538 A CATALOGUE OF STANDARD STARS. 
Tabulae Reductionum,* without further investigation. It will be often convenient to 
have them in the form here presented, which differs from that adopted in those 
tables. The secular variations given for these stars are the same which Wolfers used, 
and which are taken from the Tabulae Regiomontanae. 
Computation of the Mean Places of 25 Polar Stars. 
In this discussion the following catalogues have been employed; to the name of 
each catalogue has been prefixed the abridgment by which it is cited in the course 
of the work: — 
Br. The Fundamenta Astronomiae (full title given in this volume of the Memoirs 
of the Academy, Pt. I. p. 299). 
Gr. Groombridge (full title, loco modo citato). 
Str. 1815. F. G. W. Struve, Observationes Astronomicae institutae in Specula Univer- 
sitatis caesareae Dorpatensis. Vol. I. Pars II. Dorpati. 1817. Ato. 
Str. 1824. Stellarum Fixarum imprimis duplicium et multiplicium Positiones Mediae 
pro Epocha 1830.0 deductae ex observationibus meridianis annis 1822 ad 
1843 in Specula Dorpatensi institutis; auctore F. G. W. Struve. Petropoli 
ex typographia academica, 1852. Fol. The positions which I have used 
are a few for 1824.0 from the Introduction, page xxxxvili. et seqq. 
Schw. Schwerd's Beobachtungen von Circumpolarsternen in mittleren Positionen 
1828.0. Von Wilhelm Oeltzen. Aus dem X. B® der Denkschriften der 
Mathem.-Naturw. Classe der K. Akademie der Wissenschaften. ... . Wien, 
1856. 4to. y 
Arg. DLX Stellarum Fixarum Positiones Mediae ineunte Anno 1830. . . . [auctore] 
Argeland[ro] ... Helsingforsiae, 1835.  4to. 
Pond. A Catalogue of 1112 Stars reduced from Observations made at the Royal Ob- 
servatory at Greenwich from the Years 1816 to 1833. London..... 1833. 
Fol. 
Hend. Astronomical Observations made at the Royal Observatory, Edinburgh, by 
Thomas Henderson. ..... Vol. IIL. [to V.] for the Year[s] 1837 [to 1839]. 
Edinburgh. 1840 [—1843]  4to. e 
[The same] reduced and edited by his successor, Charles Piazzi a, Sma ‘Vol : 
VI. [-IX.] for the Year[s] 1840 [- 1845]. 4to. 
* Tabulae Reductionum Observationum Astronomicarum ab anno 1860, usque ad 1880. Anis 
Wolfers. Additur, Tabulae Regiomontanae ab anno 1850, usque ad 1860, ab Ill. T ian | 
1858. Zech continuatae. erolini, 
