The sun. [volume] (New York [N.Y.]) 1833-1916, 1915-10-03

sive only to those of a given length.
But the Poulsen arc has a draw
back. The carbons are expensive and
have to be renewed frequently, and
while the efficiency Is comparatively
high and calls for less power in the
generator. still this Is not Just the
medium needed for wireless telephony.
Still seeking to better the genera
ton Of ether waves, Dr.. Alfred Gold
smith invented his rotor for the pro-
ducing Of continuous oscillations. At
the Tuckerton station IL installed n
OF his great five ton rotors for trans
atlantic service. Besides being costly
this form Of generator is as delicate
as n watch.
The requireme hts of the wireless
telephone are vastly more exacting
than those Of tie wireless telegraph.
The ether waves need not be continue
Gus for tho telegraph receiver, but the
telephone receiver must I've actuated
by continuous waves varied %agreeably
to the variation OF the human voice.
Cur speech has sounds which differ in
their vibration widely and the wave
frequencies may alter +, ON 500. let us
say. TO 5000, depending upon the pitch
o. the voice and the changes incident
10 tho vocal sounds used. How has
this problem been solved?
According to DIR. Lee DE Forest.
the success II the long distance wire
less talk Of the past week was largely
due to the use Of a special design Of
~ircandescent lamp for receiving. The
tungsten f.ament OF this lamp. In
combination with its .cavcloping
vacuum. IS extremely sensitive TO
changes of energy.
This lamp Is one OF several allied
devices now employed in long dis
lance ~telephoning by means of wires
and In principle akin TO my own lamp
which was the pioneer in this service.
! refer to my amplifer which was en-
ployed at several points along the line
between here and San Francisco.
which was opened to service on the
25ta Of January of this year.
Through underground cables the
weak current OF a telephone circuit
makes its way with me difficulty
ard various electrical devices are en-
ployed to bolster 1t up SO that the
waves will reach their destination
properly formed: 1t is this form that
determines the difference between
mqrs sound and ineligible speech.
THE Nave characters are too weak
after tEAHell!ng = long distance L
function properly an ordinary local
circuit.
But by means of suitable amplifiers
the waves can be revived and even
made stronger than they were at the
start. In this service the mer-
curry vapor arc has proved especially
effective and it was but logical that
We should find the solution of long
distance wireless telephony in Just
such a medium.
To-day the electrical world talks
physical movement Of very minute
electrical bodies. both positive and
negative. when it undertakes to de-
scribe the flow of current and the bat
tie, 30 to speak. waged in the vacuum
tube of the X-ray apparatus and the
mercury vapor arc. &c. This is only
an ingenious theory employed TO eX-
plain largely the unseen and to ac-
count for certain electrical phenomena.
Cranky. i%onization has always
bewildered me, but in my
years ago ] detected and
the physical facts Of some
Of these manifestations when working
with the mercury vapor arc In the de-
Of my commercial lamp. |
not refer to this boastfully. but as
a link in tho chain Of laborious in
and experiments which
now eliminated in the present
reach Of wireless telephony.
when I began my work with the
mercury vapor arc the pumps were
fairly crude by which it was possible
to obtain a partial To-day,
to many mechanical improve
it. Is possible TO approach in
finitely closer to an absolute
Indeed, in the latest of N-ray tubes
the remaining pressure IL certainly
not more than a few hundreds OF "A
micron, and this measure Of imper-
may be even much less.
"In this way the investigators have
gradually identified the enemies. so to
speak. OF a true vacuum, and have
IN removing the worst of
them in largely ~neutrallzing the few
that remain. This has all tended to
bring the mercury vapor arc to Its
present high state OF efficiency and
exquisite sensitiveness. and now. per-
haps. We a get a popular idea OF
the part such a device plays In wire
less telephony.
Where feeble impulses are to be
received and in turn revivifed, so
that, like a spent runner, they may
have breath to tell their story, 1t is
necessary to use helps that Won't
further exhaust the already very
much weakened impulses or v
To obtain this end l set about expert
quite fourteen years ago.. for
I knew then that long distance tele-
phoning by wire and wireless de
nended upon an aid that would meet
these requirements.
1.-THE mercury vapor arc was the
instrument chosen for this purpose
me. In 1902 I filed my applica-
tion under the title OF means OF am
DlifyinR electrical variations and my
patent was Issued In 1905. Here is
a paragraph from the specification
which really tells the whole story,
Won see my object was to employ a
medium In which the mass OF each
unit was so small that there would be
NO inertia to be overcome; each par
ticle would move instantly when
iarred by the feeblest arriving I'M
pulse. The patent reads in part as
follnuva.