Dr. E. Bouty on the Magnetization of Steel by Currents. 201 





Moment of saturation. 



Moment of 



remagneti- 





Length. 







zation. 



Difference. 



Temporary. 



Permanent. 



Observed. 



Calculated. 



centim. 













396 



99085 



33 95 



56-834 



56834 



0000 



34-4 



82-214 



2245 



42-391 



43169 



-0778 



29-4 



60729 



15-38 









24-8 



43730 



8-92 



21-478 



22- 166 



-0-688 



22 1 



29-066 



6 91 



14-635 



15127 



-0-492 



19 6 



23422 



513 



12033 



11-883 



+0150 



156 



10712 



1-86 



6148 



5-160 



+0-988 



c x ob 



served 



... 0-40024 









c a ob 



served 



... 0-52528 



calculated 0-52924 



? 2 calculated. 



0*9630 

 0*9370 



0-8826 

 0-0232 



The values of c x and c 2 were measured by the magnetization 

 of bars of the same sort as those of the experiment, but mag- 

 netized for the first time. The " calculated " value of c 2 is 

 that which had to be employed concurrently with c x to obtain 

 the numbers of the fourth column. 



The following is a summary of an entire experiment for five 

 different values of F : — 



c, observed. c 2 observed. 



0-03688 0-9625 



0-05123 0-9370 



0-13113 0-8418 



0-77836 0-0770 



These results present a satisfactory general accordance with 

 those which M. Jamin obtained by measuring the extreme or- 

 dinates with the aid of the trial-contact*. 



Action of an inverse current on a saturated cylindrical bar. — 

 In this case the bar preserves, after the cessation of the cur- 

 rent, a positive or negative permanent moment which is very 

 well represented by the formula (1), with the value B 2 of B 

 characteristic of the permanent magnetization. It has not 

 been possible to formulate by a simple law the relation of the 

 capacity-coefficient c 2 A 2 to the corresponding permanent capa- 

 city a 2 ; the diminution A 2 (l— c 2 ) is much greater than «, and 

 appears to approach the limit 2a 2 assigned by M. Jamin when 

 successively greater forces are considered. 



The moment of the bars during the action of the current 

 can only be represented by a formula with two terms — 

 0j*. _0_2£ Pi* Pi* 



./ 2 e* — e 2 \ / 2 « « — e~ 2 \ 



y = CskiU- w — J-^U- \. (6) 



See Comptes Bendus de VAcad. des Sciences, t Ixxx. p. 417 seqq, 



