiments subsequently made have proved their superiority to voltaic currents for this purpose. But experience soon convinced Mr. Bell that a powerful inductive apparatus worked by a battery was not only unnecessary for the action of this apparatus, but that a permanent magnet, very small and weak, would provide sufficient currents. This discovery, in which, as we have seen, Mr. Peirce had some share, was of great importance, since it became possible to reduce the size of the instrument considerably, so as to make it portable and adapted for sending and receiving; and it was shown that the telephone was the most sensitive of all instruments in revealing the action of currents. If, therefore, Mr. Bell was not the first to employ the successful mode of transmitting articulate words, it must be said that he sought, like Mr. Gray, to solve the problem by means of undulatory currents, and that he obtained these currents by the effect of induction, a system which, as soon as it was perfected, led to the important results with which we are all acquainted. If he had only given to the astonished world an instrument capable of reproducing speech telegraphically, his fame would be great; for this problem had hitherto been regarded as insoluble. Mr. Gray’s claims to the invention of the telephone are given in the following summary from a very interesting work, entitled ‘Experimental Researches on Electro-harmonic Telegraphy and Telephony:’ ‘1. I was the first to discover the means of transmitting compound sounds and variable inflections through a closed circuit by means of two or more electric waves. ‘2. I assert that I was the first to discover and utilise the mode of reproducing vibrations by the use of a magnet receiver constantly supplied with electric action. ‘3. I also assert that I was the first to construct an instrument consisting of a magnet with a circular diaphragm of magnetic substance, supported by its edge at a little distance from the poles of a magnet, and capable of being applied to the transmission and reception of articulate sounds.’