ATTRACTION OF IRON BY A STEEL MAGNET. 133 



The effect is considerable if B does not touch A t but 

 much larger if B touches A. It is certain here that 

 the nature of the magnetism in the advanced end of 

 B is the same as that in the advanced end of A. 



Or, if the magnet A be held vertically above the 

 center of a small compass (in which state it will not 

 disturb the compass) ; and if the upper end of B touch 

 the magnet, and its lower end be carried conically round 

 the compass : it will disturb it in a manner which shews 

 that the lower end of B has the same kind of magnetism 

 as the lower end of A. 



58. Explanation of the attraction of soft iron by 

 either pole of a steel magnet, as an effect of induction. 



We are now in a position to explain the ordinary 

 phenomenon, (perhaps the best known of all magnetic 

 phenomena), of attraction of soft iron by either pole of 

 a magnet. In Figure 48, B is, for the time, a magnet 

 as well as A ; and the two poles (that of A and that of 

 B) which are in contact, have, one blue magnetism, the 

 other red. Therefore there is attraction. It is seen 

 that it is indifferent which pole of A is presented to B : 

 a blue pole of A produces an adjacent red pole in B, or 

 a red pole of A produces an adjacent blue pole in B : 

 and in both cases there is attraction. 



We see also that the phenomenon is entirely in ac- 

 cordance with that of the magnetization of steel by 

 double-touch, Article 8. It appeared there that the 

 blue magnetism of one end of the dominant magnet 



