xxvm 



Introduction td the Makerstoun Observations, 1843. 



31. The observations, November 14 and December 18, have also been com- 

 puted by the approximate formula in which (^ is neglected and -p' eliminated, 



namely, 



m Ti tan Uj — r' tan « 



the results are as follow : 



Nov. 14. »-i = 5-125 feet, »• = 6-750 feet ; -J = 2-8762 



ri = 5-250 feet, »• = 7-000 feet ; -^ = 2-8691 



Mean ^ = 2-8726 



Dec. 18. ri = 5-000 feet, r = 6-625 feet; -= = 2-8444 



'/•i = 5-250 feet, r = 7-000 feet ; 



2-8795 



Mean ^ = 2-8619 



m 



32. The following Table contains the values of ^ , of »n 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 



XV^eiffnt ^^ — "" " • 



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. 



X. 



Weight. 



Aug. 12 



Aug. 21 



Nov. 8 



Nov. 14 



Dec. 18 



Nov. 14 



Dec. 18 



.3 

 10 



7 

 4 

 4 



2 

 2 



69-6 

 61-1 

 43-3 

 4M 

 46-3 



2-8928 

 2-8898 

 2-9025 

 2-8682 

 2-8762 



33-2505 

 33-4536 

 33-4698 

 33-1440 

 33-1695 



9-8075 

 9-8322 

 9-8563 

 9-7501 

 9-7675 



Results from the approximate formula. 

 41-1 2-8726 33-1440 9-7576 



46-3 2-8619 33-1695 9-7431 



3-3903 

 3-4024 

 3-3958 

 3-3993 

 3-3959 



3-3967 

 3-4044 



102 



7599 



21308 



1947 



65 



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. 



