Telegraphy

Telegraphy is the long-distance transmission of messages where the sender uses symbolic codes, known to the recipient, rather than a physical exchange of an object bearing the message. Social development in the 18th and 19th centuries was characterized by increasing industrialization and the need for a faster exchange of information. Therefore, ways were sought to convey information faster than was possible through messengers or riders. Optical and later electrical telegraphs were developed which made it possible to exchange information quickly between Europe and America.

Transfer of information yesterday and today

The fast transmission of information by telephone, fax, e-mail, radio or television is now a matter of course. The situation was completely different 200 years ago or even in the Middle Ages or in ancient times.
Perhaps the best-known messenger of news comes from antiquity: According to legend, when the Athenians defeated the Persians in 490 BC A runner conveyed the message of the victory of the Greeks from Marathon to Athens and covered a distance of 42.125 km. After delivering the news in Athens, he is said to have collapsed dead. The marathon, which was first run at the Olympic Games in 1896 between the marathon and Athens, goes back to this legend.
In the Middle Ages, messages were transmitted by messengers and mail riders. The speed of the message transmission was correspondingly low. Major advances were made by optical pointer telegraphs at the end of the 18th century, electric telegraphs in the 19th century, and communications using electromagnetic waves in the 20th century.

Optical pointer telegraph

In 1792 the CHAPPIE brothers from France developed an optical telegraph system. For this purpose, signal arms that could be seen from afar were set up on buildings or mountains, which could be brought into different positions (Fig. 1). Each position meant a certain letter or a certain number (Fig. 2). The information was passed on from one station to the next, whereby the stations had to be within sight.
The first line opened in France in 1794. For the 840 km between Paris and Toulon, a signal took no more than 20 minutes. In 1795/96 the first lines went into operation in Germany and England, including a connection between Berlin and Frankfurt / Main. Even today, names are reminiscent of the optical telegraph: On today’s Telegrafenberg in Potsdam there was a station on the Berlin-Frankfurt / Mainline.
The optical telegraph had one major disadvantage: it could not be used at night or in bad weather (fog).

Excerpt from the alphabet of the optical telegraph by the CHAPPIE brothers

Electric telegraph

At the beginning of the 19th century, there were significant developments in electricity theory. ALESSANDRO VOLTA (1745-1827) created electrical sources that worked for a long time. ANDRÉ MARIE AMPÈRE (1775-1836) investigated the various effects of electric current. HANS CHRISTIAN OERSTED (1777-1851) found the magnetic effect of electric current. Various scientists and technicians tried to use these new findings to transmit messages.
Mathematician CARL FRIEDRICH GAUSS (1777-1855) and physicist WILHELM WEBER (1804-1891) built one of the first electric telegraphs in Göttingen in 1838 in order to be able to exchange observation and measurement results more quickly. The principle of message transmission was relatively simple (Fig. 3). When the switch in room 1 is actuated, a current flows through the cables and the magnetic needle in room 2 is deflected. When the switch is operated several times, the magnetic needle is deflected several times; when the polarity is reversed at the electrical source, the direction of deflection changes. The two scientists had agreed on an alphabet and were able to communicate through the number and direction of the deflections. The first telegram that was transmitted reads: ” Michelman is coming”. Michelman was the laboratory servant in Göttingen.

Principle of the electric telegraph from GAUSS and WEBER

Significant progress was made through the work of the American painter and sculptor SAMUEL MORSE (1791-1872). MORSE used a button on the transmission side as a switch, the so-called Morse code. On the receiver side, there was an electromagnet with an armature to which a pen was attached. MORSE applied for a patent for his telegraph in 1837. Learn Telegraphy bu expert of industry
If the Morse code key was pressed, the pen was pressed onto a slowly sliding strip of paper and, depending on the duration of the operation of the Morse code key, left dots or lines as an “imprint” for short or long signals.
MORSE also developed a corresponding alphabet from short and long signals, which gradually became established internationally and is still used today as a Morse code. Figure 5 shows this Morse code.

Morse code: every letter and number is represented by a combination of dots and dashes.

Scientists and technicians from other countries were also involved in the development of telegraphy and the expansion of the telegraph network, e.g. the Englishman CHARLES WHEATSTONE (1802-1875) with his pointer telegraph or the German WERNER VON SIEMENS (1816-1892), who made numerous technical improvements electric telegraphs decline.
Thus became the first underground German telegraph line, which led from Berlin via Halle (Saale), Erfurt, Kassel and Gießen to Frankfurt (Main), built under the direction of WERNER VON SIEMENS and put into operation on April 1, 1849. In 1850 the first telegraphic connection between Dover (England) and Calais (France) was made by a submarine cable. In 1857 attempts began to lay a submarine cable between Ireland and the USA. The first attempts failed, but from 1866 a stable connection existed, whereby initially only up to 50 letters per minute could be transmitted.
The cable network expanded rapidly in the following years. For example, if you wanted to Telegraphy from Berlin to Beijing in 1900, you could choose from 14 cable lines.

All telegraphers who can do Telegraphy had one major disadvantage: every message had to be converted into a special alphabet by the sender and translated back again by the recipient. This deficiency was overcome by teleprinters from the beginning of the 20th century. These TELEX connections made it possible to send letters directly from a sender to a recipient.