112 JVezo Method of determining the Longitude. 



east of Paris, and of Dorpat lA. 37m. 28s. east, the Paris 

 apparent tinties of her culmination at those places will be 

 as below. 



The true declination and semi-diameter of the moon at 

 the same times were as below. 



At Manheim. At Dorpat. 



March 3. y=]5' 44'', 4 ^=15' 44", 8 



flf=23°51'42" 5=24° 2' 18" 



Consequently the value of ^^ (——, ^^willbe0^123 



^ \cos. a cos.o/ 



Hence f— t=3'" 0% 80=180% 80— 0% 123 = 180, 677=the 

 true difference of the right ascension of the moon's centre 

 for the two moments of observation. 



The true right ascension of the moon for the times of 

 her culmination at the two observatories, (reduced to the 

 meridian of Paris,) must be computed by means of second 

 differences from the Con. des Terns, and we shall have the 

 values of a and b. Their difference will show the increase 

 in the true right ascension of the moon, or her true mo- 

 tion in the interval denoted by c—h. The results are as 

 follows : 



March 3. c=^^ 26" a=116*49' 24", 4=moon's A. R. 

 h—7 10 6 = 116 4 7, 6 



(c — /i)=l 16 a — b= 45 16, 8=moon's in- 

 crease in A. R. 



c— h 



7=1,67845 



a — o^ , 



The length of the true solar day, or the value of s, March 

 3d 1822, was 24^^ 3™ 43% 4= 86623%4. 



Hence the value of x, or the true difference of the meri- 

 •iians of Manheim and Dorpat, will be 



.T=180%677 (^^^x 1,67845- l)=l' 12"' 59% 45 



