The last note of Tchaikovsky's "Pathetique" merged effortlessly into the sound of silence. The conductor's arms, in a final, graceful flourish, swept the air. The dazzling lights dimmed, bathing the young faces on the stage with a yellowish glow and lighting the polished cellos and violins with a soft, sparkling glint. Eight hundred people stood in a thunderous ovation, which rose to a crescendo, fell, rose again and then dissolved.

Standing in the balcony Saturday evening watching the audience file down the aisle and listening to the applause in the University of Maryland's Tawes Theatre, Donald Reinhold smiled. He had reason to.

The 1990 National Orchestral Institute Philharmonic, made up of 92 students he had selected after sifting through more than 650 applications and sitting through six weeks of auditions in 19 cities across the country, had proved it. Ranging in age from 19 to 30, these students, working to be orchestral musicians, were selected as some of the finest musicmakers and some of the best dreamers of dreams.

"It's amazing. This is great," gushed the usually soft-spoken Reinhold, the administrative director of the NOI. "When I think that all these kids hadn't played this piece before this week, well, the performance says a lot about their talent."

Under the guidance of Maximiano Valdes, the music director of the Buffalo Philharmonic, the students spent the week in one long, tireless striving toward perfection, as they had done the week before for their first concert in the three-week program and would do the next week for their last.

Just the day before, as a lawn mower stuttered noisily outside in the grueling heat, they had spent the day getting the notes straight, the harmony perfect. At first sight, in their shorts and baggy T-shirts, they looked like college kids out for an anything-goes vacation.

Sponsored by the Maryland Summer Institute for the Creative and Performing Arts, under the aegis of the Office of Summer and Special Programs at the University of Maryland, College Park, the NOI, now in its third year, offers full scholarships for the intensive training program. The members work with three conductors of international renown and present three concerts in professional settings. They practice under the supervision of the conductor more than six hours a day, breaking for lunch at the school cafeteria and then continuing with their sessions in the less formal atmosphere of their dorm rooms.

"The program is so different from school," said Dianne Wittry, a University of Southern California graduate and a second-time member of the NOI, who is also the assistant conductor at the Pasadena Symphony. "While in school, one runs to death taking care of assignments and other details; here, you are free. And with some of the best conductors of the country, it is so easy to be very focused and dedicated."

Wittry believes that her experience with the NOI will be invaluable in tuning her for a career in conducting. But some members, like 20-year-old Amy Sims of the University of Southern California, do not let the apprehensions of the future jangle the symphony of the present. "I have never been ambitious to have a career with money. For me, this is more laid-back ... I don't have to scour the music. I am more free." Sims will be participating in the Chamber Music Festival in Vermont later this summer.

It is this innocent, somewhat "spiritual" idealism that accounts for these students' devotion to a career that flourishes more on unadulterated artistic impulses than the material demands of the market. For conductors like Valdes, this has an added attraction.

"They give to me their own personalities," said Valdes, a native of Chile who has conducted leading orchestras throughout Europe and South America, including the London and Royal Philharmonics and the Monte Carlo Philharmonic.

"They come with their own, individual experiences, and together we have discovered a musical truth. They are technically more skilled than their European counterparts. They are very fresh and catch ideas very fast."

This admiration is reciprocated unanimously by the members of the orchestra, who said they never felt intimidated by the power of his presence.

"Valdes is amazing. He has a very different approach," said John Kim, who at 19 is one of the youngest members of the orchestra. "We were a bit apprehensive but the minute he walked out for the first rehearsal, he didn't introduce himself. He just said, 'It's me. Let's play.' I admire him and would like to work with him some day," said Kim.

A trained pianist, Reinhold firmly believes that "when you are a musician, it's not just making music, but I think a lot of it has to be a willingness to present it to the next generation. I try to make this sanctuary absolutely perfect so that they don't have any concerns, and when they go back to school, I hope they communicate this experience to the other students and become leaders in their schools."

Reinhold may rest assured.

"I'll never forget anything that I have learned here," asserted Kim. "I'll share it with everyone else. And now that we have all come together and performed, it will be easier for me to adapt to school." And even though he spilled his glass of soda on the violin case, one can't doubt his determination.