"Those living when the balloon was discovered will testify to the world reaction it inspired, the feeling of fellowship that accompanied the balloonists, the longing in so many thousand hearts to have a part. . .and what gentle sympathy was felt for the martyrs of these trials."

Change "balloon" to "rocket" and this could be a contemporary memoir rather than one written by Goethe in 1812. But in truth the first balloon ascent was a greater step than the one taken nearly two centuries later by the first cosmonaut, because it was man's first flight.

Yuri Gagarin knew what he was getting into, but when Jean Francois Pilatre de Rozier climbed aboard the Montgolfier Brothers' hot-air balloon on the afternoon of November 21, 1783, he was fulfilling a dream that had beguiled our species almost from the dawn of time.

How it changed man's conception of the possible is shown in a small but masterful exhibit just opened in the Library of Congress Rare Book Room, tucked away in the upper rear of the real Library of Congress building, whatever they call it now, the one with the copper dome, behind the Capitol.

The casual display of rare old books is electrifying: Here, noted in passing, is a volume from Jefferson's library; there, one that Lavoisier bought new. And did you know that Kepler, that immortal of the Copernican Revolution, wrote science fiction in 1634? Here it is.

The explosion of schemes and dreams that followed the first flight is compared and contrasted with the fancies that went before it, and it is worth getting down on your knees to scrutinize the volumes mounted just above floor level. It is also curious that we should have to do so.

There was another explosion: On June 15, 1785, less than two years after he became the first aeronaut, de Rozier attempted the first flight across the English Channel. His balloon, a hydrogen/hot-air hybrid, blew up over Boulogne, as his fiancee watched. He thus became both the pioneer and the first casualty of the space age. THE BALLOON AND MAN'S WILL TO FLY -- Through April 15 in the Rare Book Reading Room, Jefferson Building, Library of Congress, 8:30 to 5 weekdays.