Graham's law
Concise Oxford English Dictionary © 2008 Oxford University Press:
Graham's law/ˈɡreɪəmzlɔː/
▶noun Chemistry a law stating that the rates of diffusion and effusion of a gas are inversely proportional to the square root of its density.
– origin C19: named after the Scottish chemist Thomas Graham.
'Graham's law' also found in these Oxford entries:

