The sun. [volume] (New York [N.Y.]) 1833-1916, 1893-04-16
NOTES Nv SCIENCE AND INDUSTRY.

One of the latest mechanical improvements
In metal working Is a system OF rolls for wrap
ping narrow plates o! steel into q bar. which Is
much stronger than O solid piece OF the same
size. The reason assigned for this additional
degree Of strength Is the simple fact that. II
tho outside layer OF metal is broken the inner
layers are intact and will resist further strain.
while in the case OF q piece q solid steel the
wrapped bars are said. to be scarcely appar-
emit to the naked eye. only appearing when the
course. requires a great amount Of force. The
advantage o. using these WRAPPED bars under
certain cert anS eonditiSS1s v gil5 b ID better soss, ss4s5st .Sst
to a refined. ductile cast iron than to a nbrous
character OF cast iron that y small scratch on
it's surface. may cause serious. trouble II the
piece is solid and exposed to vibratory strains.
The new French substitute tor porcelain. in
the production Of which asbestos Is employed.
Is coming into use in France. and with advan-
tage it would seem. for certain purposes. Ac-
cording to Investigation. the hbres OF asbestos
arc exceedingly fine. their diam varying
between .O00l0 milllmetres and .O0O2 MILL
metres. and consequently an exceedingly fine
powder can be obtained from these, and the
particles without the addition of any
tsinSd which would BIO porous in, nature. the
pores. however. being so fine as hardly to be
the result OF puiysrizi9g tie asbestos. a pro:
cess which is rather difficult with tho use of
the ordinaty mortar. but com p II nKSS F Tasy
With water and this paste i kns.aSddj
sired form. BY healing the objects in u
s sole.Iaiu 10 Is o Z lIsSPs SItn q trans 81 li aeenoy CON.
parable to that OF ordinary porcelain. Hit Is
heated for elghtesn hours at Z en- erntuIe 81
loo G.. then the porous asbestos. porcelain
10 obtained OF u light yellow or white color; II
care Is taken to wash the asbestos powder
with sulphuric acid.
In the smelling Of gold ore the process OF
separating. as practlsed at Leadville. Affords
an example OF the simplicity and thorough
ness with which tho precious metal Is now
handled In making ready for the market
Separate piles Of ore and lead are made. to
supply the furnaces whom needed. and account
is kept OF the different mixtures and tho
weight from each required to constitute the
furnace charge. About 800 pounds OF ore. $50
pounds oflIme; 200 pounds Of Stag; and l5O
In accordancs with the character Of the ore.
and e sss furnace ,mn Su WI treat sn,i ir % tS one hundred
In twenty four hours. The lead in the mixture.
when treated In the furnace, runs down inro
tho Dottofu. CutEyiuk WIN tHc ITeclOus
metals; the Stag. being lighter. floats on ton, Of
and ne lead. or rather the tplli:n, is dlpped
poured into moulds. After oooltng the bars
are taken out and SAMPLED. q hollow punch
heing used that brings out a small core; 1t is
lots OF three hundred each. and the punchings
OF each lot are assayed.
An additional as we'll as important utiliza.
tion OF dolomite Just now is noted. 1t Is well
known that magnesia. owing to Its infusibil-
ity. has como into very extensive employment
as q lining for eonverters used In the basic
process OF steel manufacture. but. owing to
certain drawbacks In the preparation OF mag.
nestle for this purpose, resort has been had
with success to dolomite. which is a double
carbonate OF lime and mag nesia- In order to
render It serviceable In this line the calcined
dolomite 10 mixed with chloride Of mag
nesium.. the chlorine In which separates
from tho magnesia and combines with
the lime. yielding a soluble calcic
chloride which. can readily be washed
out. leaving behind the insolubls magnesia.
According to another process, the calcined do
10 treated. with dissolved sugar. lead
ing to the formation OF sugar OF lime. and do
posting the %magnesia; the solution OF sugar
Of lint Is then exposed to carbonic acid gas.
which separates the lime as = carbonate. lesy-
ing the sugar ready for refuse, Both these
systems OF producing magaesis have the ad-