566 Reviews — Dr. H. R. Mill's FJiysiography. 



includes all metallic ores and their associates. Under this head 

 minerals which have a special interest for the miner are described, 

 commencing with gold. After first giving a short archaeological 

 account of the precious metal, the authors then proceed to deal with its 

 mode of occurrence, methods of testing, geographical distribution, etc. 

 Platinum is next dealt with, then silver, copper, mercury, lead, zinc, 

 antimony, bismuth, arsenic, sulphur, iron, manganese, nickel, cobalt, 

 tungsten, molybdenum, uranium, tin, and titanium. There is also 

 a short appendix dealing with meteoric irons and stones. 



Precious stones and related minerals is the next heading. This 

 section comprises all the minerals with which the jeweller is con- 

 cerned, from the diamond to 'common quartz'. These, which were 

 fully dealt with from that standpoint in Edelsteinknnde, are here 

 described from their mineralogical aspect chiefly, although methods 

 of cutting, historical, and other points of interest are touched upon. 



Part iii consists of rock-forming silicates and allied minex'als. 

 This section, apart from its purely scientific side, is one which is of 

 interest to architects and workers in stone. Here the preparation of 

 suitable sections for microscopic study of rock-structure is explained, 

 and the various rock-forming minerals are described. 



The last class is entitled ' mineral salts '. Several mineral substances 

 of great commercial value are dealt with under this heading, but it 

 also includes that group so attractive to the amateur, the fluorspars. 



In The World's Minerals Mr. Spencer gives short descriptions of 

 the minerals figured. The forty plates are also coloured, which is 

 a great help to the inexperienced collector, to whom this book should 

 prove most acceptable. The plates do not equal those in the larger 

 work, and space of course does not allow of much more than one 

 figure for each of the 116 mineral species described ; in some cases 

 the student would be glad of more illustrations to aid in identification. 

 The introductory chapters are helpful and simply expressed, giving 

 a short explanation of crystallographic systems, the physical characters 

 of minerals, and their chemical composition and classification. 



III. — Physiogeaphy. 

 The Realm of Nature ; an Otjtline of Physiography. By H. R. 

 Mill, D.Sc, LL.D. Second edition. 8vo ; pp. xii, 404, with 

 19 coloured maps and 73 figures in text. London : Murray, 1913. 

 Price 5s. net. 

 rilHE usefulness and popularity of the first edition of this book is 

 JL evident from the fact that it has been reprinted no less than six 

 times since its appearance in 1891. This edition has been thoroughly 

 revised page by page, and can be justly recommended to the reader. 

 The author sets forth to illustrate the principles of science by applying 

 them to the world we live in, and to explain the methods by which 

 our knowledge of Nature has been acquired and is being daily 

 enlarged. The greater part of the book is occupied by an outline of 

 the more important facts regarding the structure of the universe, 

 the form, material, and processes of the earth, and the relations which 

 they bear to life in its varied phases. 



