The Electrical experimenter

April, 1918 ELECTRICAL EXPERIMENTER 849
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EDITED BY S.6ERNSBACK
Under this heading we publish every month
useful information in Mechanics, Electricity
and Chemistry. We shall be pleased, of
course, to have our readers send us any
recipes, formulas, wrinkles, new ideas, etc.,
useful to the experimenter, which wili be
duly paid for, upon publication, if acceptable.
Experimenter's Aphorisms
In the following, we wish to give to the
Experimenter some hints as to the use of the
different ingredients and how to work them:
(1 Always bear in mind that exact working
of a formula requires ACCURACY, CLEANLI-
NESS, PATIENCE, and SKILL.
(2) Know what you are about, before you
start to experiment.
(3) "THE HISTORY OF FAILURES IS THE
HISTORY OF SUCCESS" goes an old adage, and
it applies well to the experimenter.
(4) Many times impure, wrong or deteriorated
raw materials, spell FAILURE instead of
SUCCESS.
(5) A great many of the chemicals and ingredients
required, cannot be obtained from
drug stores; buy them at a reputable supply
house.
(6) BEFORE CONDEMNING A FORMULA,
be sure the fault does not lie with the manner of
handling it, or the purity of the ingredients.
(7) Be sure to mix the materials comprising
a certain formula in the proper sequence.
(8) When starting to prepare a mixture,
especially one containing liquids, ask yourself:
"IS THE SPECIFIC GRAVITY CORRECT, AS
INDICATED BY A HYDROMETER? IS THE
TEMPERATURE RIGHT? IS THE QUANTITY
OR WEIGHT RIGHT?
(9) Acids and water, when mixed, should be
manipulated in the proper manner, i. e., THE
ACID SHOULD BE POURED INTO THE
WATER, and not vice versa, as the solution is
liable to be forcibly ejected from the containing
vessel and into the mixer's face.
(10) For any kind of SYSTEMATIC WORK,
a floating THERMOMETER and HYDROM-
ETER, as well as measuring glasses and scales,
should always be provided, as GUESSWORK is
EXPENSIVE, and SOMETIMES FATAL.
(11) Put labels on ALL bottles, boxes and
packages with FULL INSCRIPTION as to their
contends, it will avoid troubles and mistakes.
(12) Remember that a beginner cannot expect
to make articles AT FIRST, which will compare
with regular manufactured products.—S. G.
USING TELEPHONE MOUTH-
PIECE AS FLASH-POWDER
HOLDER.
An ordinary telephone mouth-piece forms
a handy container for flashlight powder
which is to be ignited from an induction coil
or 110 volt circuit. The mouth-piece is
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Make a Flash-Powder Holder Out of That
Old Telephone Mouth-piece. A Spark Coll
Ignites the Powder.
mounted upright on a block of wood with
two wires attached to it in such a way that
a small spark gap is left inside the mouthpiece.
Over this the powder is placed.
When the push button in the primary circuit
is prest the induction coil spark jumps
the gap, igniting the flash-powder safely
and accurately. Keep your face at least 3
to 5 feet from the powder when igniting it,
and don't let your hands get closer than
this either, unless you want a nasty burn.
Contributed by an EXPERIMENTER.
AN EXPERIMENT WITH
"THERMIT."
"Thermit" consists of a mixture of aluminum
and the oxid of an element—usually
c
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Crucible min mixture
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Do You Know What "Thermit" Is7 This
Experiment Will Get You Acquainted With
It. One Use of It Is to Weld Street Car Ralls.
a metal— to be reduced, as FeaOs, MnO*
SiOj, etc. The aluminum has such intense
affinity for oxygen that it reduces the oxides
to their metals, giving a temperature
of 3000 deg. or over.
