The hat is the ultimum moriens of respectability.

From: The Autocrat of the Breakfast-Table. viii.
Oliver Wendell Holmes

A cap, by the way, is not a hat.  It is a cap.  A hat has a brim that goes all the way around.  The fedora, the Homburg, the Trilby, the top hat, the Panama, the coke or bowler, those are hats.

There are rules about wearing hats.  The most basic rule about the hat is that if you’re unsure whether you should remove it or not you probably should.  The custom of tipping or removing one’s hat is said to come from the same place as the military salute.  In medieval times, knights would lift the visors of their helmets to show their faces as a sign of respect and their empty hands to show that they weren’t holding their weapons and therefore meant no harm.  It’s a custom that has persisted since that time.

A gentleman should remove his hat when he is indoors, except in those places that are equivalent to a public street or public location.  Such locations include lobbies and corridors of public buildings, post offices, malls and department stores and in the elevators of public buildings EXCEPT when a lady is present.  When a lady enters the elevator, the hat must be removed unless your hands are full of packages or the like and removal is impractical, in which case you should nod to acknowledge her.  Replace your hat when you exit the elevator and enter the corridor.

When you remove your hat, take care to hold it in such a way that only the outside of the hat is visible.  Consider the lining of your hat to be underwear, it should not be seen. (The same is true of braces or suspenders, by the way, they should never be seen.)

A gentleman removes his hat both indoors and outdoors when he is being introduced to a stranger or is saying goodbye to a lady or an elder.  It is removed when speaking with a lady, an elder or a member of the clergy.  In the United States it is removed during the playing of the National Anthem or when the American Flag is passing.  It is removed during funerals and the passing of funeral processions.  It may be removed when passing a lady on the street, but tipping (a slight lifting of the brim) is a quite acceptable substitute as a passing gesture.

It is considered to be an insult to tip your hat to another gentleman with whom you are not acquainted, it is akin to calling him a woman and is not done.  It is, of course, a sign of disrespect and the mark of a cad to leave your hat on when it would be proper to remove it.

Sometime soon I’ll write on the different types of hats and caps and when they’re proper to be worn.