The author, in commencing, congratulated the society, and especially Mr. W. Spottiswoode, its earliest promoter, on its successful establishment, and on the brilliant names included in the list of original members. He expressed a decided opinion that music as an art had been too much divided from music as a science, and especially from acoustics, its natural basis. Acoustics was not even, as far as he was aware, taught in musical academies, where instruction was commenced from the other side of the shield. The tendency to exclusiveness on the part of professional musicians had, perhaps, some connection with this neglect of the study of the scientific branch of the subject. Music, though one of the greatest enjoyments granted to man, is not a necessity, like food, and the rule of political economy that supply creates demand is peculiarly applicable to it. He believed it to be to the truest interest of all professional musicians to encourage amateurs, for it should not be forgotten that they formed an intelligent audience, competent to distinguish real from false art. In return, the scientific amateur could give much to the artist, as might be seen from the works of Sir G. B. Airy (the Astronomer Royal), of Mr. Sedley Taylor, and Professor Donkin. The author gave several instances in which, as he considered, professional musicians might gain from their amateur brethren, and as a case in point he alluded to the recent attempts to introduce the French pitch at the London opera-houses. Certainly the bands had played out of tune, but they had not played to French pitch, and he had no hesitation in saying that the pitch of the orchestra was at least a quarter of a note above the French diapason. If they had begun to tune from the bottom upwards, instead of from the top downwards, they would not have had to endure the cacophony which had made the performances of the season so painful. Turning to the special subject of his paper, the author said that he had been, as some of his audience might be aware, endeavouring for several years to extend the compass of orchestral instruments downwards. In the wind department he thought he might say that he had succeeded, by introducing an old instrument, the contra-fagotto, remodelled, and he hoped improved. He had found the same want in the string department. He had exhibited a double bass, strung down to the same pitch, CCC on the organ, in the Exhibition of 1872. The note was frequently used by Beethoven, Onslow, and other great writers; while Gounod used even the B flat below. The author said his object had been to obtain the low notes of the 16-foot octave without increasing the size of the instrument. There were three ways in which a string might be made to give these slow vibrations: first, by increased length; secondly, by increased thickness; thirdly, by increased weight—the last of which had been too much overlooked. The result of the first plan of increased length can be seen in the monster double-bass of the late Duke of Leinster at South Kensington, which would require a giant to play it. The first plan, then, did not answer. He next tried increase of thickness, but found that this also failed, owing to its aptness to produce squeaks, in consequence of transverse vibration. The other means was to increase the specific gravity of the string. It was this third plan which he had adopted. The gut string was covered with heavy copper-wire, like the bass strings of a pianoforte; and this proved to be fairly successful, though probably gold or platinum would answer still better. The doublebass shown at South Kensington was rather lacking in tone, as more resonance was wanting to bring it out fully, and this had led to his consulting Mr. Meeson as to the possibility of reinforcing the vibrations by means of longitudinal struts or bars. It was evident the belly of the instrument required to be made more homogeneous to vibration, and stiffer without increasing its weight or bulk. Mr. Meeson had carried out this idea most ingeniously. Four strips of white deal, curved to an elliptical figure, pass parallel, from end to end, on the inside of the belly. Thus they intercept the S-shaped sound-holes and remove a well-known cause of weakness and a break in the vibrating body. The result is the removal of what the musicians term ‘wolf,’ or inequality and falseness of tone, with a great increase of power throughout the instrument. It had since appeared that the samo process is equally applicable to the smaller members of the violin family, and the author asserted that by its adoption a common instrument can be made nearly equal in tone to an old Italian fiddle, while it strengthens the tone of old instruments in which, from decay or other causes, the power is small. The application of the process in no way damages an instrument, and the bars can be removed at pleasure. As an example of what might be effected by the system he advocated, Dr. Stone introduced to the society a young violinist, who played upon an instrument to which his process had been applied, and the original cost of which was 1s. 9d. Other instruments were shown and tried, which were of considerable age and value. By way of illustration of the practical results of thus extending the compass of the instruments of the string band, a quintet by Onslow was played, which was written by the composer down to CCC (the note now reached by Dr. Stone's method), and which could not have been played as written on the instruments in ordinary use.