The equation of the following is
Fe,0 3 + 2A1 = AUOs + 2Fe
Mix equal quantities of iron oxid and
aluminum and place in a clay or sand
crucible, thru the bottom of which a Yi inch
hole has been drilled, and the hole fitted
with a cork. Support the crucible on a
ring support or a ring stand, as shown in
Fig. 1. Place some wet sand in a pan, and
set about 6 inches under the crucible. A
small hole is made in the sand with the
finger and two nails placed in it as shown
in Fig. 2. They should just touch each
other. A piece of magnesium ribbon is
placed in the mixture in the crucible and
ignited. As soon as the ribbon is lighted
the cork should be removed with a pair
of pliers. This must be done quickly, and
the operator should step aside and avoid
being burned by the spattering which is
quite considerable. The molten mass will
now pour into the hole in the sand and
weld the nails together.
Contributed by JOSEPH GRAHAM.
GLUE RECIPES.
Glue to Resist Moisture—One pound
good flake glue, melted in two quarts of
skimmed milk.
Glue-Cement to Resist Moisture—Four
parts good glue, 4 parts black resin, 1 part
red ochre ; mix with least possible quantity
of water.
Marine Glue—One part of India rubber,
heat
12 parts of mineral naphtha or coal tar ;
gently, mix and add 20 parts of powdered
shellac pour out on ; a slab to cool. When
used, it should be heated to about 250° Fah.
Contributed by FRED WILKINSON.
A SUBSTITUTE FOR WAX
COMPOUND.
When wax compound has gone up from
20 to 40 cents a pound it is not easy for the
"lean-pocketbook experimenter" to encase
large high frequency coils in the same.
Below is a thoroly tried out system which
is guaranteed to work well.
Thoroly shellac the coil three times
with orange shellac. Let each coat dry well,
and when the last one is ready rub well with
linseed oil, place in a snug box and pour a
mixture of plaster of paris and water
:
(thick) into the box, so that it is thoroly
encased. When hard it may be left in a
box or taken out and polished with oils and
varnishes. This idea, if followed out correctly,
makes a neat and compact and truly
invulnerable coil.
Contributed by
DEWELLYN P. COTTMAN.
HOW TO "SOLDER" CARBON.
Carbon may be soldered in the following
First clean the place to be soldered
manner :
and then cover the rest of the article, which
will necessarily be submerged in the solution,
with vaseline. Now, place the article
in a concentrated solution of copper sulfate
for a few moments, then remove it and
clean ; repeat this till the platjag becomes
plainly visible. The joint may now be soldered
in the usual manner with paste and
soldering iron. It is best to make the joint
on a projection, because it can be plated
easier. This joint may be used for the pigtails
on carbon brushes, battery rheostats
made of pieces of carbon connected to
switch points and also to small battery carbons.
Contributed by E. S. COOKE.
CHEMICAL FIRE FORMULAS.
Put 9 drops of glycerol on a small piece
of paper in an evaporating dish. Then cautiously
place 6 measures of potassium permanganate
on the glycerol. Keep your face
away. It will burn brightly with a lilac
color and carbon dioxid (CO 2
) is evolved.
The lilac color comes from the element potassium.
The Manufacture of Colored Fire: Mix
thoroly on a piece of paper 4 parts of
barium nitrate, 4 parts of potassium nitrate,
y2 part of sulphur and 1 part of powdered
charcoal. Pour this mixture in an evaporating
dish. Apply match. The mass will take
fire and burn with green fire.
Contributed by JOHN R. BROSNAN.
AN INTERESTING CHEMICAL
EXPERIMENT.
Dissolve a little cobalt chlorid in some
aque regia (by heating). The mixture will
be green. Add a few drops of water and it
will turn red. Add three times as much
water as mixture and use for invisible ink
when heated it will turn blue.
Another Invisible Ink: Dissolve equal
parts of copper sulfate and ammonium
chlorid in water until it becomes light
green. When heated it will rum yellow.
Contributed by GEO. VAUGHAX.
EMERGENCY CORK SCREW.
Recently I had occasion to open a bottle
and, not having a cork extractor, very
simply accomplished my purpose by using
an ordinary screw eye in combination with
A Cork Screw in a Jiffy—Simply a Nail
and a Screw Eye Do the Trick.
a nail, as shown in the drawing. The use
of the latter provided a better means both
for turning the screw and pulling the cork
out
Contributed by JOHN T. DWYER.
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