Rayleigh and Ramsay isolate Argon (1894) and terrestrial Helium (1895), discovering Noble Gases.

Isolated inert gas Argon (Ar, Z=18) from atmospheric nitrogen density discrepancy.

Posthumous publication eliminating force as a fundamental concept in favor of hidden masses.

Constructed the Lenard Window tube, studying cathode rays in open air outside vacuum.

Wilhelm Wien proves peak radiation wavelength is inversely proportional to temperature (lambda_max T = b).

Ernst Mach critiques Newtonian absolute space and time, formulating "Mach's Principle".

Derived lambda_max T = b proving peak emission wavelength shifts inversely with temperature.

Calculated electromagnetic wave propagation inside hollow metal tubes and waveguides.

Constructed regenerative cooling apparatus for bulk liquefaction of air and oxygen.