SHUDDEMAGEN. — DEMAGNETIZING FACTORS FOR IRON RODS. 251 



No. I mentioned before. The crossing of the curves for coils M N 

 and Cat a high induction is merely another instance of the great 

 difference in magnetic quality of Rods A and B (or Rods I and II) 

 which was already noticed in the magnetization curves of Figure 15. 



From the curves in Figures 24 and 25 we see that for low fields 

 there is quite an increase in the induction for coils not at the middle 

 of the rod as compared with the induction through the central coil. 

 This means that for these low fields the magnetization is more nearly 



lOOr 



50 



25 



C^ 



10000 



Figure 25. 



20000 



Curves showing variations in the distribution of magnetic induction in rod 

 (No. I). D = 1.905 cms. and m = 25. 



uniform. The range in H' for which the sharp upward bend of these 

 curves occurs is precisely the same range for which the susceptibility 

 changes most rapidly and is from H' = to about H' = 5. After this 

 we have quite a long interval for which the susceptibility is high, and 

 the magnetization furthest removed from uniformity ; here the curves 

 showing percentage of induction as compared to that through the 

 middle coils have their minimum and run along very nearly parallel to 

 the i?-axis. However, as the induction through the middle of the rod 

 increases past B = 10,000, all the curves begin to rise, slowly at first, 

 then more rapidly. This indicates that the susceptibility is again 



