8 
the max. of nutation of the obliquity of the ecliptic =9",50+y, the 
same work, p. 348, gives for this 
155.2 mI 2 a 
maximum "eae Ne y= TS SiE063 —"—and c'=tan 5°. 8’. 48 
3,907—y 
Hence 745 ee = —73,407 
Therefore “pur, -= 0”,5062—,1296y 
Lets = 0”, 5062—,1296y 
Then the solar nutation in N, P. D=(cos. ob. ecl. sin 2@ cos A.R. 
—cos 2 sin A. R)s. 
The smallest value that has been assigned for the max. of lunar 
nutation of ob. ecl. is 8’,97, which has been deduced by Lindenau. 
This gives y= —O”,52, and therefore z=0",57. 
The greatest value for this max. is that which is deduced by 
supposing A=3 as determined at first by M. Laplace, by the tides 
at Brest. This value of gives 9,50 +y=10’,055 and the value of 
s=0",43. But the illustrious author himself has shewn, that this 
value of a is too great. (Mec. Cel. Tom. 3. p. 159.) 
There cannot be a doubt that the value of z is between 0,43 
and 0’,58. According toa high degree of probability 0”,51 is a 
very near value. 
Taking the value of the lunar nutation deduced by my observations, 
as given in the Phil. Trans. 1821, the value of s=0",537. 
_ Let us now investigate the value of 3 from actual observation. 
Observations of « Lyre. 
The observations of the zenith distances of this star are given at 
length, in order that the whole process, by which the results are 
