ANTIQUES ROADSHOW stops in Virginia's capital city, where host Mark L. Walberg attempts to stump appraiser Sebastian Clarke on Federal-era materials at the Wilton House Museum. Highlights include a 1765 Thomas Pitts silver epergne that was previously used to hold flowers instead of desserts and is now valued at $15,000 to $50,000; a Leveille-Rousseau perfume bottle, ca. 1890, bought at a Virginia flea market for around $20 and now appraised at between $6,000 and $8,000; and a Tiffany & Co. brooch, ca. 1937, found in the spare-button envelope of a dry cleaning business and valued at $65,000.