564 



NATURE 



[December 30, 1920 



the bottom of each page is excellent, but, Although 

 it is realised that a full bibliography is impos- 

 sible, fuller references to the more recent work, 

 especially in regard to the nervous system, would 

 have been a distinct advantage. 



The logical way in which the facts are put for- 

 ward, the short allusions to the history of the 

 subject and to comparative physiology, together 

 with a freedom from any attempt to compile a 

 book for examination purposes, will recommend it 

 to the purely scientific worker. 



Generally, the book is well written and produced, 

 but the language, which contains many Ameri- 

 canisms, leaves no doubt as to its nationality, and 

 does not enhance its literary value. The author 

 does not acknowledge any help in the preparation 

 of the volume, which rqust have entailed an enor- 

 mous amount of work. VVe congratulate Prof. 

 Burton-Opitz on its completion, and wish his ex- 

 cellent and ambitious text-book every success. 



Our Bookshelf. 



The Plantings Cultivation, and Expression of 

 Coconuts, Kernels, Cacao, and Edible Vege- 

 table Oils and Seeds of Commerce. A Practical 

 Handbook for Planters, Financiers, Scientists, 

 and Others. By H. Osman Newland. (Griffin's 

 Technological Handbooks.) Pp. vi 4- 1 1 1 -h xi 

 plates. (London : Charles Griffin and Co., Ltd., 

 igig.) Price 65. net. 

 Mr. Newlan'd scarcely gave himself a fair chance 

 when, to quote his introduction, he was "pre- 

 vailed upon to issue as a separate book the chap- 

 ters on 'Ground Nuts,' 'Palm Oil and Kernels,' 

 ' Cacao, ' and ' Shea Nuts, ' which originally 

 formed part of a volume on West Africa." In 

 doing this he has added chapters on coconuts and 

 other edible oil-nuts found throughout the Empire, 

 and has adopted for the whole a comprehensive 

 title, the promise of which it would require unusual 

 skill in compression to fulfil in a book of 1 1 1 not 

 very closely printed pages. Moreover, the space 

 at the author's disposal is not well distributed; 

 thus the important oil-seeds soya bean, cotton- 

 seed, and sesame are disposed of in one chapter 

 of seven pages, whilst an equal number of pages 

 are given to reprinting Imperial Institute reports 

 onstrephonema, n'gore, n'kamba, n'kula, kamoot. 

 and dika nuts. Interesting though these products 

 may be, they are not of commercial importance 

 at present, and reference to them is out of place 

 in a book of this description. The illustrations 

 are the best feature of the volume. T. .A. H. 



The Flora of Chepstow. By W. A. Shoolbred. 



Pp. X-M40. (London: Taylor and Francis, 



1920.) Price 10s. 6d. net. 

 Ix number and quality the local Floras of this 

 country probably excel those of any other, and 

 afford a satisfactory measure of the enthusiasm 

 with which systematic botany is pursued by 

 NO. 2670, VOL. 106] 



British naturalists, including a large number of 

 amateurs who are wholly free from any stigma of 

 superficiality. 



Indeed, the greatest authorities on the species 

 of the British flora are nearly all amateurs, very 

 few professional botanists, outside the great 

 museums, having either the time or the inclination 

 to devote themselves to this specialist study. 



Among these authorities Ur. Shoolbred holds 

 a place, and his " Flora of Chepstow " is a praise- 

 worthy addition to floristic literature. The area 

 of the lower Wye has long been a favourite hunt- 

 ing-ground among botanists, for its position and 

 topography give it an uncommon richness. 



While the author takes a thoroughly exclusive 

 view of the size of species, still, a list of 974 

 Angiosperms alone is pretty good for an area ot, 

 roughly, 65 square miles, now seriously threat- 

 ened by industrialism. 



The critical genera are fully treated, and Dr. 

 Shoolbred has had the advantage of assistance 

 from such men as Marshall and Ley in dealiig 

 with their many difficulties. Mosses are also in- 

 cluded, a feature worthy of further resuscitation. 



Electricity and Magnetism : Theoretical and Prac- 

 tical. By Dr. C. E. Ashford. Third edition. 

 Pp. xii-l-303. (London: Edward Arnold, 1920.) 

 Price 45. 6d. 



The chapter on Rontgen rays which has formed 

 a part of previous editions of this school text- 

 book has been replaced in the present edition by 

 one on the passage of electricity through gases. 

 In this some account is given of the broad 

 generalisations which have followed from the 

 work of Sir J. J. Thomson and his school, and 

 the application of these theories in the thermionic 

 valve. A few articles have been rewritten, and 

 an appendix on Ohm's law has been substituted 

 ^for the original description of apparatus. The 

 popularity and worth of this book are reflected in 

 the fact that it has been through the printers* 

 hands no fewer than thirteen times since the first 

 edition was published in 1903, and during that 

 period has been twice revised to meet new re- 

 quirements of theory and practice. 



A Text-book of Geology. By Philip Lake and 

 R. H. Rastall. Third' edition. Pp. xiv + 508-1- 

 xxxiii plates. (London : Edward Arnold, 1920.) 

 Price 215. net. 



A COMPLETE revision of this standard work has 

 been carried out since the first edition was re- 

 viewed in Nature for June 22, 191 1. The account 

 of coral reefs has been modified in accordance 

 with modern theories, the chapter on ore-deposits 

 has been rewritten, and sections on concretions, 

 petroleum, and natural gas have been added to 

 that on sedimentary rocks. In the stratigraphical 

 section of the book the account of the Carbon- 

 iferous system has been largely rewritten, and 

 Mr. Rastall has contributed a new chapter on the 

 history of igneous activity in the British Isles. 

 Numerous other minor alterations have also been 

 made. 



