The Washington herald., 1917-10-21

an electro-chemical unit, containing
plates of a lead composition submerg-
ed in a solution of sulphuric acid,
known as electrolyte and having a
specific gravity of 80 at 20 degrees
fahrenheit. The plates in the battery
are Of two distinct kinds, known as
positive and negative. The current
leaves the battery by way OF the
positive and returns through the neg
ative. The battery plates are made
In the form of grids. the spaces being
filled with a special composition of
lead. The positive plates have a fill
er consisting of peroxide of lead. red
dish brown in color. The negative
plates employ spongy composition
of lead.
These plates are separated by strips
Of specially treated wood, or some
times of other materials. The ele-
ments, positive and negative plates
are inclosed In Jars of hard rubber,
which are filled. or nearly so, with a
solution OF sulphuric acid. Each Of
these jars is known as a cell, and a
battery may consist OF one, two,
three, four or more cells. according
to the power needed.
The word storage" in connection
with the electro-chemical battery
conveys a false impression. The stor-
age battery does not store anything.
The actual work Of the battery con-
sists in a chemical action between
the acid solution and the active ma
terial contained in the plates Now,
this chemical action is always going
on within the battery, even when il
is not actually giving out current
But when the part is being called
upon to deliver power. the violence
Of the chemical action Is enormously
increased. electrical current in gen.
Grated and dispatched on its way as
directed by the driver of the car TO
start the motor. light the lights or
what not.
The chemical action within the bat
Terry which produces the current also
produces a substance known as lead
sulphate. which is deposited on the
plates. This sulphate is a white sub
stance. and its presence on the plates
weakens the action of the battery,
because its formation has actually
withdrawn acid from the solution or
electrolyte. Thus, if this condition
reaches its ultimate stage. the plates
would be thick with sulphate depos-
its, and all the acid would be with
drawn from the electrolyte, leaving
plain water. In this case the battery
would be able to produce no current
whatever.
Now, when electrical current from
an outside source is sent into the bat
terry, 1t causes. a reaction to take
place, which is exactly the reverse of
the former, as ii breaks up the sui
phate deposit on the plates and drives
it back into the liquid in the form of
acid. When this operation has been
completed and all the deposit has
been removed. the battery is ready
to begin its chemical action again and
produce electric current.
1t is obvious that the liquid with
which the battery cells are filed, in
the course of time, will suffer evap-
Grafton. This is doubly so. because
the chemical action of the battery
produces a certain amount of heat,
which hastens losses, due to to inevi-
table evaporation. To make up for
this and keep the liquid UP to the
proper level, distilled water must be
added at regular intervals-once a
week in warm weather and once in
two weeks during the cold season.
thtered water may be bought at any
drug store or garage, or rain water,
or water made by melting ice may
be used. When the liquid has been re-
duced by evaporation, obviously its
acid content is just the same. and all
that is necessary is to bring it up to
the necessary proper level by add
ing the plain water.
On the other hand. If any of the
liquid has been spilled or has leaked
out of the Jars. in any way, acid also
has been lost, so that in replenishing
it will be necessary to add acid and
water in proper amounts-that is to
say. with a specific gravity of 40
Fahrenheit.
whenever the owner opens his bat
terry to refill the cells with water, he
should test. the electrolyte with an
instrument called a hydrometer syr-