The U.S. Court of Appeals has told the Bar Association of D.C. that it can no longer use 7,000 square feet on the third floor of the federal courthouse for its 40,000-volume library. Appeals court Judge George E. MacKinnon recently told association president James B. Lynn that the court needs the space as of Dec. 31, 1983.

MacKinnon's letter prompted the bar association (a voluntary organization) to renew its request to the separate D.C. Bar (which all Washington lawyers must join) to buy the books, since the D.C. Bar doesn't have a library of its own. Price tag? A cool $500,000.

The two bars were close to a deal back in 1981, but the issue was put on the back burner after a vote by the D.C. Bar membership abruptly restricted that group's expenditures for public service activities, raising questions about the library book purchase.

As a result of that vote, the entire D.C. Bar membership would have to be polled before any decision could be made about the library, a much needed research source for many of the city's sole practitioners and small firms.

Back in 1981, it looked like the library, which costs about $120,000 a year to run, could be housed for free in space available in one of the old buildings on Judiciary Square that used to house the D.C. Superior Court. But that space is no longer available, so the D.C. Bar, if it wants a library, may now face some $200,000 to $300,000 a year in maintenance costs.

Lynn says that if the D.C. Bar won't buy the library, his organization will have to sell it either in full or piecemeal.