214 



RETORT ON 



Hence 



FORWARD RITCHIE COMPASS. 



o = 0.9803 + 10.000 A l + 7.482 BI 4- 3.999 C t 4 3.938 D t 2.631 E, 

 o = 0.6394 + 7-482 A t 4 6.317 JB l 4 1.969 C t 4 2.334 Z> t 3.774 l 

 o= 0.6193 + 3-999^1 + 1-969 A + 3- 6 85 C, + 3.708.0, 4 1.665^, 



o = - 0.0407 4 A + i W <7) 



= 4 0.0013 4- ., 4 BI C l 



A, = + 0.0614 = + 3 3i'- 

 B l = 0.0076 = o 26. i 

 C, = + 0.0631 + 3 36.9 



/), = -)- 0.0427 = + 2 26.6 



t = o.oon = o 3.9 



The following are the equations of condition, together with the resulting normal 

 equations, and the values of the coefficients J.,, S^ Ci, !) E^ as determined for 

 each compass from the observations made at Rio Janeiro. 



EQUATIONS OF CONDITION AT Rio JANEIRO. 



Hence 



Normal Equations. 

 ADMIRALTY STANDARD COMPASS. 



o = 1.2217 4- 17.000 AI 4- 8.442 BI 5.641 C 1 , 4- 0.924 Z, 4- 0.383 E t 

 o == 0.7991 4- 8.443 A, + 8.310 B t 4- 0.462 C, 1.205 D l 4.543 t 

 o == 4- 0.1662 5.641 AI -f 0.462 B l 4- 8.691 ", -f 3.900 Z>, 4.438 t 

 o = 0.0169 4- Z>, 4- i (B? C, 1 ) 

 0=4- 0.0009 +-, + ., C, 



A, =-. + 0.0453 = + 2 35'- 7 



B \ = + 0-05I9 = + 2 58.5 



C, = 4- o.oooi =4-0 0.2 

 D t =-- 4- 0.0156 = + o 53 5 

 t = 0.0009 " o 3- ' 



