Stephen Gray discovers the difference between conductors and non-conductors (insulators)

Two kinds of frictional electricity—from rubbing glass (vitreous) and from rubbing resin (resinous). This two-fluid theory later unified into positive and negative charges.

Ben Franklin discovers that lightning is electrical fluid.

Invention of capacitor. Electrical fluid can be accumulated and stored.

Henry Elles suspects links between electricity and magnetism.

Thomas Young vindicates wave theory of light and revived the aether.

Thomas Young assumes aether to be in a state of absolute rest.

Magnetism finally explained via Faraday’s discovery of magnetic induction

Maxwell discovers that electricity and magnetism are a single force.