)( DISCUSSION OF nil: DIURNAL \ IRIATION 



marked, the morning maximum being considerablj greater, Theie curves also sho\t 



i!m gradual shifting of the maxima and minim to a later hour in winter than in 



i ner, o phcn< mon also well exhibited in the preceding diagrams C I l>. 



•| | M . numerical values of this change of hours will be given in tabular form further 



on. The s II afternoon minimum abou( 9 P. M. is less distinctly marked than 



anj other feature of the diurnal curve 



(E.) i: .mi Botiin Dh i ■■ u \ a 1 1 vim .. i.i mi FIonifo»TAi Poi ci roi dmmeb, Wiwtbb, abd wooli Vbab. 



(Ill flllHIlllltr I I ML i 



ii, n 



i 



I :, 



14(1 



i i, 100 



i 



i 



ii, 

 ii.i.i 





/ 







y 



\ 



\ 



\\ 



\ 



\ 



i i i , 



/ 





J 



7 



/ 



/ 



/ 





■ i i 



\ 



\ 







/^\ 



i . 



ilO 



ll.l 

 llfl 



1.1731 

 327 

 282 



I BO 



i ii 



, . 



(04 

 31 

 273 

 1.17221 

 181 

 i 



I IT, I 



nil 

 BBS 



OH I I 3 4 7 I D I" n N'ii I .'. I i 5 I 10 11 12 1 ' 

 A M P.M. 



Phil icli Ipl hi i 



Tabic VIII. contains the computed values of the time I amount of the morning 



maxim and minimum, and of the nftcrnoon maximum. The values for the 



secondary afternoon minimum arc taken from the diagrams The time of the \. M. 

 maximum and minimum is within the nearest eighth minute; that <>i the P, M, 

 maximum within the nearest tenth minute, The time for the P. M. secondarj 



mi is within the nearest hour. The amount of change of horizontal force is 



expressed in Bcale dh is 



