The morning call., 1891-08-09
PHOSPHORESCENCE.
The Remarkable ADD3aTaICa Of Dark and Light
Spaces.

OF all the exciting causes of luminosity
none is more powerful or more remarkable
in its action than electricity. A discharge
OF electricity sent through rarefipd gas is
attended by a glow the color of which is
often characteristic of the particular gas :;
and not infrequently the gas continues to
give out light for some time after the ap-
parent cessation of the electrical action.
BY reason of the beauty and the remarkable
appearance of striR, or dark and light
spaces, arranged in symmetrical manner
in the track of the glow and around the
poles, together with other manifestations,
these phenomena have been the occasion of
much observation and study on account of
the light they are calculated to throw on the
physical nature and Internal constitution of
gases, and on the manner in which their
molecules behave under the influence of
electricity and magnetism.
Inc phenomena observed in gases in
conditions OF extreme tenuiiy have been es-
pecially studied by Mr.. Crookes. Under
these circumstances the tube or vessel con-
tanning the highly rarehed gas, If of soda
glass, pnoSph0reSceS with a yellowish green
light, and il of lead glass of blush light.
due TO the impact Of the rapidly moving
molecules OF the surface of the glass, and
round the negative pole in the tube is a
dark space with luminous boundary. due
probably to the collisions of the molecules
among themselves This molecular bom-
bardment Is capable of affording some of
the most striking and beautiful examples
Oh phosphorescence with which We are ac-
quainted.
Substances which are phosphorescent I'M
der ordinary conditions glow with the great
est brillancy when submitted to the negative
discharge in these highly attenuated gases.
Canton's phosphorus shines with ali the
splenuor induced by strong sunshine. Under
the same circumstances the diamond, espe-
clally that from the South African fields.
phosphoresces with n brilliant light blue
color. Diamonds from other localities were
found by Mr. Crookes to shine with all va
rletles OF color, such as bright blue, pale blue.
apricot, red, yellOwish green, orange and
bright green. A green diamond when phos-
phorescing in good vacuum gave out almost
as much light as candle, and the different
1aces OF the naturally cryStallized gems were
found to glow with different shades of color.
The ruby, which is practically almost
pure alumina. phosphoresces with rich
tull red. number of rough rubies in a
high vacuum glow, when the molecular dis
charge plays upon them, as if they were
red hot, and with an Illuminating effect al
most equal TO that OF the diamond under
the same conditions. The color of the rnby
has apparently little or nothing to do with
the phenomenon; pure white alumina
rubles OF pale reddish yellow and gems of
the pigeons blood color all emit prac-
tically the same deep red glow. The
artificial art, rubies of Messrs. Frenzy & Fell,
which are of the same chemical nature as
the natural stone, behave in preciselv the
same way when subjected to the Discharge
In a sufficiently high vacuum, showing that
in this as in all other respects the natural
and artificial rubies are Identical in char.
a as,a.l., 81 Inc sapphire, however, which in
chemical composition differs but slightly. if
at all, from the ruby. gives out blmish-
gray light, while the emerald CLOVIS with
fine crimson-red color.-Good Words