Fbbbuaey 7, 1902.] 



SCIENCE. 



225 



The author states his conviction that ahnost 

 the whole of the variations observed by mag- 

 netometers are due to earth-currents which 

 act upon the instruments as upon galvanom- 

 eters. An immense amount of patience and 

 skill has been devoted to the compilation of 

 results, and it must be admitted that the evi- 

 dence is favorable to this theory. As a work- 

 ing hypothesis it may be found of great value ; 

 but our knowledge of the phenomena, and par- 

 ticularly the mass of actual observations, 

 must be vastly extended before we can finally 

 accept the solution as a physical fact. 



W. G. Cady. 



U. S. Coast and Geodetic Subvey, 



Magnetic Observatory, Cheltenham, Md., 

 December 21, 1901. 



The Birds of North and Middle America: A 

 Descriptive Catalogue of the Higher Groups, 

 Genera, Species and Subspecies of Birds 

 known to occur in North America, from the 

 Arctic Lands to the Istlimus of Panama, the 

 West Indies and other Islands of the Carib- 

 bean Sea, and the Galapagos Archipelago. 

 By Egbert Eidgway, Curator, Division of 

 Birds, U. S. National Museum. Part I. 

 Family Fringillidse — The Finches. Wash- 

 ington, Government Printing Office. 1901. 

 Bulletin of the United States National 

 Museum, No. 50. 8vo. Pp. xxxii -1- 715, 

 pis. 20. 



The geographical scope and general charac- 

 ter of this important work is well indicated by 

 the above transcript of the title-page, which- 

 does not, however, give an adequate idea of the 

 amount of labor involved in its preparation, 

 which has largely engaged the author's atten- 

 tion for the last twenty years, and for the last 

 six years has occupied the greater part of his 

 time. The present volume is the first of the 

 series of eight required to complete the work, 

 averaging about 800 pages and some twenty 

 plates to each volume. As much of the drudg- 

 ery of collating references, and taking meas- 

 urements, for the 3,000 species and subspecies 

 comprised in the work, has been mostly com- 

 pleted, it is expected that the publication of 

 the remaining volumes will proceed with little 

 further delay. 



The present volume treats only of the single 

 family Fringillidas, or Finches, which number 

 389 species and subspecies, of which about one- 

 half occur in North America, the rest being 

 exclusively birds of 'Middle' America. The 

 introductory matter comprises an appropriate 

 dedication to the late Professor Baird, followed 

 by a preface of seven pages, stating the prin- 

 ciples that have guided the author in his 

 work, with other explanatory matter. The 

 author has to regret the necessity of beginning 

 his work with the highest instead of the lowest 

 forms, owing to the lack of adequate facilities 

 for arranging the collection of birds in the 

 National Museum, the larger birds being inac- 

 cessible for study. This state of affairs has ex- 

 isted for some ten to fifteen years, greatly to 

 the regret and inconvenience of many orni- 

 thologists besides the curator, and affords a 

 striking commentary on the neglect by the 

 government of our great but inadequately 

 housed National Museum. 



The first twenty-five pages of the main text 

 are devoted to a critical consideration of the 

 classification of the class Aves, with diagnoses 

 and keys for all the higher groups, and for the 

 families of the Oscines. His system is ad- 

 mittedly eclectic, but is on the whole a quite 

 satisfactory compromise. The Fringillidse, as 

 defined by Mr. Eidgway, embrace several finch- 

 like genera usually referred to the Tanagridae, 

 but which seem to fit better as members of the 

 Fringillidae ; yet, with these transfers, there is 

 still no hard and fast line of division between 

 the two groups. 



Mr. Eidgway's work is strictly systematic 

 and technical. Aside from the descriptions of 

 the forms, the elaborate keys, and the state- 

 ments of range, a special feature is the very 

 full bibliographical citations, which constitute 

 a large part of the text, and include all refer- 

 ences of any value, thus forming an index to 

 the literature of each species. The locality to 

 which a citation relates is stated whenever pos- 

 sible, thus greatly facilitating the labors 

 of future workers. In compiling the refer- 

 ences extreme exactness has been attempted in 

 all matters of orthography and nomenclatural 

 combinations — a feature often neglected, but 

 of the highest importance. As Mr. Eidgway 



