Transmission of Musical Sounds. 237 



dency to communicate themselves laterally from the conductor 

 to the surrounding medium, and thereby to become audible 

 without the assistance of a reciprocating instrument. This 

 lateral dispersion is scarcely observable with small conductors 

 but is very obvious when a rod of considerable diameter is 

 employed. 



I had an opportunity of observing this fact while repeating 

 some of the preceding experiments at the Royal Institution. 

 A square piano-forte was placed in the apartment beneath the 

 lecture-room ; and a conductor, placed perpendicularly to its 

 sounding-board, passed through the floor separating the two 

 rooms, but no reciprocating sounding-board was placed at its 

 upper end. By this arrangement, longitudinal undulations 

 were communicated to the conductor ; and, whether this was 

 a brass wire one-tenth of an inch in diameter, or a square deal 

 rod half an inch thick, the insulation appeared to be equally 

 perfect. But it was not so when the conductor, instead of 

 being placed on the sounding-board of a piano-forte, was made 

 to rest on the top of the bridge of a violin, and the strings, put 

 into vibration by drawing a bow across them, communicated 

 transverse vibrations to the conductor ; it was now observed, 

 that the metal wire insulated the sound tolerably well, but 

 that when the wooden rod was employed, the sound commu- 

 nicated to the air from the entire surface of the portion of the 

 rod above the floor, was nearly as loud as if a sounding-board 

 were placed at its extremity. 



n. 



I have in this paper given the general results of a variety of 

 experiments made at different and distant periods during the 

 last ten years ; but they are far from forming so complete a 

 course as I have been desirous of making. To extend these 

 experiments much farther would be attended with some dif- 

 ficulties :,but as the velocity of sound is much greater in solid 

 substances than in air, it is not improbable that the transmis- 

 sion of sound through solid conductors, and its subsequent 

 reciprocation, may hereafter be applied to many useful pur- 

 poses. Sound travels through the air at the rate of 1142 feet 

 in a second of time ; but it is communicated through iron wire, 



