The western Democrat. [volume] (Charlotte, N.C.) 1852-1870, 1858-02-09
SCIENCE AND THE MECHANIC
ARTS


IRON.-Exprrimcnts and careful Obser-
ratiuns have shown that great difference
exists in certain kinds of iron, as regards
their suitahlrncss for cemen,ing. Espe-
cially is this difference perceptible when
from the same pig iron the bar iron pro-
duccd is made in the r, fnery or the pud-
ding furnace. Both, by cementstion, give
| steel, but of essentially different quality.
That made by pudding is more dense,
more uniform, and finer in the grain, and
when cast remains so in subsequent treat
| mcmt. Direct experiment has only shown
! that the other possesses somewhat mere
| elasticity. and appears to harden better
| The pig iron "f Austria, made from the pure
| apnth">e ore, bring pnddled at high heat,
! j. sad (" ri,rr an excellent material for
| cement steel making. But, unfortunately,
"ne-half of the bar iron thus produced is
from the refinery hcarths. aud what pud-
died iron is made is of inferior quality.
INTERIOR OF TIE EARTH.-Mr Hop
kirs, in communication to the British AS
sociuti"n of Science, has presented sSme
!
Of the original and state of the Interior of
the earth. 1t is well known that the tenn
pprature of the earth increases ~ we des-
ceud, and it has been calculated that, at
the rate at which the increase takes place
in such depths as ure accessible t" Us, the
heat, at depth of eighty or one hundred
miles. would be such a. t" fuse most OF the
materials which form the solid crust OF the
globe On the hypothesis of original fluid
ity. and assuming that the rate of Increase
known to us by observation continues fur
ther and il not counterbulanced by con-
siderable increase in the temperature of fu-
sion occassoncd by pressure, the present
state of the earth would be that Of q solid
crust cf eighty to one hundred miles in
thickness envcloping q fluid nucleus. MIR
HOPKINS considers this state to be incon-
!, sistent with tho observed amount of the
procession of the equinoxcs, and infcrs
: that, if the temperature OF fusion be not IN
f creased considerably by pressure, the hy-
rothesis of internal high temperature, being
due to primitive heat cannot be correct;
whilst, on tie other hand if the temPera-
ture of fusion be considerably heightened
n by pressure, he considers the conclusion to
, he unavoidable, that the Garth must be solid
n at tie centre. .
n Pr1xr1No Goops.-An invention has
| been introduced which embodies n system
} of printing shawls and other goods, by
: stretching the fabric OH an impression cyl
inder being arranged to work in concert
with a printing roller. on which the ''re-
7" peat" of the pattern is engraved. In print
. ing border by this plan, the two opposite
parelel edges of the piece arc stretched on
the large cylinder in a lire with the cylin-
der end, and the color apparatus being SET
:, on rail in front of the cylinder, the two
! borders are printed in succession, and the
f printing apparatus being then detached, ID
removed to another cylinder. to make way
C for the succeeding colors on the first. The
printing roller is so contrived as to be ca
pable of the most accurate adjustment tc
:. the impression ylindpr on each change, sc
as to keep perfect register; and tho atten
:. dants are thus enabled to print all the col
:. ors in a series of pieces by continually run
.c ning through a series of impression cylin
- dcrs. with corresponding color rollers, one
after the other.