Chicago eagle. [volume] (Chicago, Ill.) 1889-19??, 1893-08-12
POPULAR SCTENCn NOTES.

Why CAR WHEELS WEAR OUT.-A
car wheel wears out because the metal of
which it is composed comes away in thin
scales. A microscopic examination
shows that the continual Earring has 8
tendency to destroy the Conference of the
particles, and thus gradually disinte.
CRATES the whole Car wheels long in
use become so brittle that stout blow
with heavy hammer will sometimes
cause them to fly into fragments as
though they were made of glass.
ELECTRICITY UNDER PARIS. - The
projected underground electric rail-
way to unite the Bots de Boulogne
and the Bots de Vincennes, in Paris, is
to consist of circular cast-iron tube
twenty feet in diameter and seven miles
long, in which will be laid double
track. Trains of four cars will be run
on each track at intervals of two min
utes. Stoppages will be made at seven
teen stations, and the whole distance
from one terminus to the other will be
traversed in about forty-f five minutes.
Steam engines of 1000 horse power will
generate electricity for running the cars
and lighting the subways.
METALlzING CLoTH.-An interesting
announcement is made in the French
papers of the discovery OF process for
metalizing textile fabrics, by which, it is
claimed, the latter are rendered proof
against the attacks of insects. The
materials, such as wool, flannel. calico,
etc., are for this purpose imnerse in a
boiling bath composed of two and one
half pounds sulphate of copper, one
pound of sulphuric acid, and sixty
two gallons of water the fabric being
calendered and dried after its removal
from the fluid. The finish obtained by
this process will, it is said, bear two or
three washings before it is again neces-
sary to subject the cloth to repetition
of the operation.
SMOKE CONSUMERS. Notwithstanding
che many and ingenious methods which
engineering skill has proposed for con-
Stunning smoke, especially in the case of
bituminous coal, the simple steam jet
device is proving a most satisfactory
continuance. A piece of two-inch pipe
runs horizontally along the front wall of
o furnace, just under the boiler; at one
end it is capped, and at the other it
turns outward through the front WALL
then passing downward and through the
front again into the ash pit The lower
end of this pipe is placed well to one
side of the ash pit, so that it may not be
in the way of the fireman, and opens un-
der The CRATE so that it may receive air
that has been warmed by the downward
radiation from the furnace inside of the
upper horizontal part of this pipe, a
piece of half-inch steam pipe is secured
which comes out through the setting at
the side opposite to that on which the
air pipe makes its exit, and then passes
upward and enters the boiler at its high
est part, so that the steam drawn through
1t may be dry as possible Small nozzles,
with holes one sixteenth Of an inch in
diameter, and six inches or so apart, are
attached to that portion of the steam pipe
enclosed in the air pipe in the furnace,
and these come opposite similar but
larger nozzles fitted to the air pipe itself.
On the valve being opened, steam blows
out through the nozzle, drawing air
along with it by kind of ejector- like
action, and the nozzles are so placed that
the discharge of mixed air and steam is
directed toward the angle formed by the
bridge wall and the CRATES.