The Portland daily press. [volume] (Portland, Me.) 1862-1921, 1895-08-31
HABITS OF LIGHTNING.
Some Old Ideas and Theories Explod-
ed.

Results of Recent Curious
Phenomena.
Onlv within comparatively recent
period have any but the most meager
records of lightning effects been prop erly
kept by any government. Now, how
ever nublic attention is directed toward
the results of lightning strokes in most
civilized countries. At the head Of the
list may be placed Germany, France and
Great Britain, while Japan is not far
behind in the race. In the United
States the Weather Bureau in 1891 issued
instructions to its observers to carefully
collect from all sources such information
for the purpose of furnishing reliable
data concerning lives lost and property
damaged through lightning. The recent
utilization by the United Safes Depart
ment of Agriculture OF circular OF in
formation by Alexander McAdie on "Pro-
lection from Lightning contains much
valuable information on subject un-
familiar to the majority OF the average
readers.
The whole theory of lightning discharges
and of lightning proection has been COM
pletely overturned by the Tesla, Elihu
Thomson, and Oliver Lodge experiments,
and it is now recognized fact that OF
all the lightning rods in the world the
percentage of protection from lightning
stroke is so small that in the great major
ity of instances the rods used create
positiye danger The saving clause In
the question les in the facts that where
there are the most people, and where the
most valuable property is found, and con-
ssquenty where there is the greatest num-
Der of these menaces, there is the place
If all others where there is the least
necessity for such protection in the larger
cities
Ignorance is the twin brother, If not
closer relative, of superstition, and to
speak iocularly OF sneeringly OF "God's
| fire" was once terrible sacrilege. The
writer was once severely chided for wick
edness in saying he loved to see light
ming flashes.
Franklin made long stride in advance,
when his experimental work brought out
the lightning rod, even though he did not.
thoroughly understand the nature of
lightning discharges as Lodge has shown
us by his lectures and experiments
Faraday, even, said of Sir. W. Snow Har-
ris, who was an early advocate of The sur
face theory of lightning conductiyity, that
| l. OH tho n11eGfInn
Faraday even advocated mass of metal,
and the best of metal at that, in order to
give plenty of carrying capacity to the
rod.
The oscillatory character of ming
discharges does not allow of the filling or
saturation of the body of metal according
to Hertz and kindred exp erimenters the
oscillations may be so rapid that the CEN
fire of a wire or rod may be enirely free
from current while the outer surface is
heavily burdenod.
The area of protection afforded by rods
has been variously estimated, these areas
ranging from that of a cone, the diameter
of the base of which is twice the height
of the pole to less than half that space.
Possibly even larger protection than
this has been assumed, but the erratlc
performances of lightning have set all
such calculations and guesses at naught.
Other elements, such as locality, water
courses OF springs, character OF the soil,
etc., enter into the problem, so that no
rule has so far been formulated which has
withstood the test of time and of thunder
storms.
McAdie, quoting from the Quarterly
Journal of the Meteorological Society,
1890, says Capt Maclear found that in a
thunder storm June and z, 1889, many
trees were struck within radius OF four
miles. These trees were not, as might
be supposed, the highest nor most proml-
nent in that vicinity. A cottage, hay
stack, two poplars spruce, fir and five
oaks were all struck within that area.
SIT is not easy" says Maclear, Ito see
the cause of selection, for these trees were
not on the highest ground in the vicinity,
the only feature the groups possessed in
common being that they were all either
near bitches full of running water or else
near temporary courses taken by the del
noe Of water from the higher to the lower
oround The most puzzling case is that
Of the young fir treeand three young oaks
in the middle of the copse near the pond.
They we're not higher than the other trees
Of the copse, but there certainly was
temporary water course close to them;
other trees, however, stood equally close
-z,4or Apotbor c.1riOuc
case is that of the stable struck, which
was oyershadowed by tall elms. where
it might have been supposed these would
have taken the stroke.'
The law of Ohm has sometimes teen
found fault with because it failed of ap-
plication to lightning discharges, which