Review of Dana’s Mineralogy. 
364 
Plagionite. Pyrosclerite. Fichtelite. 
Voltzite. Thrombolite. Konlite. 
Greenockite. iscite. Hartite. 
Faujasite. Krisuvigite Ixolyte. 
Malthacite. Kammererite Guyaquillite. 
Ottrelite. Fossil copal Berengelite. 
Pelokonite. Middletonite. Pigotite. 
Praseolite. 
It is surprising, considering the correctness of this treatise 
on its first appearance, to find how numerous and important 
are the changes which have been made in the present edi- 
tion. 
In the volume already quoted, we have given a full outline of 
the plan and general arrangement of Mr. Dana’s work, which it 
is the less necessary to repeat at present, since the first edition is 
in the hands of so many of our readers. The mathematical ap- 
pendix of the first edition is omitted in most of the present one; 
only a few are bound up with it for the satisfaction of those who 
wish to pursue that portion of the subject. Notwithstanding 
this omission, the present edition is considerably larger than the 
former—the whole amount of new matter being little short of 
one hundred and fifty pages. It is in fact to all intents and pur- 
poses a new book, modelled on the general plan of the former, but 
altered in many important points to suit it to the present advane 
state of the science. Without farther preface, therefore, we pro- 
ceed to give in as condensed a form as possible some of the novel 
features of greatest interest which strike our eye in the work, 
following the order of the contents. 
Irregularities of Crystals.—Under this head, (which consti- 
tutes the 3d chapter,) we have an important addition, and a0 
able exposition of a subject which is the cause’ of much pet 
plexity to the student, and, when rightly understood, unfolds 
many difficulties and apparent anomalies, both in the form and 
composition of minerals. The irregularities of crystals are treated 
of under four heads. 1. Imperfections of surface ; 2. Variations 
of form and dimensions; 3. Internal imperfections and impurities; 
- Pseudomorphous crystallizations. Under the first head we 
ave— 
1. Striated Surfaces.—* These are produced by minute planes cov 
ering the surfaces striated, and usually inclosed parallel to the seconda- 
