The Bossier banner. [volume] (Bellevue, Bossier Parish, La.) 1859-1952, 1879-06-19
USEFUL AND SCIENTlF 1C.

Cesoiul LeS6s, III appears, nave Deeu lusttte
with cotton-seed hulls as a non-co
ductor of heat in the case of freless
railroad engines. The tank or receiver
of steam was covered about two inches
or less with the material, confined to it
with canvas; this method proved to be
so successful as to induce its applica-
ton to either dummies, coating them
| with canvas, sheet iron, or wood lag
ging. An examination made after three
years. trial shows the hulls to be unim-
paired as a non conductor; they were
colored brown for one third of an inch,
but not materially cha-red, though they
had been exposed for nearly all the three
years to a temperature of 5000. Prac-
tically, they are understandable at the
temperature of steam In boilers.
COOKING BY SOLAR HEAf.-M
Mouchot's apparatus for cooking by
means of solar heat has attracted much
attention ia Paris. It consists of a
truntated cone mounted on stand
similar to the tripod of level, so con-
structed that the axis Of the cone can be
adjusted to suit the position of the sun !;
the inner surface of the cone is polish
ed, rejecting the rays of the sun toward
the axis of the cone, where glass cylin-
der is placed, serving as a receptacle
for the water that is to be distilled or the
food that is to be cooked. With cone
16 inches in diameter and 10 inches
high, M. Mouchot has succeeded in
cooking beef in 8 hours and 80 minutes
in France, while only hours were re-
quired in Algeria; poultry was cooked
in % minutes in France, and 20 in Al
geria.
THE LIGHTNING ROD.-The St. Louis
Academy of Science has been throwing
light upon the lightning-rod, concern
ing which, said Professor Nipher, there
are many popular decisions. One is,
that if one of two rods containing an
equal amount of metal be followed out,
thus giving it greater expanse, its con-
ductive power would be greater than
that of the other. The truth is that they
would be equally as good conductors.
Another erroneous impression which
the Professor proceeded to dispel was,
that a current of electricity runs along
the surface of the wire. In reality il
extends through the entire wire when
the circuit is made, Mr. Nipher said, but
when the circuit is closed, it accumu-
lated upon the surface OF the conductor
A strong point made was that lightning.
rods do not attract lightning. They are
splendid conductors-much better than
wood or air-and lightning strikes them
because they offer the least resistance to
the passage of the electric current. 1t
makes no difference whether point be
on a ightning-rod or not, so far as the
protection OF buildings is concerned
The positive electricity in the earth will
flow along the wire and accumulate al
the point, if there be one, making the
tension and the conducting power great.
er, and enhancing the probability OF
lightning striking that rod in preference
to another which has no point, but has
the positive current disseminated
through it equally.
FoOD.-The various matters which an
animal eats consists of pure food-stuff>
and of useless concomitant bodies Just
as coal consists of pure fuel and of the
useless mineral matter known as ash.
When an animal eats his dinner, the
process of digestion and assimilation
takes place, and has the ultimate result
of separating the pure food-stuffs from
the useless ccncomitants. The latter
bodies are rejected at once; but the
food-stuffS are taken up by his veins, in
corporated with the blood (Which con-
sists of food in different degrees of COM
bustion), and used for building up the
various portions of his body. Suppos-
ing the animal were g mere growing
object like crystal, with no work to
perform and no consequent waste OF
material, the process would stop here,
and the creature would wax bigger and
bigger from day to day, without any
alteration in place or redistribution OF
assimilated matter. But the animal is
essentially q locomotive machine, and the
purpose for which he has taken in his
food is simply that he might use it up in
producing motion. For while he slows
it away in his muscles, or lays it by for
future use as fat; but its ultimate DIES
tination in every instance is just as truly
to be consumed for fuel as is the
case with the coal in the steam engine
The food, however, only gives US one.
half of the necessary materials for the
liberation of dormant energy. Oxygen
is needed to give US the other half.
This oxygen we take in whenever we
breathe. Animals like fishes or sea-
snails obtain the necessary supply from
the water, by means of gills; for large
quantities of oxygen are held in solution
by water, and the needs of such com.
paratively sluggish creatures are not
very great. With them little energy
goes long way. Air-breathing ami.
mails like ourselves, on the other hand,
need relatively large quantities of the
ergy-yielding gas, in order to keep
up the constant movements and high
temperature of their bodies. Such
creatures accordingly take in the oxy.
gen by great inhalations, and absorb ii
in their lungs, where it passes through
the thin membrane of the capillalies, or
very tiny blood-vessels, and SO mixes
freely with the blood itself. Thus we
have food supplied to the blood by the
stomach. the exact analogue of the coal
in the engine; and oxygen supplied to
the blood by the lungs, the exact ana.