'The most important bells in the Western Hemisphere'

An Englishman entered a landmark of American history the other day with dirty pants and a paint-stained shirt. Up the steep, dirty tower of the Old North Church he clambered, oblivious to tales of secret lantern signals or Paul Revere's famous 1775 ride. Geoffrey Davies wasn't being disrespectful. In fact, he is one Englishman Mr. Revere probably would have welcomed.

The reason is Mr. Davies's fascination with bells.

The eight bells of the Old North Church are particularly intriguing. Black and plain-looking, they are the oldest in America. Cast in 1744 in Britain, they were rung by Revere when he was a teen-ager and have remained intact over the years. But for most of this century they've been silent - their frame, headstocks, bearings, and fittings severely deteriorated.

But Davies, now a Northeastern University chemistry professor when he's not ringing bells, changed all that.

He headed a campaign to refurbish the bells and renovate the frame, which swung precariously when the bells were rung. Money was raised and work donated by members of the state's Association of General Contractors. On Aug. 14, with the renovation nearly done, the bells returned to their tower home. On Sept. 3, they will ring for the 200th anniversary of the Treaty of Paris, which ended the Revolutionary War.

''This is a miracle,'' says Davies, perched precariously on an oak beam in the tower high above Boston's North End. ''These are by far the most important bells in the Western Hemisphere.''

The project represents more than historic renovation. It is a sign of the reemergence of an art form that was lost in the United States during Paul Revere's lifetime - the art of change-ringing.

Change-ringing bells differ from other bells because they require teams of ringers. While most bells in the US swing back and forth or are hit with hammers from the outside, change-ringing bells rotate in a full circle, with the clapper striking when the bell is upside down. This throws the sound up and out and requires skilled handling to get the right timing. For years, most change-ringing bells in the US remained unused because so few knew how to ring them.

Now, there are signs bell-ringing is on the upswing.

''When I came to Boston in 1966, the only ringable bells were at Groton School (in Groton, Mass.),'' Davies recalls. Now there are 21 working sets in North America - five of them right in the Boston area. Davies, who has taught change-ringing since he came to the US, hopes to establish Boston as the American hub for the art.

Meanwhile, new orders for bells have been placed by churches in Miami and Texarkana, Ark., and a college in Kalamazoo, Mich. Membership in the North American Guild of Change Ringers has grown rapidly in recent years. It now boasts some 250 members in North America and many more from abroad, mostly from Britain, where change-ringing is still widely practiced.

''It's on its way back,'' agrees William Theobald, who supervised the Old North Church project for Whitechapel Bell Foundry (one of two remaining foundries in Britain). ''America's the future. The enthusiasm here is absolutely terrific.''

Enthusiasm, however, won't be enough. The art is little known in the US and suffers from a lack of teachers. Those who do learn have few places to practice and US churches willing to install bells usually don't possess towers that can support change-ringing - or afford the work needed to strengthen them, Mr. Theobald says.

The reason is the tremendous sideways thrust of the bells as they rotate full circle. The largest bell in the Old North Church, called the tenor, weighs only three-quarters of a ton but can generate a side thrust up to four times its weight. To install bells this year, the old Post Office headquarters in Washington, D.C., spent almost $2 million to strengthen its tower and only some

Still, Davies sees brighter times ahead for change-ringing. He notes there is a radial design that reduces the stress and might open the way for more churches to have bells. ''This is where it's going to happen,'' he says.