January 7, 1892] 



NATURE 



volume shows that the last hundred pages include the more 

 important part, we will first deal with chapters v. to viii. 



Beginning with a sketch of the dependence of man on 

 his environment, the author proceeds to an account of the 

 effect of environment on the development of various races. 

 To the English reader one of the most interesting parts 

 of chapter v. will be the account of the effect of the 

 isolation and other physical peculiarities of Britain on 

 the development of the English race. 



In chapter vi. the author more especially deals with the 

 dependence of the native races of North America on geo- 

 graphical and climatic conditions. This section leads by 

 a natural transition to the competition between the white 

 colonists and the Indians, and to the effect of barriers 

 and strongholds in retarding or helping the gradual 

 spread of the white races in North America. 



Chapter vii. deals mainly with the relation of man to 

 soils and climate, with the introduction of the negro race, 

 and with the extent to which the negro and the white 

 races are likely to compete. 



In chapter viii., Prof. Shaler turns to the sparsely in- 

 habited regions west of the Mississippi, and here he 

 treats mainly of the capabilities for settlement of tracts 

 still untried by white men. He speaks of the climatic 

 conditions, of the probable value of the soils, of the re- 

 clamation of the arid regions by irrigation, and of the 

 probable fitness of the Western States for permanent 

 settlement by men of Aryan race : he concludes that this 

 part of America is capable of sustaining an enormous 

 population, and that white men can thrive in most parts 

 of it. 



To those who have not read Prof. Shaler's articles in 

 Scrihier's Magazine, we can recommend the last four 

 chapters of his book as giving an interesting and readable 

 account of man's relation to Nature in North America. 

 The first four chapters we cannot praise : they seem to 

 be largely made up of miscellaneous notes hastily put 

 together with little arrangement and without careful re- 

 vision ; they swell the bulk of the volume, but bear only 

 remotely on the relation between Nature and man in North 

 America. 



Chapter i. treats mainly of the zoological and botanical 

 provinces of the present day, and their dependence on 

 physical barriers and on climate. These pages are full of 

 interspersed suggestions as to what might have been if 

 conditions had been different, but some of these sugges- 

 tions do not seem to have been carefully thought out, and 

 sometimes the author adopts irreconcilable views in 

 other parts of the same volume. We find, for instance, 

 numerous speculations as to the effect that would be pro- 

 duced by the diversion of the Gulf Stream, and, among 

 others, the following passage, in which, after speaking of 

 the lowering of the initial velocity that would follow from 

 a submergence of the peninsula of Florida, the author 

 observes (p. 21) : — 



" It is mainly, if not altogether, to this initial velocity 

 that we owe the efficiency of the Gulf Stream as a warmth- 

 bringing current in high latitudes." 



But on p. 129 we read : — 



" It is a well-known fact that our oceanic streams are, 

 in the main at least, a consequent of the movement which 

 the air has in the trade-winds of the tropical district." 



NO. I 158, VOL. 45] 



The author apparently does not observe that if the 

 trade-winds are the main cause of the equatorial current, 

 it is probable that the persistent south-westerly winds of 

 the North Atlantic may also have much to do with the 

 ocean current which follows the same course. 



In chapter ii.. Prof. Shaler speaks of the nature apd 

 origin of continents, development of life, mountain 

 growth, saltness of the sea, &c. ; and in chapter iii., of 

 the permanence of continents, including a sketch of the 

 position of the shore-lines from pre-Cambrian times to the 

 Glacial epoch. Chapter iv. deals with a great variety of 

 subjects, such as the condition of the faunas and florae in 

 Cambrian time, CroU's theory of the origin of coal- 

 measures, conditions of continental growth in Europe, 

 uniformity in past time of the composition of the atmo- 

 sphere, and variations in the Gulf Stream. 



Prof. Shaler, in his first four chapters, deals so largely 

 with questions relating to the geographical distribution 

 of animals and plants, that it surprises us to find a good 

 many statements which more care in revision would 

 certainly not have allowed to pass. Thus, speaking of 

 local forms that must be developed through the long- 

 continued competition of different assemblages brought 

 into close proximity in a mountainous district, the author 

 remarks (p. 27) that : — 



" In a continent such as Europe, where a great diversity 

 in the mountain systems favours the localization of life 

 and the development of peculiar forms, the tendency is 

 to develop in separate mountain strongholds particular 

 species, and evolve their militant peculiarities until the 

 forms are fitted to enter into a larger contention with 

 their kindred species in less localized assemblages of 

 life." 



The example is most unfortunately chosen, for of all 

 the continents Europe least illustrates the process ; one 

 would have thought that no naturalist would have brought 

 forward the Europe of the present day as a good illus- 

 tration of the differentiation ot species on mountains and 

 in isolated valleys. Our Alpine flora and fauna, instead 

 of varying greatly on the different chains, are more 

 remarkable for their uniformity over all the continent. 

 Our valleys seldom, if ever, contain plants and animals 

 of local origin, for the Glacial epoch is of too recent a 

 date for many local forms to be developed, and has 

 affected Europe too seriously to allow many pre-glacial 

 forms to survive in their original limited stations. Had 

 Prof. Shaler pointed to the mountains of sub-tropical 

 and tropical America, with their local species of humming- 

 birds, we should not have objected. We have marked 

 many other equally questionable statements, which it 

 is surprising to find made on the authority of Prof. 

 Shaler. 



The occurrence of various statements of doubtful 

 accuracy, the debatable character of much of the 

 evidence, and the complicated nature of the questions 

 dealt with, make us hesitate to endorse the author's 

 opinion that this book " is particularly designed for 

 the use of beginners in the study of geology." Specu- 

 lations as to what might have been if conditions had 

 been different are scarcely suitable for the beginner in 

 any branch of natural science. The skilled naturalist or 

 geologist, able to discriminate, may obtain useful hints 

 from the present volume. C. R. 



