226 



Abstracts of the Makerstoun Observations, 1843. 



TABLE V. — Diurnal Variation of Westerly Declination deduced from the Observations at 0™ on 

 11 Term-days in 1842, and also on 11 Term-days in 1843. 



Gbtt. 

 M. T. 



1842. 



1843. 



Mean. 



Gott. 

 M. T. 



1842. 



1843. 



Mean. 



Giitt. 

 M. T. 



1842. 



1843. 



Mean. 



H. 





' 



' 



H. 



' 



/ 



' 



H. 



' 



/ 



' 



10 



000 



016 



0-08 



18 



3-86 



0-92 



2-39 



2 



1113 



7-58 



9-35 



11 



1-87 



0-45 



M6 



19 



3-69 



0-91 



2-30 



3 



1005 



6-78 



8-41 



12 



312 



005 



1-58 



20 



3-31 



000 



1-65 



4 



8-17 



5-52 



6-84 



13 



4-59 



1-25 



2-92 



21 



4-65 



0-62 



2-63 



5 



7-64 



4-07 



5-85 



14 



3-89 



0-06 



1-97 



22 



5-75 



1-66 



3-70 



6 



6-02 



3-15 



4-58 



15 



3-84 



2-00 



2-92 



23 



7-26 



3-40 



5-33 



7 



5-05 



1-99 



3-52 



16 



3-64 



2-23 



2-93 







9-69 



5-71 



7-70 



8 



4-43 



1-48 



2-95 



17 



4-19 



113 



2-66 



1 



11-50 



7-42 



9-46 



9 



397 



1-09 



2-53 



Botli years give nearly the same result; the observations at 10^ and ll** Gbtt. M. T. are affected by dis- 

 turbances in 1842. The mean shews: — 



The maximum of westerly declination, about 0^ 40™ p.m. Makerstmm mean time. 



The minimum 101'10°'p.m. 



A secondary maximum 2'* IO'^a.m. 



A secondary minimum 7^ 10"" Aja. 



\ 



Ranges op the Monthly Means of the Diurnal Variation. 



The ranges given in the last column of Table IV. are probably very near the truth, for though the mini- 

 mum takes place after 10^ Gott. M.T., the diminution after that time must be small. The range increases 

 considerably from January to April, and diminishes as much from September to December, but there is little 

 difference in the ranges of the six months from April to September. The range of the means for the summer 

 quarter is twice as great as the range of the means for the winter quarter, the former being 10-'34, and the 

 latter 5-'09. 



