CHAP. III.] 



STRINGED INSTRUMENTS. 



137 



may be, and call to mind only that the Greeks studied the lyre not 

 only as artists or poets, but as physicists, for they understood the 



FK;. 04. The tetrachord and the heptachord. 



relations of sonorous intervals and lengths of the strings, the discovery 

 of these laws going as far back as the time of Pythagoras. 



FIG. 95. Ancient lyres or cithars. 



We now come to modern instruments, the construction of which 

 is based on the vibration of sonorous strings, and which like the 



