Intelligence and Miscellaneous Articles. 



331 



to ¥ and H. The curve given by them presents the same general 

 characters as do Stoletow and Rowland's curves, but with more 

 rigid turns, a concavity towards the positive H strongly pronounced 

 for small values of F, an inflection so elongated that for a consider- 

 able portion of its extent the curve is indistinguishable from a 

 straight line ; in a word, it has the appearance of a broken line 

 with the obtuse angles much rounded : such are the results given 

 by the construction of the new curve. They confirm the facts dis- 

 covered by entirely different methods in the case of iron, at the 

 same time that they characterize the . peculiar consistence of very 

 stiffly tempered steel, and supply an unexpected verification of the 

 theoretic ideas I have put forth elsewhere on the subject*. 



Finding it impossible to effect absolute measurements, I could 

 do no more than compare Eowland's results with mine, in the 

 manner indicated by the following Table. C is the abscissa at the 

 origin of the tangent to the point of inflection, C the abscissa of 

 the poiut where the tangent meets the asymptote to the curve, L 

 the maximum of magnetization. All the ordinates are expressed 

 as functions of C, all the abscissae as functions of L. 





Iron, according to 

 Rowland. 



Chilled steel. 



Abscissae. 



Ordinates. 



Abscissae. 



Ordinates. 



Abscissa C and corresponding 1 

 ordinate of the curve J 



1-973 Ci 



0-633 L x 

 0-100 1^ 

 0-278 L, 



2-608 C 2 



0-796 L 3 

 0-100 L 2 

 0-414 L 2 



Ordinate corresponding to the j 

 abscissa C J 



Coordinates of the point of in- 1 

 flection J 



Length of the rectilinear portion 1 

 of the curve (difference of the I 



1-271 C x 

 0-190 C, 



1-667 C 2 

 0-509 C 2 









The interval from C to C might be named interval of rapid mag. 

 netization. Within these limits, distant 0-973 C^ for iron, 1*608 C a 

 for chilled steel, the quantity of magnetism increases from -fa of its 

 maximum value up to nearly f for iron and ^ for steel. The de- 

 termination, in absolute value, of C, C, and the corresponding ordi- 

 nates would furnish a good comparison of the magnetic powers of 

 different kinds of steel, iron, &c, and at the same time would fix the 

 limits which it would be absurd not to reach, or not economical to 

 exceed, in the intensity of the currents employed for the mag- 

 netizing. 



In a future communication I shall indicate the results regarding 

 the distance of the poles, as well as the changes produced in the 

 quantity of magnetism or in the polar distance when the needle is 

 passed repeatedly through the magnetizing spiral. — Comptes Rendus 

 de VAcademie des Sciences, vol. lxxx. pp. 650-653. 



* " Studies on Magnetism," IV., Phil. Mag. March 1875, p. 199 

 et seqq. 



