Optical Telegraph

Рубрикатор / City Services/Communication
OPTICAL TELEGRAPH, semaphore telegraph, a visual system of message transfer, using conventional signs (semaphore alphabet, light signals, visible at night as well) given within direct visibility. The St. Petersburg - Schlisselburg optical telegraph line was constructed in 1824; the St. Petersburg - Tsarskoe Selo and St. Petersburg - Gatchina lines were opened in 1833-35; and the longest-reaching optical telegraph line in the world, the St. Petersburg - Warsaw line (1,200 km), was opened in 1839, with the signal going through 149 retransmitting stations over a period of 15 min. In St. Petersburg and its suburbs, an optical telegraph was placed on the roof of the Winter Palace, on the Duma Tower, on the tower of the Technological Institute, on top of the Chesmenskaya Military Hospice building, in Pulkovo, Tsarskoe Selo, and other locations. Due to the appearance of electric telegraph operation, use of the optical telegraph was discontinued in St. Petersburg in 1854.

Y. N. Kruzhnov. Winter Palace
City Duma
State Institute of Technology, St. Petersburg
1824