398 



Results of Makerstoun Observations, 1844. 



TABLE LIX. — Variations of the Total Magnetic Force with reference to the Moon's Hour- Angle, 



as deduced from Tables XXXI. and XL VII. 



Moon's 

 Hour- 

 Angle. 



Lunations. 



Moon's 

 Hour- 

 Angle. 



h. 



8 



9 

 10 

 11 

 12 

 13 

 14 

 15 



Lunations. 



Moon's 

 Hour- 

 Angle. 



Lunations. 



Winter. 



Summer. 



Year. 



Winter. 



Summer. 



Year. 



Winter. ' 



Summer. 



Year. 



h. 

 

 1 

 2 

 3 

 4 

 5 

 6 

 7 



0-00 

 0022 

 0011 

 0000 

 0003 

 0023 

 0025 

 0030 

 0016 



0-00 



0078 

 0043 



0038 

 0032 

 0033 

 0028 

 0020 

 0018 



0-00 

 0033 

 0010 

 0002 

 0001 

 0011 

 0009 

 0009 

 0000 



0-00 



0041 

 0039 

 0065 

 0099 

 0147 

 0168 

 0198 

 0198 



0-00 



0000 

 0015 

 0028 

 0036 

 0026 

 0042 

 0071 

 0056 



0-00 



0003 

 0010 

 0030 

 0051 

 0069 

 0088 

 0119 

 0111 



h. 

 16 



17 

 18 

 19 

 20 

 21 

 22 

 23 

 24 



0-00 



0184 

 0169 

 0123 

 0165 

 0127 

 0147 

 0107 

 0064 

 0074 



U-(ll) 



0077 

 0082 

 0059 

 0044 

 0030 

 0039 

 0046 

 0052 

 0056 



(i-iio 

 0113 

 0109 

 0074 

 0088 

 0062 

 0076 

 0060 

 0041 

 0048 



The variations in Table LIX. give the following epochs of maxima and minima. In the winter group, 

 containing those lunations for which the moon is full when north of the equator — 



The maximum occurs about 2 hours after the moon's inferior transit. 

 The minimum 2 hours after superior transit. 



There are appearances of a secondary maximum and minimum, but they are not distinct : the whole range 

 of the mean variations for the group is 0-000200, which is only one-fourth less than the range of the solar 

 diurnal variations in the mean for the year. 



In the summer group, there are two nearly equal maxima and two minima — 



A maximum occurs about 4 hours after the moon's transit of the inferior meridian. 



A minimum 5 before superior 



A maximum when the moon transits the superior meridian. 



The minimum about 4 hours before the moon's transit of the inferior meridian. 



The range of the variations is only 0000082. 



In the mean for the year, there are only one maximum and one minimum well marked — 



The maximum occurs about 2 hours after the moon's transit of the inferior meridian. 

 The minimum 5 superior 



Minima actually occur 3 hours and 7 hours after the superior transit, but the intervening maximum is 

 very slightly marked. The range of the variations is 0-000120. 



The following mean variations for the year bave been obtained from those for the two components, pages 

 365 and 382, for which the large disturbances were rejected : — 



1 ' 0" 



2h 25>" -Ah 20" Qh i 5 m 8 b 10" 10 b 5 m 12'' 0- 13 h 55" 15'' 50" 17 h 45" 19>> 40" 21 b 35" 



0-0000 I 28 20 19 



00 



07 



25 



56 



79 



66 



45 



27 



32 



These quantities give the following epochs : — 



The principal maximum occurs about 2 hours after the moon's transit of the inferior meridian. 



A secondary minimum 5 hours before superior 



A secondary maximum the time of superior 



The principal minimum 6 hours after superior 



The secondary maximum is not well marked ; the whole range of the variations is less than 0-000100, 

 the total magnetic force being unity. The elimination of the larger disturbances renders the variation for the 

 year nearly similar in its epochs to that for the summer group ; it is probable, therefore, that the differences 

 between the variations for the summer and winter groups is chiefly due to disturbances. 





