Januaby 25, 1907] 



SCIENCE 



143 



Madagascar; and that the femur of a bird is 

 short 'because the knee is concealed. There is 

 also an occasional tendency to overestimate 

 the size of birds ; for example, it is stated that 

 the South American condor sometimes has a 

 spread of wing of fifteen feet. As a matter 

 of fact this bird is slightly exceeded by the 

 California vulture, vphose greatest recorded 

 spread is ten feet sis inches, and it is an un- 

 usually large condor that measures even nine 

 feet from tip to tip. We believe that the 

 albatross sometimes exceeds twelve feet across 

 the wings and may reach fourteen, but never 

 measured one greater than ten. However, the 

 above are but minor blemishes, the book 

 abounds in information and represents a large 

 amount of original work. 



The illustrations, mostly from photographs 

 taken by the author, are numerous, and, with 

 rare exceptions, good. One of the exceptions 

 is that on page 85, showing the shoulder girdle 

 of a pigeon, and is not only taken from a 

 diseased specimen, but fails to show the parts 

 described. Some particularly good pictures 

 are to be found in ' Heads and Necks ' and 

 ' Wings,' the young green heron and his vis-d- 

 visj the great white heron, being most excel- 

 lent. 



All in all, this volume of The American 

 Nature Series is admirable. 



F. A. L. 



Einleiiimg in die Chemische Krysiallographie. 



By P. Geoth. Pp. v + 80, 6 figures, 8vo, 



cloth, 4 marks. Leipzig, Wilhelm Engel- 



mann. 1904. English translation by Hugh 



Marshall, 12mo, cloth, $1.25. New York, 



John Wiley & Son. 1906. 

 Chemische Krysiallogra'phie. By P. Groth. 



In four volumes. Vol. I., pp. viii + 634. 



389 figures, 8vo, cloth, 20 marks. Leipzig, 



Wilhelm Engelmann. 1906. 



For nearly a score of years Professor Paul 

 von Groth, of the University of Munich, has 

 had in preparation this ' Chemische Krystal- 

 lographie' which aims to include in system- 

 atic order trustworthy data of all crystallized 

 chemical substances. 



The introduction to this monumental work 

 appeared as a separate publication under the 



title ' Einleitung in die Chemische Krystal- 

 lographie ' in 1904, and has since been trans- 

 lated into English. In the ' Einleitung ' the 

 recognized relations existing between the prop- 

 erties of crystals and their chemical constitu- 

 tion are explained in the light of modern ideas 

 of crystal structure. In so doing Professor 

 von Groth assumes a knowledge of physical 

 crystallography and chemistry. In order, such 

 topics as crystal structure and its varieties, 

 polymorphism, morphotropy, isomorphism, and 

 molecular compounds are discussed. In the 

 chapter on morphotropy much attention is 

 given to a full discussion of the ' topical para- 

 meters,' first proposed by Muthmann and 

 Becke, by means of which it is possible to 

 compare to better advantage than was hitherto 

 possible the crystal structure of different sub- 

 stances as well as to note the variation caused 

 in their crystallization by changes in chemical 

 composition. 



The English translation by Hugh Marshall, 

 of the University of Edinburgh, is in every 

 respect admirable. A copy of this introduc- 

 tion ought to be in the hands of every chemist. 



The ' Chemische Krystallographie ' proper is 

 to comprise four volumes as follows : Volume 

 I., Elements, inorganic binary compounds, 

 simple and complex haloids, cyanides, nitrites 

 and their alkyl compounds of the metals; 

 Volume II., inorganic oxy- and sulfo-salts and 

 their alkyl compounds; Voliimes HI. and IV. 

 will contain the organic compounds. Of these 

 only the first volume has been published. The 

 remaining volumes are to appear at intervals 

 of one year. 



The arrangement of Volume I., which is 

 also to be followed in the others, is such that 

 substances, which are similar chemically are 

 treated together in separate groups or sections 

 by first discussing our present knowledge of 

 the same. These discussions present a very 

 clear and concise survey of the literature, 

 point out the conclusions to be drawn con- 

 cerning the crystal structure of the substances 

 under consideration, and in many instances 

 indicate important lines of needed research. 

 The second portion of each section is devoted 

 to a systematic description of the members of 

 that group for which erystallographic data 



