Bedecked with feathers, cuddled in furs, glittering in finery, some 500 people lived the grand life circa 1914 for a brief few minutes when the Decorators' Show House, sponsored by the National Symphony Orchestra, held its preview benefit last night.

Visitors sank deep into $38,000 rugs, basked in the brilliance of an Art Deco skylight and listened to James Weaver play a decorated harpsichord -- all inside Rockville's former Charles and Hattie Corby mansion, which the Corbys bought with their bread dough.

But the guests moved rapidly into 1981 when they went down a narrow staircase and out into the green and white buffet tent.

"The wind almost blew the tent off the hill when we were trying to get it up," said Sarah Jenkins , W. & J. Sloane's interior designer. "Then the fire marshal threatened to close it down anyway if we didn't get a tent permit." But the women's committee of the symphony prevailed. The tent, in contrast to the spacious house, was packed so tightly that you never knew who was eating the other end of your taco. The upper-crust guests began to feel like loaves of Corby Bread. One man said, "I always bring my knife with me when dinner is in a tent just in case I have to cut my way to safety."

Charles Corby and his brother William rose to fame with their innovative yeast and industrial-baking techniques. The mansion, which had lost its former glory, has been regilded by about 28 of Washington's most expert interior designers.

After the show house closes, the Montgomery County Arts Council will take over the 15-acre estate to turn it into the Strathmore Hall Arts Center.

Some of the guests at the party last night went home to mansions just as grand. Among them were Brazilian Ambassador Antonio da Silveira whose wife was honorary chairman, and Lady Henderson, wife of the British ambassador. The Corby house with its two huge columned entrances (one facing Washington, the other Rockville), seemed quite grandiose enough for most tastes.

Bob Waldron, who decorated the oak-paneled library, denied finding the rumored secret panel containing the safe with the Secret of the Corbys: the recipe for Mother Corby's Bread.

The house, at 10701 Rockville Pike, opens to the public at noon Sunday and will be open through Nov. 1. Hours are: Monday, Tuesday, Thursday and Friday 10 a.m. to 3 p.m.; Wednesday, 10 a.m. to 3 p.m. and 6 to 8 p.m.; Saturday, 10 a.m. to 4 p.m.; and from noon to 6 p.m. Sundays.