CONDUCTION OF SOUN 1 ). 337 



Attention should be paid to the position of the short cross wires 

 vhich hold the ends of the communicating twine or wire; they 

 hould be placed parallel to the longer sides of the boxes. 



The sonorous vibrations which in the first instance are 

 'ommunicated to the sounding -box either by the air or 

 v striking it, or by a sounding body, such as a musical 

 >ox or a tuning-fork, placed in contact with it, are 

 ommunicated by the sounding-box to the end of the 

 wine or wire, and are propagated by the latter just as 

 ; hey would be by the air. Each particle performs a 

 : cry short oscillation to and fro, and impels the next 

 article to make a similar movement. The last particle 

 jf the wire transmits the motion to the elastic sounding- 

 card, and the latter, in consequence of its large sur- 

 ; ice, to the surrounding air. The reason that in these 

 xperiments a weak sound is heard at a greater distance 

 ! ian it is in air, is not strictly speaking the better con- 

 ucting power for sound possessed by solids as compared 

 'ith air, but it is that the sound is transmitted by the 

 .vine or wire only in one direction, and therefore with 

 ndimmished intensity; whereas in air sound is pro- 

 igated in all directions around its source, and there- 

 >re diminishes in intensity. A similar effect may be 

 i)served on throwing a stone into a pond; the circular 

 ave which spreads out from the point where the stone 

 irikes the water, becomes more and more shallow as it 

 cedes; but if a wave is produced in a long wooden 

 ough, such as is sometimes used for conveying water, 

 1 in any very narrow water-channel with straight 

 <iooth sides, the wave will be seen to move on through 

 Considerable distance without sensibly diminishing in 

 biht. 



