The herald., 1893-09-23
MISSILES FROM THE HEAVENS.
millions OF Thsm rsll. but csmparstivsl
rev Bench tho Earth.


rew Rexch tho Earth.
sit Ia mistake to suppose that mete-
orites burst In the proper sense of the
word" said scientist TO a writer. "But
1t often happens that they are broken to
pieces on striking the atmosphere of the
earth. This may seem surprising, but
let me call your attention to an analogy.
Strike the surface Of water with your
fist, and, though fluid, the resistance il
opposes to the blow seems almost as
strong as If it were solid. Now, the me-
teorite Is moving at a tremendous rate Of
speed If small, it is set on fire in an in
slant by the friction of the air, and after
glowing for a moment brightly is con-
sumed.
"On any night in summer you will
see shooting stars now and then. They
are meteorites, which on coming into
contact with the earth's atmosphere are
set afire. This is not surprising, mas
much as they approach the planet on
which we live at speed which often at
tains "A miles second. By causing the
destruction Of meteorites the atmosphere
serves as protection for people ON the
globe, who would otherwise be pelted
by such missiles to q dangerous extent.
II is estimated that not less than 0,000,-
600 of them, big enough to be visible to
the naked eye, strike the earth every "a
hours.
''By contact with this planet the me-
teorites are raised to a temperature which
reaches from 5000, 900 to 1900, 900 de-
grees-high enough to consume the hard
est known substance almost instantly.
Thus only those of large size reach the
earth before being entirely burned up.
The greatest number Of such bodies can.
be seen just before daybreak. because by
that time we are ON the front side of the
globe as it moves through space. The
elevation at which most Of them are Wis
ible has been found to be between 45 and
so miles, very few being seen at a greater
height than 100 miles.
''1t is believed by most astronomers
that some very large meteors have en-
tered our atmosphere and have passed
out into space again, their great mo-
mentum being sufficient to take them
away from the earth's attraction. What
these flying bodies are is question that
has been much disputed, but it is con-
sidered most likely that they are the
debris of broken up comets. In one re-
cent instance the correctness Of this the
ory has found striking proof. That was
the case Of the comet Of Biela. 1t was
discovered IN 1926 and was again OBJ
served in 1882, 1s45 and 1859. In 1S45 it
had split into two parts, and in 1879 it
failed to appear when and where it
should have done. Evidently it had been
smashed up, and prediction was made
that there would be great meteoric
shower composed of the remains Of the
lost comet This prediction was fulfilled
Certain groups of meteors move in
elliptical orbits around the sun. Occa-
sionally the earth passes through their
clusters, producing what are known as
meteoric showers. Such showers occur
annually from the 9th TO the 18th Of Au-
gust, and there is a similar display ir
November once every 83 years. The
stream of the August meteors Is esti.
mated to be from 5000, 900 to 10, ,000, 900
miles thick. The earth, though travel
ing with the velocity Of 2, ,000. 600 miles
day, is immersed in it for several days.
"The fall of meteorites to the earth is
sometimes accompanied by great dis
play of light, occasionally illuminating
an area of many Thousand square miles.
When such an event occurs at night, and
with loud detonations, so great in some
instances as to shake houses and fright
en- men and animals, the explosions are
caused by the breaking up of the me-
teor. Ordinarily you will find that such
meteoric bodies are coated on the out
side with black substance, which is
the effect merely Of fusion of the super
fetal material by great heat. A piece Of
Biela's comet was actually picked up in
Mexico in 1872 at the time OF the shower
of its remains. Naturally it is consid-
cred interesting.
''Such great interest is taken in mete-
orites that all Of those collected have
been carefully catalogued. They are
mostly composed of iron, with usually
percentage of nickel and cobalt and
sometimes copper and tin. It is custom
airy to saw them into slices, which is a
iaborious process, for sale or for ex-
change among museums. Sometimes
the slices are prettily polished, or the cut
surfaces are etched with acid so as to ex-
pose the crystalline structure. This
structure is In no two such bodies exact
ly the same, and the differences are
thought we'll worth studying. Attempts
have been made to counterfeit meteor
ties because they are go valuable, but