PROVIDENCE, R.I. (AP) _ When landscape artist Albert Bierstadt painted a huge canvas of Switzerland's Lake Lucerne in 1858, it was well documented in art literature. Within decades, the painting was lost - until now.

The 6-by-10-foot painting was found two weeks ago in the rural Exeter home of the late Pearl Rose, whose family had owned, but concealed, the canvas for 100 years.

During the weekend, experts used writings about the painting to confirm that the scene of the lake, with the Swiss Alps in the background, was Bierstadt's work, said Linda Ferber, curator of American painting at the Brooklyn Museum in New York.

''It's a piece of the Bierstadt puzzle and it's very nice to have it back in the public domain,'' she said.

Lewis Peck, who inherited the Bierstadt, said Wednesday the family kept the painting a secret because they owned other artwork and did not want that generally known.

''If you had a bar of gold in your house, would you tell everybody about it?'' he asked in a telephone interview from Exeter, in south central Rhode Island. ''That's about the way we did things.''

The whereabouts of the painting was last known in 1882 when Alvin Adams, of Watertown, Mass., sold it in Boston.

In 1890, it was purchased by Mrs. Rose's first husband, William Sunderland, said Peck's wife, Sylvia. Peck, a distant cousin of Mrs. Rose, inherited it in August when she died at age 86.

The landscape is so large that when the family moved it to their Exeter home 70 years ago, the roof had to be lifted to get the painting in, Mrs. Peck said Tuesday. When it was removed two weeks ago, ''we took the side of the house off,'' she said.

The Pecks will sell the painting at auction on Oct. 6.

The painting is typical of Bierstadt's earlier work, according to Ferber, who is assembling an exhibit of Bierstadt's work for early 1991.

Ferber did not know what the Lake Lucerne painting was worth. But attorney Christopher Healey said Bierstadt's ''Moteratsch Glacier, Upper Engadine Valley, Pontresina,'' about the same size as the Pecks' painting, brought $990,000 at Sotheby's auction house May 24.

Bierstadt, part of the Hudson River group of painters, built his reputation on his panoramic landscapes of the American West.

The World Book Encyclopedia calls Bierstadt ''one of the greatest American romantic landscape painters,'' and said he received $25,000 for a painting in the latter half of the 1800s, a record for a painting at that time.

Bierstadt was born in Germany and raised in New Bedford, Mass. He studied in Dusseldorf, Germany, from 1853 to 1857, and painted his Lake Lucerne picture in New York, according to Ferber.

She said there are other Bierstadt's that are unaccounted for, although ''this was certainly one of the larger ones.'' Bierstadt died in 1902 in New York City.