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superseded by the telephone, but they are a part of history.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.