Decembeb 21, 1906.] 



SCIENCE. 



807 



teacher in this way, each contributing his 

 part to a common work, and the whole ap- 

 pearing almost simultaneously in two lan- 

 guages. In the American edition it is Dr. 

 Winton with the collaboration of Professor 

 Moeller, while in the German edition it is 

 Professor Moeller with the collaboration of 

 Dr. Winton. This is a beautiful acknowl- 

 edgment of their confidence in each other, and 

 we have seldom seen the work of two men that 

 is so much alike in both drawings and de- 

 scriptions as in this instance. 



The work is divided into ten parts, as fol- 

 lows: (1) Equipment, methods and general 

 principles; (2) grain, its products and im- 

 purities; (3) oil seeds and oil cakes; (4) 

 legumes; (5) nuts; (6) fruit and fruit prod- 

 ucts; (7) vegetables; (8) alkaloidal products 

 and their substitutes; (9) spices and condi- 

 ments; (10) commercial starches. The work 

 contains in addition a general bibliography, a 

 useful glossary and a good index. 



A careful examination of this book of Win- 

 ton and Moeller's shows that in order to carry 

 on analyses of vegetable food products suc- 

 cessfully it is essential for the analyst to have 

 special botanical training, and that with the 

 knowledge gained by this training the de- 

 termination of purity and the detection of 

 adulterants is reduced to a degree of scien- 

 tific accuracy hardly possible in any other 

 kind of analytical work. The teachers of 

 chemistry and those in the biological depart- 

 ments of colleges and technical schools should 

 cooperate in arranging courses which would 

 not only qualify their students to examine 

 vegetable products, but also enable them to 

 devise methods for their manufacture. 



This book could be used as a text-book, and 

 will be found an invaluable reference book 

 for the food analyst, the agricultural chemist, 

 the pharmacist and others engaged in the 

 examination of foods, as well as the physician 

 who may be called upon to identify vegetable 

 substances in stomach contents and feces. 



Henry Kraejier. 



Essentials .of CrystallograpJiy. By Edward 

 Henry Kraus, Ph.D., Junior Professor of 

 Mineralogy in the University of Michigan. 



Ann Arbor, Mich. 1906. Pp. 162; 427 



figures. 



Unlike some related sciences crystallography 

 is not over-burdened with texts, certainly not 

 with those printed in the English language. 

 The appearance, therefore, of a new crystal- 

 lography is an event of considerable impor- 

 tance to teachers of mineralogy. The author 

 of ' Essentials of Crystallography ' was trained 

 in the laboratory of Professor Paul v. Groth, 

 of Munich, and in the two brief years that he 

 has been in the faculty of the University of 

 Michigan, has developed a flourishing depart- 

 ment which already requires the services of a 

 professor, an instructor and two assistants. 



Most writers of books upon crystallography 

 appear to go out from the idea that the sub- 

 ject is adapted to study by a very limited 

 number of persons, and those only who are to 

 become thorough masters of the subject and 

 advance it through original research upon 

 general lines. Thus the texts published in 

 England have laid stress upon mathematical 

 theorems rather than upon the symmetry of 

 crystals. The great development of organic 

 chemistry in recent years, and the prominence 

 which crystal symmetry and habit have ac- 

 quired as means for identifying chemical 

 compounds, has demonstrated that crystallog- 

 raphy is a necessary part of the training of 

 chemists as well as of mineralogists and geol- 

 ogists. Eor such students much must be 

 eliminated from consideration in order that 

 essential facts may be grasped, and the course 

 be given a practical value. 



The requirements of such students were 

 singularly well met by the ' Elements of Crys- 

 tallography ' of the late George Huntington 

 Williams, as was, perhaps, shown by the rather 

 extensive use of the book by American teach- 

 ers. Since the profound changes brought 

 about by the acceptance and introduction of 

 Gadolin's thirty-two classes of crystals, Wil- 

 liams's work has been no longer serviceable as 

 a text, and its place has not been filled by any 

 later work. 



Professor Kraus apparently makes the fun- 

 damental assumption that crystallography can 

 not be learned outside of a crystallographical 

 laboratory or without the guidance of a 



