Dr. C. Fromme on the Magnetism of Steel Bars. 197 



dent on the specific nature of the steel : the harder the steel, the 

 smaller the value of the force at which the minimum enters. 



Thus, with the harder sort under the action of the vertical 

 component the minimum appears to be reached, or even to be 

 already passed. 



Hence differently elongated ellipsoids of the same sort of steel, 

 under a constant external magnetizing force, receive different 

 values, which arrange themselves in a series descending as the 

 eccentricity increases — -that is, as the force acting on each par- 

 ticle increases. 



With an increasing force, however, these deviating values con- 

 verge to a common minimal boundary value. 



If all the values of k obtained with sort I. be arranged in a 

 series increasing in the arguments K, to the series with in- 

 creasing K a series with regularly diminishing k corresponds, 

 provided only that we take the two means indicated : — 



h. K. 



23-5034 0-0610 



18-0285 0-1062 



15-9974 0-2003 



12-6030 0-2121 



11-4105 | , -, . r9 ™ 0-3189 \ n .QK 0n 



11-8461 1 116283 0-3991 j 03590 



9-64671 1AAQQQ 0-5311 \ a , KAA 



10-4328 } 100398 0-5777 } 05544 



9-8564 0-8311 



8-6826 1-3222 



It hence follows that throughout its various pieces sort I. 

 possesses the same magnetization-function (for the extent of 

 the forces employed and for the permanent magnetism, equal 

 to zero), since with various eUipsoids the same k appertains 

 to an equal argument K. 



Accordingly Neumann and Kirchhoff s developments have 

 validity in the present case, as for soft iron, so also for steel. 



For sort II. a series so regular cannot be constructed, pro- 

 bably for two reasons : — first, because this sort was less homo- 

 geneous ; secondly, and chiefly, because the values of k are 

 near the minimum, where the differences of the values and the 

 variability of each value with increasing force are too small. 



Lastly, as regards the values obtained before the repair, the 

 first glance shows that they differ in two points from those we 

 have just considered : — (1) The values of k obtained with the 

 vertical component are greater than the foregoing, while the 

 two corresponding to the horizontal component are smaller. 

 (2) The divergences between the values for the ellipsoids of 



