THAT CHILLY OCTOBER night a decade ago when the stars of the New York art world descended upon Washington to celebrate the opening of Joe Hirshhorn's museum doesn't seem so distant -- I vividly recall flashy Larry Rivers making passes in his velvet jacket, and crusty Harold Rosenberg looking unimpressed and uncomfortable in his tuxedo, leaning on a cane to survey the antics of the people whose careers and art he had chronicled with such passion for more than 30 years in the pages of The New Yorker and other magazines.

It could have happened last week, except, of course, it didn't. Hirshhorn, the buoyant little man who so enjoyed being the center of attention at that event (as well as at two others in the three-night inaugural extravaganza), is dead. So, for that matter, is Rosenberg. S. Dillon Ripley, the Smithsonian secretary who brought little Joe and big Lyndon Johnson together, and thus secured for the Mall an art collection that other cities, states and countries had vied for, has retired. Abram Lerner, whom everybody affectionately called Al and who was Hirshhorn's hand-picked choice to become director of the museum, officially left that post last week. In fact, Lerner, in bed with a back problem, hadn't been to work in weeks and was unable to attend any of the many farewell dinners scheduled in his honor. "I wanted to go out with at least somewhat of a bang," he said, "but it looks like I'm going with a whimper."

Not so the museum he directed for 10 years. Heading into its second decade, the Hirshhorn Museum and Sculpture Garden is going strong. Though not without problems or faults, the museum has established itself as a major institution with a fully professional staff and a collection to be proud of. Lerner, associate director Stephen Weil and the rest of the museum's able (and remarkably stable) cadre can take comfort and credit in this. Incoming director James T. Demetrion, arriving at the end of the month, has an extraordinarily solid base upon which to build.

The Hirshhorn really has two separate histories: before the decision was made to go public and move to Washington, and after. The oft-told pre-Washington story is of how Hirshhorn, the Latvian-born, Brooklyn-bred, fast-thinking, fast-talking, rags-to-riches dealer in stocks and Canadian mines amassed such an amazing private art collection. The source of his love for art remains something of a mystery -- an impulse buyer of the "I'll take this, and that, and that" variety, he was not given to introspection or even explanation -- but its authenticity is in no way suspect.

Hirshhorn loved to make deals, but he loved artists even more, and he acquired their products in a binge of buying that has few parallels in the history of collecting. Between 1957, when he hired Lerner as full-time curator of a collection that even then was spread among various Manhattan warehouses, and 1966, when the deal with the Smithsonian was signed, the collection grew from 1,200 to more than 6,000 objects -- a rate of more than one art work per day. After that he started another collection of his own, and when he died he left 5,500 additional works to the museum.

Buying habits and numbers like these caused problems for the Hirshhorn's supporters during the stormy first phase of its Washington history. In those contentious days the project was attacked for many reasons, most of them bad: It was sacrilege to put Hirshhorn's name on the Mall, said some; others alleged that he was a crook (he had been fined for two minor financial infractions in Canada during World War II); and many were willing to parrot the New York gossip that the quality of the collection was questionable. The only substantial charge, that architect Gordon Bunshaft's narrow, sunken sculpture garden across the Mall would be bad for the Mall and worse for the sculpture, was solved when the location was shifted to its present site next to the museum building.

The fact of the museum was very different from the theory. Until it opened there were only two people, Hirshhorn and Lerner, who knew the quality and range of the collection. Afterward, everyone knew. Hirshhorn put together one of the world's foremost collections of sculpture dating from the late 19th to mid-20th centuries. The collection of paintings, though much spottier, is even so one of the more extraordinary gatherings of modern works anywhere. It has been fascinating, over the past decade, to watch as the curators mounted shows from storage of this or that painter the museum holds in depth -- Thomas Eakins, for instance, or Arthur B. Carles, Louis Eilshemius, Oscar Bluemner, Raphael Soyer, Larry Rivers, among others.

Bunshaft's heavy, cylindrical building has been less easy to live with. The sculpture garden, very nicely (and inexpensively) redesigned and replanted in 1981, has become a much more commodious setting for both art and people. But the plaza surrounding the museum remains a rather hostile environment for both, and there are other trying deficiencies outside and inside: The tunnel connecting the plaza and garden hasn't worked out, and remains closed like some unused subway connection; there is only one place to enter the building, even though the glassed entrance area literally invites entry from two sides; and there are not enough large, flat walls to hang big pictures on.

But despite these defects (all remediable in the long run), and despite the fact that the museum was designed when architects, without irony, liked to call their buildings "Brutalist," the building has aged fairly well. Bunshaft's Hirshhorn is above all a giant piece of sculpture, depressing in the absence of almost any modulating detail, but not without visual excitement and certainly unforgettable. (It would look a lot better if it were not surrounded by walls, but, since the walls contain much of the building's mechanical equipment, that is another story.) And on the inside it is quite a satisfying museum. The double ring of its plan -- with paintings on the outside ring and sculpture, receiving natural light from the central courtyard, on the inside -- never fails to yield the kinds of visual surprises and delights we go to museums to get.

Without question the Hirshhorn has contributed much to the general increase in Washington's cultural pace -- before it there was no major museum of modern art in the city. It has been an excellent sourcebook for Washington's artists, too. In addition to its permanent collection, the museum has housed a number of truly magnificent temporary exhibitions. (My great favorites? The De Stijl and Russian avant-garde exhibitions, and "Probing the Earth," the wide-ranging 1977 presentation of site sculpture.) Yet besides an occasional purchase in its initial decade, the museum has demonstrated very little commitment to the Washington art scene, or even much understanding that, yes, an art scene actually exists here.

The Hirshhorn, indeed, has continued to feel very much like a New York place in many respects. This is natural: The collection was put together in New York and run by New Yorkers, and they brought an inimitable style to Washington. The painter Avigdor Arikha, after meeting Lerner and Weil for the first time, exclaimed, "What warm people," and that observation encapsulates something important about the spirit of the Hirshhorn during its first decade. The museum was the new kid on the block with something to prove and, ably led, it passed the most important tests. There's plenty left for Demetrion and his successors to do, of course, but they've been given a flying start.