Proceedings of the American Academy of Arts and Sciences. 

 Vol. XLII. No. 4. — June, 1906. 



CONTRIBUTIONS FROM THE JEFFERSON PHYSiaVL LABORATORY, 



HARVARD COLLEGE. 



ON THE LENGTH OF THE TIME OF CONTACT IN 



THE CASE OF A QUICK TAP ON A 



TELEGRAPH KEY. 



By B. Osgood Peirce. 



