130 Dr. E. Bouty on t lie Magnetization of Steel by Currents. 



what is remarkable is, that if we seek, by means of the curve 



which represents the magnetizing function for the needles 



considered, to discover what the intensity x' of the magnetic 



force would have to be to produce the quantity of magnetism 



a/ 

 A after a single passage, we find for the ratio -— a sensibly 



constant value. 



The following Table refers to needles of 0*553 millim. dia- 

 meter: — 



Current xA A— B. 



1 



A. 



A 

 A-B- 



x' 



X ' 



10 

 14 



18 

 22 

 26 



30 

 34 



38 



42 



100 

 2-80 

 580 

 10=60 

 15-70 

 19-70 

 22-20 

 2360 

 24-50 



1-28 

 3-49 

 676 

 1219 

 17 50 

 21-37 

 23 49 

 24-45 

 2511 



1-280 

 1-246 

 1165 

 1150 

 1115 

 1-085 

 1-058 

 1-036 

 1 025 



1-080 

 1075 

 10581 



125 r 063 



1-077 J 

 11 12 

 11 02 

 1075 







| Mean.... 1-077 



The values of the ratio -- united by the brace are those 



x J 



which are considered the best-determined, because they refer 

 to the region of rapid magnetization, of which we shall subse- 

 quently speak. The corresponding mean differs but little from 

 the general mean, considering the multiple causes of error 



x' 

 which must accumulate in the calculation of — 



x 



It has moreover been observed that the value of this ratio 

 varies very little with the diameter of the needles, which we 

 suppose always below 1 millim. • its mean value appears to lie 

 between 1*060 and 1*065. It was natural to suppose that the 

 displacement of the poles corresponds exactly to the incre- 

 ment of the quantity of magnetism — that is to say, that the 

 final magnetization is in all points identical with that which 



inconsiderable magnetizing forces acting on ellipsoids. It appears to me 

 that under these conditions a multitude of perturbing causes must act. 

 As, however, 1 have only employed the action of intense currents, I abstain 

 from giving an opinion on this matter. But if M. Fromme will take the 

 trouble to magnetize a simple hard-tempered needh? in a powerful helix 

 excited by ten Eunsen elements, he will have no difficulty in convincing 

 himself that in this case saturation is attained at the first stroke, as is 

 known by all physicists 



