According to that which has been already explained, it is easy to construct the condensation-curves of various tones, chords, &c., and for the sake of clearness some examples follow:-- Fig. 1, Plate I.,[25] shows a combination curve of three tones, in which all the proportions of the components recur successively. Fig. 2 shows such a curve of more than three tones, in which the proportions in the drawing can no longer so evidently be given; yet the practised musician would here recognise them, even although in practice it might be difficult for him to single out, in such chords, the separate tones. This method of exhibiting the action of tones upon the human ear offers the advantage of a very clear perception of the process; and that which is exhibited (Fig. 3) shows also why a discord must affect our ear unpleasantly. This apparent digression from the aim set forth was necessary in order to indicate that as soon as it is possible for us to create anywhere, and in any manner whatever, vibrations whose curves and magnitudes are similar to the vibrations of any given tone, or of any given combination of tones, we shall have the same impression as this original tone or this original combination of tones would have produced upon us. The apparatus hereafter described offers the possibility of creating these vibrations in every fashion that may be desired, and the employment of electro-galvanism gives us the possibility of calling into life, at any given distance, vibrations similar to the vibrations that have been produced, and in this way to reproduce at any place the tones that have been originated at another place. In Fig. 4, Plate II.,[26] herewith presented, A is the transmitter (Tonabgeber), and B the receiver (Tonempfänger), which two instruments are set up at different stations. I make, however, the preliminary remark that the manner of joining the instruments for interchangeable use backward and forward is here omitted for the sake of clearness, and the more so because the whole is not here propounded as a final fact, but in order to bring that which has been hitherto accomplished to the knowledge of a wider circle. The possibility of the working of the apparatus to a greater distance than that which at present limits in practice the direct working of the galvanic current may also be left out of consideration, since these points may be easily rendered possible by mechanical precautions, and do not affect the essential part of the phenomena now described. Let us next turn to the transmitter, Fig. A. It is put into communication on one side with the metallic conductor leading to the neighbouring station, and by means of this with the receiver, Fig. B; on the other side it is connected, by means of the electro-motive power, C, with the earth or a metallic return-conductor. The transmitter, Fig. A, consists of a conical tube, _a b_, of about 15 centimetres length, 10 centimetres in the front, and 4 centimetres in the back aperture.