Sunday 30 January 2011

a bell and a porticus




















At first, men talked to each other, beat on drums and drew pictures. Then they erected buildings and built roads. They walked from town to town and from city to city relating the latest news. They wrote letters, scrolls, books. They trained horses to carry them faster than they could walk and they built boats to carry them further than they could swim. And then, for several thousand years of civilized history, while literature, architecture, art, warfare. physics, chemistry, medicine and the whole multitude of human technological achievement advanced, retreated and advanced again, the techniques of communication remained static. A message moved only as fast as the fastest horse and carried only as far as the eye could see.

Then, in 1753, the barrier was broken. Unfortunately for the memory of the person who accomplished this, he will remain known to history only by the initials "C.M." with which he signed a letter written to the Scotch Times describing a wonderful idea. He described an electric telegraph based on static electricity. The movement of "electric balls attached to the ends of a set of wires corresponding to the letters of the alphabet" would, the writer felt, improve the sending of messages from place to place. C.M.'s letter was published and was followed by a 50-year silence.

The reason for the silence was that static electricity is too limited to be effective in telegraphy, a fact apparently recognized but not verbalized at the time. Not until people like Volta, Ampere, Oersted and Faraday came along to develop and demonstrate electrical theory could the telegraph be invented. At the time of C.M.'s letter, the only thing really known about electricity was that amber-and certain other materials called "electricals" from the Greek word for amber, elecktron - could be charged by rubbing it.
While Volta and his peers were at work unraveling the mysteries of electricity, another development appeared. This was the last flowering of the mechanical, or visual, telegraph. The visual telegraph traced its ancestry back to smoke signals and hilltop bonfires and the towers used by Egyptians and Romans to pass information along. Visual telegraphy reached its highest development in France during and following the French Revolution. A weakened France, surrounded by her enemies, was saved because the enemies - the English, the Spanish, the Dutch, the Germans and the Italians - could not communicate with each other. Within France, however, a series of visual telegraph towers, designed by Claude Chappe, was built between cities to carry news and unify the revolution-torn country. By 1852, when the electric telegraph finally caught up with and passed it, the Chappe system in France covered a total distance of more than 3,000 miles and used a total of 556 telegraph towers with various semaphore arms for complicated messages.


http://www.porticus.org/bell/capsule_bell_system.html

1 comment:

xtina said...

http://el.wikipedia.org/wiki/%CE%A6%CF%81%CF%85%CE%BA%CF%84%CF%89%CF%81%CE%AF%CE%B1

φωτο, φρυκτωρία στον Αγιο Πέτρο Ανδρου