And here I may remark, that, although the conception of the undulatory current of electricity is entirely original with myself, methods of producing sound by means of intermittent and pulsatory currents have long been known. For instance, it was long since discovered that an electro-magnet gives forth a decided sound when it is suddenly magnetized or demagnetized. When the circuit upon which it is placed is rapidly made and broken, a succession of explosive noises proceeds from the magnet. These sounds produce upon the ear the effect of a musical note when the current is interrupted a sufficient number of times per second. The discovery of “Galvanic Music,” by Page,[2] in 1837, led inquirers in different parts of the world almost simultaneously to enter into the field of telephonic research; and the acoustical effects produced by magnetization were carefully studied by Marrian,[3] Beatson,[4] Gassiot,[5] De la Rive,[6] Matteucci,[7] Guillemin,[8] Wertheim,[9] Wartmann,[10] Janniar,[11] Joule,[12] Laborde,[13] Legat,[14] Reis,[15] Poggendorff,[16] Du Moncel,[17] Delezenne,[18] and others.[19] It should also be mentioned that Gore[20] obtained loud musical notes from mercury, accompanied by singularly beautiful crispations of the surface during the course of experiments in electrolysis; Page[21] produced musical tones from Trevelyan’s bars by the action of the galvanic current; and further it was discovered by Sullivan[22] that a current of electricity is generated by the vibration of a wire composed partly of one metal and partly of another. The current was produced so long as the wire emitted a musical note, but stopped immediately upon the cessation of the sound.