4-76 Scientific Intelligence. 



are left at once in the mother liquor. Samarium, europium and 

 gadolinium are much less soluble than those just mentioned, but 

 they are more soluble than terbium, dysprosium and holmium. 

 Erbium, thulium, yttrium, ytterbium, etc., collect in the least 

 soluble portions. Since the solubilities of these compounds are 

 the reverse of the usual type, they can be used for the rapid 

 purification of man y of the rare earths. For instance, traces of 

 neodymium can be easily removed from samarium by this means, 

 as the samarium compound separates before the other one. There 

 is some inconvenience in working with these salts, since they 

 undergo gradual decomposition, with the formation of a gela- 

 tinous precipitate which filters with difficulty. — Chem. JVews, 

 cix, 13. h. l. w. 



3. Qualitative Chemical Analysis, by Anton Vorisek. 8vo, 

 pp. 226. Philadelphia, 1914 (P. Blakiston's Son & Co. Price 

 $2.00 net.). — This is a text-book for laboratory use, dealing with 

 the common elements and their compounds. The course of 

 analysis presented is an unusually extensive and satisfactory one. 

 The directions are full and clear and the explanations are excellent. 

 It rarely happens that a new text-book on qualitative analysis 

 makes so good an impression upon examination as this one. In 

 connection with the descriptions of the reactions the equations are 

 put in a compact form by putting the substance reacted upon at 

 the top, the reagent below it, and the products of the reaction 

 under a line. For example : 



ZnCl 2 



+ (NH 4 ) 2 S 



= ZnS + 2NH CI 



The author has made a few modifications in the usual course of 

 analysis, such as the precipitation of manganese in the ammonium 

 hydroxide group by the addition of hydrogen peroxide, the 

 separation of the sulphide, feiTocyanide and ferricyanide radicals 

 from the rest of the silver nitrate group by means of cadmium 

 nitrate, and so on. h. l. w. 



4. Introduction to Modern Inorganic Chemistry, by J. W. 

 Mellor. 12mo, pp. 684. London and New York, 1914 (Long- 

 mans, Green and Co. Price $1.30).— This text-book is a simpli- 

 fication of a considerably larger one by the same author which 

 appeared about two years ago and was very favorably noticed on 

 account of breadth of scope and interesting style. However, it 

 did not appear to be a suitable book for the use of beginners on 

 account of its size and character. The present book presents the 

 subject somewhat more conventionally and briefly than the other. 

 It is very able and interesting, retaining to a large degree the 

 admirable features of the previous work. It is to be highly 

 recommended to readers in search of fundamental chemical in- 

 formation, but perhaps even the condensed form may be con- 

 sidered somewhat too elaborate for use as a drill-book with the 

 majority of beginners. h. l. w. 



