Mineral Point tribune. (Mineral Point, Wis.) 1869-1938, 1893-02-18
A Simple Explanation Whicl
Should be Of Interest to Ali
Laymen.
Origin Of Terms Volt and Ohm
Resistance Of the Body to
Electricity.

Probably few people when turning on
a water faucet In their house, or playing
hose in their garden, ever realize that
the laws controlling the flOw Of water
have a great similarity to those govern
ing the subtler fluid electricity; and
whether they turn on a faucet or an
electric light, certain conditions exist
and cctain actions follow which are an
alagous.
The water in the faucet is under a
certain pressure. and an amount of wa
ter flows out Of the faucet dependent
upon this pressure and upon the size
of the faucet.
An electric current In a wire is under
a certain pressure, and an amount of
current flows through the wire depend
ent upon the pressure and upon the size
Of the wire,
In a garden hose water under good
pressure, II allowed to escape through
q small nozzle, will be forced a consld-
cradle distance In an incandesecnt
lamp, current under a fair pressure is
flowed to escape through the minute
fiament Of the lamp, heats the filament
to lncandesccnce, and throws ont beams
Of light Not That electricity is a fluid
in the sense that water is, says the New
York World, or that there Is any actual
TRANSFORMED OF matter when current
passes through a wire, as ther9 is when
water flows through pipe; 1ut there
Is a close analogy between the laws
governing the two, and 1t Is Just as easy
and as simple to predict the actions OF
one within certain range of conditions
as II is Of the other,
The great trOuble has been that cleo
trlclans have thrown Il veil of mystery
over their calling by naming all their
units after French and German celebIi-
ties This has led TO no end of confu-
sion. Volts, ampers ohms, waite, dulles
and coulombs are becoming common
words in print in these days Of great
electrical activity, but they express
about as much meaning to the average
person MS Il Chinese laundryman's sign.
Pounds, quarts and the rest of our
everyday units of measurement are fa-
miliar to evrUy school child; so will volts
and amperes be some day when the
American people are better acquainted
with the doin-s of these distinguished
foreigners and the units their names now
represent
Alexander Volta was a professor of
physics in Pavia, who accomplished a
great deal in n scientific way; conse-
quently electricians not only erected n
marble tablet 10 his memory, but agreed
to name the electrical pound per square
foot after him, and so the unit of cleo
trical pressure is the volt. Similarly
we are compelled 10 write our electri-
cal gallon with an accent over the last
syllable after ampere. ohm has had
his name used as the unit of electrical
resistance ever since he gave to the
world his celebrated law on the flow
Of current Ohm slid that the amount
Of current going through a copper wire
was proportioned to the pressure under
which this current worked and to the
size of the wire.
This is not very different from what
anyhOdy'S common SENSE would see
was true of water flowing through a
hose. The amount Of water is of course
proportional TO the pressure under which
It works and to the size of the hose.
Ohm made great reputation on this
discovery, and since his time other peo-
pie have been finding out that what is
true Of water is also auaiogouSly tue
of electricity. Look at an electric road.
A wire carrying current is stretched
though the nj and all man has to do
to move q car containing 100 people
along a street is to connect the car ma
chinery with the wire by pole. II
the wire was a pipe carrying water UNI
der considerable pressure and this pipe
could be connected to the car by moY-
able hose a water motor would make
the chr move just rs the electric mo-
tor does, and moreover the water would
flow through the pipe, and the hose
and the motor 70 the ground, falling
from considerable pressure to zero
pressure Just as the current lows
through the wire and the trolley arm
ana the motor ia the ground, falling
fom 500 volts pressure to zero pressure
or potential MS II may be called, which
is the potential Of the earth, just as the
zero potential Of water is the sea level
Moreover. rs n certain number OF gal
Ions of water win dow through the pipe,
the hose and the motor, dependent up
on the size Of the pipe, the hose and the
motor and the pressure Of the water
SO VIII certain number Of amperes
of current dow through the trolley wire,
the trolley arm aud the motor Winding
dependent upon the size Of the wire IA
them an and the electrical pressure Of
the current
4 me Of electric arc lights are made
T, burn by inserting them one after thee
other III series In a line current OF 4
high pressure, and the passage Of the
current through eaeh light uses MP a
certain percentage Of this pressure just