Maxwell, JC (1890). "On the Dynamical Evidence of the Molecular Constitution of Bodies". WD Niven (Ed.). The Scientific Papers of James Clerk Maxwell. Cambridge: At the University Press. Vol.2, pp.418-438. ISBN0-486-61534-0. ASIN B000GW7DXY. A lecture delivered by Prof. Maxwell at the Chemical Society on 18 February 1875.