It was 1:15 a.m., and most of Washington was sleeping. But inside the eerily silent National Archives exhibit hall, a Pakistani cabdriver peered curiously into a bronze case holding four pieces of yellow parchment.

"It is beautiful," said Ali Abbasi, 42, softly. "It is really fabulous."

Abbasi was gazing at the Constitution, which is on display for 87 consecutive hours, a period that began Sunday night and will end Thursday morning, in commemoration of the signing of the Constitution 200 years ago.

Usually, tourists get only a brief glimpse of the first and last page of the Constitution as they are bustled along by anxious guards. This week's "vigil," sponsored by the Archives, offers late-night visitors the chance to examine all four pages at greater leisure.

For most of the early evening Sunday, it was elbow to elbow as usual in the Archives' cavernous rotunda as a tourists stood in a line that began outside the door on Constitution Avenue and snaked up to the display case.

But by the wee hours of yesterday morning, Washington's never-ending stream of tourists had become a trickle; only one or two hard-core Americana aficionados remained.

They came to be alone with the Constitution.

"It's usually so jammed here," said Donald Singer, 39, of Canton, Ohio. "I've been here five times before, but this is the first time I really had a chance to take my time and read it."

Abbasi, who has lived in the United States for 12 years, had never seen the Constitution, and he said he hadn't planned to change that. But when a late night passenger asked to be driven to the Archives for the vigil, he was intrigued and followed her inside.

"I am really amazed by the work done by the forefathers of this country," said Abbasi. Pakistan "should copy some of these ideas, especially about uniting independent states. I will write our legislature about this."

Abbasi was one of 2,700 viewers of the Constitution between 6 p.m. Sunday, when the "87-hour vigil" began, and 2 a.m. Monday, according to James Zeendar, registrar for the Archives exhibit staff, who was standing watch at 2:30 a.m. along with six guards.

Some of the visitors, such as Betty and John Day of Silver Spring, read about the event in the newspaper and decided to take a family outing with their son Chris and daughter Sarah. Other visitors, such as Thomas and Jane Lyden of Silver Spring, went partly for nostalgic reasons.

"It is the fourth anniversary of my mother's death," said Jane Lyden, 37, who works at the Greenbelt Library. "She loved Washington and history. She would have liked me to do this."

Other visitors included several giggling Girl Scouts from Richmond, a government worker from Mount Carroll, Ill., a college student from Beaver Falls, Pa., four women from Wisconsin in town for a convention, and a couple from Lugano, Switzerland.

"It was most interesting to compare it to the founding document of Switzerland," said Soldati Aldino as he left the exhibit with his wife Jackie. "The U.S. had 13 states versus our three at the time of the Constitution, the document has four pages instead of our one, and it's 200 years old while ours is 900 years old."

The vigil is being accompanied by speeches, patriotic and historical films, music, and dramatic performances. The Archives sponsored a similar event for 76 hours in 1976 to celebrate the bicentennial of the Declaration of Independence.

Actually, the 1987 vigil may last only 86 hours and 57 minutes because of a brief glitch at about 2:15 a.m. yesterday when a guard accidentally pushed a button and lowered the documents to a vault 20 feet below the exhibition hall floor.

The error was swiftly corrected, and a nation's lonely all-night communion with its supreme law was resumed.