SHORT-LINE TELEGRAPHS.
Early in the history of the telegraph
short lines began to be used for private purposes,
and as the Morse code was familiar only to those who
had studied it and were expert operators on commercial
lines, some system had to be devised that any one
with an ordinary English education could use; as the
expense of employing two Morse operators would be too
great for all ordinary business enterprises. These
short lines are called private lines, and the instruments
used upon them were called private-line telegraph-instruments.
Of course they are now nearly all superseded by the
telephone, but they are a part of history.
One of the earliest forms of short-line
instruments was called the dial-telegraph. One
of the first inventors, if not the first, of this
form of instrument was Professor Wheatstone of England,
who perfected a dial-telegraph-instrument about the
year 1839. The receiving-end of this instrument
consisted of a lettered dial-face, under which was
clockwork mechanism and an escape-wheel controlled
by an electromagnet. Each time the circuit was
opened or closed the wheel would move forward one step,
and each step represented one of the letters of the
alphabet, so that the wheel, like the type-wheel of
a printing telegraph, had fourteen teeth, each tooth
representing two steps. As the reciprocating movement
of the escapement had a pallet or check-piece on each
side of the wheel, its movement was arrested twenty-eight
times in each revolution. These twenty-eight
steps correspond to the twenty-six letters of the alphabet,
a dot and a space. On the shaft of the escape-wheel
is fastened a hand or pointer, which revolves over
a dial-face having the twenty-six letters of the alphabet,
also a dot and space. The pointer was so adjusted
that when the escape-wheel was arrested by one of the
pallets it would stop over a letter, showing thus,
letter by letter, the message which the sender was
spelling out.
The transmitter consisted of a crank
with a knob and a pointer on it, which was mounted
over a dial that was lettered in the same way as the
face of the receiving-instrument. A revolution
of this crank would break and close the circuit twenty-eight
times; that is to say, there were fourteen breaks
and fourteen closes of the circuit. If now the
transmitting-pointer and the receiving-pointer are
unified so that they both start from the same point
on the dial, and the transmitting-crank is rotated
from left to right, the receiving-pointer will follow
it up to the limit of its speed. In transmitting
a message the sender would turn his crank, or pointer,
to the first letter of the word he wished to transmit,
making a short pause, and then move on to the next
letter, and so on to the end of the message, making
a short pause on each letter. The end of a word
was indicated by turning the pointer to the space-mark
on the dial. The receiving-operator would read
by the pauses of the needle on the various letters.
This was a system of reading by sight.
There have been many forms of this
dial-telegraph worked out by different inventors at
different times, and quite a number of them were used
in the old days. It was a slow process of telegraphing,
but it was suited to the age in which it flourished.
One of the difficulties of a dial-telegraph consisted
in the readiness with which the transmitter and receiver
would get out of unison with each other; and when this
happened of course a message is unintelligible, and
you have to stop and unify again.
About 1869 the writer invented a dial-telegraph
to obviate this difficulty. In this system a
transmitter and receiver were combined in one instrument,
and instead of a crank there were buttons arranged
around the dial in a circle, one opposite each letter.
When not in operation the pointers of both instruments
at both stations stood at zero. In the act of
transmitting the operator would depress the button
opposite the letter he wished to indicate, when immediately
the pointers of both instruments would start up and
move automatically, step by step, until the pointer
came in contact with the stem of the depressed button,
when it would be arrested, and at the same time cut
out the automatic transmitting-mechanism and cause
both needles to remain stationary during the time
the button was depressed. Upon releasing the button
the pointers both fall back to zero at one leap.
The first private line equipped by
this instrument was for Rockefeller, Andrews & Flagler,
which was the firm name of the parties who afterward
organized the Standard Oil Company. This line
was built between their office on the public square
in Cleveland and their works over on the Cuyahoga
flats.
It seemed, however, to be the fate
of the writer to make new inventions that would supersede
the old ones before they were fairly brought into
use. Very soon after the dial-telegraph began
to be used, printing telegraph instruments for private-line
purposes superseded them. About 1867 a printing
instrument was devised for stock reporting, which in
one of its forms is still in use. Soon after
the invention of this form of printer a company was
organized to operate not only these stock-reporting
lines, but short lines for all sorts of private purposes.
Following the invention of the stock-reporting instrument
there were several adaptations made of the printing
telegraph for private-line purposes. Among others
the writer invented one known as “Gray’s
automatic printer,” a cut and a description of
which may be found on page 684 in “Electricity
and Electric Telegraph,” by George B. Prescott,
published in 1877. This instrument was adopted
by the Gold and Stock Telegraph Company as their standard
private-line printer. It was first introduced
in the year 1871, and at the time the telephone began
to be used there were large numbers of these printers
in operation in all of the leading cities and towns
in the United States. While this has been superseded
to a large extent by the telephone, there are still
a few isolated cases where it is used.
Short lines have multiplied for all
sorts of purposes, until to-day the money invested
in them largely exceeds the amount invested in the
regular commercial telegraphic enterprises.
The invention of the telephone created
such a demand for short-line service that some scheme
had to be devised not only to make room for the necessary
wires, but to so cheapen the instruments as to bring
them within reach of the ability of the ordinary man
of business.
This problem has been solved (but
not without many difficulties) by the inauguration
of what is known as the “central station.”
By this system one party simply controls a single
wire from his office or residence to the central station;
here he can have his line connected with any other
wire running into this same station, by calling the
central operator and asking for the required number.
It is useless to tell the public that very often this
number is “busy,” and here is the great
drawback to the central-station system. This
is especially true in large cities, where there are
a great number of lines. The switchboards in large
cities are necessarily very complicated affairs, and
it requires a number of operators to answer the many
calls that are constantly coming in. Each central-station
operator presides over a certain section of the board,
and as this section has to be related in a certain
way to every other section, it is easy to see wherein
arises the complication.
In large cities the central stations
themselves have to be divided and located in different
districts, being connected by a system of trunk lines.