America From Abroad : A British Museum Bows to Colonies : The stately 19th-Century mansion in Bath displays U.S. decorative arts and history by the roomful.

The setting couldn’t be more British: a graceful late Georgian mansion on a hill overlooking the majestic valley of the Avon River. But inside, Claverton Manor is All-American.

It is the home of the American Museum in Britain, which bills itself as the largest collection of Americana outside the United States.

The museum portrays the decorative arts of early America, illustrating domestic life in the United States from Colonial times to the eve of the Civil War.

“People here are able to gain an idea of the achievement of early American arts and craftsmanship,” says its director, William McNaught.

The museum was founded in 1961 by Dallas Pratt and John Judkyn, two Americans with a desire to bring to British attention the quality of life in early America and to foster better understanding between the countries. They bought the three-story Claverton Manor, which was designed by Sir Jeffry Wyatville, architect to King George IV, and built in the 1820s of Bath stone just east of Bath.

Since then, the museum has continually added to its collection, which is arranged as a series of period rooms fitted with original furniture, paneling and floorboards from houses in the United States. It is filled with silverware, pewter, glass, rugs, quilts and ceramics.

Dispersed through the 125-acre grounds are outdoor displays, including transportation exhibits and a milliner’s shop, a Colonial herb garden and a replica of George Washington’s garden at his home in Mount Vernon, Va.

There are two galleries on the grounds: one featuring folk art and the other, the New Gallery, housing a map collection and a library used by the public for research.

Each year, about 16,000 British schoolchildren, drawn from a 200-mile radius, troop through the grounds, according to the American-born Countess of Airlie, a museum trustee.

“They absorb some idea of what we produced in the way of culture in the 18th and 19th centuries, that we weren’t just rustics,” she says. “There’s nowhere else in Britain or Europe where you can get this experience--American life at its beginning.

“I think one of the museum’s most valuable assets is as a teaching institution. There is very little American history taught in British schools.”

On entering, the visitor climbs a circular staircase to the first period chamber: the 17th-Century keeping room, typical of those inhabited by New England colonists and a major improvement on the rough cabins of the first settlers.

Each room has a volunteer guide, and here Patricia Gale points out a small pedestal table. “That,” she says, “is believed to have been owned by Peregrine White, who was born aboard the Mayflower in 1620 when the Pilgrim ship was moored in Cape Cod Bay--the first male colonist born in New England.”

The entry hall features two items that underscore the settlers’ precarious existence: a sturdy front door with iron strap hinges, secured at night by a wooden bar; and the homespun linen “valuables bag” made to hold documents and prized articles, kept within easy reach in case of fire or Indian attack.

Next comes the Lee Room, named for an early 18th-Century house in Lee, N. H., that was painted blue-green using a mixture of skimmed milk and fresh slaked lime. The furnishings show a more sophisticated look than the first rooms. An adjunct is the Borning Room from the same date, so called because it was used for childbirth and closed off as a “measles room” during illness.

The visitor next enters the Perley Parlor, a handsome room of a wealthy colonist during the period of growing friction with the mother country. Its pine paneling is from a house built around 1763 in Boxford, Mass., by Capt. William Perley, a leader of the local militiamen who led them into action at the battle of Bunker Hill in 1775.

The Textile Room boasts a brilliant collection of 18th- and 19th-Century hooked rugs and quilts, relics of the American “quilting bees,” which were social events as well as a frugal way of recycling old clothes. Hung on racks are about 40 large quilts.

“We are fascinated,” says an American visitor, Ivy DiPiero, traveling with her husband, Ivo, from McComb, Ill. “We’ve been to Bath before, but we never came here.”

Another room, the Stenciled Bedchamber, is named for the journeymen decorators who provided householders with a wallpaper substitute in the form of stenciled wall designs. Even the bed coverlet has a stenciled motif. Beside the four-poster is a stenciled rocking chair made by Lambert Hitchcock of Connecticut, the first American to use mass production for inexpensive furniture.

The museum, which has a whaling exhibition that includes an actual captain’s cabin, then departs from the East Coast with a display of the rivers and ships that aided the movement westward, tied in with the North American Indians who were displaced by the pioneers. Cowboys and Indians are depicted in lively displays that include saloon life and bronzes by Frederic Remington and Harry Andrew Jackson.

Unusually, there is a New Mexico living room, which reflects the heritage of the Spanish colonists in America who built in the native Pueblo Indian adobe. To the side is a tiny Morada chapel belonging to the Penitente Brotherhood, a Catholic laymen’s group. It is equipped with a crucifix and religious statues.

You then come across a chronological throwback: Conkey’s Tavern, the original farmhouse tavern built in 1758 by William Conkey in Pelham, Mass. Outside the room hangs the old tavern sign, and above the huge fireplace is a lintel inscribed at the time of the tavern’s extension in 1776.

“In this room, Capt. Daniel Shays plotted his unsuccessful rebellion against the government of Massachusetts in 1786,” guide Peter Arnold says.

The last two rooms are representative of the affluent new nation.

The Greek Revival Room, based on a New York City dining room circa 1830, has Duncan Phyfe furniture arranged for an after-theater party with music provided by the harp and piano, brass flute, clarinet and Spanish guitar.

Finally, there’s the New Orleans Bedroom, an opulent chamber from a Louisiana plantation house featuring a large-scale, carved mahogany bed--with a mosquito net--adapted from the Louis XV style by Prudent Mallard, who opened a factory in New Orleans in 1838.

The museum has a country kitchen where visitors can sample American-style cakes and cookies based on original recipes, and one can sit outside enjoying the river scene.

There, sipping tea, Mr. and Mrs. Dennis Taylor from Yorkshire look contented. “What a grand view,” she says. “And the gardens! It really gave you a sense of how close America was to England way back then.”

Director McNaught’s current passion is to get “quilts from every state in the Union.” Meanwhile, he takes satisfaction in the museum’s accomplishments so far.

“When the museum was founded 33 years ago, the British had no idea of the achievement of early American arts and craftsmanship,” he notes.

“That was 2 1/2 million visitors ago.”