1751 Franklin shows lightning to be electrical

1798 Count Rumford (Benjamin Thomson) describes heat as produced by mechanical action

1800 Volta's electric battery produces current from chemical action

1800 Herschel describes heat in light as infrared spectrum

1807 Davy develops electrochemistry, decomposing compounds with electric current

1808 Davy produces an electric-powered lamp

1819 Ørsted shows that electricity and magnetism are manifestations of one force

[a magnetic needle moves when electric current flows through a wire nearby]

1820 Ampère shows that a helix of wire is a magnet when current flows through it [right-hand rule]

1820 Schweigger invents the galvanometer for measuring electric current mechanically

1821 Faraday shows that electric current can produce mechanical motion

1821 Seebeck shows that two metals having different temperatures at their junction will produce current

1822 Niepce produces the first lasting photograph (a phenomenon of light captured chemically)

1823 Sturgeon invents the electromagnet

1831 Faraday discovers electromagnetic induction [a changing magnetic force generates electricity]

1831 Faraday builds a dynamo or electric generator [moving copper wheel across magnetic lines]

[as does Joseph Henry in the U.S. at the same time]

1831 Henry invents the electric motor, using current to turn a wheel

1832 Faraday presents the basic laws of electrolysis [producing chemical reaction by passing current through a solution]

1838 Faraday discovers phosphorescence from electric discharge in low-pressure gas

1840 Antoine Becquerel discovers that light can stimulate chemical reactions that produce electric discharge

1843 Joule formulates the mechanical equivalent of heat [a fixed quantity of work = a fixed amount of heat]

1847 Joule's precise paddle-wheel experiment measuring the mechanical equivalent of heat

The chemist Friedrich Mohr, writing in 1837, on heat and other phenomena, replacing the "subtle" or "imponderable" material of heat with a kinetic action:

"Besides the known fifty-four chemical elements there exists in nature only one agent more, and this is called force; it can under suitable conditions appear as motion, cohesion, electricity, light, heat, and magnets.... Heat is thus not a particular kind of matter, but an oscillatory motion of the smallest parts of bodies."