Ivi 
General Results of the Makeestoun Observations. 
Table 53. — Mean Difference of the Observations of the Vertical Component of Magnetic Force, 
in 1844 and 1845, from the Monthly Means at the corresponding Hours in each Year, as deduced 
from all the Regular Observations. 
Mean Positive Difference. 
Mean Negative Difference. 
Mean Difference. 
Mak. 
Mean 
Nov. 
Feb. 
May. 
Aug. 
Nov. 
Feb. 
May. 
Aug. 
Nov. 
Feb. 
May. 
Aug. 
Time. 
Dec. 
Mar. 
June. 
Sept. 
Year. 
Dec. 
Mar. 
June. 
Sept. 
Year. 
Dec. 
Mar. 
June. 
Sept. 
Year. 
Jan. 
April. 
July. 
Oct. 
Jan. 
April. 
July. 
Oct. 
Jan. 
April. 
July. 
Oct. 
li. 
m. 
0*00 
0*00 
O'OO 
O'OO 
O'OO 
O'OO 
0 00 
O'OO 
O'OO 
O'OO 
O'OO 
0*00 
O'OO 
O'OO 
0*00 
1 o 
1 i 
1 
1 o 
0159 
0229 
0151 
0187 
0183 
0199 
0533 
0208 
0379 
0311 
0177 
0320 
0175 
0250 
0230 
1 0 
1 Q 
1 .1 
0147 
0222 
0183 
0187 
0185 
0191 
0431 
0252 
0379 
0303 
0166 
0293 
0212 
0250 
0230 
1 A 
1 'i 
1 O 
0138 
0226 
0173 
0197 
0185 
0259 
0567 
0283 
0400 
0352 
0171 
0323 
0215 
0264 
0243 
1 u 
I ^ 
I O 
0142 
0203 
0180 
0206 
0184 
0196 
0497 
0293 
0409 
0334 
0165 
0288 
0223 
0274 
0237 
1 (\ 
1 0 
0136 
0185 
0151 
0214 
0172 
0195 
0487 
0263 
0389 
0320 
0160 
0268 
0192 
0276 
0224 
1 1 
1 ^ 
0139 
0173 
0145 
0181 
0161 
0185 
0403 
0237 
0351 
0281 
0159 
0242 
0180 
0239 
0205 
1 Q 
1 Q 
1 A 
0135 
0148 
0140 
0153 
0144 
0179 
0274 
0201 
0304 
0236 
0154 
0192 
0165 
0204 
0179 
19 
13 
0134 
0124 
0134 
0143 
0134 
0151 
0171 
0167 
0198 
0170 
0142 
0144 
0149 
0166 
0150 
20 
13 
0133 
0101 
0131 
0130 
0124 
0141 
0145 
0154 
0156 
0148 
0137 
0119 
0142 
0142 
0135 
21 
13 
0125 
0097 
0121 
0120 
0116 
0147 
0126 
0160 
0122 
0138 
0135 
0110 
0138 
0121 
0126 
22 
13 
01 20 
0101 
01 22 
0111 
0113 
0141 
0112 
0137 
0120 
0128 
0130 
0106 
0129 
0115 
0120 
23 
13 
0120 
0115 
0132 
0112 
0119 
0120 
0115 
0124 
0106 
0117 
0120 
0115 
0128 
0109 
0118 
0 
13 
0137 
0157 
0123 
0163 
0145 
0122 
0131 
0121 
0111 
0121 
0129 
0143 
0122 
0132 
0132 
1 
13 
0140 
0146 
0115 
0180 
0143 
0127 
0124 
0125 
0123 
0124 
0133 
0134 
0120 
0146 
0133 
2 
13 
0163 
0174 
0113 
0183 
0156 
0123 
0132 
0135 
0133 
0130 
0140 
0150 
0123 
0154 
0142 
3 
13 
0289 
0251 
0131 
0246 
0220 
0155 
0144 
0139 
0157 
0151 
0202 
0183 
0135 
0192 
0178 
4 
13 
0333 
0260 
0166 
0282 
0254 
0179 
0140 
0147 
0180 
0162 
0233 
0182 
0156 
0220 
0198 
5 
13 
0392 
0368 
0182 
0359 
0315 
0189 
0181 
0152 
0198 
0181 
0255 
0243 
0166 
0255 
0230 
6 
13 
0447 
0341 
0164 
0285 
0292 
0187 
0188 
0151 
0157 
0171 
0264 
0242 
0157 
0202 
0216 
