Watertown republican. [volume] (Watertown, Wis.) 1860-1906, 1874-09-16
Scientific Items,

| SclenClnC Items.
MIXTURES OF PLASTER OF PARIS WITH
MARSH MALLow RooT. Addition of
Two to fourper cent. of powdered marsh
mallow root to plaster of Paris affords
a mass that sets in about an hour and
becomes so hard when dry that it may
be sawed and turned, and which is used
for the manufacture of dominoes, dice.
&c. With eight per cent. of the root a.
still harder mass is obtained. Ii NAV
be rolled into thin leaves, and be painted.
vanished or polished.
PREPARATION OF COMMUNICATION
a recent study of coralline, Commaille
concludes 1. That it is obtained at
temperatures from $500 to 3O2 o, the
product being larger and the process
more rapid at the lower temperature.
2. The quantity of oxalic acid required
is not as large as generally stated. 3.
Coralllne forms no definite salts, but
only lakes. 4. Yellow coralline is not
acid, and rosolic acid is consequently
mlsnomer. 5. Red coralline is no amid
OF the yellow, since it contains no nj
trogen.
| DESTRUCTION OF NIGHT-F1YING IN
sECTs.-Millions of insects injurious to
trees may be destroyed by keeping up
numbers of small fires from twilight to
midnight, and surrounding them with
circles of 20 to 80 tarred stakes, not
more than six inches apart. Although
lew insects will be found burned to
death, since they soon seem to acquire
dread of the fire, many will be caught
in the tar while moving about in the
warmed stratum of air or to and from
the fire.
| CLEANING GILT ARTICLES me-
tallc articles may be cleaned by rub
blng them very gently with a soft
sponge or brush dipped in solution of
one-half an ounce of potash, or one
ounce Of soda, Or still better, of one
half an ounce of borax i'll pound of
water, then rinsing them in pure water
and drying them with soft linen rag.
Their luster may beimproved in special
cases by warming them slightly and
then rubbing them very gently. Gilt
frames, &C., should only be washed
with pure water, rubbing very gently
With soft sponge or brush.
WEATHER-PRooF COATING FOR ZINc.-
According to Puscher, the addition of
sesquioxide of iron to solution of
basic acetate of lead affords fine
brownish red permanent coating for
zinc; and by the substitution of other
pigments lighter or darker coatings, of
any desired shade, may be impaired to
architectural zinc castings. Deep
black, permanent characters may be
formed on clean sheet zinc by writing
upon it with steel pen with solution
OF equal parts of chlorate of potash and
sulphate of copper in thirty-six times
the quantity of hot water, and washing
and drying the zinc after a few min
utes. This fact may be especially use
full to gardeners.
LPPMAN's SMALL ELECTRO CAPILLARY
M oToR.-The following fact has been
applied by Lippmann in the construc-
t1on OF very novel, small motor. pro-
ducing 100 revolutions per minute, and
which is so exceedingly sensitive to the
slightest electrical current that it's use
for electrometrical purposes is suggest
ed, as well..a it's possible adaptation to
the reception of messages by ocean
cables. If a globule of mercury.
several millimeters in diameter. covered
with water calculated with sulphuric
acid, and but slightly colored with
bichromatic of potash, in a glass or
porcelain vessel, is touched on the side
with on iron point, it at once contracts.
thus altering its shape, again expands
until 1t touches the needle point, then
again contracts, and so on, giving
rise to curious reciprocating move
ments. This peculiar effect is due to
the alternate oxidizing and deoxidiz-
ing effect of the bichromate and iron on
the mercury, whereby it's capillary
properties are modified; and singular
phenomenon is produced when the
mercury is alternately connected
with the positive and negative poles
OF galvanic cell. In applying the
force thus generated, on large scale,
Lippmann placed two vessels of mer-
curry in glass trough filed with ascid-
ulated water, and with pistons COM
posed Of capillary tubes filled with
mercury, inserted into the vessel of
mercury the alternate contraction and
expansion of the mercury in the pis-
tons, as they are connected with one
or the other pole of a galvanic battery,
furnishing the motive power in the
case.
MELTING AN EXTRAORDINARY Mass
OF PLATINUM largest mass of the
alloy of platinum and iridium that has
ever been melted at one operation was
recently fused at Paris in the presence
Of the executive committee of the
National Metric Commission. This
mass OF the alloy in question was in
tended to be run into mold of such
shape as to afford eventually number
OF new line standard meters, which will
all be cut from the single ingot, and it
is expected that the surplus metal will
even then be sufficient to make all the
required new standard weights or kilo-
grams and number of end standard
meters. The weight of the great ingot
In question was $50 pounds avoirdu-
pois; it's length about IS inches; it's
breadth inches; depth p inches.
The process of melting was facilitated
/ y first dividing the material into small
Iieces; small quantity was then
melted, and to it were gradually added
the remaining portions IN the form Of