The Indiana State sentinel. [volume] (Indianapolis) 1868-1895, 1881-01-19
SOUNDS ON THE SUN.
An Apparatus by Which Professor Bell
Thinks They May be Heard.
New York World


Thinks They May be Heard.
New York World.l
Professor A Graham Bell, who went 10
Paris last September TO receive the Volta
prize awarded him by the French Academy
for the invention of the articHlating tele-
phone, returned TO this city on Saturday by
the steamer City of Montreal He was found
Monday evening at the Gilsey House with
his co-laborer, Mr.. Sumner Taintor. He
said that the Commission of the Academy.
after determining to award the Volta prize
| TO the inventor of the telephone, considered
the question of originality for several
months, and finally awarded it to him unan-
imously. This, he thought, ought to settle
the question. The Volta prize is $4,000
francs. 1t was originated by Napoleon l. for
Improvements in electric apparatus, and has
previously been awarded to but one person
l-Ruhmkorif, in 1915 At the formal pre-
sentation of the prize Professor Bell was ten
dered a reception by the French Academi-
clans, at which he presented Their esults of
his experiments with the photophone.
The idea OF the photophone." said Pro-
fessor Bell-"the transmission Of sound by
rays of light-was original with me- but
success in practical results with il is due as
much 10 Mr.. Taintor as to myself In 1878.
in a lecture before the Royal Institution.
London, announced the possibility of hear
ing shadow fall upon piece of selenium
included in n telephone circuit. In experi-
menting with the Atlantic cable in 1878, !
discovered that a strip of selenium two
inches long and One-sixteenth cross-section
about 400, 900, 600 ohms in the dark. but
les than half that resistance in the light
We have succeeded in securing selenium in
form and shape in which its resistance is
but 800 and $50 Ohms in dark and light
thus bringing it within the field of the tele-
phone. There are two kinds OF photophones
the musical and the calculating The
musical is very simple. An inclined mrror
throws rays of light through a lens. These
rays focus near the edge of wheel, the wheel
being perforated near its edge with forty
four holes. Each revolution of this wheel
interrupts the light fcrty-four times. The
rays then pass through two more lenses
which bring them again TO a focus near
receiving disc TO which a tube Is attached
and through which sotlnds are heard. Sound
waves having greater velocity than thirty
per second are audible; so the interruption
of rays OF light by the perforated wheel
thirty times or more per second gives an
audible sound, the pitch being determined
by the rapidity of the Interruptions. and
corresponding with the vibrations of tun-
ing-fOrk Two hundred and fifty Interrupt
tions per second will give the same musical
note as tuningfork making that number
of vibrations per second. The receiving disc
is usually ebOnite or hard rubber But bv
our experiments we have discovered what
believe is new property of matter, that all
substances, when in the shape of thin dia-
phragms, emit sounds when submitted to
interrupted undulatory beams of light The
question presented by these phenomena was
whether the musical tones were due to
intermOlecular action or not, and what was
their cause? Professor Tyndall Suggested
that if w could produce sound by the use of
free Transparent gas in the tube it would
show that the sound was due to intermolec-
ular action. We tried vapor of sulphuric
ether and obtained a perceptible musical
tone, but obtained none from vapor of BIZ
sulphide of carbon. The former is a DOW
erful heat absorbent, while the latter is a
non-absorbent of heat. From this Professor
Tyndall was satisfied that the sounds were
due to molecular action, probably caused
by the heat of the rays But we found more
than this. If no receiving bridge or test
tube is used, but the rays are allowed to
converge in one end of a rubber or other
tube, musical tones can be heard at the
other end, and if the rays converge within
the Orifice of the ear distinct sounds are
produced. But this is rather dangerous
experiment. Again we found that the in
terpositiOn of two hard rubber diaphrams,
with a solution of alum between them to
cut off the heat rays between the mirror
and the lens, did not prevent the produc-
ton of these musical sounds, although they
made them more feeble. / firmly believe
we have transmitted articulate sounds by
this instrument without the electric cur
rent, but am not ready yet fully TO demon
strate the fact.
THE calculating photOphone is made by
an addition to the one just described. In
the place of the receivingdisk is put silver
1tclr Is II, a. VI
reflects the rays of light to paraboic mir
ror. at the focus of which there is a seleni-
um-cell receiver in telephone battery cir
cult. This disk is also the part of the in
strument against which the voice acts
When this is a plane surface and still, RAYS
are thrown in parallel lines to the selenium
receiver. But as it becomes alternately con-
cave and convex, the RAYS reflected converge
and diverge, and greater or smaller pro-
portion of rays are reflected upon the seleni-
um, and this is so sensitive in an electric
current to varying degrees of light that the
sounds OF the voice are transmitted by il to
the telephone circuit, and under favorable
conditions are more perfect, natural and
distinct than in any of the telephones yet
produced, the pitch of course, still depend
ing on the rapidity of revolutions of the per-
forated wheel.
'In the Solar Observatory near Paris N.
JdnSScH Was OI Tie
sun. He took them very rapidly The eX-
posture in each case was but 1-3000th of
second, and the intervals were but 1-30th of
a second. He found the surface of the sun
covered with peculiar willow-leaf-shaped
granulatiOns supposed to be due - metallic
vapors Each photograph showed marked
change in these granulations. As thirty of
these photographs are taken per second, the
changes in the EXAMINATIONS are shown to be
rapid enough to emit distinct sounds We
made some experiments, but the apparatus
was not proper for that purpose, and al
though we obtained results in the shape of
sound, they really proved nothing. My
belief is that with a minute selenium cell
and telescope, so arranged that we can get
the rays from single granulatiOn, we shall
be able to hear on earth sounds of storms on
the surface of the sun.
eve have transmitted articulate sounds
by the photophOne a mile, and musical
sounds by the musical photophone 500 feet.
An eightieth of the light of the sun is suf-
ticient to produce results. We have used
artificial lights good deal. In its present
state of perfection the photophone is of more
scientific than practical value, but when we
can transmit articulate sounds four or five
miles it will be of great value-in war, for
instance, taking the place of the heliostat or.
possible aerial telegraph"
Jay Gould, the Railroad Power, and the