39 J: Scientific Intelligence. 



by weight, in a sealed tube from which air has been expelled. 

 According to the other method the decomposition is accomplished 

 by means of a mixture of hydrofluoric and dilute sulphuric acids 

 in a platinum crucible kept full of steam, or protected from the 

 air by being surrounded by carbon dioxide. In each case the 

 ferrous iron is determined by titratiou with potassium permanga- 

 nate solution. Hillebrand and Stokes have now explained 

 why, in many cases, the Mitscherlich method gives higher results 

 than the other. It is due to the presence in many rocks of small 

 quantities of pyrite or pyrrhotite, minerals which are readily 

 oxidized by ferric sulphate under the conditions used in the 

 method under consideration. The authors find that not only is 

 the metal of the sulphide oxidized, but the sulphur is converted 

 into sulphuric acid as well. The effect of sulphur is therefore 

 very great, amounting in the maximum to an error correspond- 

 ing to 13^ times its weight of ferrous oxide, and the method 

 should not be used for rocks and minerals which contain even a 

 trace of free sulphur or sulphides. The authors have also shown 

 that pure pyrite causes very little error in the hydrofluoric acid 

 method. — jour. Am. Chem. Soc, xxii, p. 625. h. l. w. 



5. Grundlinien der anorganischen Chemie, von Wilhelm 

 Ostwald, 12mo, pp. xx, 795. Leipsic, 1900 (Wilhelm Eng'el- 

 mann). — The appearance of each new work by Ostwald causes 

 astonishment as to his prolificness, as well as enthusiasm on ac- 

 count of the excellence of his productions. Perhaps no book 

 that he has written is as important from an educational stand- 

 point as the elementary inorganic chemistry under consideration. 

 The author himself considers it in a certain sense the keystone of 

 a long and zealous activity in connection with the introduction 

 and propagation of the new foundations of chemistry brought for- 

 ward by van't Hoff and Arrhenius. Notwithstanding this aspect 

 of the work, a careful examination shows that undue prominence 

 has not been given to the new physical chemistry. Moreover, 

 the treatment of the latter as well as other theoretical topics is 

 admirably simple and philosophical. The descriptive arrangement, 

 according to elements and their compounds, is used as the basis 

 of the book, the general laws being introduced as opportunity 

 and convenience permit. No attempt is made to arrange the ele- 

 ments according to the periodic system, in fact this system is only 

 briefly dealt with at the very end of the book. The work con- 

 tains comparatively few illustrations, and not many experiments 

 are described in detail. A few inaccuracies are to be noticed in 

 the descriptive matter, particularly in the paragraphs relating to 

 metallurgy. It is to be hoped that these will be rectified in the 

 next edition. 



The author deplores the tendency that has often been shown in 

 text-books of elementary chemistry to descend to a lower intel- 

 lectual plane than is the case with works on physics and mathe- 

 matics used by students at the same period of study, and he is 

 convinced that this need not be the case now that the subject is 



