PEIRCE. — ANOMALOUS MAGNETIZATION OF IRON AND STEEL. 635 



During the last thirty years, many persons ^ have studied the von 

 Walteohofen phenomena as they affect the hysteresis cycles of straight 

 rods and of closed cores of iron, and some of these have discussed the 

 bearing of their own measurements upon the theory of anomalous mag- 

 netization. G. Wiedemann * always maintained that his own researches 

 and those of Eighi showed that eddy currents in the iron, accompany- 

 ing surges in the exciting circuit, accounted best for the observed facts. 

 It seemed to von Waltenhofen, however, that the strange reversals of 

 polarity which he had noticed could not be due to induced currents 

 caused by sudden changes in the exciting circuit, and he explained 

 them as consequences of the inertia of the molecular magnets turning 

 in a viscous medium. Fromme,^ Auerbach, Ewing, Peuckert, Zielin- 

 ski, and others who have written upon the subject, seem to agree on 

 the whole with von Waltenhofen's views. 



The present paper attempts to throw some light upon the theory of 

 the von Waltenhofen effect by a discussion of a number of experiments 

 made for the purpose of determining the conditions under which anom- 

 alous magnetization appears. It leaves to a future article a consider- 

 ation of some of the theoretical aspects of the subject. 



The Demagnetizing of Stout Pieces of Iron or Steel. 



It is to be said at the outset that almost every piece of iron to be 

 obtained nowadays in the market is more or less strongly magnetized 



3 C. Fromme, Wied. Ann., 5, 1878; 13, 1881; 18, 1883; 33, 1888; 44, 1891. 

 F. Auerbach, Wied. Ann., 14, 1881; 16, 1882; Winkelmann's Handbuch der 

 Physik, Bd. V (214). W. Peuckert, Wied. Ann., 32, 1887. P. Bachmetjeff, 

 Rep. der Physik, 27, 1891. Ziehnski, Mitt. a. d. Telegraph-Ing.-Bureau d. 

 Reichspostamtes, 2, 1896. Ruecker, Inaugural Dissertation, Halle-Witten- 

 berg, 1905. Peirce, These Proceedings, 43, 1907; 46, 1911. L. A. Babbitt, 

 These Proceedings, 47, 1911. 



* "Schon bei Gelegenheit der von Righi wiederholten Versuche von 

 V. Waltenhofen iiber die anomale Magnetisirung, hatte Ref. [Wiedemann] 

 erwahnt, dass sich dieselben volHg aus dem Auftreten alternirender Induc- 

 tionsstrome in der Masse des Eisens beim schnellen Oeffnen des magnetisi- 

 renden Stromes u. s. f. ableiten lassen, von denen ein spater auftretender 

 weniger dichter, die Magnetisirung durch einen vorhergehenden dichteren 

 Strom vernichten resp. umkehren kann. Die anomale Magnetisirung ist 

 also rein secunddr." — Beiblatter der Annalen der Physik, 5, 1881. 



' "Gegeniiber den Bemerkungen des Herrn Ref. [Wiedemann] halte ich 

 meine Ansicht aufrecht, dass ich durch meine Versuche mit Eisendraht- 

 biindeln, welche ebenfalls den Unterschied der permancnten Momente in 

 der regelmassigsten Weise zeigten, schon nachgewiesen zu haben glaube, 

 dass Inductionsstrome keinesfalls zur Erklarung ausreichen konnen." — 

 Wiedemann's Annalen, 13, 1881. 



