202 OBSERVATORY AT WEST POINT. 
whence 
y= — 5.56... . .% « Face FE. 
Bo OFOG0: . 52. . ate Be. 
These values being substituted in equations (1) and (2), the Comet was wrought out 
as in the following example for the 29th of March. 
Data from observation. 
Date Object, Sid. Time Hour Cirele | Dec. Circle 
1843, a ceti 8" 00™ 165.8 5" 06™ 18°. 3° 36’ 15". 
March 29th. Comet. pio'B28ho@hid 4-4 od. 86-28: —6 40 15. 
Columns fourth and fifth were corrected for refraction by the following formule, the 
thermometer and barometer indicating about mean refraction, namely, 
Lan s. sin 
Refr. in AM = 5755 6. sin () +9) 
Refr. in Dec. = 57’. cot () + 9). 
Tan = cos s. cot L. 
In which L is the latitude of the place, being in this instance, 41° 23’ 31”; and s the 
hour angle of the instrument; the values of o and x, for both bodies are therefore known; 
and employing o for s in equation (1) we have for 
ace. . . . Om OS 06"30'9 | comet. . .’. GO as 4" 36" 41°01 
Asin (p—s) tan d=—0O 00 00.24 A sin al tan. d=0 00 00.89 
a oe =—0 00 00.16 u tan iene =0 00 00.11 
Fw. OTS = 800 07.56 Y 800.050 et. amd OO OG BT 
$s = 5" 06™ 385,16 s'= 4 36™ 48°.31 
« whence 
s'’—s = 23" 30” 10°.15 = #—t+R— A. 
0 31 10.60 = v’—+t. 
22> 58" 59°55 = M—AM’. 
Naut. Almanac,. . . 2 54 05.40 — true M of a ceti. 
3" 55” 05°.85 = true AR’ of comet. 
And from equation (2) we have for 
a ceti, 7 be te 86°. 26 36.7 comet 7’ : . = 96° 43’ 42'.70 
A. cos (@—s). = O OL 03.72 A, conde—s),. =< 0 OL 10.82 
86° 27’ 40''.42 96° 44’ 537.52 
whence, 
n'—n = 10° 17’ 13”.10, 
P=86 31 45. true polar dist. of a ceti. 
96° 48’ 58.10 true polar dist. of comet. 
=:— 6 48 58 .10 true declination of comet. 
