524 Prof. A. M. Mayer's Researches in Acoustics. 



Fig. 6. 



ResultaDt curve, formed by combining the curve of a musical note with 

 that of its major third. X : X' : : 1 : f . 



Kg. 7. 



rotating the disk, one can readily follow the compound vibra- 

 tory motion of the spot of light ; but on a rapid revolution of 

 the disk, persistence of visual impressions causes the spot to 

 appear lengthened into a band ; but this band is not equally 



