146 



NA TURE 



[June 18, 1896 



Without tlie establishment of some base, any system of 

 numbers is impossible. A binary system is characteristic 

 of Australia, but it occurs elsewhere ; instances of qua- 

 ternary numeration are less rare than are those of 

 ternary, and there is reason to believe that this method of 

 counting has been practised more extensively than any 

 other, except the binary and the three natural methods — 

 the quinary, the decimal, and the vigesimal. There is 

 probably no recorded instance of a number system formed 

 on 6, 7, 8, or 9 as a base. 



In its ordinary development the quinary system is 

 almost sure to merge into either the decimal or the 

 vigesimal system, and to form with one or the other, or 

 both of these, a mixed system of counting. Whether or 

 not the principal number base of any tribe is to be 20, 

 seems to depend entirely upon a single consideration — 

 are the fingers alone used as an aid to counting, or are 

 both fingers and toes used? If the former, the resulting 

 scale must become decimal. The quinary is never the 

 principal base in any e.xtended system. The Celtic races 

 showed a preference for counting by twenties, which is 

 almost as decided as that manifested by the Teutonic 

 races for counting by tens. 



With such a vast field from which to collect materials 

 for his study, it is inevitable that Prof. Conant should 

 have overlooked some authors who might have furnished 

 him with additional examples, and that he should have 

 made a few slips. Among the omissions may be noted 

 Dr. Von den Steinen's discussion on the numeration of 

 the BakaTri in his " Unter den Naturvblkern Zentral- 

 Brasiliens," Mr. Ray's studies in the languages of New 

 Guinea, Mr. H. Clifford's account of the Negritos of the 

 Malay Peninsula (/. Roy. As. Soc. Straits Br., 1892), Dr. S. 

 Giinther's study on numerical systems {Beitr. Anth. 

 Urgcsch. Bayi-rns, 1890, ix.). On p. 96 the Torres Islands 

 in the New Hebrides are confused with Torres Straits, and 

 the languages of Darnley Island (p. 24) and Warrior Island 

 (p. 107) are Papuan (Torres Straits), and not Australian 

 dialects. Anthropologists would have been thankful if 

 the ethnological aspect of the question had been dwelt 

 upon a little more fully ; for example, the ethnologist is 

 not at a loss to account for the superior development of 

 the number sense in the Nicobarese as compared with 

 that of the neighbouring Andamanese. The book is 

 admirably printed, and is packed with valuable informa- 

 tion clearly and logically arranged. 



A. C. H.ADDON. 



GEOMORPHOGENY. 

 Logons lie Geographic physique. Par Albert de Lap- 

 parent. Pp. xvi. + 590. Illustrations. (Paris : 

 Masson et Cie., 1896.) 

 T F Prof de Lapparent had been writing in .America, 

 -*- he would have introduced the word Geoinorphogcny 

 in the title of his latest book ; but in Europe, he observes 

 in the preface, there is some risk of frightening those 

 whom he would wish to instruct if they are confronted 

 by an unfamiliar term at the outset The title " Lessons 

 in Physical Geography," although quite without terror, 

 is not fairly descriptive, for this fine volume is no 

 ordinary treatise of physical geography in the usual 

 NO. 1390, VOL. 54] 



vague sense. "Lessons on the Genesis of Geographical 

 Forms" would, in the author's view, and in ours, be 

 more descriptive ; but the full scope of the work would, 

 perhaps, hardly be suggested exen by such a title. 



Whatever he may call it, a book by Prof, de Lapparent 

 is sure of a cordial reception by students and men of 

 science in all parts of the world, for he combines the 

 traditional grace and charm of French scientific writers 

 with a temperateness of judgment and width of view 

 which, rightly or wrongly, foreigners do not always 

 associate with the writings of his countrymen. The 

 avott-ed object of the work is to furnish a body of doc- 

 trines, logically linked together, which shall help to place 

 geography on a truly rational basis. This basis is, in 

 Prof de Lapparent's opinion, a geological one, for he 

 argues that the knowledge of no geographical form can 

 be complete unless its antecedent conditions are known, 

 and in geology alone can the clue to these be found. 

 We might perhaps demand an even deeper foundation 

 than geology, by taking into account the relations of 

 form and position and the means of determining these 

 mathematical conditions by astronomical observations : 

 but geology may be freely accepted as the layer in the 

 pyramid of geographical science which comes imme- 

 diately below physical geography, and is most indissolubly 

 connected with it. 



The volume takes the form of twenty-five "lessons" 

 or chapters ; but it may be divided into two parts, 

 approximately equal in bulk — the enunciation of the 

 genera! principles of geomorphogeny, and the application 

 of these to the configuration and structure of each of the 

 continents. The great lines of terrestrial relief are first 

 outlined, and the conditions of land-modelling are then 

 discussed in fuller detail and with a more comprehen- 

 sive grasp than in any other book of the kind with 

 which we are acquainted. The \arious agencies at work 

 on the land-surface are treated in turn, and their action 

 illustrated by a great wealth of instances. The normal 

 course of erosion in a region is first explained, and the 

 various complications introduced by structural conditions, 

 classed as genetic and tectonic, are then introduced. 

 Genetic conditions are those produced by the original 

 formation of the portion of land under consideration, 

 e.g. whether sedimentary, igneous, or glacial ; tectonic 

 are those subsequently produced by movements of the 

 crust. Considering the predominant part played in the 

 modelling of the land by running water, it is natural 

 that several lessons should be devoted to this agency, in 

 the discussion of which a prominent place is given to the 

 view of the cycle of erosion so vigorously set forth of 

 recent years by Prof W. M. Davis, of Harvard. One 

 can hardly say of any part of this theory that it is new. 

 Geologists have worked so long at the phenomena of 

 erosion, that it is now ditificult to fit each stage of the 

 process with the name of the first observer or theoriser. 

 But there is no doubt that, however universally the 

 knowledge of the processes of the origm of scenery by 

 denudation were known, the credit for expressing the 

 nett result of them in terse and appropriate language is 

 due to Prof Davis, and his mode of statement is 

 accepted by Prof de Lapparent with full acknowledg- 

 ment. The conception of the origin of surface features 

 through a process of evolution, a continuous succession 



