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POPULAR SCIENCE REVIEW. 
classification leads to a sufficiently complex result — evidently, as the author 
justly says, the time has not yet come for a final monograph of the group. 
But in his characters of the genera, or sub-genera, and his long and detailed 
descriptions of the structure of numerous so-called species belonging to the 
sub-geuera of Montieulipora proper, Prof. Nicholson has certainly done 
important work towards the perfect elucidation of these most difficult fossil 
organisms, and the abundance of admirable figures that he has given, both 
on half-a-dozen plates and as woodcuts scattered through the text, add 
immensely to the value of his work. His opinions as to the nature of the 
organisms are still sub judice, but whether they are right or wrong, his 
contribution to the history of the Monticuliporidae will certainly prove a 
great help to future investigators. 
SYSTEMATIC MINERALOGY.* 
I N describing the various crystalline forms, the author of this volume 
deals only with their symmetry and general geometrical proportion, 
without entering into the question of the practical calculation and determi- 
nation of individual examples. In doing this, the methods followed are 
mainly those of Groth’s treatise on ‘ Physical Crystallography,’ excepting 
that the plan there adopted of considering the physical structure of crystals 
before their geometrical properties has been abandoned in favour of the 
more common one of giving precedence to the latter. 
The optical properties of crystals are considered at somewhat greater 
length than is usual in rudimentary books, and the phenomena of polariza- 
tion receive special notice. A mixed system of crystallographic notation 
has been adopted. In the text, the forms are designated by their symbols 
according to Naumann, while the notation of their forces is by indices 
on Miller’s system. It is explained that this has been done with a 
view of familiarizing the students with both systems, since, although 
the notation of Miller is probably the best, that of Naumann is more 
generally employed both in text-books and in original memoirs. The 
classification followed in the chemical portion of the volume is that of the 
second edition of Rammelsberg’s Handbuch der Mineral- Chemie. 
This book is not only a safe and useful guide to students desirous of 
acquiring a general knowledge of mineralogy, but will also serve as an 
excellent introduction to the large text-books of Dana, Miller, Descloizeaux, 
and Schrauf. 
* Text-book of Systematic Mineralogy. By Hilary Bauerman, F.G.S., 
Associate of the Royal School of Mines. London : Longmans, Green, & Co. 
1881. 
