In 1892 the social gadfly Ward McAllister published his list of "the 400"—the patricians who, in his view, made up high society in New York. Wags said that he had trimmed the list to the number that could fit comfortably into Lady Caroline Astor's Manhattan ballroom. They were wrong on both counts: McAllister's list contained only slightly more than 300 names, and when Lady Astor threw a party for everyone on the list, as she did each year, she found that she could have fit twice as many in for dancing.

As the panjandrums of society in Newport, R.I. discovered this month, it's hard nowadays to find 300 aristocrats to invite to an Astor ballroom. When the Newport Music Festival announced plans for its "400 Ball" in Beechwood, the opulent 48-room mansion that once was the Astor summer "cottage," organizers expected that such luminous descendants of the 400 as Jacqueline Onassis, Gloria Vanderbilt and Doris Duke would be on hand. But many of the some 350 who paid $200 a ticket for the festivities were, well, impostors. Some true aristocrats stayed away, speculated 400 descendant Helen Lanier, because "they simply don't have the wherewithal. I know one woman who's teaching painting!"

There were, of course, a fair share of the real McCoys—and Vanderbilts and Rhinelanders—at the party. Mrs. Lanier brought along her family tree in her evening bag. "Look at this," she announced proudly, "four Laniers, three Bishops, one Harriman, and an Appleton!" Janet Auchincloss, Jackie O's mother, showed her regal face. Jacqueline Astor stood in her great-grandmother's place in the receiving line. Still, as ball committee member George McManus clucked before the party, "Some of these guys came from nowhere socially, and now they're acting as though they came from the 400." The evening's chairwoman, Betty Reed, actually moved to Newport only a few years ago, but she took to her duties with the elan of a native. Before the ball, she laid down a ukase that all women in attendance should be clad in white or pink and let it be known that she might bar the door to those of improper hue. When Newport grande dame Mrs. Nicholas Brown arrived in black, Mrs. Reed uttered nary a peep.

Under a billowy pink-and-white tent the guests ate an elegant dinner of medallions of beef, wild rice and Pêche Melba, then watched Maria Tall-chief's Chicago City Ballet perform four dances. When some nameless churl brought down the Newport Police Department on the evening with a telephoned bomb threat, one guest cracked, "It probably came from the competing party over at the tennis club." A moderately entertaining time was had by all, although Whitney Haley, a guest at the $2,000 table purchased by the absent Doris Duke, conceded, "To tell you the truth, I'd rather be home reading. Let's face it: The 400 doesn't mean anything anymore."