TELEGRAPHY
Telegraphy (in greek: writing in distance) is, as we know, a communication system able to transmit signals which represent coded letters, numbers and signs of writing. Telegraphy has very ancient origins, and can be divided in acoustic, optical and electrical.
The greek historian DIODORUS CRONUS (IV cent. B.C.) tells how persian king DARIUS I (522-486 B.C., son of ISTAPSES, who brought the Empire to its maximum extension from Indus to Danube rivers, and who was later defeated
by the Greeks in Marathon) could send the news from the capital to the provinces of the Empire, by means of a line of shouting men positioned on heights. This kind of transmission was 30 times faster than normal couriers. In the "DE BELLO GALLICO" JULIUS CAESAR (100-44 B.C.) writes that Gauls, using human voice, could call to war all their warriors in just three days. Optical telegraphy used fire at night, and smoke or mirrors during the day. In homeric poems is often told of this way of communication. The tragic poet ESCHILUS (525-456 B.C.) describes this in details in his poem
"AGAMEMNON".
The BIBLE tells us how MOSES drove the Jews in their escape from Egypt by means of columns of fire and smoke. Unique and original is HYDRAULIC TELEGRAPH described by ENEAS THE TACTIC (IV cent. B.C.), device that, according to historians, was invented by the Cartaginese. It consisted of two cylindrical vases (a transmitter and a receiver) perfectly identicals and placed in two distant hills. Filled with water, they had a floating vertical pole at the center with conventional signs in it. To communicate they just needed to rise or
lower the pole emptying or pumping water in the vases to the desired point. Start and ending of transmission was pointed by flags or torches. Over this oddities emerged the OPTICAL TELEGRAPH by CLAUDE CHAPPE (1763-1805) and his brother IGNACE. On may 22,1792 CHAPPE showed his invention to the French Legislative Assembly which adopted it officially. The first telegram sent with this telegraph announced the victory of CondŠ over austrians
on november 30, 1794. At the time many european states installed on their territories the CHAPPE telegraph.Signals were based on the different positions taken by three wooden interlinked arms, the central one (regulator) being longer than the other two (indicators or wings), and rotating at the top of a vertical fixed pole. The two lateral arms could rotate freely around
a center, with displacements of 45ø. The different positions of the arms could transmit nearly 8.500 words of a general vocabulary of 92 pages, each containing 92 words. Only two signals were required for a single word: the page of the vocabulary and the number of the word!
A revolution in telegraphy was consequent to the discovery of electric current, to the invention of the battery by ALESSANDRO VOLTA, and to the studies of ANDRE' MARIE AMPERE (1775-1836). The first telegraphs had two electrical lines, with a galvanometer detecting signals at destination. Subsequently the system was reduced to just one line, since the circuit was closed by the ground. American inventor, and painter of some renown, SAMUEL FINLEY BREESE MORSE (1791-1872) was the realizer of electric telegraph, since others were working at the same idea: MORSE's TELEGRAPH is the oldest of all the electric telegraphs. Morse toured Italy in 1830 and painted many pictures while there; he was forced to leave Rome in 1831 due the revolution in the Papal States. In 1832 he returned to America on board the "Sully" when the concept of a "telegraph" based on electromagnetism came to him. In his studio at New York University (in New York City) he worked on his telegraph regularly for six years. He received a patent for his telegraph invention in 1838, also in the same year he completed his last two paintings.
SAMUEL MORSE was a painter of some renown. He made his experiences on electricity in his painting atelier, and his first telegraph receiving instrument was constructed on a "canvas stretcher" frame. A wooden clock motor provided the power to move a paper tape under a pen. The pen was moved by an electro-magnet, driven from the telegraph line. The canvas stretcher was used only as a frame to support these devices. This "canvas-stretcher" telegraph receiver is on display in the Smithsonian Institution, National Museum of American History in Washington, DC. Another of the oldest in the world can be seen in the historical postal and telegraphic museum of Roma-Prati opened in december 20, 1959. It comes from the old Pontificial State and was used to connect Rome and Terracina, starting his service in september 1853). On May 24, 1844 Morse sent the famous words from the Bible, Number 23:23,What hath God wrought! on his telegraph from the US Capitol Building in Washington, DC to the B7O Railroad Depot in Baltimore, MD (now the location of the B&O Railroad Museum). Morse related memorabilia are located at both locations today.
The Italian artist Costantino Brumidi was commissioned to paint one of the most famous spaces in the building: The Rotunda. Every tourist visiting the Capitol gazes at Brumidi's beautiful fresco on which he worked for 11 months, and one of the figures in the center of Brumidi's frsco is Samuel Finley Breese Morse!
The WHEATSTONE needle telegraph comes as an application of the AMPERE telegraph of 1820.In it the current delivered by a VOLTA battery reached the tip of a magnetic needle causing it to oscillate. In the very first models the number of the metal wires and of the needles corresponded to the alphabetic letters: one can understand why its use was fairly complex. A big improvement was made by STEINEL and WHEATSTONE, who used batteries with D.C. and electomagnetical devices; the english physicist CHARLES WHEATSTONE (1802-1875), the inventor of the instrument to measure the electrical resistance, was in effect the first applier of the electromagnet.
