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. 
Westerly Declination. 
Bifilar Magnetometer. 
Balance Magnetometer. 
Ranges. 
Date. 
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. 
Y=l. 
Jan. 18, 19 
1 
+ 4-05 
11 
- 5-32 
12 
+ 9-6 
0 
- 6-5 
10 
+ 7-1 
20 
- 15-0 
13-59 
000194 
0-00031 
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 
0 
- 20 
8 
- 8-6 
2 
- 0-7 
10-95 
•00263 
•00028 
M;| V 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 
0 
- 18-4 
•00231 
•00031 
July 19, 20 
1 
- 0-77 
20 
- 2-95 
8 
- 1-3 
0 
- 1-0 
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 
+ 11-3 
23 
- 8-9 
7 
+ 16-8 
15 
-148-5 
31-00 
•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 
0-0 
5 
+ 12-0 
16 
- 7-2 
6-03 
•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 10 h Gott. and 18 h 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 
which the extremes occurred, together with the ranges for the year, are as follow : — 
From the Daily Observations. 
West Declination, greatest, Feb. 24 d 4 h , + 15'-95 ;, least, Feb. 6 d 10\ - 36'-75 ; Range of Declination =59'-29. 
Bifilar Magnetometer Reading, greatest, July 25 d 4 h , +96-2 Sc. div. ; least, May 6 d 10\ -79-1 Sc. div. ; Range of Hor. comp. =0-01839. 
Balance Magnetometer Reading, greatest, April 5 d 6 b , +344-0 Mic. div. ; least, May 6 4 10 b , - 257-2 Mic. div. ; Range of Ver. comp. =0 00599. 
From the Extra Observations, and from all the Observations. 
West Declination, greatest, April 5' 1 7\ +35'-43; least, May 6 d 12\ -9C-29; Range of Declination =126'-91. 
Bifilar Magnetometer Reading, greatest, April 5 1 ' 5 h , +151-0 Sc. div.; least, May 6 d ll h . —417-0 Sc. div.; Range of Hor. comp. =0-05678. 
Balance Magnetometer Reading, greatest, April 5 d 6 h , +517-8 Mic. div.; least, May 6 d ll' 1 , —685-5 Mic. div.; Range of Ver. comp. =0-01141. 
From the Term-Day Observations. 
West Declination, greatest, Feb. 24 d 11\ + lG'-00 ; least, Sept. 21 d 7\ -16'"55 ; Range of Declination =32'-9S. 
Bifilar Magnetometer Reading, greatest, Oct. 18 d 16 u , +21-0 Sc. div. ; least, Feb. 24 d 12 h , -41-3 Sc. div. ; Range of Hor. comp. =0*00789. 
Balance Magnetometer Reading, greatest, Feb. 24 d ll 1 ', +30-9 Mic. div. ; least, Sept. 20 d 15'\ - 148-5 Mic. div. ; Range of Ver. comp. =0 00321 
