360 



Results of Makeestoun Obseevations, 1844. 



Variations of the Diurnal Ranges of the Horizontal Component, with reference to the Moon's Age. — The 

 means in the first portion of Table XXV. shew that the diurnal range of the horizontal component is a minimum 

 about conjunction, and a maximum about opposition. The same result has already been obtained for the mag- 

 netic declination. The following are means of groups : — 



14 days to 16 days, Full Moon, 



17 



21 

 25 



20 

 24 



28 



0-004710 



29 days to 1 day, New Moon, 



0-003436 



0-004235 



2 5 ... 



0-003058 



0003127 



6 9 ... 



0-003874 



0002936 



10 13 ... 



0004982 



There is the appearance of a secondary maximum at new moon. The remarks already made in the 

 case of the magnetic declination, Table IV., are equally applicable here. In the case of this pei'iod. as well as 

 that for the year, it appears that the diurnal range is a maximum when the horizontal component is a minimum, 

 and vice versa. 



Variations of the Diurnal Range of the Horizontal Component with reference to the Moon's Declination. — 

 From the second portion of Table XXV., the diurnal range is a minimum when the moon has its greatest 

 south and also its greatest north declination, and it is a maximum when the moon is near to, but north of, 

 the equator. This result is also the same as that obtained for the magnetic declination. The following 

 are means of groups : — 



27 days to 1 day, Moon farthest north, 0-003267 



2 5 days, 0004481 



6 8 ... 0-004115 



9 12 ... 0003401 



13 days to 15 days, Moon farthest south, 0003248 

 16 ..'.... 19 ... 0-003546 



20 22 ... 0003682 



23 26 ... 0-004311 



Here, also, as for the magnetic declination, we can say generally, that the diurnal range of the horizontal 

 component of magnetic force is less when the sun or moon has its greatest north or south declination, than at 

 the intermediate periods. In this case, also, the diurnal range is a maximum when the horizontal component 

 is a minimum, and vice versa. 



TABLE XXVI. 



-Hourly Means of the Scale Readings of the Bifilar Magnetometer, corrected for 

 Temperature, 1844. 



Mean Time. 































Jan. 



Feb. 



March. 



April. 



May. 



June. 



July. 



Aug. 



Sept. 



Oct. 



Nov. 



Dec. 



Year. 







Gott. 



Mak. 





























h. 



h. 



Sc. Div. 



Sc. Div. 



Sc. Div. 



Sc. Div. 



Sc. Div. 



.->.-. Div. 



Sc. Div. 



Sc. Div. 



Sc. Div. 



Sc. Div. 



Sc. Div. 1 Sc. Div. 



Sc. Div. 



13 



12 



517-59 



520-39 



518 



79 



52108 



525-54 



532-85 



534-32 



532-16 



532 



56 



532-23 



532-60 535-72 



527-99 



14 



13 



517-59 



518-69 



513 



74 



522-56 



525-33 



531-84 



533-56 



530-62 



532 



84 



531-60 



532-67! 536-74 



527-31 



15 



14 



51703 



517-96 



514 



61 



520-81 



524-28 



531-11 



532-59 



530-28 



530 



93 



531-39 



532-40 535-40 



526-57 



16 



15 



518-27 



518-64 



546 



98 



518-00 



523- 13 



530-63 



531-69 



529-88 



532 



19 



533-34 



534-19 



535-96 



526-91 



17 



16 



519-45 



518-75 



518 



29 



52012 



521-86 



529-43 



530-93 



530-21 



532 



28 



532-76 



535-28 



538-06 



527-28 



18 



17 



520-80 



522-22 



516 



59 



521-47 



523-46 



529-12 



53011 



52806 



533 



18 



531-97 



535-75 



539-08 



527-65 



19 



18 



520-84 



521-26 



521 



33 



520-48 



522-42 



526-47 



529-16 



527-62 



530 



85 



531-36 



537-27 



540-01 



527-42 



20 



19 



520-84 



521-30 



519 



37 



517-03 



520-35 



524-81 



526-24 



523-58 



526 



34 



530-70 



536-49 



54008 



525-59 



21 



20 



519-66 



521-41 



515 



05 



511-67 



516-42 



521-32 



523-01 



518-53 



523 



68 



525-59 



535-15 



538-33 



522-48 



22 



21 



518-65 



519-40 



511 



93 



508-25 



514-63 



518-94 



51907 



517-50 



519 



73 



521-41 



530-97 



536-52 



519-75 



23 



22 



516-40 



518-02 



510 



39 



508-71 



513-87 



518-95 



518-18 



517-90 



516 



92 



519-48 



528-63 



534-65 



518-51 







23 



516-72 



517-12 



512 



27 



509-82 



516-35 



521-94 



521-54 



522-34 



521 



01 



523-26 



528-76 



534-92 



520-50 



1 







317-76 



51905 



514 



50 



516-48 



521-60 



527-21 



527-27 



526-45 



524 



99 



527-69 



533-28 



536-22 



524-37 



2 



1 



519-96 



521-56 



520 



62 



520-15 



524-64 



531-16 



532-41 



532-67 



530 



84 



53110 



533-53 



536-86 



527-96 



3 



2 



521-33 



523-37 



521 



54 



523-81 



528-62 



535-35 



536-26 



536-19 



533 



52 



532-78 



535-02 



537-86 



530-47 



4 



3 



52009 



522-83 



524 



66 



526-40 



53002 



53700 



538-78 



538-87 



534 



35 



535-58 



535-30 



538-23 



531-84 



5 



4 



521-11 



52216 



525 



78 



527-64 



536-66 



539-09 



540-32 



538-67 



537 



98 



535-58 



534-13 



53819 



53311 



6 



5 



520-33 



52110 



526 



07 



532-38 



538-35 



540-80 



541-62 



542-51 



536 



70 



536-00 



537-95 



537-88 



534-31 



7 



6 



51915 



521-38 



523 



32 



531-59 



539-90 



541-33 



544-30 



541-47 



536 



84 



534-29 



537-06 



537-94 



53405 



8 



7 



517-77 



521-03 



526 



05 



528-53 



538-54 



541-65 



544-08 



541-04 



536 



77 



533-72 



534-13 



537-46 



533-40 



9 



8 



519-45 



522-08 



525 



64 



527-72 



535-35 



539-77 



540-39 



539-38 



536 



23 



534-00 



534-91 



539-07 



532-83 



10 



9 



518-70 



521-35 



519 



38 



525-22 



532- 11 



537-73 



538-07 



536-01 



536 



34 



53307 



532-69 



536-33 



530-58 



11 



10 



518-48 



518-64 



518 



08 



526-81 



530-23 



536-47 



536-68 



535-99 



535 



52 



533-72 



532-85 



535-64 



529-93 



12 



11 



518-53 



518-08 



521-29 



523-55 



527-12 



533-66 



535-27 



532-22 



534-73 



53208 



531-66 



536-32 



52871 



The true mean time at Makerstoun is 10 m in advance of the hours given in the second column of Table XXVI. 



_- 



