50 



• mean value of angle between R.M. and star at elongation 



= 83° 14' 21"-2' 0" = 83° 12' 21" 



The computation by means of the more accurate formula. 

 (7) is rather longer. In this case we write 



B = sin x4p cos j^ and /// = 



sin h sin 1 " 



and work on the same lines as before. To illustrate the 

 method the computation in this case is also worked out as 

 follows: — 



fo-f 



m. 



s. 



12 



50 



10 



57 



7 



08 



5 



18 



2 



27 





21 



3 



09 



5 



24 



12 



47 



l.j 



31 



12 130 

 44 15 



47 

 19 

 36 

 5 

 47 

 21 

 11 



00 

 30 

 45 

 15 

 15 

 00 

 45 



52 145 



20 

 05 



51 I 50 

 24 120 



57 I 17 

 56 149 

 oo 



DO 



54 I 41 35 

 54 I 10 1 05 

 53 ! 17 35 



52 I 43 50 

 50 I 53 05 

 50 1 12 i 05 



log 



siu I" 



loET sin h 



12-50960 

 12-37178 

 11-99958 

 11-74157 

 11-07136 

 9-38117 

 11-28965 

 11-75780 

 12-50621 

 12-67446 



log' 7)1 



= diflfer 

 ence of two 

 precediiij 



columns 



9-92501 

 9-92269 

 9-91788 

 9-91550 

 9-91173 

 9-90888 

 9-90401 

 9-90080 

 9-88979 

 9-88553 



2-58459 

 2 44909 

 2-08170 

 1-82607 

 1-15963 

 1-47229 

 1-38564 

 1-85700 

 2-61642 

 2-78893 



log cos 2^ ~ 

 log sin .4, = 

 W 199 



Mean value of m 



9-90031 

 9'88380 

 2*29885 



384-2 



281-5 



120-7 



67-0 



14-4 



0-3 



24-3 



71-9 



413-4 



615-1 



10)1992-8 

 ... 199 



W 121 



2-08296 



:.B m = 121" = 2' 01" 



• mean value of angle between K.M. and star at elongation 

 = 83° 14' 2r-2' 01" = 83° 12' 20" 



The difference between the results of the two calculations 

 is so small that clearly the more simple approximate method 

 is quite sufficient for the surveyor. If the computation be 

 made for the last four observations only, the difference between 

 the results of the two methods amounts to 8", and for the 

 last observation alone the difference is 19". For the surveyor 

 it is only necessary to use the more accurate method of calcu- 

 lation for unbalanced observations at a considerable time 

 from elongation. 



