The Mankato free press. [volume] (Mankato, Blue Earth County, Minn.) 1879-1924, 1880-05-21
POPULAR SCIENCE.

POPULAR SCIENCE.
An observer of Vcsuvius notes an in
creased activity in the crater at the time
of each full moon.
ENGINEERs state that speeds of over
sixty miles an hour are now common
with many Of the express trains in Great
Britain.
"PoRK worms" are not confined to
hogs and man, a large number of
trichine having been found in hippo
potamus.
AN Algerian company intends to cult
vate the Sahara, boring artesian wells i'll
carefully selected spots as means OF
irrigation.
WHEN pen has become 80 corroded
as to be useless, it can be made good as
new by holding in the fame Of gas jet
for half minute; then drop it in cold
water, take out, wipe it clean, and it will
be ready for use again.
PROLONGED exposure to very intense
cold has very little influence in destroy.
ing the terminating power of seeds. De
Candolle and II. Pictet subjected the
seeds of plants to temperature of eighty
degrees without injurlng them very
seriously.
From an investigation instituted by
the Rev. j. i. Tension Woods, it APP
pears that the large trees of the forests
of Tasmania are only half as old as they
are popularity supposed to be. Instead
of adding only one ring of wood to their
circumference III year, they add two
hot al, 30 L..
100 years old is i'll reality only 80 years
A RIFLEMAN who was at the battle of
Ulundi collected enough of the bullets
fired mt the British by the Zulus at that
place to make CRATE, fender, fire-irons,
ETC., of them. This novel conversion of
deadly missiles into model of peace
full fireplace, which is said to have been
done with taste and skill, has been pre-
scented to the museum of the Natal So
ciety.
To prevent the oxydation of n new
iron tea-kettle, first wash it thoroughly
in sapolio soap, rinse well in clear hot
water and dry over the back of the
stove. Scald out thoroughly before us
ing and put one or two clean oyster
shells into the kettle, and keep some
there all the time till the kettle begins
to grow smooth and shows no longer
any signs of rusting.
To clean smoke off marble, wet piece
of flannel i'll strong ammonia, and rub
the marble quickly with it and then wash
off with hot soap suds; or make paste
of chloride of lime and water, and brush
over the whole surface that is smoky.
Let it stand minute, then wash with
hot suds. A paste of crude potash and
whiting brushed over grease spot on
marble will cleanse it perfectly.
LOOK to your lightning-rods; the thun-
der storm season is here. Insulated
lightning rods are dangerous delusion;
they are the reverse Of protection. So
is any rod which does not run up to
every high point on the house, not well
connected with all large masses of metal
roof ornaments, water spouts, etc.
and well sunk into the ground. 1t ought
to come in contact with the damp earth;
better yet, with water.
The smell of onions and other odors
can be removed from kettles and sauce
pans. Put some wood ashes into the
utensils, add boiling water, and let it
stand n short time on the back part Of
the stove. Or, if you have no wood
ashes, use potash, soda or concentrated
I've with water; then wash in hot suds.
All cooking utensils in which onions,
cabbage or turnips have been cooked
should be thus cleansed.
DIR. CARTER says the entire absence of
sunlight on the deep sea bottom seems
to have the same effect as the darkness
of caves in reducing to rudimentary
condition the eyes of such of their in
habitants as fish and crustacea which Or
dinarily enjoy visual power; and many
of these are provided with enormously
long and delicate feelers or hairs, with
which they feel their way about, but as
blind man does with his stick.
A SIMPLE and interesting experiment
i'll magnetism has been introduced by
Prof. Thompson. A thin plate of hard
ened steel is written upon with mag
netized iron style, and the path traversed
by the style is thus magnetized. In or
der to read what had been written, iron
filings are sprinkled on the plate, and
the plate is then placed in n vertical po-
sition, when, of course, all the filings
fall off except those which happen to fall
on the part of the plate magnetized by
VIC otyie, iSaNIhS thc Wihih5 III iSiei'
A VALUABLE process for chemically
blackening zinc, and thus rendering it
particularly adapted for roof covering, is
described in the transactions of the
Frankfort "Physisches Verein." The
method consists in first securing the zinc
to be operated on with fine sand and very
dilute hyilrochloric acid, and then plung-
ing it into solution of equal parts
chlorate of potash and sulphate of cop
per in thirty-six parts of water. When
withdrawn, after a short interval, it is
found to have taken up fine coating of
velvety black, which, however, ut this
state, very readily comes of. To insure
its permanently, the zinc thus coated is
quickly washed with water, allowed to
dry, and then plunged into weak solu-
ton of asphalt in benzole. The excess
of this fluid is allowed to drain off, and
the color can then be definitely fixed by
the very simple process of rubbing the
sheet with cotton plug.