Macnetic DECLINATION. 227 
TABLE VI.—Diurnal Range of Magnetic Declination for each Civil Day, as deduced from the Nine 
Daily Observations, with the Mean for each Week and for each Month in 1843. 
January. | February.| March. il. 2 5 July. August. |September.| October. | November.| December. 
3-60 : ‘ 15-41 | 17-36 | 11-00 | 14.99 
5.29 : 14.88 | [13-93] | 11-95 | 21.77 
4-50 . : 17-63 | 15-03 | 12.62 | [14-75] 
[12-75] | 8-97 | 19-10 | 13.28 
7-75 7-84 7.16 | 11-89 
8-80 7-63 | [13-30] | 13-29 
12-05 8-17 9-46 9-64 
7-73 | 10-56 | 13-47 | 11-02 
9:04 | [9-81] | 18-02 | 16-44 
16-20 | 14-32 | 10-01 | [12-13] 
10-25 | 12:96 | 13-17 
7-92 | 15-51 8-75 
12.35 | [11-61] | 13-74 
13-03 | 10.34 
10-98 9-01 
7-19 8-07 
10:56 | [13-06] 
8-27 | 21-83 
11-77. | 15-92 
[10-83] | 13-18 
10-28 | 17-99 
14.27 | 12-86 
9:85 | 11-03 
8-77 | [12-72] 
10-76 9-89 
11-83 | 15-57 
[11-09] | 8.98 
10:17 | 11-04 
12-87 9-30 
12-12 7-07 
11-78 12-67 
Mon tury MBANS OF THE DIURNAL RANGES. 
The means of the diurnal ranges for January, November, and December, do not differ much from each 
other, but they differ considerably from the means for the remaining nine months, which differ little from each 
other. The means for the four seasons are :— 
Winter; January, November, and December, mean of diurnal ranges, . = 638 
Spring; February, March, and April, .............ccsceeceeeeeeeeeeeeeees . =10°86 
Summer; May, June, and July, .................405 Bo ti EUR ey, Ae > Si 
Autumn; August, September, and October,.......... roonbanrmoopatiacns | 137 
Phe Vear yas acteskiaseckasy seleenee Subde COnCeaEF aca REScuneeencocedardordsoccrons .  =10:10 
The quantities in Table VI. shew that the monthly means are much affected by irregular disturbing 
causes, and that if some of the larger diurnal ranges were removed, the monthly means would differ little from 
the ranges of the monthly means of the diurnal variations. It is obvious that the means of the diurnal ranges 
only differ from the diurnal ranges of the means in that the minimum or maximum of certain days does not oc- 
