Mineral Point tribune. (Mineral Point, Wis.) 1869-1938, 1885-07-16
THUNDER. STORMS.

see III 1EOm SkDhud 10 uOl VIGIL
shown; but as described by Wise, the
aeronaut, from his balloon voyage
made thirty or forty years ago, il has
somewhat the shape of great hour
class, the dark Swallowed clouds enter
ING it as they form at the base, and
presumably rising through the central
construction to supply the white, sum
lit mass that is rolling out at the top
with the appearance of vast sea of
snow, boiling and upheaving from i'm
ternal CONFUSION. Zgzags of light
ming dart from one cloud mass TO
another, or blaze out in the gloom
between the clouds and earth, or even
fash from the clouds into the open,
empty sky; but the origin OF these
violent electrical manifestations is
almost as much mystery as ever it
was. The conditions under which
electric sparks, large or small, are
discharged, is fairly well determined,
but the ultimate origin of atmospheric
electricity is a question ON which
physicians are not yet agreed.
When a lightning flash is viewed
at night through narrow radial
slit in a rapidly revolving disk it is
found to consist OF several discharges
separated by intervals too short to be
noticed by the unaided eye, but dis
coyerabie in this experiment by the
fact that the slit is commonly seen in
several different attitudes when illu-
minated By an apparently single, in
Simultaneous flash. The apparatus
may be easily constructed and used
by any high school boy or girl, and
the fact that it discovers is a remark
able one in the physics OF thunder
storms that needs more explanation
than il has yet received. Photograph
ing lightning flashes at night is an
other interesting experiment that may
be tried to advantage in these modern
days of amateur photography and in
Simultaneous plates. Some very sue
cessful views have been taken, show
ing a CON posite flash to consist of
several separate lines of light, every
one very irregular, but all closely par
allel TO one another; fine thread like
branches are given of at different
points and disappear as they divide
into fainter fibrcs in the dark sky.
Returning to the high cloud mass, if
any venturesome ballo0nist ever as
cends through the ranging vortex to
its massive summit he would have
opportunity to prove or disproye the
suggestions that have been made as
to the mechanism Of the storm. Sup
posing him bold enough to begin his
ascent under the center of the storm,
it is probable that he would rise slow
ly at first, for il is thought that the
falling rain~drops cause downward
current of air here which would re-
tard his upward fight; this current,
chilled by the RAIN is most likely the
origin Of the cool gust Of wind that
prece0es and accompanies this heavy
rainfall at the storm center. Mount
ing well into the clouds, further
ascent would there be aided by the
upward current, to which the forma-
ton Of the cloud and storm is thought
to be due. Only the large drops of
rain can fall through such an ascend
ing current; the fine water particles
may be carried higher until they
are frozen into minute hail-stones,
most Of which melt before reaching
the ground as they fall TO one side of
the up-draft; but If 1t happens that
they grow TO a considerable size by
accretion, they may fall fast enough
to reach US unmelted. Going higher
still, the vapor that is condensed at
these greater attitudes, where the
temperature even in midsummer is
below freezing, forms snowf1akes,
and of these the boiling summit
masses of the storm are supposed to
consist. The height to which these
superb clouds ascend is not well de-
termiaed, but it is very probable over
five miles, and may be over ten; a
little observation will settle the mat
ter, for to take a practical case, if a
thunder-sto passes centrally over
Arlington, Medford, and Maiden, as
would be known by the drenching
rain recorded by observers there, the
angular altitude of its white clouds
tops codld be estimated by observers
IN other towns to the north and south
at certain hours, as is provided for
in the plan proposed by the meteoro-
logical society, and then it would be
easy enough to calculate the height.
But it must be borne in mind that the
explanation of TIE storms action here
given might not be generally accept
ed, and it is with the object of learn.
nag more precisely what the facts of
the case are that the observations
above referred TO are TO be under
taken. The essential points of the
method at first are the selection Of a
number of simple phenomena, such
as the time when the rain begins, the
direction of the wind, and 80 on, which
can be observed by any intelligent
person, even without meteorological
instruments; the undertaking is thus
brought within the reach of that large
class OF our busy population who are
interested and willing enough to give
some assistance in such work, pro
vlded it does not require much time
and needs no special technical in
structioa or outfit. Scholars ia our
high schools are abundantly prepared
to do effective work in such a school
as this. Second, when a thunder storm
appears 10 sight or bursting 1t is inn
pOrtaut to know the conditions of