Year: 1874

Professor John Wise read a paper
before the Franklin institute, Philadel-
phia, receztly, upon the above subject,


in which he said:


The thundergust that passed over this
city on Monday afternoon, the 25th Of
| May, was attended with more than the


usual amount of electrical discharges.


Immediately over the city the heavens


were literally filed with flashes of light
and brilliant corruscations of lightning.


The cloud matter was so thoroughly


combined, and of such great thickness,


that the usual echoes were not propaga-


ted, but, Instead we had the hoarse,


rumbling intoLati0us Of thunder, re-


sembling the sound Of that produced by


heavy carriages running over frozen


ground. The thunderbolt discharges


sounded much like the discharges of


heavy artillery, while in smaller storms


the sound resembles that produced by
snall arms While ia all these storms
/ there is a central vortex, those OF great


dimensions have within their areas
number of vortices. In that of Monday
last the evidence of this feature of storms


was discernable in the uproOted trees
in different sections of the city. These
vOrtiees are so much broken and shat
tered in passing over a city, by the
solid distractions they meet in their
whirling action, that they become com
paratively harmless whereas, in pass
ing over an orchard or wood, the UNI
bragg of the trees presents a favorable
condition to their impact, and many of
them are twisted and lifted out by the
roots.


In addition to the great number of
thunderbolts that were discharged upon
the earth from the clouds, the vapOr
stratum overhead was for half an hour
embelGshal with brilliant scintillations
of electrical fire, resembling the burst
ing Of rockets filled with white stars.
This display of electrical pyrotechnics
were reported TO have suffered from
these electrical discharges, but these
sufferings were in most cases of the
imaginary kind, distressing enough to
be such, but not very dangerous in their
results. The pleasure afforded those
who view the phenomena in their beau
teOus and exhilarating aspect forms
an equivalent TO those who suffer from
them.


The most marked and mstruc-
tive thunderbolt brought to my notice
was that which struck the building of
Mr.. Rech, on the southeast corner of
Girard avenue and Eighth street. This
bdilding was provided with an exten-
sive arrangement of lightning rods. It
is gravel rooted, and around the whole
circumference of the roof there runs
an iron conductor. From this horizon
tai iron bar there are perpendicular
lightning rods at sixteen different equl-
distant places. It has, IN fact, sixteen
lightning rods pointing to the clouds.
Upon the roof and centerirg the avenue
front, and about twenty feet from the
front edge of the building, there stood
a flagstaff. A branch of the circumfer-
ential conductor run across to this staff
and up il about twelve feet, where it
ended ana was fastened to an iron band
around the pole. The thunderbolt, in
disregard of the sixteen lightning rods,
struck the flagstaff, and completely
shivered it down to within four feet of
the iron band, and where the branch


T5faT ne @R585dsr ss5 iyPSs 20 sE sAs bolt
rod 3? Simply because it was in the
path of the descending bolt. Now if,
as is claimed by eminent electricians,
the rod does its silent work of discharg-
ing the cloud when it is yet afar off,
why did it not quietly and decently dis
arm this nimbus artillery in this case ?
Certainly the garrison was well fortified
with these barbed protectors, expressly /
stationed there to prevent an explosion |
of electricity, by drawing the surcharge
from the clouds, if not when afar off, |
at all events when the bending cloud |
passed over the protected building. |
The lightning rod man claimed that the |
branch conductor carried off harmlessly |
the remainder of the bolt. No doubt |
it did, since that residue was of little |
momentum and energy of what was left |
of the bolt after having made splinters |
aud kindling wood of a thirty feet flag |
staff.


While this is the third flagstaff shat
tered by lightning in this city that |
have examined within a few years, and |
where the mechanical effects of the bolt |
were little beyond that of rending a !
pole, it is the only one on building
where it was surrounded by a Gordon of
rods, or in proximity to rod;
it is one of the most conclusive evil
dences of the inutility of lightning rods
that could possibly be presented. If
the rod would do what it is intended
for, to wit draw the surcharge of cleo
tricitv from the storm cloud silently ;
disarm it of its force by drawing in a
silent stream to its point, as the charge
from the prime conductor of an electri-
cal machise is drawn by any kind of a
pointed Material, glass as well as metal,
there should not be a bolt ever descend
upon a building in Philadelphia, with
its thousands of lightning rods peering
toward the cloud region.


The onlv protection from thunderbolt
that has yet been proved to be etflca-
cious is the metal roof. The greatest
damage ever done to a building thus
protected is the perforation of the metal
at the point where the bolt strikes, and
this is, in the heaviest discharges, not
over half an inch in diameter. Such has
been the result of my observations
through more than quarter of cen
tury. In all these observations l
found the mechanical effects of the
thunderbolt about the same in buildings
that were struck, with rods upon them,
and those without rods, with this DIFF
ference, that nearly all the cases OF lg-
milton were upon those with rods. Such
are the facts of the case, with all the
theories to the contrary notwlthstand-
ing.


Metal has no more attraction for light
ming than sponge has for water. In
either it may be viewed as an absorb
ent. Neither has metal point and at
tractive power to draw electricity on 1t.
Points act as recipients of conduction,
or as entering wedges to the bolt; as a
point would act in perforating soap
bubble of hydro-oxygen gas; or any
other film or attenuated matter. The
attraction of positive for negative, as
laid down in electrical science, proves
nothing more than there is present an
unbalanced condition of electrical mat
ter, and ohen necessarily disposition
to electrical equilibrium, which always
follows, just as two drops of water will
coalesce when their atmospheres come
in contact.


About Comets.


Comets are not exactly calculated to
inspire in the human heart feelings OF