The morning news. [volume] (Savannah, Ga.) 1887-1900, 1894-07-15
GLOW WORMS TINY LAMP.
Insects Furnish the Cheapest Form of
Light-Animal Phosphorescence.
From the Boston Transcript.

FROM the Boston Transcript.
The retirement of Prof. c. V. Riley
from the post of United States entomolo-
gist removes from government employ
ment one of the most eminent investi-
gators Of the day. Science under Uncle
Sans auspices has done no more import
ant work than has been accomplished in
the study of insects. In that branch of
the animal creation Secretary Langley of
the Smithsonian institution has made
perhaps the most picturesque research
relating to the light afforded by fre-fies.
This light, Prof. Langley has discov-
cred, is the most economical uluminant
in the world 1t is 100 times cheaper
than gas. That is to say, there is no
waste, whereas the waste in burning gas
or lamps is more than 80 per cent. In
other words, the consumer pays dollar
Tor ever cents worth of light he gets.
With electricity the waste is less, but
still enormous. The freely light expends
no energy in the shape of heat
SO here Is what might be termed a cold
light, without waste. If a process could
be invented for producing it in large
quantities by artifice, the discovery would
be Of enormous benefit to mankind. In
cidentally, electricity and gas would be
poses. That the secret will be found
sooner or later is not at all unlikely The
notion formerly held that the light was
part and parcel of the life of the freely,
has been exploded. 1t is now believed to
be simply product of chemical combus-
ton.
Such being the case it ought to be
practicable 10 reproduce the phenomenon
in the laboratory, or even on large scale.
This peculiar light, termed "phosphores-
cence, >" has received little attention from
scientists up to date. 1t affords an at
tractive field for investigation. The sup
position Is that it is made by the slow
combustion of material secreted under
the control of the nervous system of the
insect.
1t is produced at one four hundredth of
the cost OF energy expended in a candle
flame. Nothing is lost in the shape of
heat, the light-giving organs having the
same temperature as other parts of the
animal.
More than 100 families of animals on
land and in water, embracing tons of
thousands of species, produce such phos-
phorescent light, They yield enough Of
1t TO illuminate London, Paris and New
York. The surface of the ocean is alive
with luminous crustaceans, Jelly fishes,
etc, not tomention innumerable vegetable
organisms, each of which is tiny Ian
tern. In the depths swim lamp bearing
fishes. On land crawl glow worms and
electric centipedesn while in the air
tirehies and lightning bugs" of many
kinds disport themselves. All of this
light crowded into ono place would hardly
affect thermometer.
The most brilliant light afforded by any
land animal is that Of the famous frehv
OF the tropics, known as the "cucuio. F"
Thirty-eight OF them yield one candle
power Photographs have been printed
by two-minute exposure of bromide plates
TO their illumination. People in Cuba
contne them in paper lanterns for going
about the country at night or indoor
lighting. Sometimes they attach one of
the insects to each foot for travelling in
the dark, to serve as a guide to the path.
Also, they use them as ornaments for the
dress and hair
1t is with these frefiies that Prof.
Langley conducted his experiments. They
are beetles, beginning life as grubs, skip
Jacks" or spring tails" they are some
times called, because, when on their
backs, they jump over with a clicking
sound. A small species of the same fam
lily Is found in Florida and Texas They
have two luminous spots on the thorax,
and another on the abdomen. Damp even
lngs are most favorable to the light-giy-
ing, the object of which is presumably to
attract the sexes. The young larvae feeds
largely on snails, 10 which their bite is
poisonous. The luminous organs are de-
veloped before the insects leave the eggs.
Now, a theory formerly held was that
these frefies stored up light in the day-
time for emission at night-as is done by
the so-called luminous paint" of calcium
sulphlde. But it was found that they
shone as brightly as ever after being CON
lined for ten days in darkness. Some
that were carried all the way from Cuba
TO Hayre in the pitch black hold Of a yes
sci were brilliant on their arrival A
more striking disprOof, however, was af-
torded by batch of larvae Matched in the
dark from eggs laid in the dark in a piece
OF rotten wood, the young insects being
kept in darkness for the first six months
Of their lives. They shone.
Prof. Langley decided that the light
did not depend on the vital principle of
the insect. He found that the eggs be-
came luminous on being shaken in a glass
receptacle. Then he dried the eggs and
kept them in that condition for long
time On being moistened they shone,
The dried eggs were powdered in a NOR
tar, but they gave light on being wetted
The beetles themselves, twelve hours
after being killed by electricity, were
still luminous. So the professor infers
that nothing more than a chemical com
bustlon is concerned in the manufacture
Of this cheapest light" He thinks there
is hope that we may be able to reproduce
it some day.
To make light equal in brilliancy to
that Of this tropical insect we must pro
duce temperature of 1000 degrees. The
hrehy's lamp creates no heat that can be
detected by the most delicate iustru-
ments. Its energy is entirely expended
IN illumination. Nature, while Offering
object lessons in the art on every hand
laughs at mans efforts to initiate her in
this field. There is device known as
"Geissler's tube" by which a much
greater light than that OF the FREELY Is
made without any heat, electric sparks
being flashed through rareted gases. but
1t is only plaything Of the laboratory.
There are good many kinds of hrehies
IN the world. Those which give an in
terlnlttenU light are popularity distin-
guished as lightning bugs" The glow
worm OF Literature is the female Of a Eu-
ropean FREELY She never acquires wings.
Her luminous substance Is a soft Yellow
ish grease, extending IN a thin layer along
the inner sides Of the abdomen. A few
Fl0w-worms exist In the United States.
but they are rare. The common hrefies
OF This country have wings. females as
well as males. The laryr are stout-bod-
lea aud grub-like, found under stones ara
1898. They yield some light.