"If it weren't a fur coat, I'd leave it here," said a silver-haired man who had been standing in line for more than half an hour.

"You can't," said his wife. "It's cold out there."

They were waiting, with hundreds of others, in front of an improvised checkroom in the Daughters of the American Revolution Museum, which last night began a new career and instantly became a victim of its own success.

About 1,500 visitors flocked to the museum for the opening of the first loan exhibit in its history: "The Jewish Community in Early American: 1654-1830." For the opening ceremonies, which were highlighted by a talk by ex-president Gerald R. Ford, they crowded into a library which might have comfortably accommodated one-third their number. Then, on the way out, they discovered that inexperienced volunteers had not checked the coats in numerical order. It took long minutes to track down each one among the 1,500 at random. o

The show which attracted so many visitors, from all parts of the United States, marked several radical departures for the DAR, which has never before shown a loan exhibit in its museum and which has hardly publicized the fact that it operates a museum. "We have a sign up that says 'Museum' and 'Open to the Public,'" said Jean Federico, curator of the exhibit, "but it's still very new."

Also new is the subject matter of the exhibit, which focuses on Jewish life in early America and sharpely modifies the WASP image which (perhaps unintentionally) the DAR has acquired through the years. "We have always had plenty of Jewish members," said Frederico. "I can't tell you how many, because we don't keep track of that kind of thing." One Jewish member earlier in this century was Adeline Moses Loeb, grandmother of John L. Loeb Jr., who originated and partially financed the exhibit as a tribute to her. "A few years ago," he recalled, "I was filled with bicentennial fever, and I wanted to do something for my grandmother. The DAR officers were very enthusiastic and absorbed most of the expenses."

According to Mrs. Richard Denny Shelby, DAR president general, more surprises may be expected from the organization. "This is the beginning of a new administration," she said. "This is our first step, and you may look forward to more for the next three years."