constructing a catalogue of fixed stars. 413 
exact than the old one; but by continuing this process, a 
proper ascendancy will necessarily be acquired by the latest 
observations. 
In comparing my catalogue of right ascensions with that 
of Dr. Maskelyne, I meet with a singular coincidence, which 
seems tome to illustrate and confirm, in a very striking manner, 
the advantage of the principle in question. In each catalogue, 
the right ascension of a Aquilse, though deduced apparently 
by a different process, comes out the same, even to the 
hundredth part of a second. Accident may possibly have 
some little share in this very exact coincidence, but it appears 
to me chiefly to arise from the very nature of our respective 
processes. In Dr. Maskelyne's method, the right ascension 
of every star is derived from direct comparison with ct Aquilas, 
or in other words, the right ascension of a Aquilse is derived 
by comparing it with every star. So it is in my method ; and 
hence the same result ought to be obtained. But the advan- 
tage which in one case is peculiar to a, Aquilae, is in the other 
method extended to every star : no possible reason can be 
given, why the place 'of one star should be more accurately 
assigned than that of another, provided an equal number of 
observations be obtained of each, since the place of every star 
is deduced exactly in the same manner from a comparison of 
all the rest.* 
Though not immediately connected with the present 
subject, I wish to take this opportunity of stating, that, in 
comparing the observations of the old transit instrument with 
those of the new one, I find a much less difference than I 
* As I have nothing new to offer, as to the method of deducing the equinoctial 
point from observations of the sun, I have not taken this part of the subject into 
consideration. 
