They came from France in 1831 and have been silent for four years.
But when the bells at the Basilica of the Assumption begin chiming over Charles Street again in November, they will have a deeper and more resonant sound. They also will be equipped with the latest in satellite technology.
The basilica's main bell - a 3,500-pound behemoth considered one of the largest of its time - has been upgraded with a larger hammer and will be connected to a Global Positioning System satellite to ensure that it chimes in unison with the church clock, regardless of power failures.
The improvements are part of a $32 million renovation project to restore the nation's first Roman Catholic cathedral to the design originally intended by architect Benjamin Henry Latrobe, who died a year before construction was substantially completed in 1821.
The bells were installed in 1831. Their use was halted about four years ago because of structural problems with the bell supports, according to Mark J. Potter, executive director of the Basilica Historic Trust, which is overseeing the project.
But the supports have been repaired and the bells are in remarkably good shape for their age, said William R. Parker, vice president of operations at McShane Bell Foundry, the Glen Burnie firm installing the new hammer and GPS system.
"Bells are like musical instruments. They'll last a long time if they're taken care of," Parker said during a brief tour of the windswept, 132-foot bell tower last week.
The new hammer on the basilica's main bell is larger than the old one and will give the bell a deeper and more resonant chime - one that may be more clearly heard, Parker said. He plans to connect the bells to the Global Positioning System in September.
The bells were cast in Lyons, France, and while they could use a good scrubbing - the elements and the birds have not been kind - the original religious inscriptions are still visible on the sides, and the original clappers still hang inside them.
They are made of the same metals used in most church bells cast today - about 80 percent copper and 20 percent tin, Parker said. The larger bell is 4 feet high with a 14-foot perimeter, and the smaller bell is 20 inches high and has a 6-foot-6-inch perimeter.
If made today, the larger one would cost about $65,000, Parker said.
"Even by today's standards, that's a pretty big bell," he said.
McShane has cast bells for churches, universities and schools nationwide. It plans to ship bells this week to New Orleans for ceremonies to honor those killed by Hurricane Katrina, and its bells have tolled in remembrance of those killed on Sept. 11, in ceremonies held annually at the three sites where planes went down, Parker said.
"Our bells go everywhere," he said.
Church bells are often shown in movies swinging from rafters, with the clappers inside them banging away. But Parker said that many church bells - including those at the basilica - don't work that way any more because the repeated swinging of a heavy bell puts a strain on the tower supporting it, creating periodic maintenance problems.
"What you want here is a hammer that strikes from the outside," he said.
Both the bells and the basilica clock will be controlled by GPS receivers installed in the basilica's south tower, said Ellington E. Churchill Jr., project manager for Henry H. Lewis, the Owings Mills firm that is general contractor for the basilica renovations. The church clock was hooked up to a GPS system in April, he said.
The GPS systems ensure that both clock and bells will not be thrown off by power outages, Churchill said.
"In this day and age, it's not necessarily rare, but it is a nice feature," he said.
The bells also will be equipped with a remote-control device, about the size of a cordless telephone, that will enable a priest or church official to determine the pace and type of chimes that ring during religious ceremonies.
"The tone for a funeral is obviously going to be slower and more drawn-out, maybe one strike every 10 seconds or so, something a lot more somber than what you would have for a wedding," Parker said.
When the basilica's bells were installed in 1831, they tolled every day for the Angelus, a time for prayer observed by the faithful at 6 a.m., noon and 6 p.m. It's yet to be decided when they will toll - whether every hour, once a day or on special occasions - when the renovations are completed, Potter said.
Work at the basilica - formally known as the Basilica of the National Shrine of the Assumption of the Blessed Virgin Mary - began April 12, 2004, and is slated for completion by November. Pope Benedict XVI has been invited to attend the reopening.
The redesign is intended to bring in more natural light, as envisioned by Latrobe, Potter said.
Crews have replaced the church's stained-glass windows with clear glass. They also will install a bright, white marble floor, replace 24 skylights in the dome that were removed in the 1940s and are putting a chapel that was part of the original design in the basement.
Potter likes to point out that most of the project involves improvements to the basilica's infrastructure, including upgrades to the electrical, heating, air-conditioning and ventilation systems. Crews also are installing an elevator and wheelchair-accessible public restrooms.
"Top to bottom, this church is being completely revamped with 21st-century systems," he said.