Permeability of Iron and Steel. 93 
axes all arranged in continuous chains parallel to the axis of 
magnetization, then 
ee 
G6. —B 
The molecular permeability for given %, under these circum- 
stances, is therefore . 
p=A(GB, —B), 
which -increases continually as % diminishes, and has the 
maximum values (G=0), 
hane BP .~ .. | p= 6748, 
J (soft steel) . w=220,000. 
Nothing is more surprising in these results than the enor- 
mous values of the molecular permeability of the soft steel, 
and the way in which the effect of this is suppressed by the 
comparative immobility of the molecules. Thus:— 
Extreme variation Extreme rota- 
of average tion of average 
inclination: molecule. 
Seturon ring  .. 60°.... 24° 53! oa0 4 
Saeco de 4... 60° « ae. 09° 44790" 15740" 
The molecular permeability of the soft steel is 28°5 times as 
great as that of the soft iron. The extreme rotation of the 
average molecule is 127 times as great in the soft iron as in 
the soft steel. 
P is 287 times as great in the soft steel as in the soft iron; 
so that, assuming that the mean diameter of the molecules is 
the same, the force of torsion arising from molecular attach- 
ment has this ratio in the two cases. 
Putting together the conditions associated with early and 
late maxima in the Fourier’s-series expressions and those of 
the present theory, we have 
Early Maxima. Late Maxima. 
Octave and higher Octave and higher 
termswelldeveloped. termssmallorabsent, 
New magnetic \ . Asmall. A large. 
equations. 
Fourier’s series. 
Recalling the meaning of A, we see that the development of 
the octave and higher terms in the Fourier’s series corresponds 
to low molecular permeability, other things being equal*. It 
* A depends on the absolute magnitudes of the p’s to be represented 
as well as on their course, 
