A hundred years ago, the south lawn of the Smithsonian Institution was the home where buffalo roamed, in the institution's first zoological garden.

Last night, the land was transformed. In the soft, steamy dark, three pavilions glowed beneath domed and pyramidal roofs. They seemed to have bloomed in an enchanted garden where fountains dance and pools break the starlight into a thousand shimmers. And those who walked in the garden, lured to those magic shelters, wiped the raindrops and the moon dust out of their eyes, as if it all might vanish when the sun broke the day.

They found there's more than meets the eye.

About 500 went down, riding in the single elevator, or stepping down a ceremonial stair, or swooping down an escalator, to find the S. Dillon Ripley Center, the third unit of the Smithsonian's new Quadrangle complex. Last night a reception honored Secretary Emeritus Ripley, who waved a wand of persuasion and persistence, as his successor said, and made it appear.

"All sprang as a single vision, this complex, three-dimensional jigsaw puzzle with its moving human parts, from S. Dillon Ripley," said Smithsonian Secretary Robert McC. Adams, in praise of his predecessor.

"To put up any sort of a building on the Mall is difficult, but now in retrospect, the underground Quadrangle is an obvious solution, like ..." And then he mentioned some Smithsonian programs initiated during Ripley's term (1964-1984): Smithsonian magazine, the strengthened traveling exhibition service, the TV program "Smithsonian World," the Smithsonian Associates and now the International Center and gallery in the S. Dillon Ripley Center, beneath the ruffled and flourished copper roof of the small round building in the Quadrangle. The Quadrangle opens to the public on Sept. 28 after another week of private preview parties.

Adams said he once reacted with distaste to the term "the nation's attic" as applied to the Smithsonian.

Ripley countered that he didn't mind the term because it reminded him of toys in the attic, and the thought of the wonders you'd find there on a rainy day. (In an aside, Alan Fern, director of the National Portrait Gallery, couldn't resist saying, "And now we have the nation's cellar.")

And then Adams went on to say he thought that only in Ripley's time did the Smithsonian "truly go national."

Ripley described the evening best as "an alumni meeting, my helpmates along the way. We are all one in our acceptance of diversity, discovering realms of opportunity.

"I will never stop singing, never stop singing this song until the sirens take me away: We must eliminate the sense of unfamiliarity because that is the beginning of hostility." And yet he said he worried about the changes the modern world brings: "The dust of the jet planes shred other cultures." And he summed it all up by saying, "We all must bond together to preserve our planet."

After the speeches, another longtime advocate for international understanding, former senator William Fulbright, said, "Dillon has talked about this international center for years. You know cultural exchanges are the only way to peace. And a great deal cheaper than military force. The 160,000 or so Fulbright scholars in 40 years have cost about $900 million, or about half the cost of a submarine."

Ripley, wearing the Japanese ribbon of the Sacred Treasure in his lapel, told Roger Stevens, former head of the Kennedy Center, that it was a proud night for him: "My heart jumps out and plumps on the table.