294 



NATURE 



[May 22, 1913 



importance of his researches, which will stand for 

 all time as the foundation of our knowledge of the 

 geology of the Chinese Empire, or whether we 

 regard the fact that the author himself was only 

 able to publish a portion of his work, the greater 

 part having been prepared for and put through 

 the press by the devoted industry of his friends 

 and former pupils. 



Of the two volumes before us, one contains 

 v. Richthofen's account of his travels through 

 southern China, edited and amplified by references 

 to the observations of later travellers by E. 

 Tiessen. These additions are most extensive in 

 the account of the salt and gas fields of the upper 

 Yangtsekiang, which v. Richthofen was prevented 

 from visiting, where the ingenuity and indomit- 

 able perseverance of the Chinese have enabled 

 them, in spite of the primitive nature of their 

 appliances, to rival the achievements of the 

 modern driller and to obtain a supply of natural 

 gas from depths of 2000 ft. and even 3000 ft. The 

 detailed observations of so acute an observer must 

 always be of interest, and although all the more 

 important results of his journey have already been 

 published in one form or another, we welcome the 

 completion of publication of the record, which will 

 always be of importance and value to the student of 

 the geology and physical geography of Eastern Asia. 



The other volume is entirely the work of Dr. 

 Fritz Freeh, to whom Baron v. Richthofen en- 

 trusted the elaboration of the palasontological 

 material collected by him. The description of the 

 fossils is supplemented by a series of essays on the 

 distribution and development of the different rock 

 systems in China and Eastern Asia, and by a 

 general review of the geographical evolution and 

 the geological history of sea and land in China. 



OUR BOOKSHELF. 

 Die gnomo>iische Projektion in Hirer Anwendung 



auf kristallographische Aufgabcn. By Dr. H. 



E. Boeke. Pp. iv + 54. (Berlin: Gebriider 



Borntraeger, 1913.) Price 3.50 marks. 

 This little book on the gnomonic projection of 

 crystals is a welcome addition to crystallographic 

 literature. The standard work on the subject, 

 " Ueber Projektion und graphische Kristallberech- 

 nung," by Prof. V. Goldschmidt, of Heidelberg, 

 was published in the year 1887, before the advent 

 of the two-circle goniometer, which has both sim- 

 plified the method and enlarged the field of useful- 

 ness of the gnomonic projection. The greater 

 number of the subsequent improvements in the 

 method we owe to Dr. G. F. Herbert Smith, 

 Mr. H. Hilton, Dr. A. Hutchinson, Dr. J. W. 

 Evans, Sir Henrv Miers, Prof, von Fedorow, 

 and Prof. F. E. Wright. 



The gnomonic differs from the stereographic 

 projection in that the plane of projection is a i 

 NO. 2273, VOL. 91] 



tangent plane to the sphere (within which the 

 crystal is supposed to be concentrically situated), 

 and the eye is imagined to be placed at the com- 

 mon centre of the sphere and crystal ; while in 

 the stereographic projection the eye is situated 

 at the north or south pole of the sphere, and the 

 plane of projection is that containing the equatorial 

 great circle. Just as we have the most useful 

 stereographic nets of Hutchinson, Penfield, and 

 von Fedorow, so we have the gnomonic net of 

 Hilton, and Herbert Smith has furnished us with 

 a table to facilitate the plotting of the gnomonic 

 diagram from the results of the measurements 

 of the crystal made on the two-circle goniometer, 

 an excellent type of which he has invented. With 

 the exception that no mention appears to be made 

 of the important work of Herbert Smith (no index 

 is provided), Prof. Boeke has given in the concise 

 space of fifty-four pages a very fair account of the 

 principles of the method, together with some useful 

 tables of chords and tangents. The illustrations 

 are simple ones from original drawings of the 

 author, and are very practical, but an obvious 

 omission is that of a few typical gnomonic projec- 

 tions of fairly complex crystals belonging to each 

 system of symmetry. Such a series of concrete 

 examples would have afforded students a more 

 comprehensive idea of the scope, possibilities, and 

 actual application of the gnomonic projection. 



A. E. H. T. 

 The Extra Pharmacopoeia of Martindale and 



Westcott. Revised by Dr. W. Harrison 



Martindale and Dr. W. Wynn Westcott. 



Fifteenth edition. Vol. i., pp. xxxi+1114. 



Price 144". net. Vol. ii., pp. viii4-37o. Price Js. 



net. (London: H. K. Lewis, 1912.) 

 This valuable work has now reached its fifteenth 

 edition, eloquent testimony of its worth. The 

 subject-matter has grown to so great an extent 

 that it has been necessary to divide it into two 

 volumes : the first, of more than 1000 pages, con- 

 tains the description of the chemicals and drugs 

 and the sections on vaccine and serum therapy, 

 therapeutic index, &c. ; the second embodies analy- 

 tical and experimental work and a risumi of in- 

 vestigations on infective and other diseases. For 

 the medical man and pharmacist, the book con- 

 tains a wealth of information scarcely to be found 

 in any other work, while numerous data are 

 scattered through it which render it a volume of 

 reference which will be found of the greatest 

 service in the chemical and the biological labora- 

 tory. R. T. H. 

 Practical Physiological Chemistry. By S. W. Cole. 



Third edition. Pp. xii + 230. (Cambridge : W. 



Heffer and Sons, Ltd., 1913.) Price 7.S. 6d. net. 

 Under the title "Practical Exercises in Physio- 

 logical Chemistry," this book was reviewed in the 

 issue of Nature for March 2, 1905 (vol. lxxi., 

 p. 412). In the present edition Mr. Cole directs 

 particular attention to analytical methods. He 

 urges that medical students should be taught the 

 micro-chemical methods of urinary analysis intro- 

 duced by Folin, and that more conclusive quali- 

 tative methods should replace Fehling's sugar-test. 



