ACOrSTlCAL IXVI'.STKI ATIOX oV THE .lATAN I'.Si: lîAMI'.OO ril'i;, 1 )*> 



near the apertuiv, tlie zinc })l;ite was so adjusted that the reso- 

 nance was maximum and then the corresponding value of p was 

 measured. Next tlie length of the air column was clianged and 

 the procedure was repeated. The i-esult of these experiments 

 gave the relation hetween the dimensions of the emhouchurc and 

 the proper i)itch of the resonator for different lengths of the air 

 column. The results are given in Fig. o in which the ahscissa 

 is the numher of vihrations of the resonator and the ordinate is 

 the fourth root of the area of the aperture a. From the 

 diagram, it will be seen that : 



1. The curves n to a* for different values of / seems to 

 conver2;e toward the orisfin with a slisrht curvature. 



2. When the length of the air column becomes comparable 

 with its diameter, as for /=~).2)-3 cm., the number of vibrations is 

 nearly proportional to av. 



o. The greater the length of the air column, the slower the 

 pitch rises with the increase of the aperture. 



4. The narrower the area of the aperture of the embouchure 

 the greater is the ratio — r- 



Care was duly taken not to bring the tuning fork so near 

 to the aperture of the embouchure as to affect the nalural pitch. 



The effect of the moisture in the air column was calculated 

 and found to he insensible within the required range of accuracy. 



The pitch of a simple resonator having its three dimensions 

 comparatively smaller than the wave length :ind communicating 

 with the external atmosphere by a small opening in its surface, 

 has been investigated by many eminent physicists. Helmholtz^^ 

 obtained theoretically for a circular aperture, 



1) IlelmhoUz, Celle, Bd. LVII. l-Ti'. 1SGÛ. 



