At the turn of the century, a Chicago publisher named Sol Bloom took to lurking at the front of the main entrance to the Copyright office, then in the Library of Congress. Starting on Dec. 28, 1899, he maintained a vigil, replaced at night by a friend; three days later, the group had grown to four, which drew inquisitive reporters. The collective reply to all questions was "Sol Bloom, the Music Man, will tell you," which of course intensified press interest.

Finally, on January 2, 1900, the first copyright registration of the new century was issued -- to Sol Bloom, who had already placed newspaper advertisements proclaiming, "More than thirty millions of copyrights will be issued during the century which commenced with the present year. In line with our usual policy of being first (at least in this century), we have secured Copyright Number One, 'I WISH I Was in Dixieland Tonight!' by Raymond A. Browne / SOL BLOOM THE PROGRESSIVE PUBLISHER."

Yesterday was the 150th anniversary of the Music Copyright Law and the Library of Congress, home of the Copyright Office, celebrated in the time-honored tradition of Washington: a concert and exhibition preceded by a party. The late afternoon reception in the atrium of the newly opened James Madison Memorial Building also served as a housewarming party for the Copyright office's new home and as a welcome to the agency's new registrar, David Ladd.

The 300 guests were drawn from the industry side (Leonard Feist, president of the National Music Publishers' Association) and composers of varied disciplines: classical composers William Schuman and Jacob Brukman, popular songwriter Sammy Cahn, Charles Strouse (author of the Broadway hit "Annie"), jazz pianist John Lewis and country writer Joe South. Also in attendance were songwriter Oscar Brand, Mickie Grant, author of "Don't Bother Me, I Can't Cope" and "Your Arms Too Short To Box With God," and Irwin Levine and Larry Brown, composers of "Tie A Yellow ribbon Round the Ole Oak Tree."

Levine seemed a bit befuddled by all the attention he and Brown have been receiving over the last month. "I would never believe anything like this could happen in my own life," he admitted. This week the songwriting team released a new version of "Yellow Ribbon," rewritten in honor of the hostages. Levine also said he's been deluged with movie offers, including several that would tell the history of the songwriters and the song. He recently hired an agent at the prestigious William Morris Agency because "all this attention was taking away from my writing time."

The 68-year old Cahn was, as usual, the life of the party, flitting into dozens of conversations, punctuating his own with snatches of song played on a chest-high imaginary piano. He talked about "writing relentlessly for 50 years" and of how he'd copyrighted his latest song ("Thumbs Up, America") just three weeks ago. He also insisted that "I never brag" about the thousands of tunes he has penned. "I just state facts," he winked, "and it sounds like bragging."

The debonair Strouse fielded questions about his latest Broadway project, "Bring Back Byrdie," the first big-time musical sequel, opening in two weeks in New York. He also said he had written three new songs for the film version of "Annie," which will be shot in New York this spring, and ventured the hope that it would not be as "bungled" as the original "Bye Bye Byrdie" movie was.

About an hour into the reception, Strouse and Cahn slipped away to a piano that had appeared in the lobby of the Madison Building. Starting off with some tentative chords, the two composers started to plunk out the song they had written together last year for Frank Sinatra and Chrysler. As the lyrics to "It's Time for You" came into focus, Strouse's piano playing became more energetic. "I finally remembered the song," he explained. p

By the third go-round, with Cahn stomping his foot to accent his lines, the two had attracted a small crowd. "We don't get to work together that often," Cahn laughed, though he and Strouse have been working on a new musical, "Bojangles," based on the life of the famous dancer Bill Robinson. As he and Strouse walked back into the reception, Strouse suggested, "We ought to write more songs together." Responded Cahn, the optimist: "We ought to quit while we're ahead!"

Last night's reception honored a long, if not always easy, history of protecting creative works. The first copyrighted song in America was "The Kentucky Volunteer," which was registered as a book in 1794; that's how songs had to be protected until 1831. Since 1870, when the tallying began, close to 5 million songs have been copyrighted; in fact, musical works are the single largest category of copyrights (though the majority of them in that grouping are unpublished works).

Over the years, copyright history has been marked by legislation and litigation and there have been salty exchanges over copyright ownership.

In 1965, a songwriter brought suit against the makers of the film "Mary Poppins," claiming infringement on his song titled "Supercalafragalisticespeealadojus" by their "Supercalifragilisticexpialidosius." The court thereafter referred to the song as "The Word," possibly to save the sanity of the court reporter. In the end, they decided there were "no substantial similarities" beyond the titles.

In the late '50s, in an attempt to convince Congress to extend copyright protection from publishers, songwriters and record companies to performers, actress Julie London flew to Washington and performed the "Mickey Mouse Song" . . . in the Senate. A concurrent copyright hearing tried to grapple with the all important question of whether "copyright was a sexy subject." They decided it was.