The Osceola times., 1881-02-19
The photophone.
n m. H.nnl.llrnn-

The rapid progress reported 10 have
been made hy Prof. Graham Bell in de-
Ncloping his discovery of the photophone
promises 10 make this instrument one OF
the most important products of modern
rc rlrch. Lord Bacon once slid that u
true scientific generalization once made
troops "f practical applications will soon
follow The history ofaii investigations
i'm the dark and untrodien domain Of
molecular physics is not an exception 10
this remark Of the great inductiyc phi
losophcr, but furnishes most brilliant
illustrations Of it, force. II is unneccs-
say 10 trace in detail how the modern
electric light, the electric engine, the tel
ophOne and telegraph became the natur-
al, We might almost say the inevitable,
results Of FEraday's and other expert
mcnts in the laboratory conducted with
view 10 test antecedent hypothesis, the
glimmer Of whose light lured on the the
oretical investigator to new and unex-
pored regions of physical inquiry. In
the case of the photophone the instru-
mental device of Prof. Bell is the out
come of experiments upon the curious
action Of light in affecting the electric
CondHCtiyity of the rare metal sclcnium.
This metal was discovered in 1917 by the
celebrated Swedish chemist Berzelius,
and now promises 10 figure conspicuous
ly in the future utilization of the photo
phone. The photophone is an instru-
mcnt for the transmission of artificial
sound to distant stations solely through
the agency of beam of light. 1t effects
the transmission of sound not by means
of an electric wire, or, indeed, by any
material medium, but, like the ancient
statue of Mcmnon, which, according to
Strabo, gave forth n mysterious sound
every morning rs the rays of the sun fell
upon it, the new instrument converts the
waves of light thrown upon it into waves
of audible and ineligible sound. Its
practical operation is due to the senSi-
tiveness of the selenium plates, by means
of which the impact of rays of light of
varying intensity is made sensible to the
ear, The transmitting instrument is
simply plane and flexible mirror of thin
glass or mica, against the back of which
the speakers voice is directed at the same
time that powerful beam of light is east
upon the mirror, while the vibrations
flashed to the distant receiving instru-
ment cause its sensitive selenium disk TO
reproduce anu FcaftlCnlatt tllc original
words of the speaker. Wherever, there
fore beam of light, solar or artificial,
can be thrown there the photophone can
be employed for communication.
The difficulties yet to 'be overcome be-
fore the photophone can be put in prac-
teal Use are 10 determine how far il will
serve to transmit messages and to over
come the optical difficulties in managing
the beam of light. To perfect it will
probably require much further expert
mentation, for which purpose its inven-
tor is now in Europe at work with em-
inent scientific advice. But, as Prof
Huxley SAYS, "such an instrument may
evidently become of great value in estab-
fishing rapid communication between
distant surveying stations and especially
in military signalling, where it promises
to displace the heliograph.' While the
field of its ability may not be as wide rs
that of the telephone, it will probably
serve an important purpose in many cir
cumstanccs where electric wires can not
be placed for telephone communication,