• In your letter you apply the word imponderable to a molecule. Don't do that again. It may also be worth knowing that the aether cannot be molecular. If it were, it would be a gas, and a pint of it would have the same properties as regards heat, etc., as a pint of air, except that it would not be so heavy.

    James Clerk Maxwell, Elizabeth Garber, Stephen G. Brush, C. W. Francis Everitt (1986). “Maxwell on Molecules and Gases”, p.132, MIT Press