Evening capital. (Annapolis, Md.) 1884-1910, 1892-04-21
ANNAPOLIS Md THURSDAY EVENING. APRIL 81. lsss
MEASURING ELECTRICITY.
DESCRIPTION CT A PROCESS No7
GENERALLY UNDERSTOOD.

A sTsssr Ussd-Ths PrineIpIs Like That
OF EIecsroplatiaa and Depends oa
Carefully Adjusted Meehsntsm-Ds-
tsrminsd BY Weight.
There is no doubt that consumers OF
electric light and others interested have
frequently wondered how the ingenuity
Of man has succeeded in measuring the
amount Of electricity used in stores and
private dwellings. With all the investi-
cations and discoveries made electricity
is still something enveloped in mystery,
and its use is still largely empiric.
Open one of the meters of the Edison
Company aud you will find that it con-
Sists of two compartments; in the upper
you will fluid thin piece Of German sill
yer running in a zigzag line across the
compartment; in the lower compartment
separated from the upper by a bar, the
latter being a part Of the cast-iron con-
struction of the meter, there is a spool Of
copper wire and a bottle; in the latter
there are two pieces OF zinc. separated
from each other by means Of piece of
rubber. These three things constitute
the meter; some meters contain two Of
each kind, aud are called double meters,
being capable OF doing double the work
done by single meter.
The principle underlying the measur-
ing of electricity is that OF electroplating.
The latter is done by means of an cleo
trio battery, a piece of copper being
placed in the battery on the positive pole
nr ,vir and tho ohiaof ~ ho r,lataH ha;n.,
placed on the negative wirei by the
action of the electricity the copper is
eaten away from the positive wire, and
deposited on the article fastened to the
opposite wire. In the electric light
meter two pieces Of zinc are used this
zinc must be chemically pure in order
that the measurements may be perfectly
correct. These two pieces Of zinc are
separated by rubber, aud joined byrub-
Der bolts, so that they may be near each
other, aud still not permit of passing Of
the electric current.
One piece represents the positive pole,
the other the negative pole. Now, the
more electricity passes through these
pieces Of zinc the more zinc will be taken
from the positive to the negative pole, so
that il enough electricity Is used, in
course of time all the zinc would be on
one pole. Here you have the principle
Of measuring electricity. After the
pieces Of zinc have been in operation for
some time one will weigh more than the
other, and it is just matter Of mathe-
matical calculation how much is charged,
the chars> being relative to the amount
Of zinc decomposed.
But il the bottle were all that was used
for the measuring of electricity, il would
require bottle the size of q house to
measure the electricity used in the
average residence or store, and the con-
sumption of zinc would be something
enormous. 1t is for this purpose that
the piece of German silver is used, this
metal being selected as best fitted for
the purpose. This piece Of metal 10
called a shunt, because it shunts of
most of the electricity, and prevents it
from going through the bottle. This
piece OF metal is 80 accurately adjusted
that 1t takes just 999 parts of electricity
to one which passes through the bottle I;
the electricity from the electric light
wire. before it goes to the lamps. passes
through the meter; here one-thousandth
part passes through the bottle with i's
pieces Of zinc. the rest beiug shunted off
through the German silver. 1t is on this
account that the size Of the bottle may
be reduced to small dimensions.
The spool of copper wire is fixed be-
tween the wire and bottle. When the
solution Of sulphate of zinc contained in
the bottle gets too warm it permits more
electricity TO pass through it than the
one-thousandth part Of the whole; at the
same time the increase in Temperature
would have An opposite effect on the
German silver, and less would pass
through; this would result in a very
heavy registering, the amount of zinc
consumed being proportionally large, aud
would be an injustice to the consumer.
In order to avoid this the spool OF cop
per wire is used; when the bottle gets
too warm the copper wire is similarly sf-
fected. The copper does not permit tile
bottle to gobble up all the electricity it
would like, and thus acts as regulator.
1t will be seen that the measuring Of
electricity depends upon the most care
fully adjusted mechanism; as a matter.
OF fact. the weighing Of the zinc negative
plate is the more delicate. The pieces CT
zinc are separated. aud the negative
pieces, which are indicated by being OPP
posite to where the head Of the rubber
bolt is, are carefully washed and per-
mitted to dry.
After this their record is looked up. and
the operator knows just TO a millegram
how much each piece Of zinc weighed
before il left the works and was put in
the meter; on one of the most nicely ad-
justed scales the zinc is weighed. aud the
difference in its weight noted down; this
decrease Of Weights multiplied by figure
known as the constant, and the result is
the bill Of the consumer in dollars and
cents OF course, the zinc removed from
the positive pole is deposited on the mega
tive, and the amount of electricity used
might be ascertained by weighing the
negative piece and noting the increase in
weight; but this would not be accurate,
as some Of the zinc in process of being
transferred from pole to pole is lost in
the solution; beside that, TO determine
the amount Of electricity used in this
way would give way to fraud on the par,
OF a few consumers who understand
electricity there is no likelihood Of their
n