New-York tribune., 1874-07-22
LIGHTNING And LIGHTNIYG RODS.

THE ROD SHOULD PRESENT THE PATH oP LEAST
RESISTANCE FOR THE DISCHARGE OF ELEC-
TRICIIY-INsTANCEs SHOWING THIS REQUIRE
MENr - INSULATION OF LIGHTNING RODS
MISTAKE.
To the Edttor Of The Tribune.
SIR: There is nothing new in the story of
damage by lightning during the storm Of July
Il to building, at Astoria, provided with a
(so-called) lightning rod, nor in similar IN
ciient which occurred during the same storm
in Trumbul Conn., which has been extensively referred
TO by the newspapers exhibiting the useessness Of
rods as protectors" The opinion that Lightning rods
the danger has frequently been made to prevail
throughout entire community by like occurrences in
former years. Yet such facts have no more bearing
upon the question raised than a case OF malpractice
would have upon question OF the utility OF all medical
treatment.
The lightning rods the buildings referred to failed
TO meet the conditions upon which efficacy depends To
answer as safeguard the rod should be arranged
to present discharge OF lightning the path OF least
resistance in any and all directions. One
two termnations IN the earth do not fur
nlsh adequate ground connection. Tho practice
OF Insulation by way OF erecting barrier
against tue passage OF lightning evinces complete mis-
apprehensOn both OF the function OF the and OF
quality OF Insulation. Insuators only capable OF
resting the movement OF currents OF rareed electricity
They answer preserve the wires the currents OF
poles from being shattered If the wire is struck by
lightning.
The principle the selection OF the path OF least
sistance clearly illustrated in the OF building
on Staten Island struck years ago by discharge
OF lightning, which, although received upon lightning
rod end left the rod and went through the wall to
a looking-glass in the second story The discharge
backened the quicksilver the back OF the glass and
from thence leaped to the body OF man who
standing front Of 1t. down his limbs and through
the floor TO the OF stove-pipe Immediately
derneath. upon which 1t Travelled across and down to
stove at the opposite end OF the lower story, where Il
again went through the floor and to the ground 1t
will be easily that If there had been rod leading to
the ground both ends of this building and rod
the roof connecting them together the fluid would have
been provided with line OF conducting matter which
by OF its continuity, would have presented less
resisence than the substances which intervened be-
tween the detached conducting materials upon which
the discharge actually passed somewhat similar IN
cden occurred many years ago In Poughkeepsle where
discharge Of lightning passed across building upon
bell wire and killed man who was sitting upon the
piazza with his head leaning against the bell knob.
The position OF danger in unprotected building Is
when the body is interposed between two masses or
lines of metal but II lightningrods applied by
person competent determine and provide for what
ever may be the peculiar exgencies OF the case then
the rods will present the easiest path for the fluid n
any direction and they be relied on protection
because electricity its passage from place 10 place
invariably selects the shortest path upon the best con
ductors.
1t Is the function OF tho lghtnngrod TO facilitate the
distribution OF electricity, and especially to promote
the freest circulation of rariaed currents so as to
neuraze an electrical disturbance induced in the build
ing by a thunder-coud. Insulation, while having no
effect as barrier against discharge OF lightning does
prevent the rod from gradually collecting electricity
from the building and silently giving IL OF 70 the
atmosphere. Irinsuated tho rod cannot act as safety
valve and the electrical equilibrium OF the matter
posing the building disturbed only be restored by
discharge from the rod The experience OF the last
40 years has clearly established two things rst that fail
ures OF lightning rods to protect have resulted
ects which obvious TO competent judges and which
could have been easily avoided and secondly. that
there have been such failures In the case Of rods
erected accordance with the prescribed scientific con
| ditions O.
Seie York, July q, l37L