The Portland daily press., 1893-11-22

coffee pots and covered dishes intended
to retain heat it serves admirably.
Various accouterments for German and
French soldiers are now made of alumni
mum, such as breast plates, helmets,
belts and buckles. From the military
point of view in these days it is OF the
utmost Importance to save every posslb BILE
ounce of weight in equipment, in order
that the fighting man may carry the
maximum quantity Of ammunition.
Even cartridge shells are being turned
out in the same metal The latter is
drawn down to the finest sizes of wire.
The addition of small percentage OF it
to type metal makes the type far more
durable. The remarkable development
OF the last few years in the quality OF
steel castings is due to a mixture of alumni
mum, which renders the steel more fluid.
Even ordinary stoves now contain some
what OF the same ingredient.
Aluminium in Art Castings.
A new and beautiful alloy is produced
by mixing % parts of aluminium with
rs parts of gold, the result being rich
ruby tint The white metal is also plat
ed with gold, silves and nickel. 1t is
employed in making the finest kind of
art castings by company at Passaic, N.
j., engraved, chased and repousse work
being brought out with as much per-
lection of detail and finish as is exhibit
ed, by electrotypes. The concern referred
to turns out thousans of medallions and
groups OF human figures and an mails, i'll
bas-relief, using molds of sand and plas-
ter of paris. These articles may be
thrown across the room and will not
break, as would iron castings similarly
treated. They look like silver.
Sounding boards and stringed instru--
ments of various kinds are now being
made OF aluminium, which is elastic and
capable OF vibrations through wide
range of tone-pitch. The material has
the great advantage of being proof against
moisture, and it will not split under any
circumstances. Ever since the new metal
became available at moderate price it
has been utilized by experimenters in
flying machines. Before long it will be
extensively used for bridges, because it
is SO light and strong. 1t is the sub
stance from which the new Diana of the
Madison Square Garden, New York, is
cast. Other uses to which it is being
put are for propellers for ships, valves
for air. brakes, opera glasses, picture
frames, cigar cases, medals, vases, sal
vers, watches, bicycles, brushes and
comb and forks and spoons. For these
table utensils it has the disadvantage
that a slight coating OF its own oxide al
ways gives it a greasy feeling, SO that it
is never likely to supersede silver in
this way.
aluminium has number of wonderful
properties. Most striking among these
is its lightness. Ten cubic inches of it
weigh less than pound. Iron is nearly
four times as heavy, gold nearly eight
times.
It is not acted upon by organic secre-
tions. Hence 1t is most serviceable for
wounds, etc
1t is almost proof against seawater,
and in that respect is mu CHI better than
copper for sheathing the bottom of YES
sells. Unfortunately those pernicious
mollusks, barnacles, seem to thrive on
it. as they do on steel. But an alumni
mum bronze, made by mixing a small per-
centage of the white metal with copper,
is free from this objection and serves ad-
mirably for the purpose.
aluminium is only exceeded in mallea-
bility by gold and silver In point of
ductility it is seventh among the metals,
ranking after copper in that respect. 1t
is equal to silver in taking and retain
ing a very high polish. Fine effects are
produced by first furnishing and then
stamping it SO as to show unpublished
figures in relief.
1t is absolutely non-magnetic, and for
this reason is largely employed for cleo
tricai appliances. A small percentage of
silver mixed with it hardens and
strengthens it, making it most suitable
for many kinds of engineering and other
scientific apparatus. The demand for it
in astronomical and other instruments of
physical science is growing.
An Excellant Conductor
1t is remarkably good conductor of
heat and of electricity. On the latter
account it was selected as the material
of the pyramidal cap which now forms
the apex of the Washington monument
This cap excited great interest in 1885,
when it was put on, the metal being at
that time worth s. a pound. The monu-
ment has been struck by lightning
several times, but the dangerous fluid
has been carried from the aluminium cap
down the lightning rod $50 feet into the
ground. Perhaps if it had not been for
the safeguard thus provided the huge
obelisk might even now be in ruins
Aluminium was first isolated in 1927 by
Wohler, who had previously discovered
the metals barium, magnesium and CAL
cium, obtaining them from alkaline
earths by means of electricity. Calcium
is sold at this day for $500 an ounce,
owing to the difficulty of separating it
from the elements with which it is ordi-
holIy lOulu buOuSu IL is
reckoned that the skeleton of man con-
tains S18,0 worth of it. That some of
the existing metals remain as yet I'M
known is quite certain.
For long time this white metal was
manufactured only in the laboratory of
the chemist for the sake of experiment..
Only half dozen years ago melancholy
notices were printed in the newspapers
reporting the death of the only man
who possessed the secret of producing it
in large quantities on an econom ical
basis" Nevertheless it can now be OBJ
tanned in amounts practically unlimited
for Is cents a pound. 1t is on the mar
ket in the form of ingots, plates, sheets,
bars, wires, castings, for &c. It's property
of strength without weight renders it
far more serviceable for mechanical pur-
poses in general than any other known
substance. 1t can be dissolved out OF an
clay bank by the use of concentra ted
sulphuric acid, but the process is too
costly. Sooner or later method will
be found for producing 1t as cheaply as
iron. Senator PETER has already sug-
gested it's employment as money. In the
halcyon days Of aluminium currency
everybody will have unlimited cash and
poverty may be permanently abolished.
Until recently the only.material known
to be available for supplying aluminium
was -" cryOlite" a minera ls. attained i'm