Leave it to a Frenchman to make the flute sound like the most beautiful woman in the world. Jean-Pierre Rampal, in concert with the National Symphony Orchestra at Wolf Trap last night, made music that was at once pure and sensual in an unusually joyful evening.

The cause of all the excitement was Mozart's Concerto No. 1 in G Major for flute conducted by Rafael Fruhbeck de Burgos. After an uncharacteristically edgy series of attacks at the outset, Rampal settled into greatness. He does not resort to the muscial antics with which other famous flutists win a fad-hungry audience. Instead, there is the uncanny transformation of the flute into a glorious soprano, bringing out all the intricate vocal delicacies to be found in Mozart's writing. The cadenza became a display of legato and unabashed virtuosity tempered by taste, and the seemless and free sounds of the rondo finale brought the audience to its feet. This was one occasion when applause between movements was the result of excitement and not ignorance. At the concerto's end, everyone simply refused to let Rampal go, and the generous flutist treated all to a haunting Sarabande by J.S. Bach for an encore.

The concerto was framed by works of Rossini and Berlioz, and a suitable frame it was. In the overture to "L'Italiana in Algeri," a deliberate and almost impatient beginning soon gave way to Rossinian abandon. Although the violins were not having one of their more articulate nights, this operatic tidbit only whetted our appetites to hear the NSO in opera productions.The program closed with Berlioz' Symphonie Fantastique, that romantic enigma which liberated the classical orchestra while idealizing the human relations it portrayed.

As usual, Fruhbeck de Burgos gave the highly personal interpretation which in execution came out curiously uncontroversial. His baton will never raise our eyebrows, but he will never disappoint. The orchestra's playing under Fruhbeck de Burgos was one more indication of the growth of our symphony, and that is as exciting as the music itself.