xviii INTRODUCTION TO THE MAKERSTOUN OBSERVATIONS, 1845 AnD 1846. 
TABLE 1,—Determinations of the Value of Angle A. 
Readings of Horizontal Circle 
For Wire of Declination Telescope. For North Mark. 
Verniers Verniers 
17. The mean value of angle A from all the observations . ee 
e | =23° 50’ 24"5 
in 1844, 1845, and 1846, . : 
The mean value of angle A from all the observations 
| =23° 50’ 23"-9 
in 1844, ' ; k : ‘ : 
The value of angle Z (Table 8, Introduction, 1841-2), = 1° 37’ 388 
Whence angle A+ Z, : : : : : =25° 28° 2"7 
The absolute westerly declination, therefore, corresponding to the zeros of the 
scales, No. 8, =25° 28°04. This value has also been employed for the observa- 
tions in 1845 and 1846. For other scale readings differing from the zero by the 
angular quantity + D, the declination is obtained from the formula, declination 
= 25° 28-04 = D. 
