538 



PROF. C. G. KNOTT ON 



Let dM. be the change of the deflection when M changes by amount dM due to 

 magnetisation ; and let D x be the value of determinant. Then 



D l di = 'EndM. . 

 Finally let dj be the change of deflection due to change dndN when N is mag- 

 netised ; and let D 2 be the value of the determinant. Then 



D. 2 dj = - EmdN . 

 The values of D 1 and D 2 will depend upon the particular temperature at which the 

 experiment is for the moment being conducted. They can easily be calculated for the 

 different cases which arise. The quantities I, i, j, are proportional to the observed 



RESISTANCE CHANGES OF THE BRANCH M. 



Temperature 

 C. 



Current in 

 Amperes. 



e?M/M. 



M. 



dM. 



11 



1-616 



780 



2-361 



0-0184 



12-3 



1 



304 



658 



2-374 



156 



133 



1 



143 



596 



2-384 



142 



12-9 





981 



528 



2-380 



126 



13-4 





831 



449 



2-385 



107 



13 





57 



302 



2-381 



72 



12-8 





427 



208 



2-379 



50 



12-3 





346 



148 



2-374 



35 



12 





248 



73 



2-371 



17 



57 



1 



616 



811 



2-874 



233 



577 



1 



379 



712 



2-881 



205 



57-4 



1 



131 



619 



2-878 



178 



57-6 





854 



489 



2-88 



141 



57 '4 





704 



414 



2-878 



119 



)j 





571 



329 



J3 



95 



n 





514 



291 



)> 



837 







398 



203 



)J 



583 



57 6 





329 



149 



2-88 



429 



;j 





283 



108 



j; 



312 



» 





•237 



77 



>) 



212 



)> 





185 



43 



>) 



125 



94 



1 



•512 



752 



3-267 



246 



926 



1 



•258 



689 



3251 



'224 



93-3 



1 



•021 



595 



3-258 



194 



93 





•889 



536 



3-255 



174 



93-8 





•767 



351 



3265 



154 



93-7 





•635 



403 



3-263 



131 



93-2 





•375 



211 



3-257 



688 



93 





•306 



152 



3-253 



495 



91-5 



•237 



88 



3-239 



284 



deflections. The increment dn is known. Hence dividing the second and third equa- 

 tions .by the first we obtain equations from which the increments dM and dN can 

 be calculated. The expressions are, when reduced to their most convenient forms, 



w 



5j 



D 



dn 



n 



di 



dl' 



dN 

 N 



D 2 

 D 



dn dj 

 n dl 





