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"Secure the two ends of the wire by double-pointed tacks. Place a small pocket compass upon the block thus wound, and turn the block until the coils of wire are parallel to the needle when the circuit is open. Then pass a current through the coil. The deflection of the needle is much stronger than before, although, owing to the weakening of the cell, the deflection falls off after a time." — Avery, 1895

Galvanoscope

"Secure the two ends of the wire by double-pointed tacks. Place a small pocket compass upon the block…

"Apparatus used to detect current and its direction." -Avery 1895

Galvanoscope

"Apparatus used to detect current and its direction." -Avery 1895

A galvanoscope in a circuit.

Galvanoscope in circuit

A galvanoscope in a circuit.

"Instead of the telephone receivers normally used in telegraphs, substitute with galvanoscopes. When 1 is pressed, the needles at G and G' will be turned in one direction; when 2 is depressed, teh needles will be turned in the other direction." -Avery 1895

Telegraph Using Galvanoscopes

"Instead of the telephone receivers normally used in telegraphs, substitute with galvanoscopes. When…