664 



PROCEEDINGS OF THE AMERICAN ACADEMY. 



cable to show by the aid of very fine filings that lines emerge into the 

 air fi"om the outer filaments at one end of the specimen and go into the 

 metal again at the same end at points nearer the axis. 



The Influence of an Iron Shell upon the Magnetic Behavior 

 OF A Short Cylinder within It. 



Some mild steel cylinders of the dimensions of the cores used in the 

 combinations already described do not show the phenomenon of anom- 

 alous magnetization very strikingly when used by themselves, and it 

 seemed desirable to make a series of tests upon a short piece of very 

 soft steel about 3 centimeters in diameter, without and with shells. I 

 have used very mild steel of various kinds for most of the observations 

 mentioned in this paper, because it is much more homogeneous than 

 the best procurable wrought iron, which is apt to include patches of 

 oxide and slag which hinder the free passage of eddy currents in direc- 

 tions perpendicular to the grain of the material. 



Tables XL, XII., and XIIL, give the flux through this core when the 

 slowly applied current /, which created the field H = 4,TrnI/10 within 

 the solenoid, was in action, after it had been gradually reduced to 

 zero, and after it had been suddenly destroyed. The numbers in the 

 columns headed N, N', N", belong respectively to the cases where the 



