i88ij 
359 
A na lyses of Books] 
The book, even to naturalists who have no specific acquaintance 
with the group in question or its allies, presents undoubted evi- 
dence of sterling work. 
Text-Book of Systematic Mineralogy. By Hilary Bauerman 
F.G.S. London : Longmans and Co. 
This treatise is a worthy member of Messrs. Longmans’ valu- 
able series of “ Text-Books of Science,” and will be of great use 
to those students — not too numerous — who are engaged with 
mineralogy as distinct from geology, on the one hand, and from 
chemistry on the other. 
The author characterises minerals as inorganic natural species, 
to be distinguished from each other by considerations of form’ 
structure, and composition. The determination of the first of 
these points, i.e., crystallography, may be pronounced a purely 
geometrical question. The author points out the law, established 
by observation, though not explained, that all save the simpler 
types of symmetry about an axis, i.e., the binary, the quaternary, 
ternary, and senary, are wanting. Pentagonal symmetry, so 
common in the organic world, is here wanting. 
In the crystallographic part of the work Mr. Bauerman adopts 
a mixed system of notation, designating the forms by their sym- 
bols according to Naumann, and noting their faces by the indices 
of Miller’s system. 
We are glad to find the optical properties of crystals dealt 
with in a reasonably full and satisfactory manner. These cha- 
racters are becoming daily of more importance in the diagnosis 
of mineral species,— and we may add of chemical compounds,— 
organic or inorganic. It is therefore very satisfaaory to know 
that there exists an accessible work of moderate compass to 
which the student may be referred. The phenomena of double 
refraaion, of uniaxial and circular and biaxial polarisation, inter- 
ference figures, rhombic and oblique dispersion, are clearly 
described. J 
After due notice of the thermic and elearic properties of 
minerals the author passes on to their chemical examination in 
which he adopts the system of Rammelsberg. 
Descriptive mineralogy is reserved for a future volume. The 
work is one which may be unhesitatingly recommended. 
