Pittsburg dispatch. [volume] (Pittsburg [Pa.]) 1880-1923, 1890-12-07
THE SPIDERS WEB.
1t is a Cable Made Up of Strands
Finer Than Can be Seen.
HOW THE LITTLE ANIMAL WORKS,
A heteoric Bonn bardment of the Earth That
Doesn't Hurt Us.
THE AIR ACTS AS AN ARM0R PLATE
WRITTEN FOR THE DISPATCH j

typisy extreme fneness or delicacy Of text
ure. But II you want a simile that will dis
count that one say, Gas fine as spider s
web" There is nothing of textile kind so
fine as that. The strand spun by spider is
as much smaller than thread of silk as
the latter is smaller than telegraph pole
This seems like exaggeration when you
casually look at the spiders workmanship
and then at the silk worm. But you never
saw single strand in the spiders thread
The strands are so fine that you couldn't see
them with the naked eye. What you really
see when you look at the spiders delicate
thread Is q cable composed of thousands of
strands, and the way the little animal makes
this cable is one of natures greatest wonders
II you look closely at a spider during its
business hours you will see that its thread
comes from circular spot near the extremity.
In this spot are from four to six knobs, the
number depending upon the kind of spider.
If you happen to have particularly good
pair of eyes you can distinguish these knobs.
Each of the knobs is full of minute holes,
so small that good microscope is necessary
In order to see them. Through these holes
tn. delicate strands are spun. About an
eighth of an inch from the holes the strands
are Joined together, and the result is the
spiders thread, with which all of US are SO
familiar.
MAKING THE CABLE.
And the little spinner attends to business
as closely and as carefully as does the
weaver of the finest silk fabric. 1t has on
each foot three claws. one Of which is a sort
of thumb, while the others are toothed like
a comb. These claws are constantly used to
help to keep the strands from tangling be-
fore they are Joined in the thread. The ma
terial from which the thread is made is
secreted in the animals body. 1t is
glutinous substance, and the strands dry
while they are passing from the little aper-
lures to the point where they are Joined to-
gether. One authority on this subject,
Reaumur, calculated that it would take
1, 200 spider stra uds to occupy a space equal
to the point of needle, while another,
Leuwenweck, estimated that it would take
1000 900 OF them to make thread as large
as hair.
Eut while the spiders work is the more
delicate that of the silkworm is the more
useful. Nearly half of all the people in the
world live in China and India, and all of
them, except the very poorest, wear silky
it takes the labor OF nearly thousand silk
worms to make one pound of silk, you can
see what an enormous industry results from
this tiny thread spinning. Unlike the spi-
der, whose spinning works are at the lower
extremity, the silkworm's factory is near its
mouth. The crude material is seemingly
much alike in the two classes of spinners-a
gummv or glutinous pulp. The spinning
appurtenances, however, are entirely differ
emf, the silkworm making only two strands
for its thread, while the spider makes thou
sands.
ADVENTURES OF A SILKwoRM.
The life and adventures of silkworm
make an interesting story. The first stage
is an egg laid by butterfly. This egg pro-
duces what we call Il grub or maggot The
animal is quite small in in fancy but its
growth is sorspid that its clothes are con-
tinually getting too small. When it is a
few days old its growth makes the skin too
tight, this covering splits open on the back,
the animal comes out like the outgrown
trousers of boy. This change occurs four
or five times before the maggot becomes o
full-grown caterpillar. Then, after short
stage of maturity, the caterpillar finds the
inirmities of age coming on, and it makes
arrangements to literally 'shufle off this
mortal COLL" By this time it has secreled
in its body the raw material from which it
spins its silk.
After selecting some scaffold-like place
the caterpillar first spins some hossy silk
which attaches to whatever is convenient.
Then it begins to wind its threads round
and round until it has enveioped itself, as
the carpet moth grub does, in what is called
a cocoon, generally little larger than a
pigeons egg. When the cocoon Is COM
pleted the worm sheds its last suit of clothes
and carefully tucks them down at the lower
end of its house. Then it goes to sleep.
While it sleeps new and verv thin skin
forms, wonderful changes take place in the
animals appearance, soon the head end OF
the cocoon breaks open, and out comes not
the caterpillar but beautiful butterfyl
BoMBARDMENT OF THE EARTH.
All the common shots that have been fred
since the first cannon was cast do not equal
in point of number the bombardment that
our earth undergoes every "a hours. If you
will look at the sky one of these clear De-
cember nights you will soon see one or more
of the familiar shooting stars" so called,
darting through a portion of the heavens.
They are not stars. but small particles of the
material out of which stars and worlds are
made. They are composed of the same ele-
ments that exist in the stars, in the comets,
tributed throughout the universe.
Meteors and aereolites, which are the cor
rect names of these luminous little bodies,
are fired into the earth's atmosphere at the
computed rate of 400, 900, 600 in "a hours.
The bombardment is perpetual, though we
can see the missiles only at night. But the
earth's defensive works are perfect They
are not made OF stone or OF earth embank-
ments, but of air. Yes, the earth's atmos-
phere Is perfect defense from all the shots
fired at US from outer space, for it not only
stops the missiles, but burns them up. OF
all the meteors shot at the earth not one
reaches the ground, the friction produced by
their great velocity through the upper air
acting on them like blast furnace on
sheet of paper. and only minute remains fall
harmlessly.
THOSE THAT DO NOT BURN.
Occasionally one of these missiles is so
large that it escapes total destruc tion by the
atmosphere. That is, the terrible heat gen.
Grated by the friction does not reach the
center of the missile, and therefore the heart
of it, SO to speak, reaches the earth. This
class OF bodies are called aereolites. Not
safely runs the gauntlet of the atmosphere,
reaches the earth. and thus earns the name
OF aereolite, meaning air-stone.
There are a few, but very few we'll au-
thenticated cases of large aereolites reaching
the earth. One was found in Siberia, mass
of iron and nickle, which weighed nearly a
ton. There is one in Buenos Ayres partly
buried in the ground, whose weight is esti-
mated at 16 tons, and another in Brazil
weighing about half as much. But there is
no case on record of a person being struck