[ 8 92 ] 
obferver, the Abbe de la Caille, recited in his Fun- 
damenta Aftronomias, printed about two years fince, 
wherein alfo are contained all the obfervations, which 
he has taken of the principal fixed fiars; a work 
truly worthy of its name ! Every particular obfer- 
vation of the fame fiar is reduced to one epoch, that 
of the beginning of the year 1750, by applying the 
equations of aberration, precefiion, and deviation, to 
the obferved places ; fo that the places corredted 
ought all to agree together, if the obfervations were 
perfectly exadt, and the fiar was affedted with no 
fenfible motion, that was unaccounted for. Being 
fatisfied with the excellence of the obfervations, I 
was tempted to examine thofe of fome of the princi- 
pal fixed fiars, in hopes of difcovering fome fenfible 
differences in the obfervations made at different times 
of the year, when a parallax, if there had been any, 
would have had the greateft effedt. But I found very 
few fiars, the obfervations of which were fufficient 
in number, or taken at proper feafons of the year, 
to give room for any inference at all. Fortunately, 
however, the obfervations of the zenith diftances of 
Sirius were more in number, and, what is ftill of 
more confequence, in this cafe, made in various, and 
fome in oppofite feafons of the year : and, upon look- 
ing them over, I was agreeably furprized to find a 
very fenfible difference in the obfervations made at 
different times, agreeing in diredtion with what a 
parallax ought to produce, the zenith difiance of Si- 
rius in July coming out no lefs than 8" greater than in 
the oppofite feafon of the year, namely in December 
and January: the zenith difiance alfo in March and 
