The Fargo forum and daily republican. [volume] (Fargo, N.D.) 1894-1957, 1914-04-08

crest to crest, hen you will get some
sort Of mental picture Of the waves
used in wireless"
Or better still, take Professor Van
mis- amazing device. He uses what is
known as the Moretti arc, devised by
a young electrician Of Rome. You are
familiar with the ordinary big arc
lights of the streets which fash be-
tween two large sticks Of pressed car
bon. DR.. Moretti's arc flashes be-
tween two metal surfaces, and is so
small that you might mistake it for a
little atomizer such as you use to
! spray your throat. The distance be-
tween the two surfaces, instead of be-
ing one-half an inch or more, as in
the ordinary arc light, Is only about
a thousandth Of an inch. Yet it was
by means Of this minute lamp. inter-
rupting the current Of the arc 100000
times or more a second, that Profess
sor Vanni was able to throw enough
energy on to the aerial" Of his sta
ton to talk from Rome to Tripoli. But
how he did 1t, and how all wireless
telephoning is achieved, is far more
astonishing h n mere question of
dimensions. '.e| '-. ~
Light waves and electrical waves as
we'll all travel at. the same speed-at
about 1874, 900 miles a second. Every
time you interrupt the current of the
arc you make a little wave and, there
fore, If o 10 this as Professor Vann'
| did, at from 100, 900 to 100000 times a
second, each Of these little waves will
be about a mile long; and they are
not a millionth of an inch high. Do
you think that v e the amazing mind
Of man could devise any instrument
or any method by which these little
waves, one-millionth Of an inch high,
could be clipped off in a fashion to
create sound waves in an ordinary
telephone receiver? Yet this Is pre-
clsely what happens. 's<
Into the circuit Of the little atomiz-
er arc is shunted, as electrical men
say, the secondary Of an ordinary tel
| ephone transmitter, such az o use
every day. Then the arc Is set going.
you talk into the receiver. and the in
visible wave that go speeding through
space at such incredible velocity and
in such incredible numbers, have their
heads chopped off a little. a ten-mil-
lionth of an inch here and a five-mil-
lionth Of an inch there, with the result
that a ave exactly like the sound
waves Of your voice Is literally super
imposed upon the electrical waves
from the arc. Both sets Of waves are
carried up from the room where you
are talking by ear of wires to the
high antennae which hang from the
familiar poles OF a wireless station. AS.
the waves rush outward, the ether, or
whatever substance fills space, begins
to. culver, not alone with these waves,
but Indirectly with the sound of our
voice, and these quivers are carried
hundreds of miles. But, using the Or
binary telephone transmitter, you
cannot talk any great distance, be-
cause these waves die away just as do
ordinary waves and sound raves
Their energy is frittered away into
heat. So. to talk any distance, Pro-
fessor Vanni had to devise an entirely
new kind of m~icrophone; you could
not guess in a year what it was. Sim
ply a thin little Jet Of water playing
against two little metal plates. Be-
tween the plates n through the
water flows an ordinary electric cur
rent: but one of the plates is attached
to a little .dia; hiram like that. in d
child's telephone, and against this dit
phram y~ourspeak. This causes one OF
the little metal plates to culver back
and forth, varying the distance across
to the other plate, and hence varying
the amount of current that will flow
between them. 1t is this current. thus
modified by you voice, which in turn
modifies the trains OF rushing cleo
tricalr waves sent out by the tiny arc.
Is it not astonishing that anything SO
| simple could be used to such marvel
Gus effect? +,
The principle of this device was
thought out thirty years ago by Chi
chester Bell, a NEPHEW Of DR.. Graham
Bell, the inventor of, the magnetic
telephone; but 1t was never put to any
practical use before.
The device and the methods employ
ed by Count Arco are as different
from Professor Vanni's as anything
well could be. You know that the
electric currents which light our lamps
and run our street cars are generated
by machines called dynamos, and
these are simply devices for whirling
q coil of wire In front Of a strong
magnet. Every time the coil goes past
the magnet, a little electrical pulse Is
generated, first in inc direction and
then In the reverse direction. This re-
versal in ordinary machines takes
place about sixty times q second.
Count Arco employs q generator
wherein the reversal takes place 10000
times a second.