How was Lord Rayleigh awarded the Nobel Prize?

Name: Lord Rayleigh. 
Country: United Kingdom.
Date of Birth: 12 November 1842.
Died: 30 June 1919.
The subject of Study: Rayleigh scattering, Rayleigh wave, fluid wave, Rayleigh limit.
Noble Prize Year: Nobel Prize for Physics in 1904 for their research on the discovered isolation of argon, an inert atmospheric gas.