is) 
2 
= 
January. | February. 
0075 | 0101 
[0089] | 0110 
0094 | 0083 
oos9 | 0210 
0096 | 0164 
0075 | [0119] 
0094 | 0092 
0160 | 0119 
[0100] 
0115 
0086 
01061 | 01191 
HorizontaL Component oF Magnetic Force. 
March. 
0119 
[0161] 
0146 
0151 
0215 
0240 
0206 
01774 
April May. June. July. August. 
0-0 0-0 0-0 0-0 0-0 
0166 [0251] 0263 0229 0206 
0144 0220 0187 0173 0346 
[0193] 0236 0297 [0561] 0439 
0165 0298 0227 0703 0371 
0235 0224 [0278] 1627 0341 
0257 0438 0340 0421 0241 
eseeee 0357 0331 0278 [0297] 
sesees [0312] 0285 0231 0213 
0230 0339 0308 0372 0371 
{0231} 0252 0349 [0277] 0246 
0266 0285 0221 
03116 | 03130 | 02899 | 03683 | 03139 
TABLE XIII.—Continued. 
September. 
00 
0191 
0246 
0362 
[0245] 
0188 
0235 
0249 
0334 
0261 
0139 
02484 
237 
October. | November.| December. 
00 0-0 0-0 
0130 0124 0089 
[0186] 0042 0039 
0165 0107 0066 
0183 0150 [0094] 
0211 0128 0104 
0202 [0107] 0074 
0188 0064 0192 
0209 0099 0187 
(0214] 0096 0095 
0163 0077 0128 
0330 [0135] 
02227 01278 01223 
From the means at the foot of Table XIII. it will be seen that the least mean is that for January, and the 
greatest that for July; the same results may be deduced from these quantities as from the ranges of the monthly 
means, thus— 
Jan. & Dee. Feb. & Nov. March & Oct. April & Sept. May & Aug. June & July, 
Ranges, 0°001141 0:001234 0-002000 0:002802 0:0038134 0:003291 
Differences, 0:000093 0:000766 0:000802 0:000332 0:000155 
The mean of the diurnal ranges is about three times as great for the summer months as for the winter 
months. 
If we take the differences of the monthly means of the diurnal ranges, and of the diurnal ranges of the 
monthly means, we shall have some measure of those irregularities which cause the two to differ, 
From the means for each couple of months we have the following differences :— 
Monthly means of the diurnal ranges, minus the diurnal ranges of the monthly means. 
Jan. & Dec. Feb. & Nov. March & Oct. April & Sept. May & Aug. June & July. 
0:000514 0:000507 0:000527 0:000558 0:000493 0-:000449 
The difference is greater at the solstices than in the winter or summer, and is least in summer, 
TABLE XIV.—Diurnal Ranges of the Horizontal Component of Magnetic Force, with reference to 
the Moon’s Age and Declination for 1848. 
After 
Moon 
farthest 
After 
Moon 
farthest 
Mean 
Diurnal 
Range. 
Mean 
Diurnal 
Range. 
Mean 
Diurnal 
Mean 
Diurnal 
Range. 
0-00 
2525 
2232 
2445. 
2183 
2082 
1941 
2093 
1865 
2024 
1630 
1996 
2131 
2596 
3254 
2310 
Range. 
North. 
CHONAMNKR WMH OF 
0-00 
2217 
1792 
2015 
2198 
2237 
2037 
3207 
3227 
2756 
2337 
2303 
2405 
2430 
2422 
2321 
5 
OCONTNMHUbkwwoKeco 
Day. 
“ 
0-00 
2931 
2672 
3249 
3050 
2981 
2248 
2370 
2332 
2211 
2185 
1942 
2116 
2593 
2438 
Table XIV. was formed from Table XIII. in the manner indicated for the declination Table [I. 
MAG. AND MET. oBs. 1843. 
30 
