The young musicians warmed up for their afternoon concert yesterday, tapping their feet to keep the rhythm of "The Chimes of Liberty" march. But one trumpeter's toes dangled a foot from the floor.

At age 4, Geoffrey Gallante, by far the youngest member of the Franklin Band & Orchestra Camp, could barely peer over the top of his music stand to see the conductor. The middle-schoolers who made up the rest of the band helped him follow his part -- gesturing when it was time for the trumpets to join in. And, when he wasn't making music, he stuck out his tongue, sucked on his finger and fiddled with the toy walkie-talkie he brought along.

But band director Lawrence H. Walker Jr., who has been running the camp for 17 years at Fairfax County's Franklin Middle School, said Geoffrey's got ears and ability like he has never seen. Yesterday, the blond boy who is a bit shorter than a trombone performed alongside 12- and 13-year-olds as part of the camp's most advanced group, the symphonic band.

"Watch him," Walker said. "This is a Wynton Marsalis. This is a young Mozart. This is how your music greats got started."

Geoffrey, who also likes trucks, fire engines and swimming, describes his attraction to the horn this way: "It sounds funny."

For the past four weeks, Geoffrey, who starts kindergarten in September, joined about 480 children from Fairfax and Loudoun counties from 9 a.m. to 1 p.m. each day to sharpen their musical skills and play in a band. The students were split into four levels: beginner, cadet, concert and symphonic.

Geoffrey's mother, Beth Bingham, 46, said the root of her son's fascination with music isn't completely clear. She played trumpet and flute as a child, and his brother plays guitar. Her husband, David Gallante, 50, used to be a ballroom dancer, and she suspects that's where Geoffrey inherited his sense of rhythm.

It was around Thanksgiving last year when Geoffrey, whose family lives in the Alexandria section of Fairfax, was visiting his grandmother, Holley Simmons, in New Jersey and noticed a trumpet on the table. Simmons had decided to take up the instrument. "He just picked it up and started blowing in it," Simmons said. "I'll never forget how he started to laugh; he just giggled."

Geoffrey paraded around the kitchen table blowing the trumpet. For the next few weeks, he dragged the instrument around, trying to imitate music he heard on the radio.

Gallante said he finally decided Geoffrey might enjoy lessons and started calling trumpet instructors. They told him his son was too young, that formal lessons would destroy his love of music and even hurt his teeth.

But after a dentist gave the go-ahead, a private teacher agreed to see Geoffrey. Not every note Geoffrey plays is perfect, and he has to work his young lungs to belt out the notes, but Walker said he is playing material that would challenge an eighth-grader.

Walker, who said his youngest campers are usually about 8 years old, recalled the phone call he received from Gallante a few weeks ago.

"I thought it was a joke. I thought it was an overzealous parent," Walker said.

"When I first saw him . . . I still thought it was a joke," Walker said. Then the little boy standing in the hallway lifted the trumpet to his lips and belted a few scales and the melody to "The Stars and Stripes Forever." Geoffrey was in.

Between rehearsals yesterday, Geoffrey bounded around on all fours, crawled under a table and sipped from a juice box his mother had brought him. His fellow musicians said he often imitated a lion and, on occasion, gently bit other people's fingers. During some days of camp, the afternoon session would get to be a little too much, and Geoffrey took to running up and down the hallways.

But the older kids welcomed Geoffrey and took on the roles of proud older brothers and sisters, playing hide-and-seek and tag with him after camp ended.

"When he walked in, I though it was like a mistake, but when he started playing, he was really good," said Sandy Tanloet, 13, a French horn player.

For yesterday's performance, Geoffrey, who plays a "pocket trumpet," a smaller version of the instrument that's easier for small hands to handle, perched on a tall chair so he could see over the woodwinds.

"I've taught a lot of students over 30 years," said Dave Detwiler, the camp's trumpet teacher and a substitute trumpeter for the National Symphony Orchestra. "And I started looking on the side of the horn to see if there was a button he was pressing to make that horn play."

Geoffrey Gallante, 4, plays with children three times his age in the Franklin Band & Orchestra Camp. He first picked up a trumpet eight months ago. Geoffrey Gallante warms up before performing with fellow campers at the concert finale. Geoffrey will enter kindergarten in September.