OF THE MAGNETIC DECLINATION. 



The hourly readings commence on October 1, and are contmued to the close of 

 the series. 



To make the readings of the odd hours of the months of October, November, 

 and December comparable with those of the even hours during tlie whole year, 

 the means of the even hours for the months of October, November, and December 

 (1843) were compared with the corrected annual means respectively, which gave 

 the corrections for the even hours ; and the corrections for intermediate odd hours 

 were obtained from those of the nearest even hours. The deductions from the 

 series of observations at odd hours have but one-third of the weight of those 

 obtained from the even series. 



