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Proceedings of the Royal Society of Edinburgh. [Sess. 
axes, directed towards these axes. In the neighbourhood of the ternary 
axes, it is directed from the axes. In the neighbourhood of the binary 
axes, the force acts from them towards the quaternary axes, and 
towards them from the ternary axes. Therefore the ternary, binary, and 
quaternary axes are directions of unstable, unstable-stable, and stable 
equilibrium respectively. This condition is the reverse of that which 
held in the case of the least open arrangement of magnets. Therefore, while 
the least open arrangement gave results agreeing well with the observed 
magnetic properties of magnetite, it appears that the most open homogeneous 
arrangement cannot be the one which exists in that substance. 
The curves exhibiting the transverse component are similar to those 
given in the former paper, but positive loops become negative, and 
conversely. 
4. The longitudinal component of the internal force has its maximum 
positive value when the magnetisation is along the quaternary axes, is 
very small parallel to the binary axes, and has its maximum negative 
value along the ternary axes. The values are in the ratios 240 : 5‘5 : — 127. 
Absolute values are got by multiplying these numbers by Ma 2 /4p 5 . 
If we assume that the true value of this component along a binary 
axis is zero, the curve representing the longitudinal component in all 
directions (see fig. 5 of the former paper) in a plane parallel to a face of 
a cubic crystal would consist of four symmetrical lobes having their 
maxima coincident with the quaternary axes. If the component has 
really a small positive value along a binary axis, the lobes would not be 
completely divided along the lines of the binary axes. In either case the 
curve has its maxima where minima existed in the case of the closest 
packed arrangement, and conversely. 
In a plane parallel to a diagonal plane of a cubic crystal, again on 
the assumption of zero longitudinal component along a binary axis, the 
curve would have six lobes, — two positive, having maxima on the quaternary 
axis, and four negative, with smaller maxima on the ternary axes. If the 
longitudinal component has really a small positive value along a binary 
axis, the two positive lobes become slightly wider, the four negative lobes 
become slightly narrower, and two other small positive lobes appear with 
maxima on the binary axis. 
Again, in either case (fig. 6 of the former paper) there is no corre- 
spondence with the results which hold in the closest packed arrangement. 
5. Since the internal force has a large positive longitudinal component 
along a quaternary axis, a small component along a binary axis, and a 
large negative component along a ternary axis, it follows that the 
