439 



$m-p « - §n-p Wj the variable part of the morning and evening 

 ranges due to the lunar action ; and in the fourth and sixth, 

 the total ranges. The seventh column contains the mean of 

 the two latter. The value of & m u-A n u is 9'*81, for the 

 range between 7 a. m. and Ip.m; and 9'*33 for the range be- 

 tween 1 p. m. and 10 p. M. 



Table IV. — Diurnal Range of the Magnetic Declination dependent on 

 Moon's Age. 



Moon's 

 Age. 



Retar- 

 dation. 



Morning 



Range. 



Evening Range. 





Lunar 



Absolute 



Lunar 



Absolute 



Range. 







Variation. 



Range. 



Variation. 



Range. 





d 



h 



+ 0'-67 



10'-48 



+ 0'-15 



9M8 



9'-98 



1 



1 



+ 0-68 



10-49 



+ 0-33 



9-66 



10-08 



2 



2 



+ 0-46 



10-27 



+ 0-38 



9-71 



9-99 



3 



2 



+ 0-30 



1011 



+ 038 



9-71 



9-92 



4 



3 



+ 0-04 



9'85 



+ 0-31 



9-64 



9-75 



5 



4 



-0-40 



9-41 



+ 009 



9-42 



9-42 



6 



5 



-0-77 



9-04 



-017 



9-16 



910 



7 



6 



-0-93 



8-88 



-0-38 



8-95 



8-92 



8 



6 



-095 



8'86 



-0-38 



8-95 



8-90 



9 



7 



-0-84 



8-97 



-0-39 



8-94 



8-96 



10 



8 



-063 



9-18 



-0-33 



9-00 



9-09 



11 



9 



-026 



9-55 



-0-16 



9-17 



9-36 



12 



10 



+ 0-25 



1006 



+ 0-07 



9-40 



973 



13 



10 



+ 0-40 



10-21 



+ 0-07 



9-40 



9-80 



14 



11 



+ 0-58 



10-39 



+ 0-36 



9-69 



1004 



15 



12 



+ 0-76 



10-57 



+ 0-64 



9-97 



10-27 



16 



13 



+ 0-90 



10-71 



+ 0-81 



10-14 



10-42 



17 



14 



+ 0-75 



10-56 



+ 0-77 



1010 



10-33 



18 



14 



+ 0-60 



10-41 



+ 0-77 



10-10 



10-26 



19 



15 



+ 0-35 



10-16 



+ 0-50 



9-83 



10-00 



20 



16 



-0-03 



9-78 



+ 0-24 



9-57 



9-68 



21 



17 



-0-31 



9-50 



-0-08 



9-25 



9-38 



22 



18 



-0-60 



921 



-0-49 



8-84 



9-02 



23 



18 



-0-65 



9-16 



-0-49 



8-84 



9-00 



24 



19 



-065 



9-16 



-0-75 



8-58 



8-87 



25 



20 



- 53 



9-28 



-0-78 



8-55 



8-92 



26 



21 



-019 



962 



-0-57 



8-76 



9-19 



27 



22 



+ 0-19 



10-00 



-0-40 



8-93 



947 



28 



22 



+ 0-41 



10-22 



-0-40 



8-93 



9-57 



29 



23 



+ 0-51 



10-32 



-015 



9-18 



9-75 



2u 



