Proceedings of the American Academy of Arts and Sciences. 

 Vol. XXXV. No. 22. — April, lUUO. 



CONTRIBUTIONS FROM THE PHYSICAL LABORATORY OF THE 

 MASSACHUSETTS INSTITUTE OF TECHNOLOGY. 



XLIX.— HIS TO RIO AL NOTES EEL A TING TO MUSICAL 

 PITCH IN THE UNITED STATES. 



By Charles R. Cross. 



