Proceedings of the American Academy of Arts and Sciences. 

 Vol. XXXIX. No. 18. — February, 1904. 



CONTRIBUTIONS FROM THE JEFFERSON PHYSICAL LABORATORY, 



HARVARD UNIVERSITY. 



ON THE COOPER HEWITT MERCURY INTERRUPTER. 



By George W. Pierce. 



NEW YORK 

 -.NIC A* 

 With Three Plates. GA** D ^ 



