Parallax of the Fixed Stars. - j 
The inftrument that was ufed upon this occafton was the fame 
as the prefent zenith fedtors, which can hardly be allowed fuf- 
ficient to (hew an angle of one or even two feconds with 
accuracy ; yet, on account of the great number of oblerva- 
tions, and above all the great fagacity of the obferver, we 
will admit that if the parallax had amounted to two feconds he 
would have perceived it. The ftar on which thefe obiei vauons 
were made is marked of the third magnitude in the catalogue 
of PTOLEMY ; in tyciio brafie’s of the third; in the Prince 
of hesse’s of the third; in hevelius’s between the third and 
fecond ; in flamstead’s of the fecond ; and now appears as a 
very bright ftar of the third, or imall ftar or the ftcond mag- 
nitude ; therefore its parallax is probably confideiably leis than 
that of a ftar of the firft magnitude. Several authors who 
have touched upon this fubjedt leem to have ovei looked this 
diftindtion; and from Dr. bradley’s account of the parallax 
of 7 Draconis, have concluded the parallax of the ftars in gene- 
ral not to exceed ; but this appears to me by no means to fol- 
low from the dodtor’s obfervations. It is rather evident that, tor 
aught we know to the contrary, the ftars of tne hi ft magni- 
tude may ftill have a parallax of feveral feconds ; and I believe 
this to be as accurate a refult as that method is capable of giv- 
ing, at leaft in latitudes where there is not a ftar of the firft 
magnitude that paffes directly through the zenith ; . 
b In 
* PE la LANDE, in his excellent book of Agronomy, fays, that the parallax 
of the fixed liars has been proved to be abfolutely infenfible (Aft. liv. XVI. 
e 2-g , \ jy e reports the obfervations of tycho brahe, picard, hook, and 
flamstead, and concludes (§ 2 77 S.) from the difcovery of the aberration by Dr. 
bradley (which it feems he alfo allows to be the moil decifive upon the fubjecft) 
that now the qucftion about parallax is refolved. In giving us the opinion which 
