Review of Recent Geological Literature. 209 
instruction a very urgent demand for an elementary text book of crys- 
tallography. ‘That Prof. Williams’ book meets this demand will be con- 
ceded by the great majority of teachers and students of the subject. 
Apart from its practical aspects as an essential auxiliary to the study 
of mineralogy, petrography, chemistry and physics, crystallography has 
an important place in any thorough educational scheme as affording 
probably the best insight into the symmetry of natural forms ; and in its 
philosophical suggestiveness as to the constitution of the universe, the 
study is entirely comparable to the study of elementary astronomy, the 
laws with which the student becomes familiar in both subjects being 
alike mathematically rigid and yet extremely simple. 
For many reasons, therefore, it seems probable that the study of crys- 
tallography will in future play a more important role in American col- 
lege and university curricula than has been its fate in the past, and we 
therefore welcome gladly this clear and concise treatment of the elemen- 
tary principles of the subject as a vigorous step in that direction. 
The book is not entirely above adverse criticism, but its shortcomings 
are few when compared with its many good qualities. The considera- 
tion of the theoretical possibilities as to the mode of molecular arrange- 
ment in crystals, which meets one in the opening chapter, might with 
advantage to the student if not to the book, have been postponed till the 
concrete actualities of the subject had been discussed. The numerous 
cuts throughout the book are well executed, and the two plates, one of 
limiting forms and the other of combinations in the isometric system, 
are all that could be desired. Prof. Williams is to be congratulated on 
the success of his book and of his efforts to present to American stu- 
dents in simple form a department of science whose proper treatment 
has up to the present been found only inthe elaborate works of the 
German authors. 
Systematic Mineralogy, based on a natural classification. THOMAS 
SrerRyY Hunt. 8vo, 391 pp. The Scientific Publishing Company, New 
York. 89" 
No student of mineralogy can pass beyond the stage of the novice with- 
out becoming painfully aware of the loose, if not chaotic, condition of its 
systematic nomenclature. The most trivial circumstance or quality h s 
often been exalted above the fundamental principles of chemical compc- 
sition in assigning a mineral species a name or a place in classification. In 
the infancy of the science it was necessary to apply such designations, but 
as these became often synonyms, or as they were multiplied through the 
labors of many investigators, it became apparent that some system of 
classification and elimination must be chosen. There sprung up two 
rival schemes, known as the “natural history” method and the “chemi- 
cal” method. Werner, Mohs, Jameson, Breithaupt, Shepard, and, at 
first, Dana, employed the natural history method, and Berzelius, Clarke, 
Cleaveland, Phillips, Rammelsberg, and at last Dana, and nearly all later 
authorities, employed the chemical method. The former ignored chem- 
istry, and the latter ignored the physical characters, speaking broadly, 
