MAGNETIC OBSERVATIONS. 

 And the resulting normal equations are 



209 



Absolute Term. 



g 



h 



k 



R 



100 A A' 



o = — ii. 313 

 = + 0.311 

 = — 0.851 

 = -f- 0.840 

 = -f 1.367 



-f 129.164 



— 3-078 

 + U-3W 



— 11-053 



— 19.634 



+ 6.I25 

 -f- I. OOO 

 + O.888 

 + I.042 



+ IO.OOO 

 ~ 3-253 

 — 3342 



+ 3'6l 

 + 4-084 



+ 6.305 



Solving, we find 



g = + 0.11398 

 h = + 0.00981 



h = — 0.0509 



R = — 0.3918 



100A7? = + 0.3634 



Substituting these results in the equations of condition, the probable error of a 



Z' 



single observed value of — comes out ± 0.030, and the probable error of a com- 



Z' 



puted value of y comes out + 0.010. 



For the Admiralty Standard Compass we found % = 0.000, £) = + 0.017, and 

 G = — 0.001. We have also 



« = ?. (1 + £»_ 1 

 e = a, ( 1 — £» — 1 

 b = a (<£ — % ) 



Hence 



a = — 0.0605 

 b = — 0.0008 



e = — 0.0917 

 d = — 0.0008 



For the After Azimuth Compass Ave found 31 = 0.000, © = -4-0.112, and 

 (v — 0.000. Hence, in the same manner, 



a = — 0.0396 e = — 0.2324 



b = 0.0000 d = 0.0000 



Collecting our results, we have the following final values of the coefficients of the 



Admiralty Standard Compass. 



2( = 0.000 



53 = -f 0.0240 tan + 0.460 0.00102 -— =1= 0.001 



(S = — ■ 0.0016 tan 9 -f 0.006 — 0.00023 — ± 0.002 

 JT) = -f- 0.017 ±0.001 



(? = — O.OOI ± O.OOI 



^.= 1+ 0.0407^?-^ — 0.0050 sm ^ + 0.1006 -f 0.1665 -L + 0.000694--- ± 0.007 

 Z tan tan $ Z Z 



27 December, 1872. 



