New-York tribune. [volume] (New York [N.Y.]) 1866-1924, 1905-04-02
WTRELESS TELEGRAPHY.

Popular interest in the art to the development
Of which Mr. Marconi has so largely contributed
is stimulated by the report OF his arrival in
NeW-YoTk on the Campania Saturday. A lect-
ure recently given by him in London indicates
that he has made at least one improvement
since his last visit to America. Fully two years
ago he discarded for long distance work the use
of the coherer, which was the first form Of re-
ceiver employed by him, and he adopted in it's
stead n more sensitive device of his own inven-
ton, called a magnetic detecter. The latter en-
| abled an operator to take two or three times as
many words a minute as the other instrument
Moreover, the ability to receive at high speed
permitted the substitution of one of several me-
chanicaI systems-the WheatstOne, for instance
for the hand in sending. 1t still remained
necessary for the receiving operator to catch his
signals by ear, telephone being connected with
| the detecter for that purpose. message could
not be recorded. In ordinary telegraphy it is
customary to receive by sound, not sight but
British naval officers criticised Mr.. MarcOni's
new apparatus because IT was not adapted to
both methods. Accordingly he has modified It
so as to meet the objection, and the recording
mechanism which he has attached operated sue
cessfully in a test on land between points 152
miles apart. A greater distance could probably
be covered If occasion demanded, especially at
sea. II may be assumed therefore, that the i'm
proved detecter is fitted to meet all the require
ments likely to be imposed by commercial, naval
and military service.
While making his now famous experiments on
| the transatlantic steamship Philadelphia in 1902
Mr.. Marconi observed, among other things, that
signals transmitted from POldhu would travel
! further at night than by day. The phenomenon
was strange enough to attract the notice Of
many scientific men, and for a time was unex-
planned Without fully committing himself Mr.
Marconi now cites some theories which may dis
pei the mystery. The Swedish chemist and
meteorologist Arrhenlus believes that inter
planetary space is filed with electrons which
are continually being thrown off by the sum- and
that the atmosphere on the Illuminated side Of
the earth is thereby rendered less transparent
to Hertz waves Professor ]. ]. Thomson, of
Cambridge, England, imagines that the cleo
| irons act Obstructively by absorbing some OF the
| energy liberated at a transmitting station
These cOnjectures may or may not be verified
by future investigation, but there seems to be
no doubt as to the paralysis itself Mr. Mar
conf says that in bright sunlight a message will
go only two-fifths as far as at the darkest stage
of night
Another fascinating line Of speculation-one
which is not without practical importance-has
been opened By Mr.. MarcOn The circular
ripples on a pond which afford a simple illus
tration Of the ether waves involved in wireless
telegraphy proceed in all directions from the
centre Of disturbance, and diminish in intensity
as the area widens over which they spread.
That rule would hold good, no doubt, so long as
the surface was fat, but a globe IT might re-
duire modification. Suppose, for instance that
a station was put In operation at the North
Pole capable OF generating Hertz waves which
would actuate a receiving instrument at a dis
lance OF seven thousand miles. What would hap
pen? Thus far effective work has been done for
distance OF only about three thousand miles,
but it is conceivable that with a suitable in
crease Of power the distance could be a little
more than doubled. Well, In the case under
consideration, IL the waves still followed the
earth's surface, they would describe continually
widening circles until they reached the Equator.
which is about six thousand miles from the
Pole They would grow feebler with every de-
gree of latitude until the Northern hemisphere
was completely overspread. But south of the
Equator the form Of the earth would favor con-
centratiOn. The circles would diminish in ex-
tent very much as they would il a return ripple
proceeded from the circumference Of a fiat pond
10 its centre Is there not a probability that
the waves would then become intensified? II
they had sufficient force TO be recognizable one