MMiscellanies. 401 
¢ At the same time, care has been taken to give, in a smaller type, the systematic 
names of Mohs, and some of the important synonyms of other authors, in order to 
enable the student to refer with convenience, to the general descriptions in differ- 
ent worke upon the science.” 
Part IV. consists of the characteristic, whose province in Natural 
History it is, to furnish the peculiar marks by which we can distin- 
guish objects from each other, so far as they are comprehended in 
the ideas established by the theory of the system. ‘This is to be 
employed only with the mineral in our hand, and instructs us what 
properties are to be noticed in it, in order that we may be conducted 
toitsname. Is the mineral crystallized? such a property is the char- 
acter of the class. Is its system of crystallization the cube? such an 
observation will fix the order. ‘The determination of. its degree of 
hardness will bring it into a group of two or three species; and the 
experiment for specific gravity will identify it with the species to 
which it belongs. Or is the unknown mineral destitute of a crystal- 
line structure? such a fact establishes its class, in like manner; and 
the hardness being settled, the inquirer is led to a group consisting 
of all known minerals possessed of a similar degree of hardness, and 
which are arranged in the order of their specific gravities. The spe- 
cific gravity of the mineral whose name is sought being taken, the 
observation of one or two other easily observed properties will be 
sufficient to complete the research. 
The characteristic occupies one hundred pages of the treatise. 
The characters of the species are presented in tables; in which, for 
the purpose of diminishing the labor of determining American min- 
erals, all such as have hitherto been found in the United States are 
designated by a particular mark. These tables present us the fol- 
lowing interesting result, with respect to the productiveness of our 
country in this department of Natural History: out of three hundred 
and fourteen species—the whole number of well settled species con- 
tained in the mimeral kingdom—we have one hundred and thirty four 
species; and out of two hundred and twenty two crystallized species, 
the United States contains ninety five, which sometimes present them- 
selves under regular forms. 
These tables will be found worthy of particular attention, as afford- 
ing the most recent views of the species in Mineralogy. A great num- 
ber of minerals, which figure under distinct names im mineralogical 
works are here made to coalesce with other species; while on the 
other hand several new species of which accounts. have appeared 
