Set Charles and Joan Momjian gave a dinner party Saturday night on James Madison's 234th birthday. The guests of honor were a pair of decanters. The mood was one of celebration.

About 130 miles away White House curator Clement Conger was steaming. He had declined the Momjians' invitation, pleading a previous engagement. On his mind was The Decanter That Got Away.

The Momjians bought one of the rare, early 19th-century decanters believed to have been owned by the James Madisons at auction in December for $1,100 and that set off a feud between Conger and Momjian.

One decanter had been up for auction at Sloans in Washington, and Conger says his bid of $4,350 was lost by the auction house, letting the much lower bid take the prized piece. The second decanter will be auctioned on April 28 by Sloans.

"By the grace of God, the second decanter has turned up," said Conger on Friday. "After Momjian was so greedy over the first one."

But Conger and the White House don't have the second decanter yet. Its sale may pit Conger against several museums as well as other private collectors of presidential memorabilia. Conger has vowed to have the decanter for the White House, even though the presale estimate goes up to $25,000.

"I'll be at the auction," said Momjian at his dinner party. "I've written some letters to try and raise money to buy the decanter for the White House."

"That's a typical Momjian trick," said Conger. "He finally woke up. We'll get the second decanter, hopefully without his money. I have a donor for it. I know those people he's asked. I can go to them myself."

The continuing feud over the decanters demonstrates the depth of the passions aroused in the small, wealthy community of U.S. historical collectors. It also sheds light on the competition that rages among museums, government institutions and private persons for the limited memorabilia of America's early presidents.

Donald Webster, head of Sloan's auction house, made a surprise speech at the Momjians' dinner, saying he understood why Conger was unhappy about not getting the prize. Webster said he was surprised that Momjian didn't donate the decanter to the White House. He said Robert McNeil, another Philadelphia collector (and a member of the White House acquisitions committee) who actually did the bidding for Momjian, asked before he bid if the White House was interested. "I assured him the White House was not," said Webster.

The bid from Conger, Webster said, came into a telephone operator who left Webster a note to call Conger. Webster said he couldn't reach Conger before the sale and didn't realize the numbers at the bottom of the telephone message represented a bid.

Nine of the most important curators of East Coast museums examined the decanters Saturday at Momjian's dinner. All of them wanted to take one or both back home.

But one, Margaret Klapthor, emeritus head of the Smithsonian's political history division at the Museum of American History, expressed a caveat. After she looked at both decanters at the dinner she said, "They certainly could be the ones from Bakewell, Page and Bakewell of Pittsburgh which were given to Madison. Conover Hunt cited a letter about a pair of decanters in the exhibit 'Dolley and the Great Little Madison.' "

"The monogram M is like the one Dolley liked to use but others did use such a monogram during that period. The decanters could have belonged to Madison or Monroe or somebody else whose name began with an M. The decanters could not have been used in the White House by the Madisons. After the British set fire to the White House, Madison and his wife lived at the Octagon and then in one of the Six Houses on Pennsylvania Avenue. They didn't go back to the White House."

Momjian's decanter is held together with 19 rivets. A large hunk is lost from its mouth.

The other is in fine condition. The better of the two is the property of Micheline Geisen of Carmel, Calif., who inherited it from her first husband, a Monroe relative. Her son Daniel Robinson of Washington, who has consulted on a computer system for Sloan, owned the broken piece. Both decanters are engraved with an "M" and the Seal of the United States, which includes an eagle and 18 stars.

People see different things in bottles. Momjian sees fame. Conger sees shame in the same glass. "I tried to shame him into giving it up. It didn't work," said Conger.

"He's making the most of it," said Conger. "When I let it be known he got the decanter by a fluke, he was so thrilled over the national prominence in the press, he wrung it dry. It's sort of a joke now."

According to Momjian, "I told Conger I just got it. Let me savor it a little bit. Enjoy it. I offered to lend it to the White House. Clem said its collection is based on acquisitions, not loans."

Conger retorted, "He's never been too specific about what he wants to lend."

Momjian added, "I'm going to call Conger on Monday and take back the things I've got at the White House now." Later Momjian added he was just joking and wouldn't say what the "other things" are.

Also declining invitations for the Momjian dinner were Conger's associate curator Betty Monkman and Edward Stone, head of the White House Preservation Fund. Stone had far better than a diplomatic excuse. On March 8, in the press of a crowd during the party to preview Secretary of State George Shultz's remodeled offices, Stone ran into a glass panel and his nose was broken.

Sen. Arlen Specter (R-Pa.) said, in the presence of representatives from both the Carnegie Mellon Institute's art gallery and the Philadelphia Museum, "I hope the Momjian decanter will eventually go to some neutral spot in Pennsylvania."

The three tables of 30 guests ate off china owned by the White House during the presidencies of Lincoln, Hayes, Harrison and Theodore Roosevelt. The lace tablecloths were from a group of 40 given by Momjian during Jimmy Carter's administration.

"President Carter sent all 40 back to me just before he left office," said Momjian, who served during the Carter administration as a representative to the United Nations.

Momjian has other memorabilia. Upstairs in his house's "presidential bedroom," where Carter once slept, Momjian has a small portait of Carter, a study done by the artist of the Carter portrait now in the White House. The Momjians have a roomful of autographed photographs of themselves with the Carters and the Reagans.

After the dinner, Momjian took a vote of the curators as to whether his decanter should be restored by Corning Glass museum in New York State. Three said the rivets should stay, one said it should be restored, one voted both ways and one abstained. Jane Shadel Spillman, Corning's curator of American glass, took Momjian's decanter back to the Corning museum to be displayed through October.

In the end, Momjian decided not to have the glass repaired. "After all, 100 years from now, people will know about the controversy between me and the White House and they can identify which decanter is mine by the rivets."