Proceedings of the American Academy of Arts and Sciences. 

 Vol. XLVII. No. 9. — November, 1911. 



CONTRIBUTIONS FROM THE JEFFERSON PHYSICAL 

 LABORATORY, HARVARD UNIVERSITY. 



A NEW METHOD OF IMPACT EXCITATION OF 



UNDAMPED OSCILLATIONS AND THEIR ANALYSIS BY 



MEANS OF BRAUN TUBE OSCILLOGRAPHS. 



By E. Leon Chaffee. 



With Seven Plates. 



