60 GAUSS AND WEBER ON TERRESTIIIAL MAGNETISM. 



With this view the mean values for every twelve months have 

 in the first place been calculated. They are : 



I 



These mean values correspond to the middle day of each year 

 of observation, i. e. to the 1st of October 1834 ; and so forth. 



The comparison of the separate months of each year with the 

 corresponding mean value, gives the following differences : 



Declination, 8, a.m. 



The numbers in the last column, being mean values deduced 

 from three years' observations, are freed in some degree, though 



