Proceedings of the American Academy of Arts and Sciences. 

 Vol. XLVI. No. 9. — October, 1910. 



CONTRIBUTIONS FROM THE JEFFERSON PHYSICAL 

 LABORATORY, HARVARD UNIVERSITY. 



THE MAGNETIC PERMEABILITIES AT LOW 



EXCITATIONS OF TWO KINDS OF 



VERY PURE SOFT IRON. 



By B. Osgood Peirce. 



