Miscellanies. 389 
Part II, treats of the Physical characters of minerals, or those de- 
pending on light, electricity, magnetism and specific gravity ; also of 
the hardness, state of aggregation, kinds of fracture, and odor, 
Part III, consists. mainly of directions for the use of acids and of 
the blowpipe. | 
Part IV, treats of the classification and nomenclature of ~~ 
and discusses the relative importance of crystallographic, physical 
and chemical characters in determining identity. The author here 
brings forward the classes and orders of his natural classification, the 
genera and species of which are givenin Part VI. The classes, 
and in general the orders, are similar in their characters to those of 
Mons. The following is the statement of its grand divisions. 
Class I, Eriama, (containing two orders) includes the gases, un- 
metallic liquids and soluble minerals. ‘They have in general resulted 
from the decomposition of other species and are consequently epigean 
or superterraneous. Their specific gravity is below 3° 
Class Il, Enrogxa (twelve orders) comprises those insoluble min- 
erals which occur in or compose the several rock strata, and which’ 
are therefore appropriately described as occurring within (2”t0s) the 
earth. Specific gravity above 1-8. 
Class II], Hyrocxa, (two orders) contains those species that are 
literally hypogean, or have resulted from the inhumation of vegetable 
or animal matter. Spec. grav. above 1-8. 
Part V, contains two new tabular classifications the object of which, 
is to enable the unaided student to arrive at the names of minerals. 
The first includes all crystallized minerals and is arranged according 
to the systems of crystallization before mentioned. These classes 
(with the exception of the class Triclinata) are each divided into 
two sections, according to their unmetallic or metallic lustre. The 
individuals in these sections are arranged in the order of their hard- 
ness, under the heads of hardness, gravity, cleavage, lustre, color, 
diaphaneity, &c. The second table is independent of crystallization, 
and is distributed into the three grand classes before named, subdi- 
vided into sections and subsections depending (with the exception of 
the individuals of Class J,) on their metallic or unmetallic lustre and 
their colored or uncolored streak. The species in these several 
subdivisions are arranged in the order of their hardness, under the 
heads of hardness, gravity, structure, (including references to the 
system of crystallization,) lustre, color, diaphaneity, effects of acids 
and of the blowpipe. The minerals in several of the sections are 
