The sender was virtually composed of a sounding box K, having on its upper surface a large circular opening, across which a membrane was stretched, and in its centre there was fitted a thin disk of platinum _o_, above which a metallic point _c_ was fixed, and this, together with the disk, constituted the contact-breaker. On one face of the sounding-box K, there was a sort of speaking-tube, for the purpose of collecting the sound, and directing it to the interior of the box, in order that it might then react upon the membrane. Part of the box K is broken away in the plate, in order that the different parts of which it is made may be seen. The rods _a_, _c_, which support the platinum point _b_, are in metallic contact with a Morse key _t_, placed on the side of the box K, and with an electro-magnet A, which belongs to a telegraphic system, intended to exchange the signals required to start the action of the two instruments at their respective stations. The receiver consists of a sounding-box B, on which rest two supports _d_, _d_, bearing an iron rod of the thickness of a knitting needle. An induction coil of insulated wire _g_ is wound round this rod, and the whole is enclosed by the lid D, which concentrates the sound already increased by the sounding-box: for this purpose the box is provided with two openings below the coil. The circuit is completed through the primary of this coil by the two terminals 3 and 4, and a Morse key _t_ is placed at the side of box B, in order to exchange signals. In order to work this system, the speaking instrument should be placed before the opening T, and this instrument may be a flute, a violin, or even the human voice. The vibrations of air occasioned by these instruments cause the telephonic membrane to vibrate in unison, and the latter, rapidly moving the platinum disk _o_ to and from the point _b_, causes a series of breaks in the current, which are repeated in the iron wire _d d_, and transformed into metallic vibrations, of which the number is equal to that of the sounds successively produced. According to this mode of action, the possibility of transmitting sounds with their relative value becomes intelligible: but it is equally clear that sounds thus transmitted will not have the _timbre_ of those which produce them, since the _timbre_ is independent of the number of vibrations, and it must be added that the sounds produced by M. Reiss’s instrument were as shrill as those of a child’s penny trumpet, and by no means attractive. The problem of transmitting musical sounds by electricity was, however, really solved, and it can be said with truth that an air or a melody could be heard at any given distance.