4. HELMHOLTZ LAW

from the "Helmholtz motion"

The German physicist Hermann von Helmholtz (1821 - 1894) was interested in acoustics in 1852.   The sound of violin created from friction between the bow and strings and the string is vibrate.   When people looked at the violin string, they thought it is parabolic shape.  However, you will be find out that it is actually triangle shape using the stroboscope.  But,Helmholz observed the pattern that triangle rotating on parabolic curve in 1877.   His theory was that "the sound quality increases with the wave-form approaching the ideal Helmholz patten" (the Physics of Violin homepage).