468 



TRANS. ST. LOUIS ACAD. SCIENCE. 



Calling Ak the change in log k^ for i*^^, the moment of iner- 

 tia of the magnet may be represented by the formula 



log^, = logio + (^-64-7) ^k. 



The observations of the table give 23 equations of the form 

 e = log >^o — log kt -\- {i — 64.7) /Ik , or 

 e r= y -\- uAk. 



The value of J>^ which best satisfies these equations is 



Ak =~ 





where the square brackets indicate the summation of all expres- 

 sions similar to those enclosed. This calculation is given in the 

 last columns of the table, from which we have 



Ak = -^ 



10 5 11 



O.f 



5939-2 



• 1 7 ' 



The value for 1878 was 

 Adopting the value of Ak = o 

 of log k^ , 



log^, = 1-22294 +0-0000,7 (^-64-7) 



from which the following table is obtained : 



000 15 • 



we have for the value 



