Omaha daily bee., 1902-02-09

able after awhile to work and even to make
copious notes In a room so dark that a
stranger entering from the outside would
stumble over the furniture helplessly and
founder around generally until we led him
to a chair. The darkness, however, Is very
necessary, for 1 am now using the least
rather than the most energetic OF the ac-
tive salts. And you must not be dlsap-
pointed II you are not able to read a news
paper with It. 1 am here striving to estab-
lish a scientific principle; the Industrial de-
velopment OF 1t Is quite another matter.
But begin to see the glow now; do you
not see III"
Light Easily Managed.
l did see 1t. 1t gradually grew from a
indistinct speck in the blackness in front
until It became a luminous patch the size
Of a dollar. and 1t Frightened with the
minutes. To make sure of my eyes I
passed my hand before them. blotting out
the light entli ely, but when removed my
hand there it shone brighter than ever,
Again while l was admiring it 1t suddenly
disappeared, apparently OF its own accord.
why, II is gone" I cried.
Prof. HalIock laughed. Yes" he said,
II have removed the yellow screen. You
see how quickly the light goes out. OF
course, the rays are there just the same,
but invisible to us when not combined with
the barium- cyanide. will replace the
screen. There you see how quickly thoy
are turned into visible light. There is In
that box only two-tenths of a gram of
active material. II we had enough so that
1t could be spread out over say a square
foot of space we would get a rare efful-
gence.
well, why not do that, for the sake of
experiment?"
For the sake of experiment. he re-
piled, I'VE have dom enough, for we have
established our principle, and besides, the
present market price of that material is 81
a gram. That fact does not, however,
preclude the possibility of an economical
lighting system being developed from these
rays. And / am of the opinion that some
thing 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 lighi
itself possessed by many substances which
heretofore we're supposed to be inert
There is room at least for reflection, when
as Becquerel points out, a quiet, peaceful
bit Of white salt is capable of shooting OF
rays with a velocity Of over $500 miles g
second. There is most urgent need fol
discovering the source of this energy in
view Of its utilization by mankind.
Even in its present condition enough |,
known of the subject of phosphorescence tt
admit of a little experimentation. I be.
lieve that the owners Of office buildings
might help out the twilight materially by
the judicious use of certain luminous paints
For instance, the walls and ceilings Of offices
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 IL 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.
Cause of Animal PhOsphOreacence.
at is possible that the discovery of tbs