XXV111 
Introduction to the Makerstoun Observations, 1843. 
31. The observations, November 14 and December 18, have also been com- 
puted by the approximate formula in which q' is neglected and p r eliminated, 
namely, 
m 
X 
j*! 5 tan — r 5 tan u 
2 (^-r 2 ) 
the results are as follow : 
m 
Nov. 14. r t = 5-125 feet, r= 6-750 feet; = 
2-8762 
*i = 5-250 feet, r = 7-000 feet ; = 2-8691 
m 
X 
Dec. 18. n = 5-000 feet, *• = 6-625 feet; = 2 
8444 
^ = 5-250 feet, r= 7-000 feet ; — = 2-8795 
Mean -~ = 2-8726 
-X. 
Mean ^ = 2-8619 
m 
32. The following Table contains the values of — , of m X obtained by the for- 
mula, No. 28, from the Observations, pages 83 and 84, and the consequent values 
of m and X, together with the weight of the final results deduced from the formula 
Weight = 
Number of partial results 
Mean of the squares of the partial results minus the square of the mean 
Table 9. — Results of the observations for the Absolute Horizontal Intensity, 
reduced to the Bifilar Magnetometer reading 500. 
Date. 
Number of 
Results. 
Temperature 
of 
Deflecting 
Magnet. 
m 
IF 
m X. 
m. 
X. 
Weight. 
Aug. 
12 
3 
o 
69-6 
2-8928 
33-2505 
9-8075 
3-3903 
102 
Aug. 
21 
10 
61-1 
2-8898 
33-4536 
9-8322 
3-4024 
7599 
Nov. 
8 
7 
43-3 
2-9025 
33-4698 
9-8563 
3-3958 
21308 
Nov. 
14 
4 
41-1 
2-8682 
33-1440 
9-7501 
3-3993 
1947 
Dec. 
18 
4 
46-3 
2-8762 
33-1695 
9-7675 
3-3959 
65 
Results from the approximate formula. 
Nov. 
14 
2 
41-1 
2-8726 
33-1440 
9-7576 
3-3967 
Dec. 
18 
2 
46-3 
2-8619 
33-1695 
9-7431 
3-4044 
Giving the determinations of X, values corresponding to their weights, the re- 
sulting value is 
X = 3-39762 
the bifilar magnetometer reading 500 scale divisions. 
