The Villari critical point for aegiven sample of iron is reached with a smaller magnetizing force when the stretching load is great than when it is small; the reversal also occurs with smaller loads and with weaker fields when the iron is soft than when it is hard.
The anticipated reversal was duly found by Chree, the critical point corresponding, under the moderate stress employed, to a field of about 120 units.
I had read many books before, but never from a critical point of view.
Bear in mind, too, that under these untoward circumstances he has to cut many feet deep in the flesh; and in that subterraneous manner, without so much as getting one single peep into the ever-contracting gash thus made, he must skilfully steer clear of all adjacent, interdicted parts, and exactly divide the spine at a critical point hard by its insertion into the skull.
Steel behaves in a similar manner, but the maximum permeability is not so high as in iron, and the fall, when the critical point is approached, is less abrupt.