142 THE APPLICATIONS OF PHYSICAL FORCES. [BOOK n. 



on the instrument. The arrangement consists of four cat-gut strings 

 of equal lengths, but of unequal thicknesses. The thickest or 



FIG. 96.' The violin : longitudinal and transverse sections. The violin viewed in front 

 and at the side. 



fourth to the left, is a wire string, that is, the gut string is covered 

 with plated copper or silver wire, which gives to the notes produced 



