MAGNETIC OBSE 11 VATIOXS. 



213 



Hence 



After Binnacle. Compass. 



o = — 0.9599 + 10.000 A x + 7.482 B, + 3.999 C, + 3.938 Z>, — 2.631 E x 

 o = — 0.7253 + 7.4S2 A t + 6.317 B x 4- 1.969 C, + 2. 334 Z>, — 3.774^, 

 = — o-44i3 + 3-999 -4, + 1-9^9 A + 3-685 C l + 3.708 Z>, + 1.665 ^ 

 o = _ 0.0385 + £> x + 1 (^ _ C, 2 ) 

 = 4- 0.0018 +£,-f^ 1 C 1 + 0.0047 (B'—C?) 



A 



= 4- 0.0062 = 4- °° 21'. 3 



/•, 



= 4- 0.0S01 = 4-4 35- 2 



c, 



= 4- 0.0362 = 4- 2 4-6 



A 



= 4- 0.0360 = 4-2 3.6 



A 



= — 0.0048 = — 16.3 



Hence 



Hence 



After Ritchie Compass. 



o = — 2.5540 4- 10.000 A t 4- 7.482 B, 4- 3.999 C, 4- 3.938 Z>, — 2.631 E x 

 o = — 1.9282 4- 7.4S2 A l 4- 6.317 B x 4- 1.969 C, + 2.334 2?, — 3.774 ^ 

 o = — 1.0844 + 3-999 A l + 1-969 A + 3- 68 5 c i + 3-7°8 2>, 4" >- 66 S ^1 

 o = — 0.0340 4- D x 4- I (^ — 67) 



= 4- 0.0008 + ^,+5, C, 



A = + 0.1030 = 4-5° 54'. 2 



^ = 4-0.1385 = 4-7 56.0 



C, = 4- 0.0859 = 4-4 55-4 



z> t = 4- 0.0281 = 4- 1 36.6 



.£, = — 0.0127 = — o 43-7 



Forward Alidade Compass. 



o = — 0.5265 4- 10.000 A, 4- 7.482 B x 4- 3.999 C, 4- 3.93S Z>, — 2.631 E x 

 o = — 0.3589 4- 7.482 A x 4- 6.317^, 4- 1.969 C, 4- 2.334 />,— 3.774 E t 

 o = — 0.3022 4- 3.999 ^f, 4- 1.969 B, 4- 3.685 C, 4- 3.708 D x 4- 1.665 -^1 

 o = - 0.0235 + A + \ {B? - Cft 

 o = — 0.0007 + &\ -\- B t C, 4" 0.0125 (B x — C) 



■*i= + o-°359 = + 2 3'-5 

 B t = 4" 0.0001 = 4- o 0.2 

 C, = 4- 0.0188 = 4-1 4-8 



z>, = 4- 0.0237 = 4- 1 21.4 



£ x = 4" 0.0007 = -f o 2.4 



Hence 



Forward Binnacle Compass. 



0.1396 4- 10.000 A t 4- 7.482 B x 4- 3.999 C, 4- 3.938 Z>, — 2.631 E, 

 0.0593 4- 7.482 ^, 4- 6.317 B x 4- 1.969 C, 4- 2.334 Z>, — 3.774 E x 

 0.1831 4- 3.999 A, 4- 1.969 .ff, 4- 3.685 C, 4- 3.708 Z>, 4- 1.665 E x 

 o.o 3 69 4-^ 1 4-i(A 2 -C 1 J ) 

 0.00 1 1 4"^i + B x C, 



^, = — 0.0159 = — o° 54'. 7 

 B x = 4- 0.0072 = 4-0 24.6 

 C, = + 0.0253 = + » 20 -9 



z>, = 4- 0.0372 = 4-2 7.8 



.£", = 4- 0.0009 = 4-0 3.2 



