1816

Electrical telegraph

• Many people realized
• electricity could be used
• to communicate over distances.
• People tried using
• a wire for each letter and digit
• and detecting a charge on the other end of the wires
• using pith balls or bubbles produced in tubes of acid.
• Francis Ronalds made the first working telegraph
• using pulses of static electricity on a single wire
• to turn a dial marked with the letters and digits
• and standard phrases:
• 1 2 3 4 5 6 7 9 10
• A B C D E F G H I K L M N O P R S T V Y
• PREPARE
• READY
• REP^T SENT^CE
• REP^T WORD
• FINISHED
• ANNUL SENT^CE
• ANNUL WORD
• NOTE FIGURES
• NOTE LETTERS
• DICTIONARY.

Other electrical telegraphs

• In 1833, Carl Friedrich Gauss and Wilhelm Weber
• put up a wire running nearly three-quarters of a mile
• and communicated with a positive or negative charge
• detected by a galvanometer on the distant end.
• They generated a positive or negative electric pulse
• by moving an induction coil over a permanent magnet,
• and they developed a binary code for the alphabet,
• eventually obtaining a transmission rate
• of seven letters per minute.
• Two years later, David Alter
• in Elderton Pennsylvania
• invented and demonstrated his own telegraph
• but he didn’t develop it for actual service.
• In 1836, Samuel Morse and Alfred Vail
• developed and patented Morse code
• and a recording electric telegraph.
• Meanwhile, William Fothergill Cooke
• and Charles Wheatstone were working
• on a system that didn’t transmit codes,
• but completed a circuit across two of six wires
• to cause needles to point to a letter on a triangular grid.
• A Cooke and Wheatstone six-wire system
• installed in 1838 on thirteen miles of the Great Western Railway
• between Paddington station and West Drayton
• was the first commercial telegraph.

Marital telegraph

• First Spouse. “I’m taking the garbage out.”
• [subtext] I’m trying to be a responsible adult.
• Second Spouse. “What?”
• [subtext] Why bother me with that?
• First Spouse. [Points to the trash bin;
• then points to the door.]
• Second Spouse. “OK.”
• [subtext] Thank you.