236 
Abstracts of the Makerstoun Observations, 1843. 
Besides the occurrence of some considerable disturbances, the number of observations seems too few to 
exhibit the secondary maximum and minimum well. The results for the principal maximum and minimum are 
the same as those deduced from Table XI. It may perhaps be added, as true for both, that the principal mini- 
mum occurs nearer noon in winter and summer than at the equinoxes. 
The secondary minimum occurs near midnight in the mean for the months about the winter solstice ; per- 
haps aborit the same time in the mean for the months about the equinoxes, but this part of the diurnal curve 
is very irregular from disturbances ; the secondary minimum cannot be said to be at all visible in the mean for 
the months about the summer solstice, and it is very imperfectly shewn in the means for the year. 
The secondary maximum occurs about 6 a.m. in the winter solstitial and equinoctial months, and perhaps 
earlier in the means for the year. 
Ranges of the Monthly Means of the Diurnal Variations of the Horizontal Component 
of Magnetic Force. 
The quantities given in the last column of Table XI. are rather less than the true ranges, the minimum 
occurring near 23 h . The least diurnal range is that for December, and the greatest that for July. The range 
is nearly constant for the winter months, and also for the summer months, the most rapid increase occurring 
at the equinoxes ; the following means will exhibit the rate of increase : — ■ 
Jan. & Dec. Feb. & Nov. March & Oct. April & Sept. May & Aug. June & July. 
Ranges, 0-000627 0-000727 0-001473 0-002244 0-002641 0002842 
Differences, 0-000100 0-000746 0-000771 0-000397 0-000201 
The range of the monthly means is more than four times as great for the summer as for the winter months. 
TABLE XIII. — Diurnal Ranges of the Horizontal Component of Magnetic Force for each Civil Day, 
as deduced from the 9 Daily Observations in 1843, with the Weekly and Monthly Means. 
Civil 
Day. 
January. 
February. 
March. 
April. 
May. 
June. 
July. 
August. 
September. 
October. 
November. 
December. 
O'O 
0-0 
O'O 
0-0 
0-0 
0-0 
0-0 
0-0 
0-0 
0-0 
0-0 
0-0 
1 
[ ] 
0067 
0046 
0214 
0231 
0322 
0385 
0266 
0328 
[0220] 
0194 
0116 
2 
0067 
0045 
0109 
[0389] 
0249 
0308 
[0344] 
0230 
0375 
0206 
0192 
0215 
3 
0127 
0092 
0091 
0190 
0213 
0207 
0378 
0461 
[0294] 
0175 
0237 
[0124] 
4 
0089 
0070 
0113 
0215 
0198 
[0271] 
0395 
0696 
0278 
0204 
0169 
0067 
5 
0111 
[0104] 
[0172] 
1265 
0302 
0285 
0251 
0319 
0278 
0261 
[0162] 
0110 
6 
0173 
0162 
0174 
0515 
0939 
0229 
0224 
[0425] 
02S1 
0212 
0097 
0154 
7 
0029 
0172 
0346 
0207 
[0447] 
0272 
0289 
0287 
0217 
0240 
0155 
0097 
8 
[0138] 
0085 
0199 
0391 
0476 
0278 
0412 
0255 
0265 
[0226] 
0124 
0259 
9 
0227 
0088 
0189 
[0331] 
0288 
0224 
[0330] 
052S 
0405 
0239 
0242 
10 
0104 
0092 
0139 
0197 
0482 
0302 
0442 
0427 
[0252] 
0182 
[0199] 
! ! 
01S7 
0142 
0169 
0289 
0275 
[0295] 
0281 
0311 
0213 
0222 
0102 
0305 
12 
0079 
[0132] 
[0166] 
0388 
0256 
0417 
0337 
0294 
0231 
01S9 
[0142] 
0141 
13 
0002 
0182 
0242 
0292 
0170 
0361 
0330 
[02S9] 
0182 
0149 
0213 
0149 
14 
0120 
0144 
0121 
0340 
[02S1] 
018S 
0290 
02S5 
0144 
0277 
0153 
0070 
15 
[0097] 
0146 
0136 
0362 
0366 
0307 
0231 
0222 
0132 
[0274] 
0103 
0045 
16 
0099 
0149 
0219 
[0317] 
0333 
02S5 
[0275] 
0196 
0152 
0567 
01 14 
0043 
17 
0140 
0090 
0182 
0332 
0287 
0321 
0259 
0239 
[0200] 
0196 
0109 
[0058] 
18 
0078 
0139 
0335 
0355 
0274 
[0303] 
02S1 
0213 
0183 
0207 
0119 
0102 
1!) 
0098 
[0117] 
[0217] 
0223 
0202 
034 S 
0256 
0251 
0370 
0182 
[0101] 
0028 
20 
0983 
0115 
0143 
0193 
0280 
0294 
0212 
[02S2] 
0220 
0242 
0099 
0061 
