Pistols for two and coffee for one. That was the quip, between the Revolution and the Civil War, when the dual was not only fought by the Code Duello, but by that basic American precept: If a thing is worth doing, it's worth overdoing.

Even honor.

"I am informed you applied to me on the day of the election the epithet of 'Puppy,' wrote a lawyer named Charles Lucas in a short, blotted note which, even in a glass case at the National Portrait Gallery, is full of haste, anger, honor, coarseness and the death of Lucas.

The exhibit is called "The Code Duello in America," and the note was written as a challenge to Sen. Thomas Hart Benton on Aug. 11, 1817. On the 12th, they met on a sandbar off St. Louis ("opposite to Madame Roy's," said the seconds' specifications), and fired smoothbore, flintlock pistols at each other from 30 feet. Benton was bruised below the knee. His bullet hit Lucas' neck badly enough that he could not continue.

In Europe, of course, this would have been the end of it. Alexis de Tocqueville wrote in 1831 that "In Europe one hardly ever fights a duel except in order to be able to say that one has done so; the offense is generally a sort of moral stain which one wants to wash away, and which most often is washed away at little expense. In America one only fights to kill; one fights because one sees no hope of getting one's adversary condemned to death."

Since calling a man a "puppy" was not a capital offense in Missouri, Lucas had no choice but "calling out" Benton. Since he survived his wound, nothing would do but they meet again, and so on Sept. 27 they did, with the distance shortened to 10 paces (dueling takes the worry out of being close). Benton shot Lucas in the chest and killed him.

This was called "satisfaction."

Benton, who'd also taken on Andrew Jackson in a street brawl with pistols and knives, gave up dueling, but continued to argue that the Code Duello was not "so bad as its substitute -- revolvers, bowie knives, black-guarding and street assassinations under the pretext of self defense," which is to say life the way we live it nowadays in America.

"It was public scorn and ridicule that ended dueling," says Jeannette Hussey, the research historian who has put together this Code Duello exhibit for the portrait gallery. "Duelling was for gentlemen. If you dueled, it meant you were a gentleman, so it could even be means of advancing yourself. Andrew Jackson made a name in Tennessee by shooting Charles Dickinson. Ironically, it was Jackson who created the kind of democracy that ridiculed dueling as unnecessary and pretentious, a class phenomenon."

It was also more of a Southern phenomenon, after Aaron Burr horrified New York and New England by killing Alexander Hamiliton in Weehawken, N.J. on July 11, 1804.

In the catalog to the show, Hussey quotes a New Orleans lady saying that "The score of duels was kept like the score of marriage offers of a belle. Some individuals claimed as many as fifty. One man fought a duel against his brother-in-law; another man and his son both scheduled duels on the same day. On one Sunday in 1839 in New Orleans alone ten duels were fought."

Dueling had everything to recommend it to any ruling class: It excluded everyone else, it was virtually pointless, it involved expensive and usually foreign-made equipment, such as the braces of pistols on display in this show (including the Hamilton-Burr pieces) beneath the portraits of their users, and it was based on an extraordinarily detailed etiquette with a pedigree going back to antiquity or thereabouts. Some sources trace the duel to Cain and Abel, or Achilles and Hector. Others say it was Germanic tribes, who favored trial by battle -- may the best man win, and no need for lawyers.

The first duel in America was between two Pilgrim servants in 1621, but it was considered scandalous, they not being gentlemen. Others were fought, but the custom didn't blossom until the Revolution, when suddenly everyone had the right to be a gentleman.

The rules were epitomized by an Irish code duello with 26 rules for insults, retorts, blows, shooting, sword-play, apologies, refusals and so on. It got complicated.

"VI. If A gives B the lie and B retorts by a blow (being the two greatest offences), no reconciliation can take place until after two discharges each or a severe hit, after which B may beg A's pardon for the blow, and then A may explain simply for the lie, because . . ."

And so on.

In 1838, the year that the District of Columbia passed the nation's first law against dueling, thus ending the fine times out at the Bladensburg dueling ground where naval hero Stephen Decatur was killed, a treatise was published by Gov. John Lyde Wilson of South Carolina entitled: "The Code of Honor, or, Rules for the Government of Principals and Seconds in Duelling," a copy of which is on view at the gallery.

It worked out to be pretty simple: I insult you. You challenge me. I choose weapons and place. You choose the distance. We both show up with seconds and doctors. The seconds load the pistols and give the command to fire. We shoot lead balls of about half an inch in diameter at each other at several hundred miles an hour. We keep shooting until one of us apologizes, falls badly wounded or dies.

Swords were popular in New Orleans, but disdained elsewhere in America as being not only primitive, but unfair, if one duelist was taller than the other. b

Americans also had the custom of "posting." Should a challenge be refused, the challenger would "post" the refuser, nailing up a notice that he was "an unprincipled villain or coward," which is what Mark Twain called rival newspaperman James Laird in Virginia City, Nevada when Laird refused to fight. Twain then headed for San Francisco, lest Laird change his mind. He wrote later: "I had no desire to fight a duel. I had no intention of provoking one. I did not feel respectable but I got a certain amount of satisfaction out of feeling safe."

It's a tidy, spooky little exhibit. The portraits of great American heroes shine from the walls: Hamilton, Jackson, Lafayette, Decatur, Perry, Clay, John Randolph and DeWitt Clinton among them as veterans of the field of honor, and preachers such as Lyman Beecher or Yale's Timothy Dwight holding them in contempt. (Though Dwight was careful enough to preface a sermon opposing dueling by saying that no hotheaded gentleman should get upset at him, "it being the preacher's design to examine principles and not to give characters.")

It's hard to imagine a world in which men were more afraid not to duel than to die, but then again the men in the portraits probably couldn't have imagined a world in which the notion of death before dishonor lingered only as a tattoo on the forearms of 19-year-old Marines, and people were proud to state that nothing was worth dying for.

"The Code Duello in America" will be on view through April 19, 1981.