The U.S. Government has just doubled its income on an investment.

The bonanza comes in the form of 97 maquettes, paintings and drawings recently transferred to the National Collection of Fine Arts by the General Services Administration -- all proposals for existing monuments works which GSA has commissioned through its Art-in-Architecture program. These are preliminary studies, but many stand alone as first-rate works of art by Louise Nevelson, Frank Stella, George Rickey, Alexander Calder, Mark Di Suvero and a host of others.They constitute a major addition to the contemporary American sculpture collection of the NCFA, where they have just gone on view.

"Across the Nation: Fine Art for Federal Buildings, 1972-1979" documents and surveys, for the first time, the government's largest experiment in direct art commissioning since the WPA. If you can't cross the country from Maine to Alaska to see the originals, this show is the next best thing. It should leave even the severest critics -- and they are legion -- thinking that all this art, including both monuments and maquettes, was quite a bargain at $5 million, the cost of one good Van Gogh at current prices.

In 1962, at the behest of President John F. Kennedy, 44 works of arts were commissioned to adorn GSA buildings. The formula established was that one-half of 1 percent of all new building costs would thereafter be put aside for commissioning art.After a hiatus of six years, the program was revived in 1972 under GSA Administrator Arthur Sampson. It was continued and expanded under Jay Solomon to include new forms, including photography, ceramics, fiberworks, light sculpture, earthworks and site-specific sculpture. Solomon's last act before departing GSA was to secure the future of these maquettes by transferring them to NCFA. By then 140 works had been commissioned.

The results are all here in one form or another, from the now famous Oldenburg "Batcolumn" in Chicago to lesser-known works like "Chignik Rose" by Aleut artist Alvin Amaspon, which combines paint with real walrus tusks and hangs in the U.S. courthouse in Anchorage. Washington artists have had their share of the action. Rockne Krebs' fine "White Tornado" in Topeka, all prisms and neon, is one of his few permmanent pieces. Ed McGowin's "Mississippi Inscape" is a major work, and William Christenberry and Sam Gilliam have also done well by their assignments. The balancing of various styles -- from the realism of Leonard Baskin, Jack Beal and George Segal to the minimal aesthetic of Sol Lewitt, Robert Morris and Robert Mangold -- is admirable, like them all or not.

Several exciting projects are currently in the works, some due for installation in the works, some due for installation soon in or near Washington. They include Kenneth Snelson's sculpture for NIH in Bethesda and Richard Fleischner's environmental project for a wooded area adjacent to the Social Security Computer Center in Woodlawn, Md. Robert Irwin's proposal for the inner courtyard of the old Post Office Building on Pennsylvania Avenue will astonish some people.

Controversies have raged since the program began, and the objects of those battles -- notably a George Sugarman sculpture in Baltimore and a Guy Dill piece in Huron, S.D. -- are here to see. The Dill flap has led to recent changes in the selection system which should protect both taxpayers and artists from similar unpleasantness in the future.

Meanwhile, the proposed work by John Chamberlain for the Patrick V. NcNamara Federal Building in Detroit -- entitled "McNamara's Band," it is made from wrecked, mashed automobiles -- should reassure anyone that artists can still make big statements bespeaking their times.

A slim catalogue has been published for this show, which continues through Sept. 1 before moving on to Chattanooga. For those who want to know more, Donald Thalacker, director of the Art-in-Architecture program, has just published a lavish history of the program, "The Place of Art in the World of Architecture."