  In 1900 Lord Kelvin identified two problems for 19th century physics, two
"clouds" as he puts it: the relative motion of the ether with respect to
massive objects, and Maxwell-Boltzmann's theorem on the equipartition of
energy. These issues were eventually solved by the theory of special relativity
and by quantum mechanics. In modern quotations, the content of Kelvin's lecture
is almost always distorted and misrepresented. For example, it is commonly
claimed that Kelvin was concerned about the UV-catastrophe of the
Rayleigh-Jeans law, while his lecture actually makes no reference at all to
blackbody radiation. I rectify these mistakes and explore reasons for their
occurrence.
