p and reversal magnetization curves for a Bessemer Bofl steel rod of diam< 

 eter 0.8175 cm. 



Laboratory — that heating the iron specimen white hot and then 

 allowing it to cool slowly will not get rid of the consequent pole- 

 Nor will subjecting the iron to higher magnetizing fields, and then 

 decreasing the held while reversing constantly, so as to demagnetize, 

 help the matter, for the poles come back straightway in their old 

 position-. 



After this the iron rods used in the long solenoid were carefully tested 



