The farmer and mechanic. [volume] (Raleigh, N.C.) 1877-1885, 1878-02-14

ours between the hornblende and
cranitic rocks in this State, and tale
| itself occurs associated with chrysolite.
in fact IN the chrysoite beds. and
chrvsolite is a usual constituent OF
some eruptive rocks, and occurs IN or
among metamorphic rocks. Tale and
soapstone are found in many localities
in this State.
Their uses in the arts are various !;
thsy are used for diminishing friction
in machinery, for marking on glass or
chalk, for engraving. This last use Is
due to their property of hardening
under heat tale is so soft as to be
| easily scratched with the finger nail
even, but on continued application of
strong heat, it is rendered hard, !. q,
the water is driven out. The I'M
preston, whatever it may be, is en-
graved upon the stone, which IS then
heated, and the impression thus made
lasting. Finely pulverized tale is used
together with black lead graphite IN
the manufacture of black lead cruel
bles, which resist very strong heat. 1t
cannot be polished until heated,
then it is susceptible of a beauti-
full polish. and is often colored with
metallic solutions and used in orna-
mentation. 1t is used also in the
ufacture Of porcelain, but while rem
dering the biscuit semi-transparent its
use is open to the objection that it
makes it brittle and apt to break
with slight changes of heat. Slabs 2
feet long and 6 or eight inches square
have also been bored out and used for
conveying water instead of lead pipes.
1t will polish alabaster. glass, serpen-
tine, &c. Venetian Tale will remove
oil stains from wooden cloth. Soap
stone is also used for the sizing rollers
in cotton factories DR.. G.. L. Jackson
mentions this fact and says also that
one of these rollers IN use as Al feet
long and ) to six inches in diameter.
Every body knows that it is used for
hearths, fire-jambs, and in furnaces.
The fine grained varieties are
times carved into ornaments, ink
stands pipes, &c. And too, we all know
what a great and valuable service it
oftentimes renders in helping a fellow
put on a tight pair of boots. Potstone
is used in Lombardy for. making Gull
nary vessels.
1t is stated on the authority Of Bron-
giart that the inhabitants of New Gale
doniaeat a kind Of soft, friable, greasy
dirt, and that this dirt contains Mag
nesia Sc per cent, SILICA 81 per cent and
Iron Il per cent. And Humboldt is
quoted as saying that IN the Orinoko
River, the people eat dirt. This singu-
lar habit may be accounted for on the
'upposition that they had an inward
craving for magnesia.
VIM. Baird, In his :" C~yclopedia Of
Sciences" published in 1853,
asserts that in some countries(China. l
,hink, for one,) Tale is used for win
panes, and also that it is used as
he basis of a rouge. Asto the chemi
al formula of Tale, chemists are unde
,ided. However, the formula COM
monty taken is Mg6(SiO2)5 4f2H2O.
some analyses, Genth, Kersten, Seuft,
&C., give Mg2(SiO2)5 as the formula,
nd Dana suggests that there may be
rec silica present, and hence the occa-
ional excess of this ingredient.
There seems to be some doubt as to
he origin of the name Tale. Some
erive it from the Arabic talk, 9TH
rs say that it is Of Moorish origin.
Agricola, a writer Of the 10th century,
ives Table as the synonym of magne-
is, but this is wrong as he meant mi
a. Calsius, a writer of the 18th centu-
on minerals, says Talchus. 1.-The
7ord Steatitis occurs in Pliny as the
anne of a stone resembling fat, but no
urther description is given that can
nth certainty identify it" Dana.)
w. B. PHILLIPS.