OF THE EFFECTS OF PARALLAX AND REFRACTION. 47 



S. Example from the Requifite Tables, page 41 & 43, 3d Edition, ad fin* 



App. alt. * 24 4S o „ True alt. * 24 45 57 



3$ 12 30 Ho. Par. 56 15 J$) 13 20 42 



2) 12 18 2) 11 25 15 



~ Nat. fine 1071313 5 42 37§ L. S. 3.9978259 



| App. dift. 25 44 17f — 4342618 2 



Log. 9.7335131 = 5413936 = S. 0099004 = 7.99565 la 



Log. 9.5147204 = 3271300 = D. 1765564 



Tab. IX. Log. 9.9986500 1864568 = 19.2705783 



19.2468835 == 1765564 Sine 25 3456 = 9.635289J 



2 



True diftance = 51 9 52 



t. July 6th, 1790, at 9* 13' 15" A. M. apparent time, the apparent alti- 

 tudes and diftance of the fun and moon's centers were obferved as 

 follows: Moon's alt. 25° 29' Jl", Sun's alt. 15° 54' 5" diftance 

 66° 19' 32'', Moon's Ho. Par. 54' 2,5" reg d the true diftance. 



J\pp. alt. © 25 29 1 1 True alt. ]$ 26 16 28 



' l5 ;34< 5 Q 15 50 55 



Difference 9 35 6 Tab. II. 0069802 10 25 33 Tab. II. 0082550 



App. dill. 66 19 32 Tab. II. 2992304 2903825 



Leg. 9.4657548 = 2922502 T. dift. 66 15 4 Tab. II. 2986375 



Tab. IX. Log. 9.9972157 ' . 



9.4629705 sfe 2903S25 



Note. — In the three firft examples the computation is car- 

 ried on by the help of the tables that are in common ufe, but 

 in this kit example, by referring to the propofed table of tha 

 fquares of chords, under the title of Table II. fome idea may 

 be had of the labour required in the more improved method of 

 computation. There is nothing farther to add than that, if 

 after the many modern improvements in the way of clearing 

 the obferved lunar diftances of the effects of parallax and refrac- 

 tion, the prefent mode fhould be thought of utility, and worthy 

 of adoption, the neceflary tables, or at leaft that part which 

 Knew, will be published in a feparate oclavo volume. 



Analyfis 



