Weeks ago they cut the ribbons at a formal ceremony thick with the homilies of congressional chaplains, the transfer of the keys from the architect to the librarian of Congress and discourages about James Madison the man. Yesterday the celebration at the New James Madison Memorial Building resembled an old-fashioned family christening as a couple of thousand Library of Congress employes toured and toasted their new workplace.

"Today this is a family affair. We celebrate not only a great building but our well-being and working conditions," announced Librarian Daniel J. Boorstin, who wore his 13-star American flag clip-on tie to mark the occasion. Around him the employes, many bused in from the Library's outposts around Washington and Crystal City, took photographs, ate cookies, drank Coke, and listened to the bluegrass, string and gospel groups of their fellow employes.

Yesterday, on the cement patio in front of the massive, marble building at 2nd Street and Independence Avenue SE; the problems that have plagued its construction and the institution for 20 years were nearly forgotten. When the idea was first proposed during the Eisenhower administration, Capitol Hill residents loudly resented the movement of the library into ther neighborhood. Later, congressmen tangled with librarians over which group needed a new building and then debated the costs of the eventual $60 million structure; and the employes have long complained about poor working conditions and racial discrimination. Yet yesterday the remarks were polite, following the etiqutte of a family gathering.

"Some features, like the cafeteria, are like a breath of fresh air. Before you felt like you were eating in a cell," said Linda Theberge of the catalogue additions and corrections division."The cafeteria is beautiful, but most of the offices don't have windows," said Cortez Austin of the subject catalogue division.

The two-hour party helped morale, according to several people who ate their lunches outside. "This party had been announced a long time ago, but everyone forgot it. So when the official ceremony was announced, everyone was miffed. This helps restore some good feelings," said Myrl Powell of the subject catalogue division.

The event had an exciting start. A false fire alarm prompted the evacuation of the sixth floor cafeteria, with its sweeping view of monumental Washington. "I had to leave with only my lunch half gone. All I could think of was 'here we go again," times at the Navy Yard were always like that," said Kathleen Barret, a retired Library employes.

The rest of the event was anticlimactic, with Boorstin throwing in a jingle for history: "Let's all be jolly, with James and Dolly."