PREFACE. IX 



limes of the Royal Society's Catalogue of scientific papers. Of un- 

 published material I have been permitted to examine two precious 

 treasuries : the Smithsonian MS. list, the extension of its printed 

 catalogue, freely opened to me by the late Professor Henry ; and a 

 MS. catalogue, not unlike the present and which ought to have ante- 

 dated it in publication, prepared by Dr. H. Carrington Bolton, of 

 Trinity College, Hartford, and most generously placed by him at my 

 disposition.* Besides these the libraries of the Boston Society of 

 Natural History and of the Acadenry of Natural Sciences at Philadel- 

 phia have been examined, book by book ; as well as many volumes in 

 the Public Library, the Athenaeum, and the American Academy of 

 Aits and Sciences, in Boston, the library of Harvard University (in- 

 cluding that of the College proper, the Observatory, and the Museum 

 of Comparative Zoology), in Cambridge, and that of the Essex Insti- 

 tute, Salem. The Astor Library, New York, the American Philo- 

 sophical Society's library, Philadelphia, and that of the Smithsonian 

 Institution in the Congressional Library, Washington, have also been 

 visited. 



All the standard general bibliographies of every country have been 

 examined, and all serial bibliographical works (like the Bibliographic 

 de la France) from their beginning to the present time. It would oc- 

 cupy too much space to recount them all. All the library catalogues 

 also, and the other aids which may be consulted at those bibliograph- 

 ical centres, the Boston Public Library, the Harvard University 

 Library, and the Boston Athenaeum, have been examined with care, 

 including every special scientific bibliography known to me. Cata- 

 logues of accessions to the libraries of the learned societies, published 

 by many of them in their weekly or monthly Comptes-Rendus or their 

 annual volumes of Proceedings, have been carefully examined and 

 have afforded much valuable and otherwise inaccessible material, often 

 buried nearly out of sight. 



Advance copies of the sheets, as printed, have been forwarded to 

 some person in each European country represented in the list, and 

 these have been returned, in almost every instance, with valuable in- 

 formation. Mr. W. H. Dalton, of II. M. Geological Survey of Eng- 

 land, has not only added many titles to the English list, but has 

 kindly examined the sheets of the greater part of the whole work, 

 made many valuable corrections and additions, and has revised most 

 of the Hungarian and Polish titles while still in MS. Baron R. von 



* This I had in my possession for a month. It is an exhaustive catalogue of 

 independent journals in all branches of science, pure, applied or spurious, down 

 to the year 1874, prepared at great pains and which awaits the dilatory action of 

 Congress for its publication. For a description of it, see a letter by Dr. Bolton 

 in the Library Journal, vol. I., p. 114. Had not the present list been nearly 

 completed when the existence of this catalogue became known to me, my own 

 work would have been dropped. The two lists, however, duplicate each other 

 only in the field of independent journals of pure science. 



