NIPHER MAGNETIC OBSERVATIONS IN MISSOURI, 1S7S. Sj 



Where A^ is the charge in log. ^i for i° F., we have from the 

 nine observations above, nine equations, of the form 



e = log. /^o-log- ^t-\- (r-73-7) A/^', or 

 e ^ y -{- 'u./\k. 



The vahie of A-^' which best satisfies these equations is 



A^= - 



[uyj 



Ak = -\- 



_. 68.3 



hence 



448.61 



= 0.152 ; 



log. k, = 1S2328 + 0.0000152 {t-73.7.) 

 From this formula the following table has been prepared 



Determination of q for C^. 



The deflecting magnet Cg was surrounded by a copper jacket, 

 with water lining of one inch thickness, so arranged and so 

 heated as to produce a circulation of the water. 



