Notices respecting New Books. 519 



This system of observing, he thinks, may probably account in 

 some degree for the comparative deficiency in the catalogue of double 

 stars of the first or closest class, i. e. stars of which it can be con- 

 fidently asserted that the angular distance of the individuals is under 

 2". But he states, that independently of such drawbacks, although 

 he has no direct statistical facts to bear out the assertion, he cannot 

 help putting on record " a strong impression that the extra- tropical 

 part of the southern hemisphere is really poorer in very close double 

 stars than the northern, at least in those regions of it which come 

 to be observed on the meridian in the best seasons for definition. 

 The almost total absence of objects of this description from the Cata- 

 logue in the last six hours of right ascension is the more striking, as 

 these are precisely the best hours for definition, coming to be ob- 

 served from June to October, when the atmosphere is in the most 

 favourable condition." Under circumstances of the best possible de- 

 finition, when the discs were reduced to mere points, and when it 

 was hardly possible that an interval from centre to centre of mode- 

 rately unequal stars exceeding three-fourths of a second, or at all 

 events a whole second, could escape detection, remarks of the fol- 

 lowing kind stand recorded in the Journal : — " July 23, 1835. The 

 extreme paucity, or rather total absence of close double stars in the 

 late sweeps, in such wonderful nights and such perfect action of the 

 instrument, is really surprising."—" July 24. I begin to think I shall 

 never see another close double star. It is wonderful how entirely 

 devoid of these objects are all the last sweeps, and that in the finest 

 picked opportunities for detecting them. It is a remarkable feature. 

 Eo ipso notanttir quod nan videntur." — P. 166. » 



The present chapter contains two Catalogues : — I. Reduced. Ob- 

 servations of Double Stars made with the 20-foot Reflector ; and 

 II. Micrometrical Measures of Double Stars with the 7-foot Equa- 

 torial. To the last is appended a Synopsis of the Results of the 

 Micrometrical Measures, and a Comparison of Angles of Position 

 taken with the two instruments ; and the chapter concludes with 

 some " Special Remarks on particular Double Stars in the foregoing 

 Catalogues." 



The first Catalogue includes 2103 stars, not found marked as 

 double in former Catalogues, and interspersed with which are a large 

 number which had been noted by previous observers. The new 

 double stars are numbered (in continuation of the lists formerly given 

 by the author) from 3347 to .5449, both inclusive. Among them are 

 a few respecting whose double nature, owing to their extreme close- 

 ness, doubts may be entertained. " The unnumbered stars occur for 

 the most part in Struve's Catalogue ; some are noticed as double in the 

 Brisbane Catalogue, and a considerable number are identifiable with 

 objects described in Mr. Dunlop's Catalogue of 2.53 double stars, pub- 

 lished in the third volume of the Memoirs of the Royal Astronomical 

 Society." TIjc Catalogue likewise includes such double stars (not 

 previou.sly noted by other observers) as were encountered in the 

 course of an examination, with the equatorial, of the Brisbane Stars, 

 as well as those which occurred in the partial and imperfect execution 



