450 Zoological Society, 



other Englisli authors, of whose writings these specimens are the only- 

 explanation. To the pleasure of working in so rich a collection must 

 be added the command of a colossal library, to which not one work 

 of importance is wanting. All this, with the aviaries of magnificent 

 living birds, from every zone of the world, must have the greatest 

 charm for the naturalist, and make Knowsley Hall for him a perfect 

 Eden, which once seen shall never be forgotten. ' 



The new birds described here include only one portion of my re- 

 searches, because I could not finish so many genera. The materials 

 of the very rich family of Muscicapidce are too extensive, for a com- 

 plete elucidation during the limited period of my visit from a foreign 

 country ; I wish my descriptions therefore to be considered only as 

 fragments. 



The object of my visit to England was to collect materials for a 

 complete monography of the MuscicapidcB ; but notwithstanding the 

 many favours I received, and the extreme liberality with which my 

 labours were facilitated in every English collection, I must confess 

 with sorrow that I shall never be able to make a complete whole (per- 

 fectly free from objection), with materials collected in different mu- 

 seums. A perfect arrangement can only be achieved by the study of 

 the materials present together, so that at every moment a compari- 

 son may be made between any two or any number of the species. 



Were it my good fortune to assemble the whole materials of one 

 family in my rooms at Darmstadt, one winter only would be neces- 

 sary to finish each family in such a manner as to satisfy the require- 

 ments of modern science. 



Were any one museum willing to accord me the whole materials in 

 its possession, it is probable that all the supplementary species not 

 contained in that collection would be readily furnished by other mu- 

 seums, as the absence of a few species for a short period would be of 

 little or no importance. 



That we can only climb to the summit of our science by means of 

 well-made monographies, there can be no possible doubt ; and I attach 

 a higher value to a monography constructed on philosophical prin- 

 ciples, than to the best fauna of any single part of the world : for 

 only by a strict comparison of the birds of the five parts of the globe 

 can we know what is a family, a subfamily, genus, species and sub- 

 species. Only in this way — a difficult way no doubt — can we learn 

 the true harmony of nature ; and thus shall we be filled with admi- 

 ration, when we see that every species, genus, family or order repre- 

 sents a certain type, and must receive its place in a scheme of classi- 

 fication according to fixed laws, which man must discover, but over 

 which he has no control. 



This charm can never belong to merely descriptive ornithology, 

 because even the best descriptions are only like mosaic stones, which, 

 when placed without rules, or arranged according to false principles, 

 give us only a scattered mass of heterogeneous materials, or a picture 

 destitute of truth. 



These claims I have urged over and over again in my dissertations, 

 but hitherto without effect. When shall the time arrive when a 



