The herald., 1898-10-28
vAGRANT ELECTRICITY
DOES MORE DAMAGE THAN THE
oLD-STYLE HOBO
Public Property of Many Kinds En-
dangered by Electrolytic Action
of Escaping Currents

NEW YORK, Oct. pa. A. Knudson
read paper before the last meeting OF the
American Institution OF Electrical En-.
gineers on yagrant electric currents and
| the vast amount of damage that may be
inflicted by them on all metallic structures
| in whole or in part Of subterranean char'
acter.
| Mr.. Knudson showed as result OF ex
haustiye tests made by him that the escape
of the electrical current from overhead troll
leys exercised damaging influence on the
elevated structures and the system OF water
pipes in the upper parts Of the city.
He also showed that currents escaping
| from trolley lines in Brooklyn found their
| way into ali the lower section of New York
affecting by electrolysis not only the pillars
OF the elevated railroads, but possibly the
very anchorages of the bridge itself. he rec
commended that legislative action be taken
to check the danger, declaring that unless
regulations were adopted the life of public
property would be greatly shortened: :.
Dealing with the results of electrolytlc
action on the terminal rails Of the trolley
system, it was found that large amount of
metal had been removed by electrolysis, the
bottom of the rails having been cut down
to knife edges for several ieet back OF the
ends 1t was also found that IN many m
stances the tie rods and cross bars, which
keep tne rails Ill positi"ii, Ai"" oS.A ~~
entirely through.
In describing one of the most remarkable
of his discoveries, Mr.. Knudson said:
Coming down the west side of the city,
was surprised to encounter tull-ftedged
trolley current in the extreme lower part
of the city
"The first iptimation was found at Rector
and Greenwich streets, it becoming more
pronounced in the vicinity OF South Ferry,
where, in testing between the rails OF the
Metropolitan Cable Road and an elevated
piIlar. variation of one-thirtieth to eight
thirtieths volt was found, the rails positive
and the same reading between the rails and
the water-pipes.
"After making further tests the current
was found to come from the Brooklyn
bridge. Having pointed out how an over
head trolley using the water-plpes and IN
cidentally the rails as a return can spread
it's influence for twenty blocks north and
south, the existence of this current through
the bridge is accounted for
The very serious question presented IT.
self, he continued, in what condition might
we expect to find the anchor bolts and the
iron foundation of those pillars, for previous
to any use of electricity on the bridge 1t
had been known that currents were escaping
over that structure from trolley lines in
brooklyn, and passing over, would hnd
their way through the city by underground
routes and then, crossing the river, arrive
back to the power house in Kent avenue.
In conclusion he said:
ct appears to be the duty of engineers
to exercise every precaution against the
effects of this invisible element of destruc-
ton, which, if left to itself, will certainly
shorten the life of valuable city property.
"The damage already done by electrolysis
to public works in England has led to the
establishment of regulations to prevent such
action in the future, and similar legislation
may be expected in this country if these con-
ditions be allowed to continue. Preserva-
ton is simply question of additional ex-
pense.
"The incandescent light currents ! do
not consider as particularly dangerous at
the moment, on account of their light volt
age, but it having been established that the
fraction of a volt difference of potential
will cause electrolytic action, it simply
comes down to a question of time when
these straying incandescent currents will
have to be seriously considered
'It is my opinion that ordinary caution
would suggest that periodical tests should
be made in every city where trolley road
using ground return is in operation. In
this way threatened damage by electrolysis
to water and other pipes, as well as to
bridges, might be arrested and finally con-
trolled."