477 
the parallax of a Lyrce. 
the five years, gives 12 0 53' 48", 93 + 0,83 p 
the mean of all the 337 observations, gives 12 0 53'49",29 + 
0,12 p 
Thus, from the Greenwich observations, the parallax of 
a Lyras is half a second greater than that of y Draconis. 
It may be safely asserted, that this conclusion is entitled 
to more weight than any thing in Table XI. of Mr. Pond’s 
paper. 
We have not yet considered the year 1815. In this year 
the discordances will be found greater than in either of the 
other years, if we except 1812, when the position of the tele- 
scope was varied. 
In 1815, by 13 days observation in July, the mean inter- 
cepted arch, January 1, 1813 - - = 12 0 53' 55 n » 59 
by 18 days in August - = 12 53 57 ,14 
by the standard catalogue = 12 53 56 ,97. 
The difference of the two former quantities will appear 
almost incredible, if we merely consider the circumstances 
favourable for obtaining exactness. If, of the 31 observations 
in July and August, we compare the first 15 with the first 13, 
in winter, from the beginning of November, we shall find 
the constant of parallax = -f- o",72. 
The following 16 in summer, compared with 16 in winter 
immediately following the above 13, give 
the constant of parallax = «— 0^,58. 
This seems fully to prove the imperfection of results from 
which such consequences are deduced. 
The conclusions relative to the parallax of « Lyras, which 
Mr. Pond deduced from his observations of that star and 
y Draconis, formerly appeared to me more adverse than any 
thing else to my results. 
