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Astronomical and Nautical Collections. 409 



Consequently, by Mr. Henderson's method, we have, 

 Log. sec. alt. 47° 27' 17"= 0.169942 Orb. A. 65^ 29^ n.e. ) N. 

 Log. COS. lat. 28 17 = 9.944768 Compl.-24 31 

 Log. sin. H. A. 21 51 =r 9.570751 Par. A. +29 



Log. sin. P. A. 29 = 9.685461 C.P.O.A .+4 29 



rP. L. red. H. P. . . 54' 9 . . . 0.52167 



Log. sec. Alt. . . . 47 27 17 . . . 0.16994 



Log. cosec. compl. A. 4 29 . . . 1.10696 



Orbit. Parallax . . + 2 52 P.L. 1.79857 



Log. tang, compl. A 8.89437 



LPerp. Parallax . . - 36 30 P. L. 0.69294 



Nearest distance . . . . +50^31" 



Perp. Parallax . . . . — 36 30 

 Sum . . . 

 Semidiameter 



(^)/Sum 28 47 P.L. 0.79613 



Difference * 45 P.L . 2.38020 



2)3,176.33 



Side ... +4' 39" P.L . 1.58816 



l^Orbit. Parallax +2 52 

 4-7 31 



The hourly motion being 29' 42", this gives 15"' 1 I'', which 

 subtracted from 3'* 17'" 1", the time of nearest approach, 

 leaves the 



True time at Greenwich 3'^ l*" 50'' 

 True time at ship . . 1 37 49 



Difference of time . . 1 24 1 = 21° 0M5" W. Long. 



To find the difference of the apparent altitudes, and from 

 thence the error of the foregoing solution : — 



Semidiameter 14' 46" P.L. 1.08599 



Sum before found .... 14 1 P.L. 1.10863 



Angle A . , 

 90°-4°29' = 

 Difference . . , . . 13 



