C. G. Sloan's auction last weekend set a sales record for the Washington/Baltimore area with total hammer sales at $1,533,760, about $400,000 more than any previous area auction, according to Donald Webster, Sloan's president. In addition, buyers paid a 10 percent buyers premium on all sales.

Star of the sale was a painting on a wood panel, "View of an Estuary" by Salomon van Ruysdael, a Dutch painter. The painting is signed and dated 1642. A London dealer paid $185,000 plus the 10 percent premium to set a new American record for the Dutch painter.

Russell Burke, the auctioneer, found the painting in a Boston basement when he went to collect a John Constable from an estate. The painting had been valued at $1,500. When he took it out in the sun, he found the date and the signature.

The Constable, "Village of Harnham, 2 August, 1820," went for $90,000 to another London dealer.

Joseph Hirshhorn, the collector, paid $75,000 for a portrait by John Singer Sargent of a Venetian Woman.

A group of Persian gold 19th- and 20-th century copies of antiquities sold for $38,300 for the 100 ounces of better than 20 carat gold. A Tiffany poppy table lamp brought $23,000. A pair of portraits of Virginians William Knox and his wife Susannah Stuart FitzHugh by John Hesselius, 1771 brought $32,000. A pair of rosewood chairs, attributed to Joseph Meeks sold for $5,000.

None of the above prices includes the 10 percent surcharge.

Webster said the gold and silver market has been reflected in the current auction prices. A set of Hungarian silver flatware went for $7,500. A pair of Georve IV entre dishes went for $4,250, about $18 an ounce.

The buyers premium, added to purchase prices, has been very successful, Webster said. "There has been little buyer resistance. It has enabled us to lower by 10 percent the amount charged to the seller. For this reason, a great many goods which had been going to New York are now being sold in Washington."

Adam Weschler and Son will have a catalogue auction Friday through Sunday. nections have been useful to him, particularly on the House Ways and Means Committee, which his father chaired.

"He has a tremendous advantage with all the members who worked with his Dad," said the administrative assistant to a member of the Ways and Means Committee. "He arrives in the office and the reaction is, "Oh, yeah, you're Tommy Boggs."

"He loves to entertain people," said his wife, Barbara. "There are 900 examples. I turn around and he's invited 22 people to dinner on a quiet evening." His wife also pointed out his and her careers complement each other. She has run a convention planning business called Washington Whirlaround for 12 years now. "His clients are sometimes my clients," she said. The husband of one of her partners is Sen. William Proxmire, chairman of the Banking Committee, which will be handling the legislation concerning a government-guarantted loan to Chrysler. When Ellen Proxmire threw a surprise party for her husband, it was held at the Boggs home. Marshland Mystique

When Boggs is not huddling with the team at PB&B or haunting the halls of Congress, he goes to his retreat on the Eastern Shore of Maryland for relaxation. "He likes to go duck and geese hunting," said his wife Barbara. His mother said the mystique of birds, water and marshland remind him of his Louisiana childhood.

The day before one of Chrysler's meetings with the Treasury Department, Boggs took the top Chrysler management to his place on the shore where they sat out on the water in his Chrysler-made boat."He's not the briefcase-under-the-arm type," said his wife. "He works hard and relaxes hard."

Boggs has also been directly and deeply involved in Democratic politics as a campaigner, a fund raiser, a contributor and a candidate. In 1964 he went aboard the Lady Bird Special to help Mrs. Johnson convince the South to vote for Kennedy. In 1968 he took time off to work for Humphrey in Maine; in 1972 he campaigned for Ed Muskie.

Because of their influence with mammoth economic interests, lobbyists like Tommy Boggs sometimes find that congressmen have turned the tables on them: the lobbyist becomes the lobbied. Rep. Jim Jones (D-Okla.) former special assistant to Lyndon Johnson, now a member of the Ways and Means Committee, was a classmate of Tommy Boggs at Georgetown Night law school. "We studied together for exams and took turns holding his baby," said Jones. Discussing a bill he is co-sponsoring Jones said that it is important for legislators to turn lobbyists into allies he explained are often crucial to passing a bill.

"You say to lobbyists: 'Who can you deliver? Who can you talk to?' That's the way to build support for passing a program you believe in." said Jones.

At the age of 29, Boggs ran for Congress from Maryland with the support of his father, the Montgomery County Democratic organization, Gov. Marvin Mandel and Teddy Kennedy. In his campaign he said Congress' first priority should be to legislate an end to the Vietnam War. He also supported reduced interest rates and tougher environmental controls. After gaining the Democratic nomination in a hard-fought race, he was defeated in the general election.

Boggs now describes himself as a "progressive liberal."

Consumer advocate Ralph Nader pointed out the dichotomy between Boggs the lobbyist and Boggs the private citizen. "Tommy is the type of lobbyist who would slip through your fingers if you tried to pick him up. But you always have a feeling that if he were a member of Congress he'd be a liberal."

When Boggs was asked if he had qualms about representing members of the business community, he said that he doesn't "mix politics with business." He does, however, occasionally turn down a case on "philosophical grounds." Where does he draw the line? "I wouldn't raise money for Ronald Reagan," he said.

Tommy Boggs may often leave the city on behalf of his clients, but he has achieved a different kind of permanence in a town whose political hallmark is impermanence. "Washington is like a series of escalators," said Robert McCandless. "The people going down now will be coming back two years from now. But Tommy Boggs is a Washington institution. The others may come and go, he will still be here."