542 



NA TURE 



[September 26, 1907 



the colour scheme, giving crepuscular and storm 

 ejects — where none are intended — to many of the 

 landscapes, as plates 2 and 4. In the case of illustra- 

 tions showing figures, the tone of the whole group 

 may be so lowered that people, houses and utensils 

 show up in scarcely differentiated tints of brown 

 against a sky for the colour of which the writer 

 knows no warrant (illustration 19). 



But there are also many charming and realistic 

 pictures, such as plates 3 and 33, though in the last 

 the excellence of the drawing and colouring of the 

 canoe and the figures seated therein is perhaps some- 

 what discounted by the excess of grey and brown in 

 the landscape. 



Plate 16 may be picked out for special praise. It 

 gives a very real impression of the Rigo dubu, seen 

 at midday, when the glare of the sun lightens the 

 grey of its weather-beaten posts and renders the 

 yellowish soil on which it stands almost white. 



In spite, then, of defects of the kind mentioned, the 

 illustrations of this book give a better idea of 

 Melanesia than can be obtained by photographs or 

 black and white drawings, and so the work must be 

 pronounced a success. Mr. Hardy is also to be con- 

 gratulated on the accuracy of his observation, for in 

 so few instances are there ethnographical inaccuracies 

 in the plates or their accompanying short descriptions 

 that it may be useful to point out the chief of these 

 in as far as they affect New Guinea. Probably no girl 

 ever danced her way to " the dubu dance " flirting her 

 petticoats the while, as is shown in the frontispiece. 

 Kaivakuku masks do not exist among the Roro 

 tribe, though they occur among the Waima and 

 Kevori, both Roro-speaking tribes. The feather 

 head-dresses of the girls (illustrations 14 and 15) are 

 distinctly yellowish, not red as shown in the plates; 

 indeed, red feathers are carefully excluded from this 

 dancing head-dress, the parrots providing the 

 feathers being subjected to special treatment in order 

 that their feathers may be of the desired colour. 



In this book the illustrations so far exceed the 

 text in importance and quality that little need be 

 said concerning the latter, which contains many in- 

 accuracies and misprints, is written in poor English, 

 and generally falls far below the level of other 

 volumes contained in this series. C. G. S. 



A Text-hook on Hydraulics, including an Outline of 



the Theory of Turbines. By Prof. L. M. Hoskins. 



Pp. V+271. (London: Archibald Constable and 



Co., Ltd., 1907.) Price los. 6d. net. 

 This book is intended for the instruction of engineering 

 students during their university or college course who 

 have already acquired a good practical knowledge of 

 pure mathematics, and possess a fair elementary ac- 

 quaintance with the principles of mechanics. After a 

 short introductory chapter dealing with definitions and 

 principles, followed by a chapter on hydrostatics, the 

 flow of water through orifices under "different condi- 

 tions is considered, and Torricelli's theorem is stated, 

 and instances of its application explained. Bernoulli's 

 theorem, which the author calls the general equation 

 of energy, and upon which he bases his explanations 

 of the problems of the steady flow of liquids, and its 

 •applications, form the subject of the next four 

 chapters. Various formulas for the flow of water in 

 pipes under definite conditions are then deduced from 

 the general equation of energy; whilst a separate 

 chapter is devoted to a discussion of the methods of 

 estimating the frictional loss of head in pipes. 



In treating of uniform flow in open channels, the 



author, after referring to Ch^zy's formula, v = c^/rs, 



as the basis for calculating the mean velocity, and 



alludmg to Bazin's experiments for determining the 



NO. 1978, VOL. 76I 



inlluence of the nature of the surface and the shape 

 of the channel in modifying c, deals fully with the 

 well-known, general, empirical formula for c deduced 

 by Ganguillet and Kutter from the measurements of 

 flow in a wide range of channels, which is a function 

 of the slope, the hydraulic radius, and a coefficient of 

 roughness depending on the nature of the surface of 

 the channel. To facilitate the adoption of this com- 

 plex formula, a table is given of the values of c com- 

 puted for a certain range of conditions, and also a 

 graphic diagram from which they can be obtained by 

 measurement. The more complicated question of 

 non-uniform flow in ojjen channels is next discussed, 

 deduced in the first instance from the general equa- 

 tion of energy for streams of variable cross-section ; 

 and the portion relating to hydraulics is concluded by 

 a consideration of the different methods, direct and 

 indirect, by which the discharge of streams differing 

 greatly in volume can be measured. 



The theory of turbines forms the subject of the last 

 seven chapters of the book, under the respective head- 

 ings dynamic action of streams, theory of steady 

 flow through rotating wheel, types of turbines and 

 water wheels, theory of the impulse turbine, and of 

 the reaction turbine, the tangential water wheel, and 

 turbine pumps. The book terminates with three 

 appendices, in which the general equation of energy 

 is applied to the steady flow of gases, relative motion 

 is explained, and tables of conversion factors are 

 given. The subjects dealt with are elucidated by one 

 hundred and thirty-seven simple diagrams in the text, 

 and examples are added in almost every chapter relat- 

 ing to its contents, for the student to work out, to 

 which the answers are appended. This book will be 

 valuable in training engineering students possessing a 

 fair knowledge of mathematics to solve any problems 

 in hydraulics they are likely to meet with in practice, 

 and it will also furnish them with an insight into the 

 principles on which the working and efficiency of tur- 

 bines are based. 



Flora oj Sussex, or a List of Floivering Plants and 

 Ferns found in the County of Sussex. By Rev. 

 F. H. Arnold. Pp. xxii+154. (London: Simpkin, 

 Marshall and Co., Ltd.; Arundel and Horsham: 

 Mitchell and Co, 1907.) Price 5s. net. 

 This is a new and revised edition of the flora, includ- 

 ing phanerogams, pteridophytes, and Characeae, 

 brought out by the author in 1887. The principal 

 changes will be found in the additions to the species 

 and many new localities. The introduction is not 

 altered except for the increase in the list of contribu- 

 tors, to which are added the names of Mr. C. E. 

 Salmon, Mr. W. Whitwell, Rev. E. Ellman, and Rev. 

 E. S. Marshall. The last-named has been a most 

 energetic worker, especially in West Sussex, and 

 several of the new species were first discovered by 

 him. A complete revision will be noted for the species 

 of Rubus, for which the localities are provided chiefly 

 on the authority of Messrs. Salmon, Marshall, and 

 Rogers, and also a revision of the genus Salicornia. 

 -Among the species added to the county list are 

 Epilobiuni Lainvi, Wolffia arrhiza, Utricularia neglecta. 

 Chenopodium botryoides, Spartina To-wnsendi, and 

 Spariina altcrniflora, first found by the author. Most 

 of these species were previously known from adjacent 

 counties, as noted in the appendix, where the list has 

 escaped revision. The author was not fated to see the 

 publication of this book, which will be welcomed by all 

 systematic botanists sojourning in Sussex ; a note 

 saying that he dictated the preface on the very day 

 that he was taken ill is added by his daughter, who 

 has also prepared the three illustrations which are 

 included. 



