546 A CATALOGUE OF STANDARD STARS. 
be the case if we made a doubtful application of the method of least squares. The 
method here employed is the best I could devise for bringing down the relative errors 
of near stars. 
The form of reduction proposed, and to some extent actually carried out, will enable 
the following things to be done with great ease: firstly, to reduce (if desired) the 
observations of each star so as to depend directly on the Tabulae Reductionum, and, 
secondly, to re-compute from our own observations the places of all the stars of the 
present list, so as to depend solely on our own observations, so far as our instrumental 
means will permit. 
The positions derived from the Greenwich results for 1855, compared with Bessel's 
for 1755, will, assuming the correctness of the latter, require the addition of x em) j 
where 4 is a correction applicable to the places for 1855. 
The positions given in the Edinburgh observations of 1838, 1839, 1840 were com- 
pared then with our calculated places, and would give in the mean the quantity 
0.84 x = a) 2. 
after correcting them, to reduce to the equinox of Wolfers. See Tabulae Reduc- 
tionum, p. xliii, at bottom, where we find 
N. C. — Henderson = + 0*.038 (for 1830) . 
Reducing this to 1839, the mean epoch of the observations used 
N. C. — Henderson = 0*.043 (for 1835). 
The number + 0*.044 was used instead ; the change will be insensible. 
The Edinburgh observations after 1840 were not used. The same catalogue had 
been employed to reduce them that was also employed at Greenwich for the same year, 
and the resulting numbers (it was feared) were not precisely homogeneous with those 
of the former years. The few observations made at Edinburgh on the new list of 47 
stars introduced in 1857 into the Nautical Almanac were omitted. The Greenwich 
catalogue for 1850, depending, as is well known, upon the two instruments employed 
at Greenwich, —the old Transit and the new Transit-Circle, — was also compared. 
The Greenwich observations from 1854 to 1858 were compared; after the work was 
nearly complete, the volume for 1859 was received, and used for a few stars inado- e 
quately observed in the preceding years. | 
The Paris observations of 1856 and 1857 were also used. To my gebat regret, the 
