A CATALOGUE OF STANDARD STARS. 539 
Rob. Places of 5345 Stars observed from 1828 to 1854 at the Armagh Observatory, 
by Rev. T. R. Robinson, D. D...... Dublin, 1859. 8vo. 
Airy. Airy's “Twelve-Year Catalogue,” “Six-Year Catalogue,” “Greenwich Observa- 
tions” from 1854-1858. (For full titles see my paper previously cited, in 
the present volume, pp. 300, 301.) 
The “Greenwich Observations” for 1859 and 1860 have come to hand since 
the main part of these calculations were made. 
Joh. The Radcliffe Catalogue of 6317 Stars chiefly Circumpolar reduced to the 
Epoch 1845.0, formed from the Observations made at the Radcliffe Ob- 
servatory under the Superintendence of Manuel John Johnson, M. A., late 
Radcliffe Observer. With Introduction by the Rev. Robert Main, M. A., 
Radcliffe Observer. Oxford. 1860. 8vo. 
Car. A Catalogue of 3735 Circumpolar Stars observed at Redhill in the years 1854, 
1855, and 1856, and reduced to Mean Positions for 1855.0, by Richard 
Christopher Carrington. London. 1857. Fol. 
LeV. Annales de l'Observatoire Impérial de Paris publiées par U. J. Le Verrier, Di- 
recteur de l'Observatoire. Observations. Tome XII. [XIII] Paris. 1860, 
[1861]  4to. 
Tomes XIV., XV. were received later. 
I found, when too late to use them, that Airys Cambridge Observations contained 
two or three places which should have been inserted. 
No use was made of the Histoire Céleste, or Fedorenko's Catalogue; nor of Piazzi, 
nor Groombridge's right-ascensions. Any material from these sources is of uncertain 
accuracy; or would require insecure systematic corrections. 
The method by which mean places for 1855, and proper motions referred to 
the ecliptic of the same year have been found, is as follows: The positions of the 
Fundamenta, where such existed, were reduced from 1755 to 1855 by the use of 
Struve and Peters's data. In some cases where there was no observed declination for 
1755, a value for 1755 referred to the ecliptic of 1855 was assumed, and by a slight 
modification of the method given in the introduction (p. ix.) to the Tabulae Regiomon- 
tanae (see, also, Wolfers's Tabulae Reductionum, pp. lii, lii. of the Introduction) 
was made to serve the same purpose. For if (see the place just cited) A be supposed 
known, we shall have ([32]) » — ED . In this case the declination for 1755 
corresponding to that assumed for the ecliptic of 1855, will be à = d — d + (8 — «) a. 
The indirect form of Bohnenbergers method which Bessel has given, and which 
