A record-breaking crowd of 54,577 came pouring into the National Gallery's new East Building on Sunday - along with a little rain.

At the same time, 17,584 visitors werer clicked into the old building, bringing the combined total for the two buildings to 72,161.

"Sunday may well have been the busiest day in the Gallery's history, but we can't be sure that some visitors weren't counted in both buildings - there's no way to do that with the underground connection," said administrator Joseph English.

Previous highs at the building, which opened June 1, have been "around 25,000," usually on rainy Sundays, officials said.

The previous attendance record at the Galery was set in 1948 during the German Exhibition, paintings found in salt mines after the World War II. "According to our records, there were 67,000 visitors one day and 61,000 on another," said English. "Mona Lisa brought in 61,000 in one day in 1968, and on the busiest days during King Tut, there were around 25,000 in the building."

No one seemed to notice a puddle near James Rosati's sculpture on the mezzanine level of the East Building, which seemed to indicate that I. M. Pei's dramatic "sky frame" was not absolutely watertight. "We can't really see where the problem is until the rain stops," said English, "meanwhile we'll just keep mopping."

It was a very small puddle, considerably smaller than another puddle under the sky-lit roof of the underground Buffet/Cafe, where ugly yellow streaks on the ceiling indicated that the problem was not a new one.

'The problem is that when the cold rains hit it, the glass contracts and breaks the seal. We've had this trouble with other skylights." Presumably, they'll keep mopping that puddle, too.

Yesterday the Gallery wasstill mobbed, with lines of visitors waiting to get into the Dresden show, and Cafe/Buffet and the overcrowed rest facilities. "But it's nothing like Sunday," said one guard. "On Sunday they just kept pouring in: I don't know where they all came from."

"It was horrendous," said a Gallery staffer assigned to the entrance of the Dresden show. "(Some) people have been a litte rede: most of them because they were furious to discover they could not enter the show without a pass. They can't understand why there weren't more signs around telling them they needed free passes before they got all the way over here." A half-dozen visitors proved her point, sputtering profanties as they fumed off.

Figures would seem to indicate, however, that it is the new building rather than the Dresden show that is drawing the crowds this time. Only 6,411 visitors went through the Dresden exhibition on Sunday. There have been days when as many as 10,000 passed through.

Carter Brown, meanwhile, phoned from out of town to say how pleased he was with the new attendance record. "The exciting thing from my point of view is to see the way the building has been able to absorb people."

And what did he think about the leaks? "The leaks? Oh dear, I hadn't heard about that."