Juan Monroy — Week 5, Telegraph

Optical Telegraphy
- communication by sight
- line of sight
- Optical Telegraphy Lives at the Vatican
- Code
Optical telegraphs
- visual signals
- line-of-sight
- ship-to-shore
- overland
- relay stations
Heliograph
- helios: sun
- line-of-sight
- code
Flag Semaphore
- visual signals
- ship-to-ship and ship-to-shore
- alphabetic codes
Semaphore
- Claude Chappe
- France, 1793–1850s
- semaphore arms
- military strategy
- messages could be sent between 5–10 minutes
- shutters to make letters
Electromagnetic Telegraph
- Samuel Morse
- electromagnetism, Michael Faraday
- received Congressional appropriate of $10,000, 1843
Morse Code
- bits: dot-dash
- alphabet bytes: sets of dots-dash
- transcribed on paper
“What Hath God Wrought” (1844)
- May 24, 1844
- first message sent between Morse and Alfred Vail
- Washington, DC to Baltimore
- 40-mile connection
- used over B&O railroad right-of-way
Telegraphs in the United States
- Morse sold and licensed telegraph
- telegraph network grew
- Washington to New York, 1846
- Western Union Telegraph Company formed 1856
Telegrams
- message dictated at telegraph office
- transcribed to Morse Code
- sent over telegraph by dot-dash
- received at destination by dot-dash
- transcribed into words on a telegram paper
- delivered by messenger, usually young boy
Railroads
- first telegraph came by “right of way” over Baltimore & Ohio train
- communications for long-distance railroads
Commodities Markets
- prices were based on local market conditions
- distant conditions would keep
- space would be annihilated
Standard Time
- local meridians, usually a church or town square
- railroads had their own time zone until 1883
- synchronized time across various regions
- International Meridian in Greenwich, October 1884
- U.S. Standard Time Act, 1918
- time would be annihilated
Transatlantic Telegraph Cable
- Cyrus Field
- undersea cable
- gutte percha insulation
- 1866
- Victorian world united by cable
Disruptive Effects of Telegraph
- Local vs. Global Communities
- Commerce and Exchange
- Newspapers
- Personal Identities