582 Intelligence and Miscellaneous Articles. 



are sorry that two of these clever pre-Raphaelistic pictures are not 

 lodged in the text; one is on the title-page, and one indeed is 

 seen only gilded on the cover. 



Altogether, this interesting work, partly descriptive o£ a new set 

 of discoveries, and partly a compilation of more or less relative 

 matter, is calculated to incite a taste for seriously hunting up the 

 history of Primeval Man ; and, by showing how and where the 

 study may be practically followed, it will satisfy, to some extent, 

 many enquiring minds, putting them on the right lines for investi- 

 gation, and affording some clues to other and more important 

 systematic works on archaic anthropology. 



LIX. Intelligence and Miscellaneous Articles. 



ON THE MAGNETIZATION OF IRON AND NICKEL WIRE BY RAPID 



ELECTRICAL OSCILLATIONS. BY PROF. I. KLEMENCIC. 



T)T the aid of the formulae of Lord Rayleigh and Stefan the author 

 ■*-* endeavoured to determine the strength of magnetization, or, 

 in other words, the value of /m, from the disengagement of heat 

 which occurs in a magnetizable wire when electrical vibrations are 

 passed through (number of vibrations about 9 x 10 7 ). The deve- 

 lopment of heat was measured by means of a delicate thermo- 

 element near the wire under experiment, and was each time 

 compared with the disengagement of heat in a non-magnetized 

 wire. Observation gave the following values for fi : — soft iron, 

 118; steel (piano wire), soft 106, hard 115; Bessemer steel, soft 

 77, hard 74 ; nickel, 29. These values agree well with those 

 which Baur and Lord Rayleigh found for very feeble magnetic 

 forces. As the experiments of these observers teach, the per- 

 meability is a constant magnitude up to certain values of the 

 magnetizing force while it thus rapidly increases. The present 

 observations show that in these experiments \x varies within a 

 certain range. This fact can be explained either by assuming that 

 the magnetizing forces used here are very feeble, and of the order 

 of magnitude of those strengths of field in which fi is really con- 

 stant ; or by assuming that we are dealing with much greater 

 magnetizing forces, but that the magnetization cannot follow the 

 rapid change so quickly as to reach that part of the curve of mag- 

 netization which corresponds to the variable and far greater values 

 of /a. An approximate estimation of the field- strengths under 

 consideration shows that at any rate on the surface of the wire 

 and at the beginning of the oscillations we have magnetizing forces 

 which are several hundred times as great as that limit within 

 which ju is constant. There would accordingly in this case be a 

 retardation of the magnetization, which, however, must not be 

 confounded with hysteresis. It must in this be assumed that the 

 results of Baur and of Lord Rayleigh which refer to longitudinal 

 magnetization are also applicable to circular magnetization. 



Within the limits of the constant /j. there is no remanent mag- 

 netism ; the magnetization in this region is similar to the deforma- 

 tion of a body within the limits of elasticity, while the further stages 