7 
13 
0336 
0227 
0152 
0213 
0225 
0166 
0142 
0130 
0148 
0147 
0222 
0175 
0140 
0175 
0178 
8 
13 
0209 
0153 
0124 
0131 
0151 
0131 
0128 
0122 
0131 
0129 
0161 
0139 
0123 
0131 
0139 
9 
13 
0172 
0131 
0108 
0110 
0127 
0138 
0157 
0119 
0180 
0146 
0153 
0143 
0113 
0137 
0136 
10 
13 
0150 
0160 
0103 
0114 
0132 
0176 
0246 
0121 
0189 
0179 
0162 
0194 
0111 
0142 
0152 
11 
13 
0150 
0150 
0115 
0148 
0142 
0199 
0273 
0137 
0322 
0222 
0171 
0194 
0125 
0203 
0173 
105. The approximate epochs of maxima and minima for the mean positive iind negative differences, the 
principal being indicated by + and — , are as follow : — 
Mean Positive Difference. 
Mean Negative Difference. 
Nov. Dec. .Jan. 
Feb. Mar. April, 
May, June, July, 
Aug. Sept. Oct. 
Min. Max. 
-lOJI' A.M. +6^'' P.M. 
- GJl" A.M. 4-5J-'' P.M. 
P.M. +5'' P.M. 
■ lOJ'' A.M. + 51> P.M. 
Min. 
9'' P.M. 
■lOh P.M. 
• gji" P.M. 
Max. 
A.M. 
+ A.M. 
■4'' A.M. 
Min. 
— 0'> Noon. 
-lOP A.M. 
— Oil Noon. 
-WV' A.M. 
Max. 
5f t P.M. 
61> P.M. 
of!" P.M. 
P.M. 
Min. 
Si'' P.M. 
8^1' P.M. 
-gk P.M. 
8^ P.M. 
Max. 
+ 2P A.M. 
+ 2^ A.M. 
+ 2J'> A.M. 
+ SI- A.M. 
106. The mean positive difference has two maxima and two minima in each quarter excepting wiiiter ; rhe 
principal maximum occurs between 5'' and 6'* p.m. ; in summer tl\e two maxima have an eqiuil value : the 
values of the two minima differ little. 
107. The mean negative difference has two maxima and two minima in each quarter; the principal maxi- 
mum occurs between 2^* and 3'^ a.m. ; in winter the two maxima differ little in value ; in the other quarters the 
secondary maximum is very small compared with the otlicr ; the values of the two minima in each quarter 
differ little. 
108. It ap]iears, thei'efore, that the principal maximum of tlie mean positive ditierence occiu's at the same 
time as the secondary maximum of the mean negative diflerence, and vice versa. It seems probable that if differ- 
ences were taken with reference to mean midistnrhed positions, the secondary maximum would disappear in 
each case ; thus, if we consider that the effect of distiu-bance is to increase the mean vertical component to a 
large extent about G'' p.m. (No. 103, \st), it is obvious that both the value and the number of the negative 
departures from this increased mean will be givator than if tlie undisturbed mean were taken as the zero. It was 
accordingly found in the discussion of the observations for 1844, (jip. 388, 389), when tlie mean position was 
employed as deduced from the days selected nearly free from intermittent disturbance, that the maximum of 
