Early British Phonograph Exhibition

Nature Vol. XVII, Mar. 21, 1878, p. 415.

Physical Society, March 2. – Prof. W. G. Adams, president, in the chair. – The following candidates were elected Members of the Society: — Mr. J. P. Kirkman and Dr. W. J. Russell, F.R.S. – Mr. Sedley Taylor exhibited the colours produced in thin films by sonorous vibrations.  A piece of thin brass perforated with a triangular, circular, or rectangular aperture, and bearing a thin film of soap solution, was placed horizontally on one end of an L-shaped tube; the beam of the electric lamp, after reflection from it, was received on a screen.  It was shown that when a sound is emitted in the neighbourhood of the open end of the tube, the film takes up a regular form which is indicated by the different colours of the reflected light, and each note has its own particular colour figure; and further, with different instruments, we have different figures.  Thus when a square film was employed a kind of coloured grating was the result, which was modified by changing the note, and with a circular film concentric rings traversed by two bars at right-angles were observed. – Mr. W. H. Preece exhibited and described the phonograph.  After referring to the manner in which the preceding communication bore on the subject of the telephone, he went on to explain the construction of the two instruments exhibited, which have been made in accordance with the published accounts of the apparatus and details received from the inventor, Mr. T. A. Edison, by Mr. Pidgeon and Mr. Stroh respectively.  In the first of these the receiving and emitting discs are distinct, the former being ferrotype iron, and the latter of paper, whereas, in the second form of apparatus, both these functions are performed by one and the same disc of iron.  They also differ in that Mr. Pidgeon’s apparatus the drum receives its motion by hand, and in that of Mr. Stroh a descending weight is caused to communicate motion by a suitable train of wheels, which motion can be controlled and regulated by an adjustable pair of vanes.  In both cases the drum is of brass traced over by a spiral groove, and the whole is mounted on a spiral of the same pitch.  The manner of using the phonograph is extremely simple.  The drum having been covered with tinfoil, a uniform movement of rotation is given to it, and a fine metal point, firmly fixed to the centre of the receiving plate, is [416] brought in contact with it, care being taken to place the point accurately over the groove.  If now this plate be sung or spoken to, the tinfoil will be indented in accordance with the vibrations communicated to the plate.  The emitting plate having been provided with a resonator, its point is now brought into the position initially occupied by the point of the receiving plate, and on rotating the drum, with the same velocity, fairly identical sounds are given out.  It will be seen that Mr. Stroh’s apparatus has an advantage over that of Mr. Pidgeon, in that it secures a constant rate of rotation; but on the other hand, the sounds emitted by the paper disc appeared to be more distinct than those from the iron.  A number of experiments were performed with the instruments.  The sounds were reproduced at times with remarkable distinctness, and when Mr. Spagnoletti and Mr. Sedley Taylor sang “God Save the Queen,” as a duet, through a double mouthpiece, the two voices could be clearly distinguished on its being reproduced.  It was shown that even when an indented piece of tinfoil has been employed to emit sounds, it retains its form with such perfectness that the sounds can be reproduced by means of it a second, and even a third time, with nearly equal distinctness.  Prof. Graham Bell pointed out that the articulation of the instruments was very similar to what he had observed in the earlier forms of the telephone, and he had no doubt, judging from his own experience of that instrument, that the phonograph will ere long be so adjusted as to articulate much more perfectly.  He anticipated that the quality of the sound would be found to vary as the rate of rotation was altered, as well as the pitch, and this proved on experiment to be the case.