THE GREAT art of etiquette was invented to translate the incoherent jumble of human feelings, to which we are all subject, into something more presentable. When we cast it aside and let our emotions run around naked and exposed to public comment, as we have done by abandoning the formal customs of mourning, everybody suffers. That saddens Miss Manners.

Whensomeone dies, the bereaved are either grieved or they are not. Yet both true grief and the absence of grief are, in their natural states, socially intolerable. What we expect is quiet dignity, a kind of steadfast, restrained semblance of sorrow. Either joyous relief, or the ricocheting between hysteria and hilarity that is the natural reaction to deeply felt loss, is mistakenly perceived as an unnatural reaction.

Miss Manners approves of the return of the widow's veil, or its jazzier equivalent, the pair of oversized sunglasses, for funerals. She would like to see a more extensive return to formal mourning, in however modified a modern way, to protect survivors from public scrutiny of their inner feelings.

Before mourning was abolished, the deep crepe veil was worn away from the face for a year of deep mourning; a widower wore a black band, on hat or sleeve. Clothes for both ladies and gentlemen were black, with dull surfaces, rather than shiny suede gloves, for example, rather than kid. No jewelry was permitted except for pearls, diamonds and black onyx. One did not go into society, and one's letters were written on black-bordered paper.

Second mourning, a year or sometimes two after the death, consisted of lightening the all-black effect with touches of lavender, purple, gray or white.

Miss Manners can just hear the cries of how morbid this all is, and how life must go on. Of course, life goes on. The strictest instructions about old_fashioned mourning always had to include the information that a widow should cease to wear mourning immediately upon selecting her second husband. Do you think the Victorians didn't understand the charm of woefulness, or how fetching many ladies look in black? The value of mourning is not to remind people to be unhappy, but to relieve them from the necessity of acting out unhappiness for the benefit of others. The most deeply grieved people will have, even quite soon after a death, moments of merriment, sometimes based on memories of the deceased and some unrelated to the death. If these occur when the person is gaily dressed and out socially, they will be taken as indications of callousness. If, however, a person in those circumstances suddenly bursts into tears on no apparent provocation, which can also happen, the same critics will be annoyed at the lack of control and may go so far as to level a charge of hypocrisy.

If mourners stay away from other people's parties they do not subject themselves to this criticism. They needn't isolate themselves, but simply conduct their social relations in their own homes, where they may choose companions who share or at least understand their behavior.

Wearing mourning -- the modern version would be somber, conservative clothes, although not necessarily black -- serves, like the black borders on letters, as a warning that this is a person taking a death seriously. Establishing that fact through symbols saves one the trouble of having to prove it.

You know, and Miss Manners knows, that whatever you may say about getting back to normal, there is nothing that the acquaintances of bereaved people enjoy more than being shocked at their behavior for seeming so -- normal. MISS MANNERS REPONDS

Q. I am an actor who is not exactly between jobs, because I have not yet gotten my first professional engagement, but sort of before jobs. In the meantime, I am supporting myself as a waiter -- something many actors, some of them big stars, have traditionally done. This is really my first paying job, and although I don't plan to make a career of it, I would like to do it well. Can you give me some suggestions?

A. Allow Miss Manners to congratualte you: You do have your first acting job. Good waiters have always been great actors, such as those of maitre d'hotel or butler. There is not much competition, as most waiters and waitresses nowadays believe in "acting natural," which is to say that they don't know how to act.

The mechanics of the part, you may learn on the job (although attentions to Miss Manners' rules of meticulous table service will put you ahead of most people in the field), but you must work on motivation and character.

This means showing the pride of a person who performs his job well, and the dignity inherent in gracing a well-defined position. In plain language, this means that you do not behave as if you are trying to show that you are just as good as the people on whom you are waiting, by either chummy or surly demeanor. The waiter who joins in the conversation or snaps at the patrons is clearly saying that he feels defensive and inferior. The one who executes his tasks with an impenetrable air of detachment and impersonal efficiency conveys that he is flawless in handling the role -- and therefore probably also excellent in a variety of other roles, professional and social.