Two centuries earlier nonetheless someone must have thought to use magnetic needles to communicate, otherwise the matematician and physicist GALILEO GALILEI (1564-1642) wouldn't have written in his "DIALOGS", and namely in the one between Sagreto and Simplicio, the story of the man who wanted to sell to Sagreto the secret of the system "to talk to somebody two or three miles away by means of that certain attraction of magnetic needles". But when Sagreto wanted a demonstration in his house, the man told him that it was not possible, due to the narrow environment.
In Italy institution of telegraphy starts in 1847, with BREGUET equipments, in the Grand Duchy of Tuscany. In the Reign of Two Sicilies the start of a telegraphic CHAPPE system goes back to 1802: it is described by the historian Pietro Colletta in his "History of the Realm of Naples from 1734 to 1825", published posthumous in 1835. EDUARD HUGHES realized in the U.S. in 1855 a device able to print letters of a dispatch making the paper to advance towards a wheel of types, so that every type could face properly the paper (the system was similar to the one of the old drum typewriters). The current necessary to the printing mechanism was sent by a dial transmitter; a keyboard needed to be sinchronous with a crank, which pushed the types to the printer. The multiple printing machine of HENRY AUGUSTUS ROWLAND (1848-1901, improved the diffraction reticles and built an extremely precise spectroscope) was activated between Rome and Naples in 1904. It used persisting A.C. with the frequency of 60 periods per second. The signal was obtained with the conversion of two non consecutive hemiwaves out of a sector of eleven. Since each station (the sender and the receiver) had four sectors, it was possible to send eight simultaneous dispatches. The french engineer JEAN-EMILE BAUDOT (1845-1903), employed in the French Telegraph Administration intended to obtain many kinds of telegraphic transmissions. He had to overcome many difficulties, especially to avoid timing errors between phases of transmission and reception: his studies lasted many years, and only in 1875 he could obtain satisfactory results with a receiver, in which time units needed to print any letter of the alphabet were reduced to five, with the use of all possible combinations (in HUGHES' device time units were 28!). In BAUDOT's alphabet (not code) signals which compose letters differ not only in length but also in their respective position. Emitted signals can control five magnets in any receiver: every signal which occupies only one unit controls only one magnet; if it occupies two units, it controls two successive magnets, etc. until five units. Transmission is made with five keys similars to those of a piano, which are lowered according to a metronome. BAUDOT'S system adopted in Italy permitted two or four transmissions, depending on the importance of the line.
The CASELLI PANTELEGRAPH resolved wonderfully, in the field of electrochemical telegraphs, a problem faced by the english BAIN and BACKWELL at the end of the first half of last century. In 1846 BAIN could reproduce electro-chemically conventional graphic signsusing paper soaked in potassium ferrocyanide. BAIN's idea was taken again and even surpassed by BACKWELL, who could send writings instead of conventional signs. Nonetheless both BAIN and BACKWELL were unsuitable: reception obtained with BACKWELL's method was poor, lacking of synchronism between transmitter and receiver. CASELLI overtook both of them with his PANTELEGRAPH or UNIVERSAL TELEGRAPH.
CASELLI's history is very interesting. GIOVANNI CASELLI was born in Siena in 1815; he studied literature and science. From 1841 to 1849 he lived in Modena as tutor of the sons of Marquis of San Vitale, but as he took part in the riots for annexation of Duchy of Modena to Piedmont, he was expelled from the Duchy. He spent all his money saved during his modenese period in experiments who eventually led to his PANTELEGRAPH. Such experiments started in 1855, and ended in Paris, where CASELLI met one of his most enthusiastic admirers: Napoleon the 3rd. With the help of the Emperor he could have at his disposal, for his tests and trials, the whole french network. His first invention was registered in 1861. In 1865 the PANTELEGRAPH started his duty between Paris and Lyon, duty which ended in 1870 following the defeat of Sedan, having been planned new lines. At the time in which the Paris-Lyon PANTELEGRAPH worked regularly, Napoleon, having in vain proposed to CASELLI the french citizenship to allow him acceed to the rank of general inspector and co-ordinator of the the french telegraph, awarded him the Legion of Honor. The PANTELEGRAPH worked also between London and Liverpool in order to build up a public service. But the program was withheld because of the economical crisis which in 1864 stroke badly England and the Financial Society, with which CASELLI had undertaken the final agreements. Even Russia was interested in his PANTELEGRAPH, but instead of creating a public service, it was used to send messages between the two imperial residences of St. Petersburg and Moscow. Some of CASELLI's inventions were: an electrical marine torpedo which came back to the launching point in the event of missing the mark, an hydraulic press and an instrument that measures the speed of the locomotives. CASELLI died in Florence in 1891.
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