The times. [volume] (Richmond, Va.) 1890-1903, 1898-10-02
ELECTROLYSIS
IS EXPLAINED.
Superintendent Thompson Makes the
Subject Very Clear.
HOW THE PIPES ARE INJURED.
A Subject Not New 10 Practical Elec-
tricians, But Strange to the Aver
age Layman, Pleasantly
Discussed.
HOW THE PIPES ARE INJURED.

In view of the Importance which the
discussion Of "Electroiysis" is assuming.
a reporter OF The Times sought to secure
Superintendent Of Fire Alarm and Police
Telegraph Thompson's views on the SUBJ
ject. and after considerable persuasion
got the following:
Electrolysis proceeds on the same line
and under somewhat similar conditions,
as the well-knoWn method of electro
plating, the moist earth being an immense
plating bath Of various resistances
while the gas and water pipes are the
positive and negative poles COrrosion Of
the metals due 70 the electric current
goes on as surely as fate. There Is
little difference. however between the
working effects of an electro-plating bath
and the destructive corrOsion OF iron and
lead pipes.
CAUSES DESTRUCTION.
All currents following into the earth
seek the best conducting medium and
cause the destruction of the latter az the
point where they seek the earth again.
The corrosiOn OF metals Is due 20 the
water surrounds these metals and it is
decomposed into Oxygen or Hydrogen by
the electric current oxygen when freely
released is always intensely active I'm
combining with any metal present Lead
and iron pipes buried ia the earth are
frequently covered with a film of water
Ga an cases the lead pipe takes the place
of the positive and negative plates in the
eiectro-plIung bath.
~ the current of electricity. after
travelling along tho surface of the lead
leaves it 90 seek "a point where the
earth potential IS lower than that OF the
lead. 10 decomp0scs the water. and the
free nascont Oxygen Immediately enters
into combination with the lead surface
To- produce lead oxide in the form of
paste. and iron oxide or rust in iron.
The crust OF oxide being permeable by
water "a fresh surface of the metal is In
contact and presented 90 the moisture
and the process is CONTINUED indefinitely
until the lead is destroyed or the trouble
sought after and remcdied. The amount
Of metal thus decomposed depends on the
amount OF current flowing from the metal
TO the ground while the potential may
be very low.
THE TROLLEY SYSTEM
"Now. II 7 have made the matter Of
electrolysis perfectly plain 10 YOU" said
the Superintendent "and without going
too deep into scientific dehniations. 1 will
tell you something about the trolley sys-
TENS and viii try and avoid the use of
technical terms SO as % give those un-
familiar with the subject some idea of
how the current from the trolley seeks
tho underground pipes.
"ihe current is generated AT the power
station by dynamOs and .onveyed by
means of large copper wires strung on
poles 90 the single trOlley-wire which eX
tends the whole length of the road, and
which Us called the positive wire. The
current is taken from the troley-wire bg
means of q metal wheel pressing up
against the trollcy-wire. and conveyed
thence TO the motor, where after per-
forming its duty. it is returned TO the
crack by means of the car-wheels.
Just here is where the t'1ubie COM
mences. it is necessary 10 carry the cur
rent back 10 the starting point. or dyna-
mo at the power house This is done hy
means of the rails themselves. and if the
rails do not extend all the way to the
power house. a wire OF sufficient size is
attached 90 them 10 carry the current
back go the dynamo. and thus complete
the circuit This current, after leaving
the wheels always seeks the easiest path
back 10 its source in the same manner,
So DO speak, ass water Will seek its leve
theoretically tho current is supposed 10
return by the rails, but it does not always
do SO. as imperfect joints and tire want
of carrying capacity in the rails will inn
pede it's progress, and 10 viii az once seek
through the moist earth. some easier
path. such as gas and water mains and
the Ike. After getting on these pipes, the
danger line Us when 10 leaves them again,
seeking for still easier path for its re-
turn DO The power house.
NOT a NEW SUBJECT
"This subject IS not at all new TO prac-
teal electricians. 10 having been discussed
ana re-discusf by electrical conventions
of which I am "a member for the past
five or six years. until finally we have
decided that la order to avoid the trouble
of electrclysls. We must stop using the
rail CAS- a return and while i have made
no official test ass TO the damage being
done 20 our gas and water mains. Sc viii
be a hard matter 20 suggest "a remedy In
part or as a whole. as the soil In each
city has a great deal to DO with fhe prob
lem. and the fact that our roads nave
been running for the past twelve years,
and that only recently has electrolysis
come 20 light in this city.
"A5 electric roads are among us 10
stay. and / do not think that the public
would do without them, ana as the water
supply is a puolic necessity on which
the lives and property depend. I think
this Is a matter that should be thor
oughly investigated. that is, volt and
ampere readings should be taken all over
the city, and when leaks are found. the
rails should be properly re-bonded and II
necessary. large copper returns used In
addition 20 the rails.
These tests could be easily made by
any one connected with the Gas or Water
Departments. after being shown how TO
use the instruments. Wherever defects
are discovered they should be al once at
tended to and steps taken 20 preyentitheir
occurring again"