Janssen and Lockyer discover a brilliant yellow line (D3) in solar eclipse spectra, identifying helium.

Boltzmann formulates the Boltzmann factor exp(-E / k T) for particles in external potential fields.

Norman Lockyer establishes Nature, creating the premier global weekly scientific journal.

Clausius coins the term "Entropy" (S) and formulates the two laws of the Universe.

Kekulé discovers the cyclic six-carbon ring structure of benzene (C6H6).

Maxwell presents his 20 field equations, unifying electricity, magnetism, and light.

Maxwell formulates vector field equations, proving electromagnetic waves travel at the speed of light.

John Newlands arranges elements by atomic weight, discovering repeating properties every 8th element.

Proved electromagnetic waves propagate through space at speed c = 1/sqrt(mu_0 epsilon_0).