Ad Review of Cleaveland’s Mineralogy. 
common ore of nickel) is ever magnetic, till purified, and 
whether cobalt is ever magnetic unless impure. 
Professor Cleaveland’s remarks on fracture are uncommonly 
discriminating and instructive, and would lead a learner toa 
just comprehension of this important point in the characters of 
minerals. 
The section relating to the chemical characters is concise, 
and professedly proceeds upon the principle of selection. It 
might perhaps have been, to some extent, advantageously en- 
larged ; although, it is true, the author refers us to the par- 
ticular minerals for individual instances; still it might have 
been well to have illustrated the general principles by a few. 
well chosen instances, e. g. how, by the blowpipe, galena is 
distinguished from sulphuret of antimony 3 carbonat of lead 
from sulphat of barytes, or carbonat of lime; garnet from tita- 
nium ; plaster of Paris from soapstone, &c. 3 and, among trials 
in the moist way, how by nitric acid and ammonia, iron pyrites 
is distinguished fram copper pyrites ; and how, by acids, sulphat 
of lime is known from carbonat of lime. As the acids are used 
principally for trials on the effervescence of carbonats, most 
of which form with sulphuric acid, insoluble compounds, we 
should doubt whether sulphuric acid is so advantageously em- 
ployed as the nitric or muriatic, in such cases, on account of 
the clogging of the effervescence by the thick magma, produced 
by a recently precipitated and insoluble sulphat. 
According to our experience, the nitric or muriatic acid, dilu- 
ted with two or three parts of water, is most eligible. 
With respect to the blowpipe: it is a convenience to have @ 
mouth-piece of wood, or ivory, joined to a tube of metal, a8 
Mr. Cleaveland recommends; and some authors direct to have 
the tube attached to the hollow ball, for the sake of condensing 
the moisture of the breath ; but every thing which adds to. the 
expense and complication of the instrument will tend to discou- 
rage its use ; we have never found any difficulty in performing 
every important experiment with the common goldsmith’s brass 
blowpipe; and are confident, that, after the learner has ac- 
quired the art, or knack, of propelling a continued stream of 
air from hig mouth, by means of the muscles of the lips and 
tidied 
