The daily dispatch. [volume] (Richmond [Va.]) 1850-1884, 1874-06-11
LiEhtning-Rois Have mo PROTECTING
Pewcr-Mctns Roofs a Protection
from lightning. s2 &E

logical Section OF the Franklin Institute, of
| Philadelphia, by Professor John Wise, and
| reported expressly for he EDening Bulletin !:
The thundergust that passed over the city
on Monday afternoon, the 25th Of May, was
Intended with more than the usual amount
| of electrical discharges. Immediately over
the city the heavens were literally filled win
flashes of light and brilliant corruscatlons
of lightning. The c.oud.mattcr was so
thoroughly combined, and of such great
thickness, that the usual echoes were not
propagatcd, but, instead, we had the
hoarsc, rumbling intonatons of thunder,
resembling 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 more that produced by small arms:
| While in all these storms there Is Il central
vortex. those of great dimensions have with
| in their areas a number OF worthless. In that
of Monday last the evidence Of this feature
of storms was diScerniblc in the uprooted
trees in different sections Of the city. These
worthless are so much broken and shattered
in passing over city by the solid obstruc-
tious they meet in their winding action that
they become comparatively harmless: where
as, in passing over an orchard or woods, the
| umbrape of the trees presents favorable
condition to their impact, and many OF them
are twisted and lifted out by the roots.
In addition to the great number OF thun-
derbots that were discharged upon the
| Garth from the clouds, the vapor stratum
over head was for half III Eour embeIlshcd
with brilliant horizontal scintlllatlons OF
electrical fire, resembling the bursting OF
rockets filled with white stars. This display
of electrical pyrotcchnics was truly sublime.
Many persons were reported rs having SUI
| fcred from these electrical discharges, but
| these sllil':rin@S were III most cases OF the
imaginary kind- distressing enough. to be
sure, but not very dangerous in their results.
| The pleasure afforded those who view the
| phenomena III their bcauteous and eXhlla-
rating ASPECTS forms all equivalent to those
who suffer from them.
The most marked and instructive thunder
| bolt discharge brought 10 my notice r::!- nat
which struck the building Of Mr.. Rech, on
the southeast corner Of Girard avenue and
Eighth street. This building is provided
| with an extensive arrangement Of lightning
rods. 1t is gruYcl-roofrd, and round the
whole circumference of this roof there
runs an ironrod conductor. From this
| horizontal iron bar there are perpendicular
| advantageous at sixteen different equi-
distant places. II has, in fact, sixteen
| lightningrods pointing to the clouds.
| Upon the roof and centering the avenue
| front, and about twenty feet from the front
edge of the building, there stood Il flagstaff.
! A branch of the circumfprential conductor
runs across TO this staff and up it about
! twelve feet, where it ended, and was fastened
1 ha hn
| thunderbOlt, in disregard of the sixteen
| lightning rods, struck the flagstaff, and COM
| pletely shivered it down to within four feet
! of the iron band, and where the branch con-
duc,or ended. Why did this bolt prefer the
| wooden pole to the advantageous? Simply
because it was in the path of the descending
bolt. Now if, rs is claimed by eminent cleo
tririans, the rod does its silent work Of dis
charging the cloud when it is yet atar of,
did it not quietly and decently diSarm this
nmbus artillery in this case? Certainly
the garrison vas well fortified with
these barbcd protectors, expressly stationed
there TO prevent An explosion of electricity,
by drawing the Surcharse from the cloud, if
not when vet aiar OF, at all events when the
pending cloud passed over the protected
building. The lightning-rod man claimed
that the branch conductor carried of harm
lesslv the remainder OF the bolt. No doubt
It did, since that residue WIS OF little mo-
mentum and energy OF what vas lett OF the
bolt after having made splinters anu klndIlng
wood OF thirty-tOot flagstaff
White this is the third flagstaff shattered
nv lightning in this city that | have exam
| med within few years, and where the me
cbuuical effects of the bolt were little be-
yond that of rendiDS The pole, it is the only
one on i building where it was surrounded
| by Gordon of liyhtnng-rods, or in proXim-
ity to a rod. 1t is one of the most c0ncu-
siye evidences of the inutil!ty Of lightning
| rods that could possibly be presented. Il The
rod would do what it Is intended for, to wit:
Draw the surcharse OF electricity from the
storm cloud silently, diSarm it of its force
by drawing in silent stream TO its point, rs
the charge from the prime conductor OF an
electrical machine is drawn by any kind of
pointed material, glass rs we'll as metal,
there should not be 4 holt ever descend
upon IL building in Philadelphia, with lis
thousands of lightning-rods peering toward
the cloud region.
The only protection from thunderboIt that
has yet been proved to be etl&acious is the
metal roof. The greatest damage done to I
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 from Il half to an inch in diameter.
Such has been the result Of my observations
through more than quarter OF century.
In all these observations found the mechl-
ncal effects Of the thundcrbolt about the
same in buildings that were struck, and with
| rods upon them, as those without rods, with
| this difference, that nearly all the cases OF
ignition were upon those with rods. Such
are the facts of the case, with all the theo-
| rieS TO the contrary notwithstanding.
Metal has no more attraction for lightning
| than sponge has for water. In either case 1t
NAV be viewed as an absorbent. Neither has
metal point an attractive power 10 drd,c
electricity on it. Points act as recipients OF
conducton, or as entering wedges 10 the
bolt, as a point would act in perforating a
soap-bubbe of hydro-oXygen gas or any
other film of attenuated matter. The attrac.
ton OF positive for negative, as laid down in
electrical science, proves nothing more than
| that there is present an unbalanced condition
of electrical matter, and then, necessarily, a
disposition to electrical equilibrium, which
always follows, just as two drops OF water
will coalesce when their atmoSpheres come
in contact.
TYPHOID FEVER AND LL.BCILT DWELL
ISGs.-The British Medical Journal finds 4
new text for its advocacy of good drainage
in an outbreak Of typhoid fever in Lord Cad
ocan's family in London. The Journal says
"Much sympathy is felt in London society
at the outbreak of typhoid fever in Lord
Cadogan's family, and the circumstances are
not without an important public lesson.
y,hi .t,