Los Angeles herald., 1908-09-13

ing, while, in the case of the arc light, the pen
! ellis are heated in ordinary air, and conse-
quently they gradually burn away and form
carbon dloxidc with the oxygen OF the air.
Having explained the principles on when
the lamps work, | will now give fuil details
how to set up a small number for amusement
and home use. / say for amusement, be-
cause we shall not be able to make them
take the place of oil or gas to any extent
without mourning great expense and more
bother than they are worth.
| But il we arrange only to use one lamp at
a time we set up two or three, each IN
different room, and it will be most convent
cnt for any one who only wants to go into
one of the rooms for a few minutes and does
not want the s.reuble Of lighting candle or
lamp.
There are two methods of lighting the
lamps which are most in vogue at the present
time-that is, by means of machine called
dynamo" and by means of battery
| The former has the advantage that when
the lamps are wanted for a long time, they
will continue to burn as long as the dynamo
| is turned, a continual current being produced
by turning the wheel.
| A dynamo is too elaborate a machine for
my readers to make, and if they care to get
one for the. fun of seeing it light the lamps
when turned, they can buy one for from three
to fifty dollars, and upward, according to the
length of their purses and the number of
lamps it is wanted to light.
| The difficulty, when a dynsmo is used. is
to find the motive power to turn the wheel.
/ One cannot victimize oneself the whole even
| ing in order that others may be able to see
| to carry on their work, and If the dynamo
ceases turning the light at once stops.
| If water-power is at hand, and any inge-
nious reader can think out method whereby
motor can be constructed to turn the dyna-
mo, or procure one ready made, this is the
/ best plan; otherwise a small steam OF gas
engine will have to be used, or a hot-air en-
CINE if strong enough; but all this adds to
| the expense.
The advantage of using battery is that
| if suitable one is chosen. the light win be
very little bother to attend to, and none at
all at the time required.
The battery being always ready for use,
there is no trouble about starting the dynamo
i to light the lamps. A switch fixed in
some convenient place turns them on in amin
slant without attending to the battery in
any way Only land it is very large "only' }
we cannot light our lamps for more than halt
an hour at a time, unless we are prepared to
give great deal of time and attention to the
battery.
We can run them for twelve hours consecu-
lively, but only by sacrificing the solution and
starting the battery afresh at the end of the
twelve hours.
If we are content not to run the lamps for
more than half an hour at time, we can
manufacture battery which will work for
at least a month without recharging, and
which will be ready to work at any moment,
/ day or night, during that time. If worked
for shorter time, the battery may last two
or even three. months, under exceptional cir
i cumstances, without recharging.
First of all comes the question how to make
| this battery. There are certain parts of It
that we must get from a dealer, as we can
not make them ourselves. Any responsible
dealer in electrical goods will supply our
needs and give valuable directions in the
bargain.
To begin with we must order FIVE carbon
plates, SIX inches by one and a half inches,
with binding screws attached, five cast zinc
rods with terminals, and FIVE porous pots, p
in diameter. This would bring the cost OF
the purchases to three or four dollars.
Having procured these necessaries we must
find or purchase five large glass jars about
seven inches high and five in diameter. The
porous pots. are now put into the jars and
the zinc rods inside them, the carbons being
placed outside in the jar
1 We now join esca zinc rod to the carbon in
top of the carbon, pushing the wire attached
to the zinc down over the screw, and screw
ing on the nut again.
This win leave one zinc and one carbon not
connected together if the jars are placed in a
row, We now fasten a piece of covered wire
i to the carbon which is not connected. and
another piece to the zinc at the other end
Of the battery.
/ Now we have to charge the battery, which
we do by dissolving four ounces of bichro-
mate Of potash in one pint of boiling water,
and leaving it to get cool. We also make up
a solution of sal ammoniac by dissolving six
ounces of it in hot water, using one OF the
porous pots to measure the water and filing
liz five times nearly full.
When these two solutions are cold, ten
ounces Of common hydrochloric acid are add
ed to the sal ammoniac solution, and it is then
noured into the porous pots, in which the
zines have been placed, nearly to the tops Of
the zines.
In the outside jar we put two parts Of bi.
chromate of potash solution and one OF com
mon hydrochloric acid till the jar is nearly
full.
These chemicals can be obtained from any
druggist It win cost about thirty cents to
charge the battery.
If this is found too expensive The sal am.
moniac solution can be replaced by weak
eoIuficn ~ chIo,ide of zinc (the odd hits can