264 Proceedings of the Royal Society. 
foration, which was as carefully closed as possible, but to its 
vitiation by respiration, and by the absorbent power of the pleura, 
Thursday, March 11. 
A paper entitled Remarks on the Parallax of a Lyre. By 
J. Brinkley, D.D. F.R.S., Sc. &c. §c. ,was read. 
The author’s object in this paper was principally to form a correct 
estimate of the absolute and relative degrees of accuracy of the 
instruments at Dublin and at Greenwich. He first considered the 
difference of parallax between y Draconis and « Lyre, and 
secondly the absolute parallax of « Lyre. 
He exhibited in a table the whole of the results of 337 observa-= 
tions of Mr. Pond for the intercepted arc, reduced to 1 January, 
1815; chiefly by Mr. Pond’s own computaticns. From 46 of the 
observations, made in the year 1812, he deduced 0".28 for the co- 
efficient of the effect of parallax: and from such of the ob- 
servations as were made in the same day the number deduced 
is 0”.54. 
In 1813 there was a difference of half a second between the mean 
of 22 observations in June and July, and of 17 in August; hence 
Dr. Brinkley was led to examine the observations of this year 
alone, and he found that 61 of them from June to December, as 
reduced by Mr. Pond, gave 0”.42 for the co-efficient of parallax: 
and omitting the last 5 days of observation 0’.89, whicl. is little 
less than the result of his own researches. 
On the other hand, when 5 double observations, in January and 
February, 1814, were added to these 61, they reduced the result 
for the co-efficient to 0”.18. So that the discordances seem to 
be too great to enable us to place any reliance on the conclu- 
sions respecting the actual magnitude of the annual parallax. 
A similar fluctuation is observable in the results obtained for 
the following years: and though it might, on the whole, be in- 
ferred that the parallax is about 2.as great as that which the 
author has assigned from his own observations, yet he contents 
himself with concluding that the mural circle of Greenwich has 
not sufficiently proved the identity of the distance of the two stars 
