The national era. [volume] (Washington [D.C.]) 1847-1860, 1851-05-08

from iron to lead, but Itself forms combination
with that acid In two proportions, forming the
chromate and bichromate Of potash, both largely
used In the arts, especially In calico printing
Several other combinations Of chrome, effected
by chemical agency, are we'll known, both in the
useful and fue arts
In all the magnetism rocks, magnesia is found
in chemical combinations, but dffused too mi
nutey for being obtained for the various uses to
which II is applied either in the art Of healing or
the purposes Of business. II is also found In
veins or immediate connection with magnetism
formations, in masses nearly pure, and sufficient
ly large to be changed, by chemical agency, into
various combinations we'll known both to physi-
clans and artists. Common magnesa Of the shops
is the carbonate Of magnesia IL is also used as
a chemical agent for effecting changes in other
combinations.
In a large deposit of serpentine at Hoboken,
opposite to New York, ON the Hudson river, is
found the hydrate Of magnesa, tabular crystal,
and srsre mineral, as yet known in very few places
in the world. Msrmalite, nemalite, and gurro-
phite, are other magnetism minerals more or less
crystalized At Soldiers Delight and the vicini-
ty, bordering on Pennsylvania and Maryland,
magnesite is quarried in large masses. This is
the best deposit yet discovered for the material
changed by chemical agency into epson salts and
other compounds
Asbestos is magnetism mineral. Ii sometimes
has the appearance Of wood when il is called lig-
inform asbestos Ii also, in different forms, ex-
hibits the appearance Of cork, leather, fax cot
ton, and silk. From it have been made both cloth
and paper. A handkerchief made Of this mate
rial, to be cleansed needs only to be thrown into
the fire, from which it can soon be taken perfect
ly clean, white and unimpsired. Several tons of
the silky ssbetos have been obtained from one
In Morvlond far 6ra- proof aafaa n he
used In stores, banks, and other business estab-
lshments.
Tale, frequently known as French chalk, is an
other magnetism mineral 1t is the principal ele-
ment in soapstone. Both the mineral and the rock
of which il is the principal ingredient are cut with
an axe or saw, smoothed with a plane, turned in
a lathe, and thus easily formed into any shape
required for the various purposes to which it is
applied.
Chlorite has about the hardness and much the
consistency OF sospstone, and like that, is easily
wrought into any required form. In Little Brit
ain, Pennsylvania, are large masses OF chlorite
containing crystals Of octahedral iron about the
size of pea, enclosed in eight squlateral trian.
giles, all perfectly equal and alike The rock and
crystals furnish good cabinet specimens, and in
any quantity.
EXPERIMENTS I'm the United States are about
one hundred thousand schools and six millions of
families. Each school and family, il requested by
teachers and parents would form at once vigorous
and effective "erploring ageneyn for bringing to
2;gt. ssd 70 use the mineral Srner resourcsa
science and of wealth within their reach. The
fruits Of such agencies, aided by drawings, me-
chanism, and other works of art collected, CON-
pared, and exchanged at annual national scholars
fairs at our national metropolis, would be " in
dustral exhibitions of most effective chsrsc-
ter, eminently calculated to increase and diffuse
knnMledQe among men,