For fifth-generation stone carver Vincent Palumbo, working on the construction of the Washington National Cathedral over the past 30 years has been nothing short of an act of worship - and love.

"You work and you pray, work and pray," Palumbo said, gesturing with his thick hands, which are as dusty as the chisels that fill his workshop at the building's base. "And always there is the feeling - all these things you do because . . . it is a church. It's for God. It's for Christ."Today, 83 years after the building's cornerstone was laid, the last finial that Palumbo has carved will be hoisted atop the southwest tower, setting off two days of dedication celebrations that will draw officials and clerics from around the United States.

President Bush will attend today's ceremony, which will feature the U.S. Marine Corps Band as well as the cathedral's own bells and carillon. The sermon will be delivered by former Dean Francis B. Sayre, a grandson of President Wilson.

More services, bells and carillon ringing will follow Sunday.

Although the cathedral is ecclesiastically a part of the Episcopal Church - indeed, it is the seat of the denomination's Washington diocese - the structure has become the closest thing the United States has to a national church.

Its staff is imbued with a more temporal calling as well. "It is part of our sense of mission to be both the Washington Cathedral and the National Cathedral," said the Rev. Leonard Freeman, one of the cathedral's canons.

The cathedral, he said, is a church, but a church with a national vision. And it is Episcopal because "well, frankly, you have to be something."

The cathedral's roots go back almost to the creation of Washington, D.C., as the nation's capital.

Although the Bill of Rights forbade the establishment of any state religion, the initial plan for the capital city set aside a site for "a great church for national purposes." That church was never built, and the U.S. Patent Office now occupies the site.

In the late 1800s, a group of prominent Episcopalians revived the idea, buying a parcel of land on then-rural Mount Saint Alban Hill and laying the plans for what eventually became the Cathedral Church of St. Peter and St. Paul.

Today, the Gothic American masterpiece literally towers above secular Washington. Its site on Mount Saint Alban's - near the intersection of Massachusetts and Wisconsin avenues - is higher than the Capitol. And its spires top the Washington monument by a full 135 feet.

Construction, which has continued piecemeal (with some significant interruptions) since 1907, has been fraught with problems - some of them physicial, others financial.

As in the Middle Ages, Washington's cathedral was built stone by stone, without a steel framework beneath. Blocks of Indiana limestone were placed on top of one another and bound together with mortar. The only 20th-century concession: They were hoisted by motorized crane.

The building was financed soley by private donations.