50 



DISCUSSION OF THE VERTICAL COMPONENT 



The numerical values of the coefficients B l B z B 3 in the general equation 



A.= A 4- B l sin ( + CJ + B 2 sin (20 + (7 2 ) + B 3 sin (30 + (7 3 ) 

 expressed in parts of the horizontal force, are given in Table V. The first three 

 decimals (0.000) have been placed in front of the table. 



The next table contains the numerical values of B t B 2 B 3 expressed in absolute 

 measure, and the angles C l C% C 3 obtained by the addition of 180 to their pre- 

 ceding values, so as to make increasing values correspond to increasing force. The 

 first two decimals for B are placed at the head of the columns. 



The next diagram (E) exhibits the general feature of the diurnal inequality for 

 the year and its summer and winter season, as computed by means of the preceding 

 formulae. The greatest difference between the observed and computed values at 

 any one hour is but 2j scale divisions at 2 A. M. in the winter season, and 1 1 

 divisions at the same hour in the annual curve. The absence of the secondary 

 wave in the early morning hours during summer is as conspicuous as its presence 



