accompany the Magnetization of Iron, Nickel, and Cobalt. 55 



III. 



I have now to allude to the deportment of iron when raised 

 to a high temperature. Mr. Faraday has shown, in the last page 

 of his ' Experimental Researches/ that a moderate degree of heat 

 does not alter the magnetic capacity of iron, but diminishes the 

 magnetic force of nickel and increases that of cobalt. At a 

 greater elevation of temperature it is well known that nickel first 

 loses its ordinary magnetic character, then iron, and finally co- 

 balt. But Mr. Faraday has also stated (§§ 2343-2347) that 

 though the magnetism of iron, nickel, and cobalt, as ordinarily 

 exhibited, disappears at a high temperature, yet a feeble mag- 

 netic state remains, however exalted the temperature may be. 



Some time ago several specimens of very tough fibrous iron 

 were shown to me that had been obtained directly from cast iron 

 by bringing high magnetic power to bear upon the latter metal 

 when in a molten state. The process, which was patented, was 

 thus popularly described by the ' Athenaeum ' for April 20, 

 1867 : — " The experiment has been tried at one of the leading 

 iron-works in Sheffield, and with complete success. The mode 

 of operation, as roughly described, is to place a fixed electromag- 

 net opposite an opening in the side of the furnace, to excite the 

 magnet by means of a Smee's battery, so that the magnetism thus 

 evoked may act upon the molten metal. The effect is surprising ; 

 the metal appears to bubble and boil, the melting is expedited, 

 which economizes fuel; and the quality of iron is so mueh im- 

 proved that for toughness and hardness it can hardly be equalled. 

 It appears that some, if not all, of the impurities which remain 

 after the ordinary process are eliminated by the use of mag- 

 netism." The scheme is so opposed to the ordinary views re- 

 garding the inertness of molten iron to magnetism, that any 

 physicist must be naturally incredulous at this report, and would 

 expect the patent to meet with the oblivion it has received. 

 Nevertheless is it not possible, from Mr. Faraday's experiments, 

 that some magnetic effect, not of translation but of direction, 

 may be impressed on the molecules of molten iron ? This is an 

 inquiry to which I hope shortly to give more attention. 



iron wire by magnetization might be made in the following manner : — 

 Two soft iron wires were stretched on a monochord ; round one wire, and 

 nearly its whole length, a helix was coiled, leaving free space for the 

 stretched wire to vibrate within. The wires were tuned to perfect 

 unison ; I then hoped that when the current animated the helix and so 

 magnetized one wire, beats would be heard, owing to the diminished 

 tension of the magnetized wire and, hence, unequal rate of vibration of the 

 two. But I cannot say positively that such was the case. The experi- 

 ment, however, was made under unfavourable circumstances, and needs re- 

 petition. With an optical representation of the combined vibration of the 

 two wires a better effect might be anticipated. 



