Messrs. H. Nagaoka and K. Honda on Magnetostriction. 287 



Table III. 



H. 



k. 



i 



( - y xKT. 



V 



k' 

 (calcul.). 



(cacul.). 



SI 



(calcul.). 



£1 

 (exp.). 



5 



140 



8-0 



050 



4-93300 



-56300 



184 



1-2 



10 



101 



260 



079 



64600 -74400 



860 



56 



15 



78-0 



294 



097 



36S00 -29100 



394 



5-8 



20 



610 



31-5 



111 



21100 -19400 



394 



41 



30 



423 



340 



130 



10090 - 9290 



2-84 



1-5 



40 



32-5 



32-8 



1-41 



5650 - 4620 



1-72 



04 



50 



267 



31-8 



150 



3660 - 2590 



1-05 



-01 



75 



18-6 



280 



1-62 



1590 - 685 



Oil 



-06 



100 



14-5 



241 



1-70 



870 - 121 



-347 





125 



1 11-8 



204 



1-77 



530 4- 58 



-5-45 





150 



100 



168 



184 



353 4- 134 



-678 



... 



200 



7-8 



9-7 



1-99 



183 4- 183 



-8-57 





300 



5, 



-4-6 



2-23 



65 4- 170 



-994 





The above table shows that k' and k" are of the same order 



of magnitude as for nickel ; they are, however, of opposite 



k n 

 sign. The approximate relation // + — =0 does not hold for 



iron, the quantity kf + -~ amounting to several thousands in 

 o 



low fields. It therefore appears that the effect of hydrostatic 



pressure must result in considerable increase of magnetization, 



which is irreconcilable with the experiments already described. 



The change in magnetization due to longitudinal pull 



(0'38 kg. sq. mm.) is calculated in the seventh column ; in 



low fields there is increase of magnetization, which ultimately 



reaches a maximum in 11=12 nearly ; the magnetization 



then begins to diminish very slowly until it becomes less than 



in the unstrained state in H = 90. This theoretical conclusion 



agrees with experiment, although the actual numbers are 



somewhat different, as will be seen in the last column. 



If, on the other hand, we make use of the experimental 



result that the effect of hydrostatic pressure is negligible 



compared with that of longitudinal pull, we obtain the following 



values of k!= — ^k" by easy calculation from experiments on 



-stretching. 



Table IV. 



H, 



* 



yXl0 7 (calc). 



\Sl 



-Xl0 T (calc). 



^-Xl0 7 (exp.). 



V 



10 



1 0000 



20-2 



25-5 



11-4 



08 



15 



12640 



31-9 



29 3 



172 



10 



20 



9730 



44-6 



31-5 



167 



11 



30 



4120 



45-2 



33-0 



18-2 



1-3 



40 



1420 



37-4 



32-8 



18-8 



1-4 



50 



360 



30-0 



31-8 



20-2 



1-5 



70 



-100 



232 



283 



214 



1-6 



90 



-160 



21-7 



25 6 



1 



242 



1-7 



