, 1889-07-04
HOSPHORESCENCE.
THE LIGHT WHICH ILLUMINes WITH
OUT CREATING HEAT.

There is no subject which the re-.
searches of scientists have more COM
pletely failed to elucidate than that of
the cause of animal, mineral and vege-
table phosphorescence-the light which,
unlike all other lights, illumines with
out either consuming OF giving out any
perceptible heat The ocean is the great
~storehouse of phosphorescent light. On
its surface myriads of noctiluce Qittle
creatures just visible to the naked eye)
are often seen lighting the waves for
miles, and presenting wonderful effects
when the water is broken by the bow of
a ship or the oars of a boat. Persons who
have passed through a stretch of water
crowded with noctiluc@ say that the
light they give dims that of the stars,
and makes the sea look as though it were
a vast heaving mass of metal at white
heat.
The intensity of the light is explained
by the immense quantity of the little
animals, which are computed to number
thirty thousand or 30 to the cubic foot.
Batheys in waters where they abound
nav often been amazed to find, on
emerging, hat their bodies are rendered
luminous by the noctiluce that cling to
them.
A kind of sea slug that is met with in
h Mediterranean and the Pacific emits
light from certain spots in the body. 1t
is capable Of being kept in an aquarium,
and there are usually some specimens in
the famous one at Naples. When dis
turbed or swimming the light makes it
look like a flame in the water.
PYRosoME-
The most splendid of the many lumi-
nous inhabitants Of the sea are the pyro-
some. AT night they look as though
made Of glowing white hot iron; difus-
ing 80 strong a light that other fishes are
rendered visible when they happen to
swim within thesphere of their radiance.
A distinguishing feature of the pyro-
soma is the variety of tints that it gives
forth-orange, green, azure, blue, white,
and various shades of dark red having
been all noticed by various observers.
A tiny kind of shark that is met with off
the shores of the southern states of
America is a noted light giver. Speci-
mems captured and taken into o dark
apartment present an extraordinary spec
tacla. The entire surface of the mead
and body emits a greenish CLEAN that is
constant, and is not, as in the case of
most of these luminous inhabitants of
the sea, increased by friction and agita-
ton.
The smallness of the fins of this fish
show that it is not an active swimmer
and the assumption is that its light is
useful in attracting its prey, on the prin-
ciple of the torches used by many saw
ages in fishing. Several kinds of crabs
are luminous. IN named the sapphirina
Is noted for the intensely vivid character
of the light that proceeds from it. So
brilliant is it that it does not need dark
ness to make its presence known, but
corruscates blue, purple, green, gold and
sapphire rays in full daylight. The
presence of u school of mackerel is often
indicated by the phosphorescent CLEAN
which these fish produce. Fishermen
often descry them at a great distance by
this light, and hasten to surround them
by their nets. 1t is thought that mack
erel make a secretion which gives the
light, as after they are captured n gleam-
ing fluid is noticed running off their
bodies, and sometimes covering the hands
of the mea who toss them from the boat.
FREFLIEs.
1t has been urged that the poet was
guilty of an -exaggeration in describing
the frefiies as giving sufficient light to
be of any service; but the accounts of
travellers in South America, who tell us
that the natives light their path while
journeying by a couple of these insects
tied to their feet, show that he was
speaking quite within the bounds of pos
sibility. At evening entertainments in
that part of the world it is customary
far ladies to decorate their hair and
dresses with firefies, confined by deli
cate silken threads.
The natives of Vera Cruz do quite q
large trade in f~irefies, which they catch
by waving a blazing coal at the end of q
stick. The insects fly toward the light,
and are captured in nets. The ~firefies
of Northern America differ from those
just described in the fact that they emit
their light in capricious flashes, instead
of with a steady, uniform glow. This
peculiarly has gained for them the name
of lightning bugs" Their light is very
similar to that of our glowworm. A
story is told of some French peasants
who were returning homo one night and
saw a meteor fall through the sky in
AAOAib VI " hdll u Dlll luIInGI
on they came to a glowing mass in n
ditch and rushed away terrified, declar-
ing hat a star had fallen upon the earth
and was burning it up. On investigation
it was found hat this burning star was
nothing more uncanny than a mass of
frogs eggs that had developed phosphor-
scene
Several varieties of the vegetable king
dom are luminous in a greater or less
degree. One of the fungi, which is not
at all ncommo on the walls of damp,
dark mines, caverns, etc., occasionally
ernits sufficient light to admit of the
reading of ordinary print by it. The
emission of light from the common po-
tato when in u state of decomposition is
sometimes very striking. Several of the
Indian plants and grasses are also lumin-
Gus, and it is said that in 1s45 the noun
tains near Syree were nightly illuminated
by their means. The root stock of q
plant from the Ooraghum jungle, sup
posed to be an orchid, possesses the pc