Herschel's Catalogue of Nebulce. 449 



well, though both wrong." In another, an entry in the Cata- 

 logue of Auwers is curious, " for the great number of per- 

 fectly accidental errors which have heaped themselves toge- 

 ther :" there being a numerical misprint in the synonym of 

 the nebula, in its Eight Ascension, and in its Declination ! 

 " This is not to be taken as a specimen of M. Auwers's work, 

 which is an admirable example of painstaking devotion, and 

 far beyond any eulogy in my power to offer. But it is a striking 

 instance of the way in which, in the great run of chances, 

 unlucky coincidences will happen." 



With regard to the possible movement of nebulas in space, 

 a highly interesting observation is to be found in an important 

 memoir by the Earl of Eosse, published in the Philosophical 

 Transactions for 1861. He there says, " The most remarkable 

 case of suspected change is perhaps H. 1905. Herschel gives 

 a drawing of it, the axes of the two nebulas in a line. On 

 April 11, 1850, Mr. Johnston Storey remarks the two nebulas 

 not in a line. April 17, 1855, Mr. Mitchell remarks the two 

 nebulas are not in a line, but the axes are parallel, and gives a 

 diagram. At the present time they are neither in a line nor 

 parallel, but inclined at an angle of about 16°." A copy is 

 here given of the engraving of these 

 nebulas in Sir J. HerschePs first Ca- 

 talogue of 1833. In the General 

 Catalogue each is separately numbered 

 4051 and 4052 ; but no allusion is 

 made to the Earl of Eosse's observa- 

 tion in the description or the notes. 

 These objects should be carefully 

 watched and drawn at sufficient inter- 

 vals : they are probably too faint for general observation, but 

 as some of our readers who may possess instruments of ade- 

 quate light may wish to look for them, the place of the larger 

 (4052), as given in the new Catalogue, is E. A. 15h. 1m. 9s. 

 N. P. D. 69° 56' 2" (or D. K 20° 3' 58"), consequently a little N. 

 of a line from Arcturus through £ Bootis, and rather less than 

 half as far again. They are at the extreme edge of both Nos. 

 3 and 4 of the star maps of the S. D. U. K., and marked 751 

 and 752 II. ; i. e., of $'s second, or faint class of nebulas. 



The Earl of Eosse's memoir, just cited, to which we may 

 have to refer on future occasions, contains abundant proof of a 

 material point, as to which, from his long silence, some doubt 

 had been entertained — the continued and complete efficiency 

 of his magnificent instruments, as well as of their wonderful 

 optical capabilities. He states that for the purpose of bringing 

 out minute stars his 3 -foot reflector will occasionally carry a 

 power of more than 2000 ; and as much, or even more, might 



