It hangs now, all official and public, in the National Gallery, but for Euge'nie Prendergast, the monotype "Nouveau Cirque (Paris)" is something more than a beautiful, anonymous piece of art on display.

"I cried the day it left me," said the 90-year-old woman at last night's dinner for the opening of an exhibit of her brother-in-law Maurice Prendergast's monotypes in the East Wing. "I went in the room and missed it so, I burst into tears."

Euge'nie Prendergast, whose husband Charles was also an artist, recently sold the monotype to Daniel J. Terra, ambassador-at-large for cultural affairs and founder of the Terra Museum of American Art in Illinois. Terra owns 55 Prendergast monotypes (there are only about 150 of them in existence), and if Euge'nie Prendergast misses hers, Daniel Terra is pretty happy with his.

"This is the first monotype he ever did," Terra said, pointing to "Esplanade," "so we had to have this one."

It was a collector's evening at the National Gallery. Terra and his fiance' Judith Banks showed guests through the exhibit, pointing out the one said to be Maurice Prendergast's favorite ("Nouveau Cirque"), speculating that the exhibit will encourage contemporary artists to make monotypes (which Prendergast created by painting with oils on a copper sheet, pressing paper over the paint and rubbing with a spoon on the paper) and generally sounding encouraging about Prendergast in particular and art in general.

"I practice what I preach," said Terra, after explaining that his main goal as ambassador-at-large is to encourage private people and groups to contribute to the arts. He preaches the importance of private contributions and, with a jaunty, diplomatic smile, the importance of a certain kind of government involvement. The White House would like to cut the budget of the National Endowment for the Arts by 11.7 percent in the next fiscal year, but last night Terra skirted that issue quickly to point out that the NEA contributes only a small fraction of money spent in this country in support of the arts.

"I hope that the concept of how we support philanthropy does not change," he said, quickly steering the conversation back to the private sector, "because it works better than any system in the world."

Appearing on behalf of governmental support for the arts last night was Rep. Sidney Yates (D-Ill.), chairman of an appropriations subcommittee that oversees the arts.

NEA chairman Francis S.M. Hodsoll "appeared before our committee from time to time and said the administration supports appropriations for the arts," said Yates, "which is more than they indicated some years ago -- because the endowments have such popular support throughout the country."

The concept of philanthropy was represented by an assortment of collectors, including Paul Mellon, who said he has never experienced the sadness of losing a beloved object that Euge'nie Prendergast described.

"I've been collecting for over 50 years," he said, "and a lot of the things we've lived with for a long time. We've lived with almost everything we've ever collected, but then the time comes when there isn't room for things, and I don't believe in leaving things in storage where no one can see them."

But one other collector, during the lobster and venison dinner for 100, said he could not bear to part with any of his pieces.

"I just don't like to take them off the walls," said the New York collector of American art dating from 1850 to 1950. He collects, he said, because he loves the art.

"You don't do it for money," he said. "You do it because you see something, and it burns a hole in the back of your head and you can't think of anything else."