The Romance of Modern Invention: Containing Interesting Descriptions in Non-technical Language of Wireless Telegraphy, Liquid Air, Modern Artillery, Submarines, Dirigible Torpedoes, Solar Motors, Airships, &c. &c. — John Shaqi
The Romance of Modern Invention: Containing Interesting Descriptions in Non-technical Language of Wireless Telegraphy, Liquid Air, Modern Artillery, Submarines, Dirigible Torpedoes, Solar Motors, Airships, &c. &c.Williams, Archibald
Science
The Romance of Modern Invention: Containing Interesting Descriptions in Non-technical Language of Wireless Telegraphy, Liquid Air, Modern Artillery, Submarines, Dirigible Torpedoes, Solar Motors, Airships, &c. &c.
Williams, Archibald
Inventions
The Wheatstone recorder has been worked up to 400 words a minute, and
when two machines are by the multiplex method acting together this
rate is of course doubled.
As a speed machine it has, however, been completely put in the shade
by a more recent invention of two Hungarian electricians, Anton Pollak
and Josef Virag, which combines the perforated strip method of
transmission with the telephone and photography. The message is sent
off by means of a punched tape, and is recorded by means of a
telephonic diaphragm and light marking a sensitised paper.
In 1898 the inventors made trials of their system for the benefit of
the United Electrical Company of Buda-Pesth. The Hungarian capital was
connected by two double lines of wire with a station 200 miles
distant, where the two sets were joined so as to give a single circuit
of 400 miles in length. A series of tests in all weathers showed that
the Pollak-Virag system could transmit as many as 100,000 words an
hour over that distance.
From Hungary the inventors went to the United States, in which country
of “records” no less than 155,000 words were despatched and received
in the sixty minutes. This average--2580 words per minute, 43 per
second--is truly remarkable! Even between New York and Chicago,
separated by 950 odd miles, the wires kept up an average of 1000 per
minute.
The apparatus that produces these marvellous results is of two types.
The one type records messages in the Morse alphabet, the other makes
clearly-written longhand characters. The former is the faster of the
two, but the legibility of the other more than compensates for the
decrease of speed by one-half.
[Illustration: _Specimens of the punched tape used for transmitting
messages by the Pollak-Virag system, and of a message as it is
delivered by the receiving machine._]
The Morse alphabet method closely resembles the Wheatstone system. The
message is prepared for transmission by being punched on a tape. But
there is this difference in the position of the holes, that whereas in
the Wheatstone method two holes are used for each dot and dash, only
one is required in the Pollak-Virag. If to the right of the central
guiding line it signifies a “dash,” if to the left, a “dot.”
The “reversal-of-current” method, already explained, causes at the
receiver end an increase or decrease in the power of a permanent
magnet to attract or repel a diaphragm, the centre of which is
connected by a very fine metal bar with the centre of a tiny mirror
hinged at one side on two points. A very slight movement of the
diaphragm produces an exaggerated movement of the mirror, which, as it
tilts backwards and forwards, reflects the light from an electric lamp
on to a lens, which concentrates the rays into a bright spot, and
focuses them on to a surface of sensitised paper.
Public-domain text, read in full here on John Shaqi.
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