Walking away from the camera, down a dirt road, his cane bobbing behind him, Charlie Chaplin is not a comedian but a clown. Emmett Kelly was the same kind of clown, smiling through a painted-on frown.

In Chaplin's films, the frown is painted on with a camera, and the audiences have to supply the smile themselves. Chaplin's deadly seriousness makes it clear that he does not understand why the joke should be on him….

The difference between Chaplin and the other great screen comics was that Chaplin played a clown. The others, by and large, played comedians, with a few exceptions such as Lahr, Keaton, and possibly Jerry Lewis.

Comedians and clowns aim in opposite directions. Comedians live in imaginary worlds that look just like our own. In "The Apartment", for example, Jack Lemmon inhabited a flat as realistic as it was unlikely.

Clowns, on the other hand...