CHANGE OF ELECTRIC RESISTANCE OF NICKEL. 



539 



Since only the ratios of the currents enter into these expressions, they may be 

 assumed to be proportional to the deflections. Thus every term is known on the right 

 hand sides of the equations and the ratios dM/M and r2N/N can be calculated. Finally, 

 multiplying these proportional changes by the actual resistances of the corresponding 

 branches at the moment of the experiment, we get the total changes of resistance in 

 ohms. These are the changes due to the magnetisation of the nickel portions of the 

 branches M and N which are included within the magnetising coils. The results on 

 carrying out these various operations are shown in the accompanying tables, of which 

 the first and second give the resistance changes of the branches M and N at the various 

 temperatures at which the last and most satisfactory series of experiments were carried 

 out. 



RESISTANCE CHANGES OF THE BRANCH N. 



Temperature Cm 

 C. An 



■rent in 

 iperes. 



asfs. 



N. 



<£N. 



12-3 1 



61G 



732 



2-373 



00174 



12-5 1 



304 



611 



2-375 



145 



14 1 



143 



540 



2391 



129 



13-4 



981 



469 



2-384 



112 



137 



831 



387 



2-389 



92 



13-6 



57 



249 



2-387 



594 



12-8 



427 



167 



2-378 



399 



12-1 



346 



119 



2-371 



282 



12 



248 



63 



2-37 



149 



56-6 1 



616 



813 



2-863 



233 



581 1 



379 



678 



2-878 



195 



56-9 1 



131 



579 



2-866 



166 



57-6 



854 



435 



2873 



125 



57-4 



704 



355 



2-871 



102 



>> 



571 



277 



) j 



794 



>) 



514 



238 





684 



>» 



398 



164 



» 



472 



57-6 



329 



120 



2-873 



346 



J) 



283 



87 



n 



249 



J) 



237 



65 



>i 



187 



)> 



185 



31 



)j 



111 



95-8 1 



512 



769 



3-268 



254 



95-4 1 



258 



653 



3263 



213 



9.3-2 1 



021 



546 



3-26 



178 



93-6 



889 



478 



3-256 



155 



93-8 



767 



416 



3-259 



136 



93-4 



635 



338 



3-254 



110 



93-0 



375 



168 



3-25 



546 



92-9 



306 



119 



3-248 



388 



91-9 



237 



68 



3-237 



221 



In these tables the resistances headed M and N are the resistances of the whole 

 branch in the Wheatstone Bridge containing the nickel wire. But the changes dM. and 

 dN due to the effect of magnetisation are produced almost entirely in the parts of the 

 nickel wires enclosed in the anchor ring. Hence these changes should be compared, not 



