XVI 



General Results or the Makerstoun Observations. 



lowing quantities, the means for groups of days from four years' observations, are obtained from the last column 

 of the first parts of Tables 28 and 45. (Prefix 0000.) 



Moon's Age, 



14d_i6d 



17d_20d 



211— 24'i 



25<i— 28'J 



29*— 1* 



21—51 



e^-g* 



10<i_l3* 



Variations, 



- 024 



+ 007 



+ 024 



+ Oil 



+ 001 



+ 008 



+ 009 



- 034 



The total force, therefore, is least near opposition, and it is greatest near the quadratures. (See No. 96, 1st.) 



140. Variations of the Daily Mean Total Magnetic Force, with Reference to the Moon's Declination. — 

 The following variations are derived from the final columns of Tables 28 and 45. (Prefix 0-000.) 



Day after Moon 

 farthest North. 



27'i— Id 



2'i— 54 



61— 8<i 



91—121 



131—1.51 



161— 191 



201-22* 



231—261 



Variations, 



+ 024 



- 004 



-016 



- 010 



+ 017 



- 004 



- 001 



-005 



These variations indicate that the total force is a maximum when the moon is farthest north, and also 

 when it is farthest south, and that is a minimum between these epochs. This result is quite analogous to 

 that for the sun's position in declination (see No. 136). In both cases, the total force is greatest when the body 

 (sim or moon) has its greatest north and south declinations, and it is least during the intermediate positions, 

 or when the body is near the equator. 



141. Mo7ithly Variations of the Range of the Total Force. — This law is the same as that for the vertical 

 component (No. 97), but has not been deduced for the total force, for the reason given No. 127. It may be 

 stated generally, whether the position of the sun or the moon be under consideration, that the diurnal range of 

 all the magnetic elements is greatest when the body is rather north of the equator, and that the range is least when 

 the body is farthest south and farthest north. It has been found, generally, that when undisturbed mean 

 variations are examined, the diminution of diurnal range, when the sun is most northerly, disappears, and 

 it is probable that the same would be true with respect to the moon ; the excess of range, when the bodies 

 are near the equator, being due to the greater amoiuits of disturbance which occur at these times. 

 (See No. 23.) 



Table 62. — Diurnal Variations of the Total Magnetic Force for each Month, as deduced from the 

 Regular Daily Observations made during the Four Years 1843 to 1846. 



Mak. 

 Mean 

 Time. 



Jan. 



Feb. 



March. 



April. 



May. 



June. 



July. 



Aug. 



Sept. 



Oct. 



Nov. 



Dec. 



h. m. 



0-on 



0-00 



0-00 



000 



000 



000 



0-00 



0-00 



0-00 



0-00 



0-00 



000 



12 13 



0078 



0036 



0125 



0000 



0051 



0201 



0162 



0049 



0017 



0078 



0000 



0021 



13 13 



0083 



0014 



0026 



0072 



0012 



0151 



0113 



0026 



0000 



0053 



0006 



0028 



14 13 



0000 



0000 



0000 



0021 



0000 



0138 



0082 



0000 



0009 



0024 



0008 



0003 



15 13 



0075 



0006 



0061 



0122 



0005 



0161 



0083 



0041 



0025 



0033 



0033 



0000 



16 13 



0094 



0030 



0124 



0113 



0080 



0170 



0096 



0107 



0077 



0000 



0052 



0029 



17 13 



0116 



0055 



0157 



0189 



0151 



0170 



0090 



0132 



0140 



0033 



0067 



0046 



18 13 



0136 



0073 



0213 



0249 



0200 



0181 



0121 



0163 



0173 



0089 



0085 



0063 



19 13 



0146 



0091 



0239 



0266 



0190 



0178 



0117 



0162 



0176 



0154 



0082 



0061 



20 13 



0139 



0085 



0232 



0233 



0132 



0134 



0081 



0118 



0159 



0150 



0072 



0060 



21 13 



0132 



0056 



0189 



0186 



0080 



0062 



0026 



0088 



0125 



0133 



0036 



0036 



22 13 



0124 



0046 



0141 



0154 



0024 



0014 



0001 



0072 



0136 



0115 



0012 



0014 



23 13 



0161 



0061 



0146 



0155 



0038 



0000 



0000 



0081 



0170 



0143 



0039 



0035 



13 



0182 



0100 



0177 



0216 



0105 



0068 



0072 



0151 



0271 



0234 



0129 



0064 



1 13 



0248 



0147 



0286 



0310 



0229 



0150 



0174 



0303 



0412 



0332 



0185 



0112 



2 13 



0288 



0208 



0410 



0447 



0349 



0251 



0311 



0420 



0541 



0411 



0237 



0167 



3 13 



0301 



0272 



0495 



0574 



0485 



0347 



0475 



0559 



0656 



0521 



0314 



0234 



4 13 



0307 



0287 



0549 



0658 



0517 



0453 



0589 



0652 



0715 



0517 



0344 



0245 



5 13 



0319 



0291 



0612 



0800 



0701 



0513 



0662 



0738 



0712 



0498 



0365 



0255 



6 13 



0306 



0288 



0574 



0821 



0699 



0546 



0663 



0738 



0586 



0460 



0443 



0298 



7 13 



0309 



0264 



0529 



0718 



0676 



0535 



0616 



0659 



0529 



0407 



0328 



0261 



8 13 



0315 



0248 



0454 



0563 



0547 



0479 



0517 



0532 



0390 



0344 



0245 



0165 



9 13 



0263 



0177 



0323 



0421 



0385 



0396 



0378 



0334 



0272 



0278 



0145 



0136 



10 13 



0121 



0123 



0154 



0352 



0289 



0305 



0293 



0262 



0184 



0216 



0072 



0105 



11 13 



0078 



0040 



0202 



0247 



0196 



0227 



0228 



0099 



0123 



0131 



0019 



0067 



