National Republican., 1885-06-06
sREssoFELEorR1csc SCIENCE

Third of n Series oT Popular Articles
by G. j, Kintner, Examiner Glass
Electricity, United states Patent
Once.
The late Prof. Clerk Maxwell, of Eng
and, defnes electric induction to be q
strain of some kind and light to be a
similar strain each acting through tho
medium of ether in space.
So closely allied are these two phe-
nomena that he was led to make an OK
tended sorios of experiments to prove
their actual identity, and had he lived no
doubt he would have succeeded. Indeed,
he did prove mathematically that both
magnetic and electric disturbances act at
right angles to lines of force. just as light
vibrations travel with relation to ray of
light.
He aud others also proved that induced
electricity travels through space at the
rate of 192, 900 miles per second-the ac-
cepted velocity of light according to tine
known proofs-thus establishing an ad-
ditional relation.
Following closely upon the experiments
of Prof. Maxwell, others discovered that
1y related to sulphur, and foundin nature
in the Hartz mountains Of Germany--
had peculiar electrical properties whom
acted upon by light.
Messrs. Adams and Day. members Of the
Royal Society, made an extended series of
experiments with selenium to ascertain
the peculiar relations found to exist be-
tween light and electricity. They dis
covered that upon connecting a stick or
bar Of selennium directly in an electrical
circuit containing galVanometer or
electrical indicating instrument and then
causing a light to bo thrown upon the So
lenium, the galvanometer indicated q
change of strength Of current dependent
upon the square root of the illuminating
power. Specializing upon the wonderful
effect thus produced by light upon an
electric current they were led to make an
experiment to ascertain if 1t were possi-
BILE to generate electricity by simply throw
ing light upon the solenium cell, when
connected in circuit with a delicate gal
Yanometer or indicator of electricity, and
without any prime generator in the cir
cult. To their astonishment and delight
the delicate little instrument indicated
the presence Of electricity. Here, then,
was case of transformation Of light di-
rectly into electricity, a most wonderful
discovey.
With that persistence with which the
ever curious scientist seeks the reason for
unexplained phenomena, they labored
unceasingly for weeks and months to as
certain If this were case OF transforma-
tion Of one kind of energy into another,
or II IL were an actuaLproof Of the iden-
tity Of electricity and light. Thoy dis
cerned that selenium in hardening after
having been fused, assumes a crystalline
condition dependent upon the rapidity
with which it eools, tho outer surface
cooling the moro rapidly. Hence tho
/, whole oell, when ultimately cooled, is in
such q varied state of capitalization
that the passage of light through 1t tends
to further promote capitalization in tho
inner parts of the cell, and it is this ex-
ereiEe Of the radiant energy of light
which sets up a current, by creating q
change of electrical potential or pressure
between the outer and the inner portions
of the cell.
Light in its passage through certain
transparent bodies is known to very
materially aid in their capitalization
and its passage through the selenium
cell tends to create current running
from the outside to tho inside Of the cell
That this is the action was eHectually
proven by casting selonium cell and
by allowing IL to cool gradually under
exposure to the light, so that its crystal
line condition was identical throughout.
From such cell not the slightest trace of
current was detected upon submitting
ID to the above tests.
Little or no use has been made OF these
interesting discoveries In the art, the
first practical application being Prof A.
Graham Bells radiaphone for transmit
ting speech through space by tho agency
OGtefOcted light, Ofwhioh We shall have