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J. Perelman
"Entertaining physics". Book 2.
Chapter 10. Sound. Wave motion


It was, however, a time when even this method of transfer news would be considered very fast. A hundred years ago no one dreamed of the electric Telegraph and the telephone, and send news for 650 km in a few hours would be recognized by the ideal speed.

Tell that the crowning of Tsar Paul I of notice of the commencement ceremony in Moscow was transferred to the Northern capital in the following way. Along the entire route between the two capitals were placed soldiers, 200 m from one another; when the first bell of the Cathedral nearest soldiers fired into the air; his neighbor, hearing the signal, also immediately discharged the gun, he was shot a third time, and thus the signal was transferred to Leningrad (St. Petersburg) during the entire three hours. Three hours after the first attack of the Moscow bells already roaring guns of the fortress, at a distance of 650 km

If the ringing bells of Moscow could be directly heard in Leningrad, the sound of this, as we already know, would come to the Northern capital with a delay of half an hour. So, three hours, used for signal transmission, 2.5 hours left on it that the soldiers perceived sound impression and made it necessary for a shot of the movement; no matter how insignificant it procrastination, yet thousands of such small intervals accumulated 2.5 hours.

Similarly acted in the old days, the optical Telegraph, transmitted light signals to the nearest station, which in turn passed them on. System light transmitting signals often used in tsarist times revolutionaries for the protection of the underground meetings: chain revolutionaries extends from the meeting location to the premises of the police and when the first alarming signs made aware of this meeting outbreaks pocket electric lanterns.

Entertaining physics J. Perelman


System Orphus


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