XXviil 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’ eliminated, 
namely, 
m 7? tan u,—2° tan uy 
XX 2 (72-7) 
the results are as follow : 
Nov. 14. 7,=5-125 feet, r= 6-750 feet ; x = 2.8762 Fa 
Mean xo 2.8726 
1, = 5-250 feet, r=7-000 feet ; z = 2.8691 
Dec. 18. 7,=5:000 feet, r= 6-625 feet; x = 2.8444 2 
Mean er 2.8619 
1, = 5-250 feet, r= 7-000 feet ; _ = 2.8795 
32. The following Table contains the values of oe 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 
Number of partial results 
Mean of the squares of the partial results minus the square of the mean’ 
Weight = 
TABLE 9.—Results of the observations for the Absolute Horizontal Intensity, 
reduced to the Bifilar Magnetometer reading 500. 
Temperature 
Number of of 
Results, Deflecting 
Magnet. 
Weight. 
° 
69-6 . 33-2505 9.8075 
61-1 . 33-4536 9-8322 
43:3 : 33-4698 9-8563 
41-1 y 33-1440 9-7501 
46:3 . 33-1695 9-7675 
Results from the approximate formula. 
41-1 2.8726 33-1440 9-7576 
46-3 2-8619 33-1695 9-7431 
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. 
