44 



Dr. A. Stoletow on the Magnetizing -Function of 



augmentation of ^ does not occur in the same degree with all 



ellipsoids, and thinks that " it may be too soon, in the present 

 state of our knowledge, to expect to deduce a determinate law 

 in relation to this "*. And yet this dissimilar behaviour of dif- 

 ferent ellipsoids is a direct consequence of the theory. 



Indeed, let us first contemplate the two less-elongated ellip- 

 soids numbered 2 and 3 in v. Quintus Icilius, and which were 

 cut out of the same piece of iron as No. 1 (/=199, ^=1*97). 

 For No. 2, I was = 200, d= 20*41 ; for No. 3, /= 51, d= 19-84. 

 We may therefore, in the expression 

 m 1 



X' 



neglect r in comparison with S, or put ^ = «• We then get 



^=3*80 for No. 2, and 0*608 for No. 3. 

 X 



From the experiments of v. Quintus Icilius there result the 

 means 4.34 f or No. 2, and 0*596 for No. 3. 



M. v. Quintus Icilius t has, further, investigated also a more 

 elongated ellipsoid (7= 100*5, ^=5*24), with which the approxi- 

 mative calculation just used would be inadmissible. In order 

 to test the theory in this case also, let us proceed as follows. 

 First, for every X given we seek the corresponding R, using 

 Table II. (as the more extended): that is, we first put fc=0, 

 therefore 11 = X; we find for this value of R the corresponding 



k from the Table, calculate again R = -j — 751 &c. until two con- 



I -f- AO 



secutive values of R come out nearly equal. Then we have 



n% 

 found A-, and can calculate ^ = and compare it with the 



result of experiment. 



In this way I find, for example, 



X. 



^ calculated. 



— observed. 





X 



X 



48-2 



76 



7-09 



275 



100 



9-67 



553 



100 



9-99 



1701 



60 



751 



2851 



4-5 



5-00 



4436 



2-9 



3-52 



* Pogg. Ann. vol. cxxi. p. 135. 



t Ibid, pp. 132 & 138. 



