An 18-year-old Prince George's County man was sentenced to 38 years in prison yesterday for hurling rocks at motorists on the Capital Beltway last May, an attack that injured more than two dozen people, including a teenage girl who suffered irreparable brain damage.

"You are young, and it grieves me now that I must impose this sentence upon you," Circuit Court Judge William D. Missouri told John L. Burgess, one of three men charged in the May 27 incident.

Referring to the most seriously injured victim, a 16-year-old Hagerstown, Md., girl, the judge said, "But it also grieves me that Destiny Morris will never rise above the {mental abilities} of a third- or fourth-grader. And when I look at the artistic talent that she had, and when I look at what she has now, it grieves me even more deeply."

Yesterday's sentencing in Upper Marlboro came about 12 hours after another reported rock-throwing incident on the Beltway.

Police said a 20-year-old Montgomery County woman was cut by flying glass when a stone slightly larger than a baseball crashed through her car's windshield near the Connecticut Avenue exit about 10 p.m. Sunday. She told police she saw three young men fleeing from a nearby hill.

In the Prince George's case, Burgess, convicted of numerous charges Nov. 1 in a nonjury trial, had admitted to police that he was among three people who hurled five- to 15-pound landscaping rocks at Beltway motorists in about 45 minutes of drunken, predawn mayhem.

Nearly 30 people in 24 vehicles were injured, including Morris, an aspiring artist who suffered a skull fracture.

She has undergone intensive therapy since emerging from a six-week coma.

"I hope this {sentencing} sends a message that this type of activity won't be tolerated," said Maryland State Police Sgt. Vernon Herron, who investigated the May 27 attack.

He said reports of rock-throwing on the Beltway are not uncommon, "but I've never seen anything of this magnitude, not for as long as I've been a police officer, 15 years."

Besides Morris, the injured include a Landover man who lost his right eye and a Manassas woman who lost the hearing in her right ear.

Missouri, calling Burgess a callous young man, imposed a total of 81 years in prison, but suspended all but 38 years and four months of the term. Burgess's first parole hearing will come in about 10 years.

Destiny Morris, who is not expected ever to function beyond the mental level of a 9-year-old, testified at Burgess's trial but did not attend his sentencing. Interviewed by the Associated Press last week, she said of the rock-throwers: "They should be hurt, too. They should be knocked out unconscious. They should have either a broken arm, a broken leg or a broken head."

Burgess's mother, Dahlena Johnson, dabbed her eyes with a hand-kerchief in the courtroom gallery as her son stood before the judge and apologized, saying he "never meant to hurt anybody."

Investigators said Burgess and Maurice E. Ford, 18, had finished their senior year at Oxon Hill High School May 25, and were celebrating with Donnel R. Petite, also 18, in the early hours of May 27. They began throwing rocks at Beltway traffic near the Livingston Road exit after becoming intoxicated on a cheap, potent wine, police said.

Like Burgess, Petite, who was tried last week and is to be sentenced Jan. 7, was found guilty by Judge Missouri of one count of assault with intent to maim, seven counts of assault with intent to disable and more than two dozen other charges. Ford's trial before Missouri is set for Feb. 25.

Noting that Burgess showed disregard for the lives of motorists when he began throwing the rocks, Missouri paraphrased the 17th century English poet John Donne after passing sentence yesterday.

"I'll leave you with this," he said, as a sheriff's deputy stepped toward Burgess with handcuffs. "Each man is part of the whole, part of the main. You should never send to know for whom the bell tolls, because it tolls for thee. And this time, Mr. Burgess, the bell tolls for thee."