150 THE APPLICATIONS OF PHYSICAL FORCES. [BOOK n. 



light deal elliptical in form, like the " sound bar," longitudinally on the 

 inner side of the belly across the /holes, where the belly is weakest. 

 The result of this is that the "wolf" is, indeed, no longer perceptible, 

 but, on the other hand, the quality of the tone of the instrument 



FIG. 101. A violin of the Ouadjiji. 



generally is impaired. This remedy, therefore, cannot be recom- 

 mended for adoption. To the performer the "wolf" is always more or 

 less of an obstacle, but one which, for all practical purposes, can be 

 effectually surmounted by paying close attention first to the position 

 of the " sound-post," which must be ascertained by experiment, and 



FIG. 102. African violin. 



secondly to the size of the string, since it will be found that the 

 " wolf " increases in intensity in proportion to the thickness of the 

 string. The "wolf" is found in all instruments of the violin family, 

 but is most apparent in the violoncello. 1 



1 The "wolf" occurs in its worst form in the wind-viol. When the string is 

 forced to speak at the obstinate point, the instrument seems inclined to shake to 

 pieces with the intense constrained vibration. 



I think " wolf" might be generally defined as sympathetic " interference." I have 



