118 



HENKY A. EOWLAND 



netism; second, ditto with magnetization contrary to original mag- 

 netism; third, when used as a permanent magnet with magnetism the 

 same as the original magnetism; fourth, ditto with magnetism oppo- 

 site; and fifth, same as third, but curve taken after several days. The 

 permanent magnetism was given by the current. 



The observations in Tables XI and XII can be compared together, 

 the quantities being expressed in the same unknown arbitrary unit. 

 It is to be noted that the bars in Tables XI and XII were subjected to 

 the same magnetizing force. 



TABLE XII. 



STUBS' STEEL. 



First of all, from these Tables and figures (p. 119) we notice the 

 change in distribution due to the quality of the substance; thus in Fig. 5 

 we see that the curves for steel are much more steep than that of iron, 

 and would thus give greater values to r in the formula a result to be 

 expected. We also observe in both figures the great change in distri- 

 bution due to the direction of magnetization. In the case of the elec- 

 tromagnet this amounts to little more than a change in scale; but in 

 the permanent magnet there is a real change of form in the curve. It 

 seems probable that this change of form would be done away with by 

 using a sufficient magnetizing power or magnetizing by application of 

 permanent magnets; for it is probable that the fall in the curve E is 

 due to the magnetizing force having been sufficient to change the 

 polarity completely at the centre, but only partially at the ends. 



On comparing the distribution on electromagnets with that on perma- 

 nent magnets, we perceive that the curve is steeper toward the end in 



