473 
the parallax of a, Lyrce , 
" mean of all these observations, to be about o",25, which 
“ quantity, by the French refraction, would be reduced one 
“ half, or to an insensible quantity/* 
Now any person reading these passages might understand, 
that Mr. Pond means, by the angular distance thus measured, 
the angular distance measured on the same day ; not one 
star observed on one day, and the other on another ; and 
that in the latter passage he means the same by the words 
“ observed together/* 
Yet on examining the observations it will be found he can- 
not mean this, for his Table XI. shows the contrary, the 
number of observations of each star being there unequal ; 
and it will also be found that the days in the five years (181® 
to 1816 inclusive) on which both stars were observed, only 
amount to about 337, not reckoning about 40 in 1812 and 
1813, rejected or not used by Mr. Pond. Of these 337 ob- 
servations, 146 were in summer (in opposition), and 87 in 
winter (conjunction), and 100 in autumn (in quadrature). 
These observations however would be quite sufficient for 
the purpose, if they admitted of the exactness which they 
seemed to promise. But if the results obtained be compared, 
it will be found surprising, that so simple an operation, per- 
formed by such an instrument as the Greenwich mural circle, 
could furnish such discordant results. 
The observations of these five years have been long before 
the public, and were made at a time when the circle was 
considered in its best state. The results of each day's obser- 
vation are now also here placed before them. 
The differences of N. P. distance, or intercepted arch be- 
tween these stars, will be found in Table I. for each of the 
mdcccxxiv. 3 P 
