XXVI HI8T0BICAL PREFACE. 



and twelfth (the two latter volumes having appeared in 1859) ; others were those con- 

 tained in the " Mexican Boundary Eeport " which had appeared under Professor Bairu's 

 editorship in 1859; about half of them were new. 



I have spoken of the collaboration of Cassin and Lawrence in the production of this 

 remarkable treatise. Considering it only as one of a series of reports upon the Pacific 

 Railroad Surveys, I should bring into somewhat of association the names of those who 

 contributed the ornithological portions of other volumes, as the fourth, sixth, tenth, and 

 twelfth, — Dr. C. B. E. Kennerly, Dr. J. S. Newberry, Dr. A. L. Heermann, Dr. J. G. 

 Cooper, and Dr. George Suckley. Nor should it be forgotten that numberless other col- 

 lectors and contributors, whose specimens are catalogued throughout the volume, brought 

 their hands to bear upon the erection of this grand monument. 



But what of the genius of this work 1 — for I have not measured my words in speak- 

 ing of Wilson and Audubon. Can any work be really great without that mysterious 

 quality ? Certainly not. This work is instinct with the genius of the times that saw 

 its birth. This work is the spirit of an epoch embodied. 



But here I must pause. jSIy little sketch is brought upon the threshold of contem- 

 poraneous history, — to the beginning of the Bairdian period, of the close of which, as 

 of the duration of the Bairdian epoch, it is not for me to speak. When the splendid 

 achievements of American ornithologists during the past quarter of a centur}' shall be 

 seen in historical perspective ; when the brilliant possibilities of our near future 

 shall have become the realizations of a past ; when the glowing names that went before 

 shall have fired another generation with a nolile zeal, a lofty purpose, and a generous 

 emulation — then, perhaps, the thread here dropped may be recovered by another hand. 



Yet a few words of Preface proper to the present work appear to be required. The 

 original edition of the "Key" was published in October, 1872, in an issue of about 

 2,200 copies. It was not stereotyped, and has been for some years entirely out of print. 

 It formed an imperial octavo of 361 pages, illustrated with 238 woodcuts in the text and 

 6 steel plates. It was designed as a manual or text-book of North American Ornithology. 

 To meet this design, the Introduction consisted of a general account of the external 

 characters of birds, an explanation of the technical terms used in describing them, and 

 soTne exposition of the leading principles of classification and nomenclature. An artificial 

 " key " or analysis of the genera, constructed upon a plan found practically useful in 

 botany, but seldom applied to zoology, was introduced, to enable one who had some 

 knowledge of the technical terms to refer a given specimen to its proper genus. Then, 

 in the body of the work, each species was briefly described, with indication of its 

 geographical distribution and references to several leading authorities. The families and 

 orders of North American birds were also characterized, and a synopsis of the fossil birds 

 was appended. The work introduced many decided changes in classification and nomen- 

 clature which the then state of the science seemed to require, and systematically recog- 

 nized a large number of those subspecies or geographical races which are now indicated 

 by the use of trinomial nomenclature, — a method now fully established and recognized 

 as peculiar to the " American school." The central idea of the treatise was to enable one 



