1791,1820

Galvanometer

• Luigi Galvani discovered the frog galvanoscope
• by accident, studying the nerves
• of twitching frog legs.
• Galvani and his nephew Giovanni Aldini
• put the frog leg in a test tube
• and wired it up.
• Improvements accelerated after Hans Christian Ørsted
• showed that a magnetic compass is deflected
• by an electric current.
• Johann Schweigger made the first sensitive galvanometer
• using current in a coil of wire to deflect a magnetic needle
• from Earth’s magnetic field.
• It’s not for nothing that Schweigger
• named the galvanometer
• after Luigi Galvani.

Personal connections

• Galvani knew Volta
• who made the first battery.
• Galvani’s nephew helped him
• develop the frog galvanoscope.
• Ørsted was inspired by Volta’s work.
• Schweigger edited the journal
• that published Ørsted’s paper,
• and published critiques of Volta’s theory
• on metal contact in animal electricity.

Moving the dial

• You indicate an interest
• when your experience
• pushes against what you know.
• Your sense of the situation
• matches instinctual patterns,
• pulling you into a dance.
• A small number of basic faces
• are behind many masks.
• Moving toward the impulse
• enforces your confidence.
• What you know is a record
• of when you were not thwarted
• and when you fought it.