370 



NA TURE 



[March 23, 1922 



there given (1452° and 1755°) have since been almost 

 universally accepted. Also, in view of the thorough 

 work of Prof. Callendar on the specific heat of water, 

 it is somewhat surprising to find that the values 

 given are " the mean of various determinations, 

 including Calendar and Blonsfield, 1912 " ; one 

 frequently observes that the names of observers are 

 misspelt as in this quotation. 



It is hoped that before the next edition is issued 

 the various sections will be submitted to expert 

 scrutiny, for the value of the book would be greatly 

 enhanced if the user could feel sure that the most 

 trustworthy data are quoted. E. Griffiths. 



Our Bookshelf. 



Illustrations of the Flowering Plants and Ferns of the 

 Falkland Islands. By Mrs. E. F. Vallentin. With 

 descriptions by Mrs. E. M. Cotton. Pp. xii + 64 

 plates + text + ii. (London : L. Reeve and Co., Ltd., 

 192 1.) 845. net. 



Since the publication of Sir J. D. Hooker's " Flora 

 Antarctica " much progress has been made in the study 

 of the Falkland flora and from a taxonomic standpoint 

 it may now be said to be well known. Neveitheless, a 

 well-illustrated compact flora has been a desideratum 

 and it is thus additionally unfortunate that owing to 

 a serious breakdown in health the completion of Mrs. 

 Vallentin's work has been indefinitely postponed. The 

 volume now under notice contains 64 plates illustrating 

 in colour, and with excellent dissections, many of the 

 most characteristic Falkland plants. Each plate is 

 accompanied by a short description of the family, 

 genus and species. It seems a pity that with the space 

 available fuller descriptions and more detailed ecological 

 notes have not been provided. The repetition of the 

 description of the family appears to be unnecessary; 

 thus the same diagnosis of the Compositae is repeated 

 eleven times. 



The work as a whole illustrates many of the essential 

 features of the Falkland Islands flora. The predomin- 

 ance of dwarf herbaceous and subshrubby perennials, 

 especially characteristic of steppe and heath forma- 

 tions, is emphasised both by the plants chosen for 

 illustration and by the small number of therophytes 

 and the absence of phanerophytes, except for a few 

 nanophanerophy tes . 



We have no doubt that this work will prove most 

 useful to inhabitants of the Falkland Islands who take 

 an interest in the natural history of their country by 

 enabling them to identify easily many of the common 

 plants around them, and that it will also be used in a 

 more general manner by workers in systematic and 

 geographical botany in other countries. 



W. B. TURRILL. 



The Microscope : Its Design, Construction and Applica- 

 tions. A Symposium and General Discussion by many 

 Authorities. Edited by F. S. Spiers. Pp. v + 260 

 + plates. (London : Charles Grifiin and Co., Ltd., 

 1920.) Price 21s. net. 

 The addresses and papers given in 1920 at the con- 

 joined meeting of the Faraday, Royal Microscopical, 



NO. 2734, VOL. 109] 



Optical and Photomicrographic Societies and Technical 

 Optics Committee of the British Science Guild are 

 gathered together conveniently in the volume under 

 notice. All the papers are by specialists in their 

 respective branches and the whole constitutes a valu- 

 able contribution to microscopical science. The Presi- 

 dent, Sir Robert Hadfield, in his introductory address 

 traced the history of the development of the micro- 

 scope, and papers on the earliest steps in the invention 

 of the microscope and on the history and design of 

 photomicrographic apparatus are contributed by Dr. 

 Singer and Mr. Martin Duncan respectively. The 

 future of the microscope is dealt with in suggestive 

 papers by Mr. Barnard and Mr. Schneider, while Profs. 

 Cheshire, Conrady and Porter discuss the mechanical 

 design and optics of the instrument. Many experts in 

 their particular subjects give practical details on the 

 application of the microscope in fermentation industries, 

 in petrology, metallurgy, engineering and metrology. 

 Methods of illumination, the testing of objectives, and 

 optical glass and its manufacture are other subjects 

 dealt with. In addition to the papers themselves, a 

 summary of the discussions following their reading is 

 included and the volume is illustrated with many 

 plates and figures. The work, which has been ably 

 edited by Mr. Spiers of the Faraday Society, is indis- 

 pensable to any one desiring to follow the trend of the 

 modern developments of the microscope and of micro- 

 scopical science. R. T. H. 



Introduction to the Study of Minerals and Guide to the 

 Mineral Collections in Kelvingrove Museum. By 

 Prof. P. MacNair. Second edition. Pp. viii + 94 + i 

 plate. (Glasgow : Hay Nisbet and Co., Ltd., 1921.) 



IS. 



Prof. MacNair is to be congratulated on having intro- 

 duced many improvements in the second edition of his 

 useful guide-book. The figures illustrating the crystal- 

 forms are much more accurate than those published in 

 the first edition, though there arf» still a- few which 

 should have been replaced. The part dealing with 

 crystallography has been much increased and the 

 systems have been subdivided into groups, the intro- 

 duction of which in place of the classes of the accepted 

 systems of crystallography is rather confusing. 



The guide includes a clear account of the optical and 

 other properties of minerals, a description of some of 

 the commoner species, a glossary of terms, and a list 

 of species in the collection. The book is based very 

 much on the lines of Fletcher's " An Introduction to the 

 Study of Minerals," of which the fifteenth edition is 

 still used as the guide to the Mineral Department of the 

 British Museum (Natural History). It will be noted 

 that Prof. MacNair in Glasgow has produced his book 

 at sixpence less than the price of the British Museum 

 Guide. 



The Secrets of the Self. (Asrdr-I Khudi.) A Philo- 

 sophical Poem. By Sheikh Muhammad Iqbal. 

 Translated from the Original Persian with Intro 

 duction and Notes by Dr. R. A. Nicholson. Pp. 

 xxxi-i-147. (London: Macmillan and Co., Ltd., 

 1920.) Price 75. dd. net. 

 This poem has an interest beyond that of its artistic 

 form or aesthetic content, for it reveals the effect on the 

 oriental mind of contact with the culture and philo- 



