The workingman's advocate. [volume] (Chicago [Ill.]) 1864-1877, 1870-07-02
SCIENTIFIC AND MECHANICAL.

TWENTY years ago all the slate pencils in
America came from Germany. In 1850,
q young man in West Rutland, Vermont
eighteen years Of age, discovered supply
of stone from which be could make as good
slate-pencils as were sold il the stores. He
bought the quarry for one hundred dollars,
and commenced operation on limited scale
in saving out penciIs. The business grew
on bis hands; machinery was invented to
facilitate the process, and to day upward Of
hundred men manufacture daily $4,000
pencils The mills are valued at $500, 900.
An express train on the Allegheny Val
ley Railroad, running at the rate Of forty
miles an hour, was lately brought up ali
standing against an obstruction on the track,
consisting of rocks and dirt, the result Of a
landslide This train was fitted with Mill
er's platforms, buffers, and couplers. Not
withstanding the fearful velocity Of the train,
no lives were lost, as the ears did not tee-
scope, as ordinary fastened cars would have
done under the same circumstances.
Mlller's inventions should be adopted on all
railroads without delay. On the Missouri
Pacific Railroad, nineteen passengers were
lately killed By the telescoping OF the cars
Tue Boston Journal of Chemistry gives
the following recipe for making cement for
acquariums Take ten parts, By measure
Of lltharge, ten parts Of plaster Of Paris, ten
parts of dry white sand, one part of finely
powdered resin, and mix them, when want
ed for use, into pretty stiff putty, with
boiled Gnseed oil. This will stick to wood,
stone, metal, or glass, and hardens under
water. 1t is also good fer marine acquaria,
as it resists the action of salt water. 1t is
better not to use the tank until three days
after it has been made.
Nj. DIDIERyEAN read a note at q recent
meeting Of the Academy of Sciences, call
ing attention to the fact that milk is a
Ps1Ss.v~tivv from tSo poisonous rfFoote
produced by lead upon the workmen who
are engaged in the preparation its com
pounds.
The Viceroy Of India recently visited
the ancient salt mines Of Pind- Dadun
Khan, in the PuDjab, 10 miles north
west Of Lahore. These mines are inter
estiDg as dating from the days Of Alex.
snder, and as being worked by the actual
descendants Of the original miners One
Of the mines (nine in all contains a circu-
lar ball ninety feet across and forty feet
high. The supply of salt seems inexhaus-
tible.
The MANUFACTURE OF CHLORoFoRM.-
According to the late James Y Simpson,
there is a single manufactory Of chloroform,
located in Edinburgh, which makes as
many as eight thousand doses day, or
between two millions and three millions Of
doses every year-evidence to what an
extent the practice is row carried Of wrap
ping men, women, and children in a pain
less sleep during some of the most trying
moments Of human existence.
AN invention has recently been intro
duced for the purpose of increasing the
Illuminating power Of gas. The apparatus
is simply thin disk Of some incombusti
bic material-glass, porcelain, or metal
which is pierced with one or several holes,
the apertures or aperture being proper
toned to the diameters Of the different
burners. The size of the pierced disk may
be the internal diameter Ct the chimney. 50
that it may be fixed at the upper part ; or
it may be little larger, SO that it may be
placed directly upon the chimney.
ZINC RoOFING.-The rapid oxidation
of zinc when used as roofing may be
obviated by coating it with a liquid
prepared as follows; One part By
weight of copper scales, with one part
Of sulphuric acid and three parts Of
hydrochloric acid, are heated in a por-
celaln vessel until red fumes cease to Be
evolved and the copper Is entirely dis
solved; to this sixty-four parts Of water