In 1820, the German physicist and chemist Johann Schweigger invented the galvanometer at the University of Halle in Germany, shortly after learning of Orsted's discovery of electromagnetism. By winding a coil of wire around a compass needle, Schweigger created a device that could detect and measure extremely small electric currents by the deflection of the needle. The galvanometer, developed at Halle, became the essential measuring instrument of all electrical research and remained the standard tool for detecting electrical currents for over a century.

The galvanometer's ability to make invisible electrical currents visible through the movement of a needle provided a powerful metaphor for the literary imagination's capacity to detect and amplify hidden emotional and spiritual currents. The device's extreme sensitivity, capable of responding to currents too feeble for any other detection method, resonated with the Romantic literary project of perceiving subtleties invisible to ordinary perception. In German literary culture, where the Humboldtian ideal of uniting science and the humanities was particularly strong, instruments like the galvanometer symbolized the refined sensitivity that both scientists and poets aspired to cultivate.