ABSTRACTS FOR THE MAGNETIC DECLINATION. * 137 
TABLE II.—The Monthly Means of the Declinometer Readings, rejecting disturbances, in Westerly Declination, 
for the Hours 20, 23, 2, and 5. 
Mean of 
205 and 5h, 
25° 
1841. 1 
July 29-60 
August 35-88 
September : 32-23 
October 30-11 
November 31-07 
1842. 
January 28-60 
February : 30-86 
March 29-52 
April . 33-39 
May . 29-03 
June } : 29-12 
July . 28-55 
August : 26-49 
September . 27-80 
October : 27.35 
November : 26-78 
December 25-21 
Each month shews markedly an increase of Westerly Declination from 20% till 25, and a decrease from 2 
till 55. 
The means cannot be trusted for indications of an annual period. The diurnal range, however, increases 
considerably in summer compared with winter, and the ranges of the months in 1841 and 1842 agree very well. 
The maximum range occurs in May 1842, but it seems probable that the ranges for April, June, and July, 1842, 
are less than they should be, owing to disturbances, which have not been eliminated by the previous rule. 
The two following Tables are formed from Table II. 
TABLE III.—The Westerly Declination at the Observation Hours for periods of Three Months, for the Summer 
and Winter Months, and for the Year 1842. 
Period. : 3 . 5 Mean of 
20» and 5}, 
25° 
1841. : 
July, Aug., Sept. 32-57 
Oct. and Nov. 30-59 
1842. 
Jan., Feb., March 29-66 
April, May, June : : 30-52 
July, Aug., Sept. : 27-61 
Oct., Nov., Dec. 26-45 
Jan., Feb., March 
Oct., Nov., Dec. \ 28-05 
‘ April, May, June 
2 July, Aug., Sep. ae 
4 The Year. 28-56 
MAG. AND MET. OBS. VOL. I. 2 
