Unified electrodynamics into 4 fundamental field equations.

In July 1865, Rudolf Clausius formally introduced the state function Entropy (S = integral dQ_rev / T), concluding with his famous summary: "The entropy of the universe tends to a maximum."

In 1865, German chemist August Kekulé proposed the cyclic ring structure of benzene (C6H6) with alternating single and double bonds, founding aromatic organic chemistry.

In 1868, French astronomer Pierre Janssen and English astronomer Norman Lockyer independently discovered a new element in the solar spectrum (yellow line D3 = 587.49 nm), naming it Helium.

In 1868, 24-year-old Ludwig Boltzmann published his first major paper extending Maxwell's velocity distribution to particles subjected to external potential force fields V(r).

In 1868, English astronomer Norman Lockyer founded the scientific journal Nature (first issue published November 4, 1869), establishing a peer-reviewed forum for scientific discoveries.

On March 6, 1869, Russian chemist Dmitri Mendeleev presented the Periodic Table of Elements to the Russian Chemical Society, organizing elements by atomic mass and predicting undiscovered elements.

In 1870, James Clerk Maxwell published his textbook "Theory of Heat", introducing the famous "Maxwell's Demon" thought experiment that challenged the Second Law of Thermodynamics.

Derived Maxwell's thermodynamic partial derivative relations connecting T, P, V, S.

Formulated the H-Theorem, proving H quantity decreases over time as gas approaches equilibrium.

Published comprehensive two-volume treatise on electrodynamics and wave propagation.

Derived van der Waals equation (P + a/V^2)(V - b) = RT incorporating molecular volume and attraction.