242 



Abstracts of the Makerstoun Observations, 1843. 



Variations of the Vertical Component of Magnetic Force, with reference to the 



Moon's Declination. 



The second portion of Table XVI., in groups, gives the following means : — 



27 days to 1 day, Moon farthest North, 0-000107 



2 5 ... 0-000099 



6 8 ... 0-000066 



9 12 ... 0-000043 



13 days to 15 days, Moon farthest South, 0-000077 



16 19 ... 0-000027 



20 22 ... 0-000016 



23 26 ... 0-000034 



These means indicate a well marked minimum at the passage of the equator northwards ; a well marked 

 maximum at the period of greatest north declination ; a diminution of the component from thence till after the 

 passage of the equator southwards ; and a secondary maximum at the greatest south declination. Though the 

 latter is not well shewn in these groups, the means on the whole shew, maxima of the vertical component at the 

 periods of greatest north and south declination, and tninima when the declination is zero. 



Variations op the Vertical Component of Magnetic Force, with reference to the Moon's 



Distance from the Earth. 



Means of Groups. 



6 days after Apogee to 6 days before Perigee, 0-000116 

 5 days to 2 days before Perigee, . . 0-000110 



1 day before to 1 day after Perigee, . 0-000084 



2 days to 5 days after Perigee, . . 0-000098 



6 days after Perigee to 6 days before Apogee, 0*000060 

 5 days to 2 days before Apogee, . . 0-000054 



1 day before to 1 day after Apogee, . 0-000036 



2 days to 5 days after Apogee, . . 0-000084 



TABLE XVII.- 



-Means of the Balance Magnetometer Readings corrected for Temperature at the 

 Observation Hours for each Month in 1843. 



Month. 



ISh. 



20i>. 



22'". 



23''. 



Ob. 



2K 



4". 



6K 



Sh. 



10". 





Mic. Div. 



;Mic. Div. 



Mic. Div. 



Mic. Div. 



Mic. Div. 



Mic. Div. 



Mic. Div. 



Mic. Div. 



Mic. Div. 



Mic. Div. 



January 



756-0 



762-6 



765-7 





768-3 



769-2 



767-7 



774-4 



777-0 



774-7 



February 



740-0 



745-5 



746-6 





744-2 



745-4 



753-2 



761-9 



763-9 



757-2 



March 



707-5 



713-8 



715-9 





708-6 



707-1 



715-8 



730-0 



735-5 



7220 



April 



662-2 



668-9 



676-9 





669-7 



670-4 



688-3 



721-6 



709-2 



685-9 



May 



659-8 



667-0 



664-5 





650-5 



649-4 



665-2 



674-7 



679-6 



657-4 



June 



662-2 



671-4 



668-6 





655-6 



651-4 



664-6 



677-3 



675-8 



669-4 



July 



638-9 



647-6 



651-3 





643-7 



648-6 



659-4 



664-5 



667-8 



653-7 



August •< 

 September 



628-2 



638-5 



641-7 





624-8 



634-5 



643-6 



656-4 



653-3 



638-8 



793-1 



803-4 



803-1 





790-2 



790-5 



799-7 



807-6 



8060 



793-4 



805-9 



823-5 



829-0 





817-8 



824-4 



831-5 



836-0 



824-7 



810-9 



October 



801-1 



812-0 



821-1 





819-4 



821-5 



830-9 



829-9 



821-3 



814-0 



( 



804-2 



808-4 



817-8 



819-3 



821-2 



827-0 



829-5 



821-3 



818-9 



816-9 



November < 























841-1 



843-1 



845-4 



840-7 



841-3 



849-3 



856-9 



856-0 



859-3 



855-9 



December 



824-2 



826-1 



830-2 



829-6 



833-4 



839-9 



848-1 



849-1 



853-4 



842-9 



Table XVII. is intended chiefly as a key for comparing the tabular observations. The cross lines in the 

 Table indicate that a break has occurred in the series ; the means so separated are not comparable with each 

 other. The periods at which the needle was removed have been already mentioned. — See remarks to Table 

 XV. 



