The Beiderbecke Affair (1984) is a clever romantic comedy detective story written by Alan Plater. It has the virtue of being available on DVD. [His even better Oliver's Travels (1995) is also available on DVD.]

In one of the later scenes Detective Sgt. Hobson, fresh from university, tries to enlist two veteran police constables, Ben and Joe, in his plan to expose the corruption of their mutual boss, Chief Superintendent Forrest, who has come up through the ranks and is always putting Hobson down for his zany schemes and general ineptitude.

As Hobson is plotting with Ben and Joe, Forrest appears unexpectedly, and the following dialogue ensues:

Forrest: Morning.

Others: Morning, Sir.

Forrest: Busy catching thieves are we?

Joe: Sgt. Hobson was asking our views on community policing.

Ben: So we quickly abandoned our normal duties for a discussion on the subject, Sir.

Forrest: And when you've discussed community policing, presumably you'll also exchange a few thoughts on what? The theory of relativity? Today's race card at Pontefract? The early novels of Thomas Hardy? Catch some thieves, Hobson! That's what we're here for.

Hobson: Very well, sir.

Hobson clicks his heels and leaves.

Forrest: What d'you think of him?

Ben: Compared with what, sir?

Forrest: Exactly!

Ben states our second GREAT QUESTION - second only to "How do you know?"

The first appearance of this question in Chem 125 regarded the assertion that a substance whose structure is properly characterized by two or more Lewis structures, in "resonance" with one another, should be "unusually stable."

In that case the answer is "Compared to the stability one would predict for a substance characterized by just one such Lewis structure."

How one would predict stability from the Lewis structure, or determine the stability experimentally? We'll address these questions toward the end of the semester.

The second appearance is in the present case of the apparent absence of electron difference density that should constitute a C-F (or O-O, or N-N) bond. Obviously a "difference" density depends on what you subtract, and, as Dunitz points out, you should probably not be subtracting a spherically averaged atomic density when the atom has more than four valence electrons.