OF ARTS AND SCIENCES. 413 



knowledge, we are really fitted to decide whether a color-scale is pos- 

 sible, than musicians who lived when a three-stringed harp was the 

 most perfect instrument were to discuss diatonic intervals. 



The writer desires to express his unusual obligations to Professor 

 H. P. BowDiTCH for suggestion, criticism, and supervision of labora- 

 tory work, and to Dr. B. Joy Jeffries for the free use of his valuable 

 library. 



