Year: 1869

OF late years, numerous patents nave Deen
obtained for more or less grotesque and COM
plicated notifications in the construction Of
Lightning Rods and the pateDtees, in their
energetic efforts TO make q market for their
wares, have tried to reopen certain questions
which were settled long ago, and which could
not now be raised, were it not that the laws of
electricity, and Of thundcrs storms, especially in
their relation to the subject of protection from
lightning, have been quite beyond the range Of
general study and education.


There is beginning to be diflused better
knowledge of the natural laws involved, as
the popular mind becomes famiarized with
the operation of the Electric Telegraph. Public
attention is not infrequently arrested by news
paper accounts of the influence of atmospheric
electricity upon the telegraph-wires, and the
occasional prevalence of "earth-currents," Of
sufficient uniformity to admit of being actually
used 20 transmit messages


Although great advances in the science have
been made since Franklin's time, the question,
What is Electricity 7 remains unanswered; and
a not uncommon result Of such new discov-
cries as have been made has been the over
throw Of preGxisting theories upon the subject.
We appear to be tending toward the conclusion
that what we call electricity, instead of being
substance, may be property or cOndi-
ton of matter-perhaps some unexplained
kind of molecular or atomic motion. Specu-
lative inquiry in this direction, however, is
less important and useful than investiga-
ton of the laws governing electricity or
electrical manifestations and the consideration
of observed facts concerning which there is no
disagreement


The most important law of electricity is, that
it seeks what is called q state Of equilibrium
that is, if we consider it n single fluid, that it
tends TO diffusion III equal proportions through
out all matter; or, if we choose to adopt tho
theory of the existence Of two distinct fluids,
then that these two fluids tend to unite in
equal proportions everywhere. When cleo
tricity is so dilused, or Off there be two fuids)
when they are SO united, no electrical effects
are observable, and there is then q state of
rest OF equilibrium. But this state of rest is
constantly disturbed by the operations of ma
ture-by evaporation, changes in temperature,
friction, motion Of all kinds, even the move
ment Of our bodies; and currents of cleo
tricity are Immediately set in motion TO
neutralze tho disturbance These currents
may be of such low tension as TO admit
of detection only by tho aid Of tho most
delicate apparatus; or they may be devel-
oped with such spasmodic iTegularity and
force as TO interfere with the use of the telo-
graph; or, again, with such constancy of di-
rection and tension as to be made use Of in
sending messages on the wires. Finally, in
state of extreme tension, they exhibit them
selves to us in the form of explosions or dis
charges Of lightning.


We may familiarly illustrate the idea of these
currents of varying tension by reference to the
spectacle OF tea-kettle or boiler filled with
water, which, when first placed on the fire,
sends forth from any opening gentle clouds of
vapor AS the heat increases, the steam rushes
out with a spiteful hiss and finally, when it
has acquired sufficient tension, if the means of
escape are inadequate it bursts the boiler with
n violent explosion. SO electricity flows in cur
rents of moro or less tension, according to the
degree or extent TO which its equilibrium is
disturbed and manifests its greatest known
tepsional force in the form Of a discharge Of
lightning The discharge or explosion being
the consequence either of interruption in the
flow of currents of low tension, or of an imme-
date and extensive evolution of electricity; in
other words a sudden and extreme disturbance
of the equilibrium.


Hence the insulation of liGhtning-rods is not
only an absurdity-as indeed DR.. Franklin per-
ceived a hundred years ago, when it was first
suggested-but 1t is also grave error because
the insulatOrs, to some extent, arrest the flow
Of currents of rariaed electricity. which it is
the true function Of the lightning rod to faoil-
itate. On the other hand, the insulator amounts
to nothing as n barrier against discharge of
lightning, which can either pass through il or
leap tho short distance RstYsGs the rod and tho