Evening star., 1912-03-10
Odor of Brass

Ooot VI LNdSS
BRASS, as everyone knows, has an awful
= odor; yet the two things of which brass
consists. zinc and copper, give no odor what
| ever in their separate states. This is
problem that has given great deal OF work
to scientists. 1t is one as yet not entirely
solved.
TO arrive at the general law, it has been
found that almost all alloys or mixtures of
two metals, will give an odor, while the
metals themselves do not. Brass is not the
single example, though probably the. most
odoriferous.
The explanation is as follows: All sub
stances, including metals, are always CIV
ing off small particles of their substance to
the air; that is, evaporating. Some solids
give these off so rapidly as soon to disappear.
Gum camphor is conspicuous example. To
smell any substance, particle OF that sub
stance has to tickle a nerve ending in the
nose. If a small particle of copper, we shall
say, does this by itself, no effect is noticed.
But if a particle of zinc and particle of
copper strike at the same time. the effect is
such as to cause a perceptible impulse to the
nerve. The chance for these two to strike
at the same time is given only when they
are intimately mixed in an alloy.
Odd Way to Make Steel Rods
THERE is employed in Great Britain
comparatively new process OF making
bars of steel and other metal. This process
consists in heating metal until it becomes
plastic, and then forcing it, with the aid of
hydraulic ram, from the COMPRISING cylin-
der through die. 1t issues from the die in
the form Of a rod, like sausage from sausage
| machine. The rods are round, square, or
hexagonal, according to the shape of the
die, and it is said that they possess greater
tensile strength than rolled bars of equal size.
Wire so small that it weighs only one-hun-
dredth of a pound to the foot in length
as well as heavy bars, are produced in this
way.
New Use for Aluminium
MYTH pencil of aluminium indelible
characters may be written or drawn
| on glass or porcelain, and when treated with
hydrochloric acid the surface covered by the
characters becomes etched. When the char
acters are not etched, but simply FURNISHED,
they exactly resemble inlaid silver. This
property of aluminium was discovered by
| Swiss scientist.
| 1t is indispensable first to remove every
trace of grease from the surface to be orna-
mented by polishing with chalk, else the
feet is produced only on substances contain
ing silicic acid, it has been suggested that an
aluminium pencil would be an unerring de-
| tector of false diamonds. Magnesium, cad
nium. and zinc act in similar manner; but
their traces readily oxidize.
Iron Bearing Plants
EXPERIMENTS are under way at the
- agricultural psychological station at
Vienna to increase the quantity of iron car
ried in certain plants, with view to the
effect on the human system when those
plants are used as food. Artifcially pre-
pared foods containing iron do not always
produce the desired effect, because the iron
is not completely assimiated.
This difficulty, it is thought, may be avoid
ed by causing plants to take up an increased
quantity of iron during their natural growth.
BY adding hydrate of iron to the sol. in
which it was growing, the experimenters have
succeeded in producing spinach containing
percentage of iron seven times as great as
that found in ordinary spinach. 1t is be-
lieved that the process will prove successful
with other ferruginous plants.
Thorium : =,
FRENCH inventions frequently call into
l use natural products that had pre-