37« 



Results of Makerstoun Observations, 1844. 



TABLE XL. — Diurnal Range of the Vertical Component of Magnetic Force for each Civil Day, as 

 deduced from the Hourly Observations, with the Mean for each Week in 1844. 



Civil 

 Day. 



Jan. 



Feb. 



March. 



April. 



May. 



June. 



July. 



Aug. 



Sept. 



Oct. 



Nov. 



Dec. 





0-00 



0-00 



0-00 



o-oo 



0-00 



0-00 



0-00 



0-00 



o-oo 



0-00 



0-00 



0-00 



1 



0317 



1111 



0302 



2010 



1535 



0318 



0349 



1553 



[1322] 



6078 



0424 



[0436] 



2 



0606 



1571 



2773 



2298 



1036 



[0259] 



0340 



1860 



0457 



1653 



0511 



0160 



3 



0269 



0820 



[2066] 



1710 



1637 



0214 



0352 



1555 



0432 



0899 



[0504] 



0132 



4 



0584 



[1002] 



1876 



1187 



0239 



0328 



0442 



[1048] 



0875 



0492 



0597 



0529 



5 



1144 



1030 



2597 



0420 



[1008] 



0229 



0298 



0678 



0379 



0514 



0367 



0522 



6 



0675 



0973 



3232 



1911 



1095 



0405 



0215 



0410 



0369 



[0491] 



0630 



0103 



7 



[0737] 



0505 



2498 



[0736] 



0494 



0375 



[0519] 



0231 



0536 



0302 



0150 



0146 



8 



0733 



1295 



2837 



0366 



1549 



0298 



1170 



0344 



[0427] 



0504 



0261 



[0218] 



9 



0625 



0704 



1550 



0281 



1902 



[0427] 



0549 



2309 



0338 



0236 



0260 



0102 



10 



0662 



0576 



[1442] 



0252 



0676 



0389 



0441 



0712 



0623 



0173 



[0634] 



0285 



11 



0207 



[0523] 



0318 



0480 



0394 



0814 



0319 



[0735] 



0315 



0166 



1200 



0148 



12 



0225 



0232 



0884 



0221 



[0973] 



0279 



0347 



0523 



0261 



0140 



1604 



0101 



13 



0223 



0206 



0567 



0304 



0420 



0318 



0589 



0353 



0216 



0196 



0332 



0149 



14 



[0195] 



0124 



0134 



[1196] 



0409 



0322 



[0500] 



0169 



0634 



0166 



0581 



2310 



15 



0114 



0381 



0233 



0391 



2039 



0360 



0514 



0318 



[0481] 



0286 



0180 



[0602] 



16 



0157 



0136 



0158 



0495 



0777 



[0520] 



0580 



0355 



0368 



0243 



6560 



0631 



17 



0245 



0376 



[0315] 



5284 



0422 



1181 



0654 



0579 



0852 



0471 



[1591] 



0244 



18 



0463 



[0248] 



0483 



0835 



0265 



0680 



0878 



[0342] 



0557 



0246 



0743 



0176 



19 



0169 



0127 



0514 



0328 



[0527] 



0257 



0225 



0267 



0305 



0283 



1219 



0539 



20 



0201 



0326 



0368 



0211 



0249 



0520 



0303 



0286 



2274 



[1541] 



0266 



1081 



21 



[0334] 



0142 



0406 



[0445] 



0512 



0870 



[0368] 



0249 



0902 



6204 



0256 



1295 



22 



0594 



0624 



0186 



0347 



0940 



0440 



0240 



1600 



[0990] 



1109 



5668 



[0582] 



23 



0387 



0341 



0228 



0636 



2794 



[0483] 



0337 



2366 



0447 



0936 



2555 



0263 



24 



0189 



0107 



[0373] 



0311 



0467 



0303 



0227 



1248 



0558 



0657 



[1533] 



0159 



25 



2178 



[0392] 



0320 



2827 



0593 



0123 



1454 



[1093] 



1454 



1309 



0418 



0157 



26 



0245 



0214 



0285 



2166 



[0893] 



0345 



0719 



0554 



3858 



2762 



0151 



0431 



27 





0285 



0816 



1860 



0646 



0381 



0987 



0363 



1328 



[1164] 



0153 



0328 



28 



[0746] 



0783 



0895 



[175.3] 



0517 



0312 



[0789] 



0429 



1566 



1354 



1271 



0212 



29 



0481 



1615 



1299 



1005 



0340 



0460 



0816 



1704 



[2997] 



0641 



0382 



£0648] 



30 



0385 





5495 



1123 



0208 



[0366] 



0306 



2741 



3505 



0259 



0142 



1465 



31 



0439 





[2284] 





0255 





0451 



1723 





0496 





1057 



Annual Variation of the Diurnal Ranges of the Vertical Component. — The following are the monthly 

 means of the diurnal ranges : — 



Jan. 



0-00 I 0481 



Feb. 



0584 



March. 



1202 



April. 



1164 



May. 



0830 



June. 



0433 



July. 



0522 



Aug. 

 0944 



Sept. 



0936 



Oct. 

 1058 



Nov. 



1034 



Dec. 

 0489 



The diurnal range is a minimum at the solstices and a maximum near the equinoxes. 

 When the means of the diurnal ranges are compared with the ranges of the mean diurnal variations (see 

 Table XLIII.), we obtain the following quantities, excesses of the former : — 



Jan. 



0-000 I 210 



Feb. 



311 



Mar. 



514 



April. 



459 



May. 



314 



June. 



200 



July. 



224 



Aug. 



357 



Sept. 



320 



Oct. 

 356 



Nov. 

 446 



Dec. 

 197 



so that the causes which render the mean diurnal range greater than the range of the mean diurnal variation 

 have their minimum effect at the solstices, and their maximum in March and November. The same result has 

 been obtained for the horizontal component and magnetic declination. 



