What term did Faraday introduce for the curves representing magnetic influence?

Faraday introduced the term “lines of force” for curves representing magnetic influence.

The phrase described the patterned paths Faraday used to visualize how magnetic effects extend through space. Iron filings around a magnet made these patterns visible, forming curves that were denser where the magnetic influence was stronger. Faraday treated the lines as more than a drawing aid: they expressed a physical field filling the region around magnets and currents.

Earlier in his research, Faraday also referred to such patterns as “magnetic curves.” He later used “magnetic lines of force,” shortened in many contexts to “lines of force.” This terminology became central to his field-based interpretation of electromagnetism.

James Clerk Maxwell later translated Faraday's qualitative ideas into mathematical theory, sometimes using related language such as “tubes of force.” Modern physics usually speaks of magnetic field lines rather than literal force-bearing threads, but the visualization remains standard. “Current loops,” “flux rings,” and “field vectors” are different concepts or modern descriptions, not Faraday's canonical term.