Peirce — Permeabilities and Reluctivities for Steel. 285 



An isthmus, cut from this rod gave for a long series of 

 observations for values of iTup to 16300, the same final value 

 for /, within a fraction of 1 per cent, as the results tabulated 

 above. 



In view of the importance of Frohlich's Law for magnetic 

 metals at commercial excitations, figure 5, which shows the 



Fig. 































































.j 



r- 



■N 



M 













j 





< 







1 



1 









> 



> 



r 











l 

 1 



\ 





J 



y 

 >" 



<■ 















1 



V 



i 



^ 









































1 

























O 10 H 



Fig. 8. This curve shows the reluctivity of the compressed steel between 

 £r=3jind jB"=100. 



reluctivity of this specimen of soft Bessemer steel for values 

 of ^H up to 160, is of some interest. 



Table III. — Half-Inch Rod of Norway Iron in Long Solenoid. 



H 



B 



H 



B 















1-0 



1960 



24 



16180 



2-0 



6950 



28 



16320 



3-0 



9780 



30 



16400 



4-0 



11380 



40 



16650 



5-0 



12400 



50 



16920 



6'0 



13080 



60 



17180 



7-0 



13640 



70 



17400 



8-0 



14140 



80 



17600 



10- 



14800 



100 



17940 



12- 



15200 



120 



18220 



14- 



15460 



160 



18800 



16- 



15620 



200 



19100 



18- 



15780 



240 



19840 



20- 



15960 



280 



20200 



At low excitations, the determinations of B for this rod 

 were a little uncertain because of the difficulty of demagnetiz- 



