Lifting Power of the Electro-Magnet. 



523 



Table XXXII — continued. 



Here the first point to be noted is the inferior magnetism as compared to that 

 which the same -f would excite in iron. The inferiority is, however, chiefly in 

 the lower numbers. Thus, for 1^= 200, the two L's are as 1:5-6; at 2600 

 as 1 : I'2. This shows that they would ultimately become equal, and that the 

 difference arises not from steel being less capable of magnetism, but from its 

 greater coercive force requiring a higher -^ to bring it out. This follows still 



more plainly from the values of -— -, which above 600 actually exceed those of 



iron, in accordance with the inference which I made from the phenomena of A, 

 that the coercive force increases more slowly than the magnetism. 



With this magnet A was not observed ; for in 1851, when these experiments 

 were made, I was not aware of its importance. 



The series of \ is complete ; this is the permanent magnetism which re- 

 mains after the current is stopped, and after the keeper has been raised from 

 both cylinders.* As might be expected, it is much greater than in iron, and' it 

 requires a certain continuance of excitation to produce its full amount, for 



* If raised only from one of them, the keeper remains in tlie state A, and of course is much 

 more magnetic than in K. This may give twice as great a value for X as the true one. 



