O F T HE HORIZO N T \ L FO K CE. 

 The first three decimals (O.OOO) have been placed in front of the table. 



53 



In Tabic VII. the same quantities are given in absolute measure; the first two 

 places of decimals (0.00) are placed at the head of the columns. (Increasing num- 

 bers denote increase of force.) The numerical values of A will be found in con- 

 nection with the discussion of the annual variation of the horizontal force. 



On diagram E the average value of the diurnal variation throughout the year. 

 together with the summer and winter value, has been represented as resulting from 

 the numerical quantities in the above table. It exhibits the noticeable feature in 

 the annual curve of a greater morning maximum (about 6 A. M.) than afternoon 

 maximum (about 3| P. M.), whereas in the summer curve it is the afternoon maxi- 

 mum which is the greater of the two. 1 In the winter season the contrast is more 



1 The same is the case at Prague ; in May, Juno, and July, the afternoon maximum was the greater 

 of the two. Karl Kreil, in vol. VIII. Proceedings of the Academy of Sciences of Vienna, 1855: 

 "Resultate aus den niagnetischen Beobachtungen zu Prag." 



