Evening star. [volume] (Washington, D.C.) 1854-1972, 1902-02-08

two-tenths of a gram of active material. If
we had enough so that 1t could be spread
out over say a square foot Of space We
would get a rare effulgence.
We'll, why not do that, for the sake of
experiment.
For the sake of experiment" he replied
we have done enough, for we have estab-
Eshed our principle, and besides, the pres
ent market price of that material is five
dollars gram That fact does not, how
ever preclude the possibility of an econom-
ical lighting system being developed from
these rays. And I am of the opinion that
something practical may be made out of
this general subject of phosphorescence or
self luminosity of objects. Not only have
we discovered that most natural objects
have the capacity for storing sunlight, but
here Is the apparent capacity for creating
light itself possessed by many substances
which heretofore were supposed to be inert.
There Is room at least for reflection, when,
as Becquerel points out, quiet peaceful
bit of white salt is capable of shooting off
rays with velocity of over 90, 500 miles a
second There Is most urgent need for dis
covering the source of this energy in view
OF its utilization by mankind.
Luminous Paints.
Even In its present condition enough is
known of the subject of phosphorescence to
admit of little experimentation. believe
that the owners of Office buildings might
help out the twilight materially by the
For instance the walls and ceilings of Of
fees could be covered with these paints and
made to emit light enough to last with the
twilight on winter evenings until the close
Of office hours. And If the Railways of
houses and public buildings were to be
coated in like manner one could get about
them at night without the aid Of more arti-
fetal light
''It is possible that the discovery of the
source of the energy of Becquerel rays
might lead US to the cause of animal and
vegetable phosphorescence. This has been
subject of investigation during all ages
and especially during the last century, but
1t cannot be said to have been solved. Yet
some of the manifestations are truly won
derful. There are over 800 kinds of lumin-
Gus beetles in the world and they form only
a small proportion of the lower animals
which carry their own light with them.
You have yourself perhaps heard wonderful
stories Of the light emitting capacity of
some tropical insects and of certain deep
sea animals. Lord George Campbell told
of huge pyrosoma trawled up from 2,250
fathoms during the voyage of the Chal-
lenger. 1t emitted a great quantity of
light when irrftated. 1t was a large sac
shaped animal and as 1t lay in the tub at
night the men wrote their names in full
length on It's back, the names standing out
brilliantly in letters Of light. There are
other tales quite as wonderful, but the the
cries accounting for these lights are really
too numerous to be told at sitting
But In the efforts of Becquerel and of
Mime. Curle we have something tangible"
concluded Prof. Hallock leading the way
out into the laboratory. 1--WE have some
thing to go upon. To- be sure we do not
know exactly what 1t is we have 1t may
be the energy Of the sun stored without
our present knowledge, although that is
hardly likely; 1t may be some property of
the ether; it may be as Nine Curie sug-
gested, the result of transcendental ra-
diation more penetrating than the X-ray
and pervading all space, although Prof.
aTIYa6 O &c,
diations easily penetrate hundreds of yards
or rock, for radfum was still active at the
bottom of the deepest mine in which he
was able to descend. At least 1t is the
newest force with which we have to deal.
You have seen how 1t can be turned into
light and when You think that In spite of
Its speed Of $500 miles a second the waste
from less than half inch of surface Is only
a milligram In thousand million years
you must admit that the possibilities for
the substance are great"