PHILOSOPHICAL SOCIETY OP WASHINGTON. 101 



on all other work of the same kind. Only those who have done 

 this nature of work know how easily errors may slip in and how 

 omissions may occur, and the accuracy of this list shows that 

 extraordinary care lias been taken in its compilation. I have 

 found but one misprint in it, viz., Comptes Rendus, vol. 28, p. 

 53Y, should be p. 573. The name of Bode has been omitted by 

 the printer. 



HoLDEN, E. S. : Catalogue of papers and memoirs relating to 

 Nehulse and Clusters. MS. 



(Exhibited to the Society.) 



The necessity of supplementing the Royal Society's Catalogue 

 of Scientific Papers, which, it will be remembered, is arranged 

 solely by authors, and only contains papers published in periodi- 

 cals since ISOO, and which excludes books separately published, 

 was impressed upon me some two years ago when I was endea- 

 voring to acquire a thorough acquaintance with the literature of 

 a single subject — that of Nebul* and Clusters. I have, as occa- 

 sion served, prepared such an index catalogue of all papers, 

 memoirs, and books on these topics, and have arranged the refer- 

 ences according to authors, alphabetically, giving for each refer- 

 ence volume and page. Where the title of a book or paper 

 explains the subject of it, such title is, in general, alone given. 

 Where a paper is quite important its title is given, and if neces- 

 sary, a note, more or less brief, expressive of its contents. The 

 works of the elder Herschel on these subjects I have analyzed 

 at considerable length, in order partly to supply the great want 

 for an edition of his collected works. For papers of minor 

 interest a reference to the periodical, volume and page is 

 alone given (no title), and a note of its purport. In addition to 

 this, and following Mr. Knobel, I have given a very condensed 

 reference to the papers in each periodical consulted. In this way 

 a person consulting the catalogue will find all the works of any 

 author upon the general subject, with brief notes of the contents 

 of each paper ; or again, any person desiring to refer to the va- 

 rious papers on this subject contained in any serial publication, 

 as the Philosophical Transactions for example, will find refer- 

 ences which will save him much time. The index is practically 

 complete to the present date, and contains perhaps 1000 refer- 

 ences. It contains also a complete list of all published (and 

 many unpublished) dra\Vings of nebulte and clusters. It is evi- 

 dently of special value only, but knowing the labor it has 

 already saved to me, I cannot doubt that similar works in other 

 specialties in Astronomy, like Mr, Knobel's for example, will 

 be of much use. 



Mr. E. S. Holden also made a communication on 



