256 



Abstracts of the Makerstoun Observations, 1843. 



TABLE XXX. — Differences of the Extreme Readings of the Three Magnetometers from the Monthly 

 Means, for the Hours at which the Extreme Readings occurred during the Term-Day Obser- 

 tions in 1843, together with the Ranges of the Three Magnetic Elements during each Term-Day. 



Date. 



Westerly Declination. 



Bifilar Magnetometer. 



Balance Magnetometer. 



Ranges. 



Greater than 

 Mean. 



Less than 

 Mean. 



Reading 



greater than 



Mean. 



Reading less 

 than Mean. 



Reading 



greater than 



Mean. 



Reading less 

 than Mean. 



Declina- 

 tion. 



Hor. Comp. 

 of Force. 



Ver. Comp 

 of Force. 



1843. 





h. 



' 



h. 



- 



h. 



Sc. Div. 



h. 



Sc. Div. 



h. 



Mic. Div. 



h. 



Mic. Div. 



' 



X = l. 



Y = l. 



Jan. 18, 



19 



1 



+ 4-05 



11 



- 5-32 



12 



+ 9-6 







- 6-5 



10 



+ 7-1 



20 



- 15-0 



13-59 



0-00194 



000031 



Feb. 24, 



25 



11 



+ 16-00 



13 



- 7-35 



11 



+ 7-3 



12 



-41-3 



11 



+ 30-9 



13 



-101-6 



23-91 



•00501 



•00124 



Mar. 22, 



23 



1 



+ 4-61 



7 



-11-42 



13 



+ 26-8 



13 



- 8-8 



7 



+ 8-1 



14 



- 86-3 



19-90 



•00363 



•00114 



Apr. 19, 



20 



2 



- 1-91 



21 



- 3-39 



7 



+ 4-1 







- 2-0 



8 



- 8-6 



2 



- 0-7 



10-95 



•00263 



•00028 



May 26, 



27 



2 



+ 0-26 



10 



-15-30 



10 



+ 20-5 



22 



-13-9 



9 



+ 7-0 



10 



- 88-3 



22-74 



•00489 



•00096 



June 21, 



22 



... 





... 





7 



+ 3-8 



19 



- 3-7 



20 



+ 0-5 







- 18-4 





•00231 



•00031 



July 19, 



20 



1 



- 0-77 



20 



- 2-95 



8 



- 1-3 







- 10 



21 



+ 9-6 



1 



- 5-8 



10-69 



•00249 



•00017 



Aug. 25, 



26 



1 



+ 2-19 



9 



- 6-08 



9 



+ 7-2 



23 



- 7-2 



5 



+ 28-9 



16 



- 28-1 



1517 



•00388 



•00063 



Sept. 20, 



21 



14 



+ 6-46 



7 



-16-55 



5 



■f 11-3 



23 



- 8-9 



7 



+ 16-8 



15 



-148-5 



3100 



•00396 



•00176 



Oct. 18, 



19 



16 



+ 9-33 



9 



- 6-68 



16 



+ 21-0 



22 



+ 4-6 



22 



+ 1-9 



16 



-117-7 



16-80 



-00283 



•00127 



Nov. 24, 



25 



13 



+ 4-89 



12 



- 1-14 



10 



+ 14-0 







0-0 



5 



+ 12-0 



16 



- 7-2 



603 



•00170 



•00032 



Dec. 20, 



21 



2 



- 1-34 



10 



- 6-84 



12 



+ 12-1 



8 



- 2-0 



3 



+ 1-5 



10 



- 21-3 



11-23 



•00124 



•00021 



When the hours at which the extreme positions occur are between lO** Gott. and 18^ Gbtt., approximate 

 means have been taken, in order to deduce the differences between the extreme position and the mean position. 



The differences of the greatest and least readings in the year from the monthly means for the hours at 

 whicb the extremes occurred, together with the ranges for the year, are as follow : — 



From the DaUy Observations. 



West Declination, greatest, Feb. 24'' 4'', +15'-95; least, Feb. &^ IQi^, -36'-75 ; Range of Declination =59'-29. 



Bifilar Magnetometer Reading, greatest, July 25* 4'', +96^2 Sc. div. ; least, May 6* IC", — 79'1 Sc. div.; Range of Hor. comp. =::0'01839. 



Balance Magnetometer Reading, greatest, April 5^ 6^, +344-0 Mic. div. ; least, May 6"* lOi", — 257"2 Mic. div. ; Range of Ver. comp. =:O"O0599. 



From the Extra Observations, and from all the Observations, 



West Declination, greatest, April 5* 1^, +35'-43; least, May 6* 12'', -90'-29; Range of Declination =126'-91. 



Bifilar Magnetometer Reading, greatest, April 6* 5^, +151-0 Sc. div. ; least, May e* 11'', —4170 Sc. div. ; Range of Hor. comp. =:0'05678. 



Balance Magnetometer Reading, greatest, April 5"i 6'', +517*8 Mic, div.; least, May 6* 11'", -685-5 Mic. div.; Range of Ver. comp. =0*01141. 



From the Term- Day Observations. 



West Declination, greatest, Feb. 24'i 11'', + 16'-00 ; least, Sept. 21<i 7'', -16'-55 ; Range of Declination =32'-98. 



Bifilar Magnetometer Reading, greatest, Oct. IS* 16'', +21-0 Sc. div. ; least, Feb. 24<i 12'', -41-3 Sc. div.; Range of Hor. comp. =0-00789. 



Balance Magnetometer Reading, greatest, Feb. 24d 11'', +30-9 Mic. div. ; least, Sept. 20>i 15'', - 148-5 Mic. div. ; Range of Ver. comp. =0-00321. 



