June 25, 1897.] 



SCIENCE. 



997 



mind when accompanied by a weathering of the 

 rock, to be regarded as a secondary effect. 



All that Professor Merrill has to say regard- 

 ing the processes and products of weathering is 

 timely and important. From the difference in 

 kind of weathering in cold and warm climates, 

 a matter which has been studied by the geolo- 

 gists of India, it is pointed out that the study of 

 the sedimentary rocks may be made to furnish 

 a clue to past climates. It is to be regretted 

 that there is not a chapter on the application of 

 this principle to ancient rocks. The writings 

 of Pumpelly, the work of Willis, Hayes, Camp- 

 bell and others, together with the published 

 evidence of ancient periods of base-levelling 

 with peneplains and their complementary clastic 

 records, constitute a basis for an interesting and 

 valuable resum6. 



As an extension to the treatment of the sub- 

 ject of rock-weathering in standard text-books 

 on geology, this work can well be recommended 

 to the student. For the student of agriculture 

 and soil problems, it will probably give him as 

 much of geology as he needs to know for practi- 

 cal purposes. 



The book is well illustrated with diagrams 

 and photographic reproductions. The mechan- 

 ical execution of the book leaves nothing to be 

 desired. There is a fairly complete index of 

 authors cited and of subjects. 



j. b. woodworth. 



Haevaed XJniveesity. 



Bird Life ; A Guide to the Study of Our Common 

 Birds. By Frank M. Chapman. With 

 seventy-five full-page plates and numerous 

 ' text drawings by Ernest Seton Thompson. 

 New York, D. Appleton & Co. 1897. 12mo. , 

 cloth, pp. xii + 269. $1.75. 

 Confessedly addressed to the uninitiated 

 rather than to the scientific ornithologist, this 

 little volume nevertheless possesses an attraction 

 for anyone interested in birds. The author ap- 

 parently aims to present his subject in such a 

 manner as to aid and incite further study and 

 observation, the numerous footnote references 

 in the first part of the book rendering the litera- 

 ture on the various subjects easily available. 

 The whole is pleasantly written, and in lan- 

 guage sufficiently untechuical to be easily com- 



prehended. The first seventy-three images treat 

 of birds in general ; the rest contain accounts of 

 more than a hundred common Eastern species. 

 The opening chapter briefiy outlines the place 

 of birds in nature, first with reference to their 

 taxonomic position and phj'logeny ; then with 

 reference to their relations to man, as profit- 

 able objects for scientific study, as valuable and 

 efficient aids of the agriculturalist and as beings 

 that appeal strongly to the resthetic emotions. 

 Under another caption are discussed the ' Fac- 

 tors of Evolution,' this being succeeded by an 

 enumeration of the principal forms, variations 

 and uses of the wing, the tail, the feet and the 

 bill, illustrated by numerous text figures. In a 

 chapter on the 'Colors of Birds' are detailed the 

 changes and difierences in colors due to age, 

 season, molt, food, climate, haunts, habit and 

 sex. Migration forms the subject of Chapter 

 IV., and is discussed with regard to extent, 

 manner and origin. This is followed by a 

 short treatise on the ' Voice of Birds, ' attention 

 being called to both song and call notes. Under 

 the next heading, 'The Nesting Season,' the 

 value of observations during the breeding sea- 

 son is emphasized, and the time of nesting, 

 mating, the details of nest and eggs and the 

 care of the young, each in turn receive atten- 

 tion. Instructions on ' How to Identify Birds,' 

 with suggestions upon points for obsei'vation, 

 are also added, together with a field key to 

 common land birds of the eastern United States, 

 this taken, with additions and alterations, from 

 the author's 'Handbook of Birds of Eastern 

 North America.' 



In the remaining portion of the book particu- 

 lar attention is devoted to some 125 species, these 

 little biographies ranging from a few lines to 

 nearly a page and a half, with usually a short 

 account of the family to which each belongs. A 

 number of other birds are incidentally noticed. 



The 75 full-page plates with which the vol- 

 ume is adorned figure 99 species. In praise of 

 their artistic finish, fidelity of form and minute- 

 ness of detail much might be said, and, though 

 all are not of equal excellence, we are inclined 

 to consider as not extravagant Mr. Chapman's 

 claim that for beauty and accuracy these, as a 

 whole, excel any black and white bird drawings 

 that have ever been published in this country. 



