Discovered Gallium (Ga, Z=31), confirming Mendeleev's predicted Eka-Aluminum.

Proposed the existence of a fundamental unit of electrical charge in electrolysis.

Invented the Crookes Radiometer, demonstrating radiation pressure and thermal gas transpiration.

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 …

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

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

Maxwell publishes his thermodynamics textbook, introducing "Maxwell's Demon" thought experiment.

Mendeleev formulates the Periodic Law, organizing elements by atomic mass and predicting undiscovered elements.