April 26, 1888] 



NATURE 



60 



most severe critic must admit that the style, without being 

 in the least laboured, is far superior to that of the ordinary 

 writer on natural history, and the book is consequently 

 in the highest degree readable. Many a Wiltshire man, 

 woman, and child will have reason to be grateful to Mr. 

 Alfred Charles Smith. 



A HAND-BOOK FOR TRA VELLERS. 

 Fiihrerfur Forschutigsreisende. Anleitungen zu Beobacht- 



ungen iiber Gegenstdtide der physischen Geographie wid 



Geologic. Von Ferdinand Freiherr von Richthofen. 



(Berlin: Oppenheim, 1886.) 

 TT is now thirteen years since Dr. Neumayer issued his 

 J- "Anleitung zu wissenschaftlichen Beobachtungen 

 auf Reisen," a joint production of himself and repre- 

 sentatives of various departments of science, the geo- 

 logical section having been contributed by the present 

 author. The volume now under consideration is virtually 

 an enlarged and completely revised edition of that 

 section, which it seemed desirable to publish separately. 

 A re-issue of the complete work is, however, in con- 

 templation. The qualifications which Von Richthofen 

 possesses for the task he has undertaken are of no com- 

 mon order. Himself a traveller of wide experience, 

 whose work on China deservedly ranks as one of the 

 classics of geographical literature, he brings to bear upon 

 his subject a wealth of practical knowledge combined 

 with scientific attainment, in which few are his equals. 



In the preface it is explained that the primary object of 

 the work is to enable those travellers whose previous 

 scientific training is not extensive, such as missionaries, 

 merchants, and others, who may be thrown in regions 

 but little explored, to make observations which shall be 

 of permanent value. Under these circumstances, no 

 attempt is made to furnish the reader with references to 

 the literature of the subject which would almost certainly 

 be inaccessible to him, although notice is taken here and 

 there of modern treatises on particular questions. The 

 body of the work opens by an introduction, the scope of 

 which may best be indicated in a general way by stating 

 that it contains such headings as " Outfit," " Modes of 

 Travelling," and "Miscellaneous Practical Hints." These 

 last are especially valuable, and might with advantage be 

 carefully studied by anyone who is starting on a first 

 expedition, on account of their eminently suggestive and 

 practical character. The emphasis laid upon the neces- 

 sity of noting all observations on the spot, and even upon 

 such minutiae as having the pencil suspended round the 

 neck so as to be always ready, indicates an experience of 

 the temptations to procrastination which beset travellers 

 in common with humanity at large. Among other divi- 

 sions of this section may be mentioned " Measuring and 

 Drawing," in which sufficient directions are given for 

 mapping unexplored countries in a preliminary fashion, 

 and also " Climatic and Biological Observations," the 

 latter of which are treated with extreme brevity, as not 

 falling within the author's special province. 



The next portion of the book is entitled "Observations 

 upon Externally Modifying Processes," and includes 

 chapters upon rocks and soils, on springs and flowing 

 water. It contains a dissertation of some length on the 

 important subject of glaciers, in which the phenomena 

 accompanying their present existence, as well as the 



traces of their past actfon, are carefully described. In 

 another chapter an abstract is given of the present state 

 of our knowledge regarding coral reefs and islands. In 

 addition to the time-honoured theory of Darwin, the 

 most recent researches of Semper, Rein, Murray, and 

 Studer are summarized ; one misses, however, the name 

 of Agassiz in this connection, and it is noticeable that, 

 although Dana's soundings off Tahiti are quoted in some 

 detail, no mention is made of the series executed by the 

 Challenger, although their results agree well with the 

 author's diagrammatic section of a reef No one theory 

 is embraced to the exclusion of all others, but stress is 

 laid upon the need for further investigation, and upon the 

 fact that " each reef has its own special history of origin 

 and development." Upraised coral reefs are indicated 

 as being likely to throw light on the question— a sug- 

 gestion which has been independently canied out by 

 Dr. Guppy in the Solomon Islands with such brilliant 

 results. A few pages give what is known regarding the 

 changes of level of the ocean, and the terms " positive " 

 and "negative displacement" are adopted instead of 

 "■ sinking " and " upheaval '' of the land respectively. 



The third section is devoted to " Observations on the 

 Crust of the Earth, on Rocks, and on Mountain Struc- 

 ture." It contains an outline of the principal facts 

 of petrology and of stratigraphical geology. 



The author treats his subject in considerable detail ; 

 his volume occupies more than 700 pages— that is, a some- 

 what larger bulk than the whole of Neumayer's original 

 work. Indeed, if a fault is to be found in the book, we 

 should be disposed to say that, considering the fact that 

 only one aspect of Nature is discussed, the amount ot 

 detail is rather excessive. If botany, zoology, anthropo- 

 logy, and all the other matters which have an equal 

 claim upon the traveller's attention, were elaborated in 

 the same fashion, the result would be an encyclopaedia of 

 no small dimensions. The work is, however, thoroughly 

 practical in character. There are no lengthened discus- 

 sions upon abstract questions, but divergent theories 

 regarding unsettled points are summarized in such a way 

 as to indicate how both the traveller who has time at his 

 disposal, and also he who is compelled to hasten through 

 the country, can each make the best use of their respective 

 opportunities. W. E. H. 



OUR BOOK SHELF. 



Geometry in Space. Edited by R. C. J. Nixon, M.A. 

 " Clarendon Press Series." (London: Henry Frowde, 



1888.) 



This book is a sequel to " Euclid Revised " by the same 

 author. It consists of one hundred pages, divided into 

 three chapters and an appendix. The first chapter is 

 devoted to the discussion of planes and solid angles, cover- 

 ing much the same ground as Euclid's eleventh book ; it 

 contains, besides, some very useful notes on elementary 

 perspective and the drawing of solid figures. This is an 

 excellent feature of the book, and the author might with 

 advantage have given more than a couple of pages to it, 

 for there is no doubt that, to most students, the representa- 

 tion of solid figures, other than the simplest, is a real and 

 often a permanent stumbling-block to the development of 

 the science in their own minds. The second chapter 

 is concerned with polyhedra. It begins with Euler's 

 theorem establishing a linear relation between the 

 numbers of edges, corners, and faces, and Listing's 



