The Democratic advocate. [volume] (Westminster, Md.) 1865-1972, 1891-06-27
The Best way to ward on Lightning
From the Baltimore Sun, June D.


Prof. Henry A. Rowland, of the Johns
Hopkins University, in recent interview
gave some interesting facts in the develop
meat of the study of lightning and light
ming conductors Dr. Rowland said =
"Recent scientific study has swept away
some of the old notions about conductors.
The method now considered the best for
the protection of buildings is to provide
metal roof, with an ample number of metal
conductors leading to the ground, which
will receive and carry off the electric bolts
from the clouds. Copper is the best ma
terial, but Tin or iron will answer the pur-
pose, and l always suggest the placing Of
the conductors at the corners of building,
so that all parts will be equally protected.
Though rods may be used, rain spouts
will answer the purpose equally well The
physical laboratory of the Johns Hopkins
University is protected from lightning by
the roof and spouting You can safely
class all patented lightning rods as being
of little value beyond conducting rods that
any man can put up himself, because the
simple principle underlying all is that the
lightning will follow the best conductor.
The idea so largely adopted in the erection
of lightning rods, that small band of glass
will prevent the electric current from
passing to better adjacent conductor,
seems playful While it is true that light
ming is attracted to an elevated point or
angle, when you cast your eyes over a city
like Baltimore and see the large number
of such points and angles, the use of
pointed rods fades into insignifcance as
compared with the method of roofing with
Il good conductor This was well illus
trated by the incident of lightning striking
the great monument in Washington several
years ago.
The monument is capped with piece of
aluminium which has metallic connection
with the ground by means of the iron work
of the interior, but the lightning did not
strike the top of the cap. 1t descended to
some copper fixed in the side of the pyra-
midal top, some distance from the apex,
burst portion of the stone, and, running
along the copper into the interior, leaped
without any metallic connection to the iron
framework and passed to the ground. A
framework Of copper rods covering the an
giles and crossing the sides of the immense
cap was recommended by me at that time
for the future protection Of the monument
and has probably been constructed. The
| ground connection was TO be through the
internal iron work spoken of. Somewhat
, similar to these methods is that of the
Peabody Library. The iron shesSing con-
: nected with the metallic roof, and resting
on stone foundation which might be
shattered by a stroke of lightning, has been
G connected with the ground by metal con
c ductors, and no danger from lightning is
t apprehended.
E Lightning has no fixed portion of a
/ building to strike The stroke may fall at
r the centre of roof, and while it runs
e along the surface of body, the body may
be broken or crushed by the enormous
5 pressure brought to bear upon it, in the
+ same manner that an explosion of dyna-
{ mite IT nitroglycerine would cause a
Q fracture. | have some fragments of a
church spire struck by lightning which are
$ bound together in their former relative
: positions, but exhibiting all the fractures
d produced by the concussion. There is a
IS vast difference between the quantity Of
e electricity and what is known as electrical
: pressure. This is illustrated in simple
n manner by the compression of air. A
: small quantity of air can be compressed to
r. the same degree to obtain as great an ex-
# pansive force as large quantity, The
e quantity of electricity in a stroke of light
9 ming is not nearly as much as passes along
; almost any electric wire on the street, but
: the voltage or electrical pressure Of the
h street wire is rarely 5000. A volt is the
a basis on which the pressure is estimated,
n The voltage of the lightning stroke is
e roughly estimated at 6,000,0O0,000 volts.
In addition to this appalling difference it
;. may be said that the current of the wire is
: constant and continuing, while the light
e ming dart is delivered in the one two
f hpndredth part of second. Such an
s astounding force is capable of doing many
! strange things. A volt may be rated as
}, equivalent to the pressure of an electrical
Y door bell.
n In speaking of places of safety during
! an electrical storm DR.. Rowland said that
5 probably as safe place as ary other would
t be an iron bedstead, provided the ground
connection is perfect, this being in line
e with the above theory, that the lightning
e would follow the best conductor.