At the Columbia Historical Society there is often grumbling that few in Washington know the organization near Dupont Circle even exists. It may be that the society doesn't even know what it has. On Wednesday, historian Barbara Kraft, who had been there only two days doing volunteer work, was digging around and found a piece of stationery signed by President Lincoln and his Cabinet. There was also an order by Lincoln's secretary of the treasury, Hugh McCulloch, ordering all Treasury officers to wear crepe on their left arm for six months. Who knows what else is stored there? A couple of months ago, someone discovered the bullet that killed President James Garfield . . .

If the Supreme Court hadn't recently released the justices' financial disclosure forms, few would have learned that Justice William H. Rehnquist was writing a book on the nation's highest court. There is no definite publication date set for what is described as a "largely historical book," for which Rehnquist received a parsimonious $9,000 royalty advance from William Morrow. . . .

A New York federal judge yesterday dismissed a lawsuit brought by the public relations firm Carl Byoir & Associates against former Alexandria Gazette publisher and author George Mair. The lawsuit attempted to stop publication of Mair's upcoming book, "Inside Home Box Office: The Cash Cow That Almost Ate Hollywood," scheduled for a major fall release by Dodd Mead & Co. Mair had worked as a part-time consultant with Byoir, where he worked on the Home Box Office account . . .

Five Democratic senators who were all elected in 1978 have made a point of frequently getting together and having special guests for dinner. Sen. Max Baucus and his wife Wanda hosted a dinner at their Georgetown home Wednesday night for special guest Soviet Ambassador Anatoliy F. Dobrynin and his wife Irina. The other senators and wives who attended were Carl and Barbara Levin, Bill and Ernestine Bradley, David and Barbara Pryor and David and Molly Boren . . .

Susan Garner, who ownes Garner Galleries, is a woman in a hurry. She showed up at her Georgetown hairdresser, Ury and Associates, for her 9:30 a.m. appointment Wednesday only to find Ury cutting a man's hair at her appointed time. Garner pointed out she had always asked for an early appointment and wanted to know why this man was ahead of her. Ury explained he cut men's hair earlier because it was less work. Garner then complained to the man about how unfair it was. She grumbled on, but the man in the chair did not seem to want to enter the discussion. It was only when he got up to leave a few moments later that Garner realized she had been complaining to the Redskins' John Riggins . . .