1890.) Recent Literature. 1053 
RECENT LITERATURE. 
G. H. Williams’s Elements of Crystallography. Holt & 
Co., New York., 1890, pp. VIII., 250, Figs. 383.—At last mineralogists 
iipraid specialists as well as tühchers-äre to be congratulated on 
the appearance of a treatise which discusses the numerous forms of 
crystallography in such a logical manner that they need no longer 
confuse the mind or bother the student, Dr. Williams has given us 
the first clear statement of the beautiful truths of crystallography that 
has appeared in English. Not only has he done this, but he has pro- 
duced the best concise treatise on the subject that has anywhere 
appeared. In this country there has long existed a demand for a con- 
nected description of the relation of the various crystallographic forms 
to each other, in order that the excellent discipline afforded by the 
methods used in developing these from each other might be availed of 
in college instruction. 
All who have studied crystallography as a system are agreed that 
no subject exists which has a higher value than this as a corrector of 
loose thought and hasty expression. Its tardy introduction into the 
curricula of our colleges has been due more to the lack of a good text- 
book than to anything intrinsically hard in the subject itself. Happily 
there is no longer an excuse for the neglect of this important science. 
The little book before us comprehends within its small volume all of 
the most essential principles of the science. It is well written, concise 
in expression, clear in the statement of the thought, and logical in the 
development of the ideas contained in it. 
It opens with the discussion of the molecule, takes up in order the 
general principles sig ing Si Sabina be treats each of the seven 
systems in detail, t ggregates, and describes 
the various methods made use eti in the Esdr representation of 
crystal. Both the Naumann and the Miller systems of nomenclature 
appear side by side whenever the symbol ofa plane or form is needed, 
and so the reader is brought into frequent contact with these two rival 
claimants for ascendency. The notion of symmetry is everywhere 
emphasized, and this it is that gives the treatise its logical connection. 
The book is very well illustrated. It contains few typographical errors, 
and in general make-up it leaves but little to be desired. 
The publishers, as well as the author, deserve the commendation of 
all mineralogists for their successful attempt to place before the Eng- 
lish-reading public a volume which shall be worthy of their unqualified 
