MISCELLANEOUS METHODS.
"It never rains but it pours." Almost simultaneously with the
demonstration of the Morse telegraph other types were devised. There
were the needle systems of Cooke and Wheatstone, the chemical telegraph
of Alexander Bain, and soon the printing telegraph of House, and later
that of Hughes. The latter is in use on the continent of Europe, and a
modification of it has a very limited use on some American lines. The
Bain telegraph used a key and battery the same as the Morse system, but
it did not depend upon electromagnetism as the Morse system does. When
in operation a strip of paper was made to move under an iron stylus at
the receiving-end of the line. The paper was saturated with some
chemical that would discolor by the electrolytic action of the current.
When a message was sent the paper was set to moving by a clock mechanism
or otherwise, under the stylus that was pressing on the paper as it
passed over a metal roller or bed-plate. The transmitting-operator
worked his key precisely as in sending an ordinary message by the Morse
system. The effect was to send currents through the receiving-stylus
chopped into long or short marks, or the dots and dashes of the Morse
code, and recorded on the tape in marks that were blue or brown,
according to the chemical used. A few lines were established in this
country on the Bain system, but it never came into general use.
A number of systems, called "automatic," grew out of the Bain system.
Bain himself devised, perhaps, the first automatic telegraph. The
fundamental principle of all automatic telegraphs depends upon the
preparation of the message before sending, and is usually punched in a
strip of paper and then run through between rollers that allow the
stylus to ride on the paper and drop through the holes that represent
the dots and lines of the Morse alphabet. Every time the stylus drops
through a hole in the paper it makes electrical contact and sends a
current, long or short, according to the length of the hole. The object
of the automatic system was to send a large amount of business through a
single wire in a short time. It does not save operators, as the messages
have to be prepared for transmission, and then translated at the
receiving-end and put into ordinary writing for delivery.
The automatic system is not used except for special purposes, and the
one that seems to be the most favored is that of Wheatstone. The system
is in use in England and in America to a limited degree.
Early in the history of the telegraph a printing system was devised.
Wheatstone and others had proposed systems of printing telegraphs in
Europe, but these never passed the experimental stage. The first
printing telegraph introduced in America was invented by Royal E. House
of Vermont, and first introduced in 1847 on a line between Cincinnati
and Jeffersonville, a distance of 150 miles. In 1849 a line for
commercial use was established between New York and Philadelphia, and
for some years following many lines were equipped with the House
printing telegraph instrument. The late General Anson Stager was a House
operator at one time. All printing telegraph instruments, while
differing greatly in detail, have certain things in common, to wit: a
means for bringing the type into position, an inking device, a printing
mechanism, a paper feed, and a means for bringing the type-wheels into
unison. There are two general types of printing instruments, the
step-by-step, and the synchronously moving type-wheels. The House
printer was a step-by-step instrument and consisted of two parts, a
transmitter and a receiver. The transmitter consists of a keyboard like
a piano, with twenty-eight keys. These keys are held in position by
springs. Under the keys is a cylinder having twenty-eight pins on it
corresponding to the twenty-six letters of the alphabet and a dot and a
space. This cylinder was driven by some power. In those days it was by
man-power. It was carried by a friction, so that it could be easily
stopped by the depression of any one of the keys that interfered with
one of the pins. One revolution of the cylinder would break and close
the current twenty-eight times, making twenty-eight steps.
The receiving-instrument consisted of a type-wheel and means for driving
it. It was somewhat complicated, and can only be described in a general
way. If the cylinder of the transmitter was set to rotating it would
break and close twenty-eight times each revolution. (There were fourteen
closes and fourteen breaks, each break and each close of the current
representing a step.) The type-wheel of the receiver was divided into
twenty-eight parts, having twenty-six letters and a dot and space, each
break moved it one step and each close a step; so that if the cylinder,
with its twenty-eight pins, started in unison with the type-wheel, with
its twenty-eight letters and spaces, they would revolve in unison. The
keys were lettered, and if any one was depressed the pin corresponding
to it on the cylinder would strike it and stop the rotation of the
cylinder, which stopped the breaking and closing of the circuit, which
in turn stopped the rotation of the type-wheel--and not only stopped it,
but also put it in a position so that the letter on the type-wheel
corresponding to the letter on the key that was depressed was opposite
the printing mechanism. The printing was done on a strip of paper, which
was carried forward one space each time it printed. The printing
mechanism was so arranged that so long as the wheel continued to rotate
it was held from printing, but the moment the type-wheel stopped it
printed automatically.
The messages were delivered on strips of paper as they came from the
machine.
In 1855 David E. Hughes of Kentucky patented a type-printing telegraph
that employed a different principle for rotating the type-wheel. The
electric current was used for printing the letters and unifying the
type-wheels with the transmitting-apparatus. The transmitter, cylinder,
and the type-wheel revolved synchronously, or as nearly so as possible,
and the printing was done without stopping the type-wheel. Whenever a
letter was printed the type-wheel was corrected if there was any lack of
unison.
This type of machine in a greatly improved form is still used on some of
the Western Union lines, especially between New York, Boston,
Philadelphia, and Washington. It is also in use in one of its forms in
most of the European countries.