244 E. T. Wherry — Amphisymmetric Crystals. 



Summary. 



The fact that different methods may not agree in their 

 indications as to the symmetry class of a given crystal 

 is re-emphasized, and the term amphisymmetric is pro- 

 posed for this relation. Physical methods show the sym- 

 metry of the structure, chemical methods bring out latent 

 symmetries of the separate atoms or molecules. It is 

 recommended that in stating the crystallization of an 

 amphisymmetric substance the two classes indicated be 

 given, one designated structural, the other latent. 

 Finally, a table of a large number of substances which 

 give evidence of being amphisymmetric is presented. 



Bureau of Chemistry, 



U. S. Department of Agriculture, 

 January, 1922. 



