3 6q Mr. Pond on the parallax of the fixed stars . 
at those times when the parallax is at a maximum. To the 
observations themselves is subjoined the process of compu- 
ting the correction to be applied for deducing the true polar 
distance. This correction, which is of the nature of an Index 
error, is usually found by comparing the observed places of 
all the stars, during the same period, with their computed 
places deduced from a standard catalogue derived from the 
instrument itself. 
If all the stars were used indiscriminately for this purpose, 
the method would be liable to an objection stated by Dr. 
Brinkley, for if of the stars from which this correction is 
deduced, several were themselves subject to considerable 
parallax, the effect of this parallax would be involved in the 
correction, and, if they were selected near to the star whose 
parallax was sought, the effect of this would be to conceal 
the parallax, by showing only the difference of parallax in- 
stead of the whole. To obviate entirely this objection, I 
reject those stars supposed by Dr. Brinkley to have parallax, 
and likewise y Draconis, whose parallax arrives at its maxi- 
mum nearly at the same period with that of a. Lyrae, a. Aquilae* 
and a Cygni. I employ chiefly those stars whose parallax 
must be neutral, and those opposite in right ascension, which 
method has rather a tendency to exaggerate the effect of 
parallax by exhibiting to a certain degree the sum of the 
parallaxes of different stars. The difference of these two 
methods, however, as may be seen in the annexed Tables, 
does not amount to one tenth part of a second. The above- 
mentioned objection, therefore, though theoretically just, 
cannot be made to explain the discordance which exists 
between Dr. Brinkley’s observations and mine. 
