When David N.C. Robson tried to visit Supreme Court Justice Lewis F. Powell Jr. in Richmond. Monday, he had no idea if Powell would remember him. He also had no idea that his efforts would land him in jail.

Robson, a 24-year-old Briton, was free yesterday after a letter from Powell erased a misunderstanding that had left Robson languishing in the Richmond jail for five days on charges of carring a concealed weapon.

Robson's problem began Monday when he reached Richmond on the end of a four-month swing across America. His parents were friends of the Powells, and Robson knew the justice was form Richmond. So when he happened upon the Virginia Supreme Court building, Robson said be became curious.

"I thought it a bit odd that the national Supreme Court would be in Richmond," he said yesterday, but he decided to see if Powell had as office there anyway.

But it was a Capital policeman who believed something was odd when Robson asked where he might find Powell. In his arm was a blanket and under it was a rifle, and yes, Robson told the officer, it is loaded.

Within moments, Robson was in police custody, patiently trying to explain to FBI agents and police why he was carrying a gun.

Bears, he said. They are often a problem in national parks where he had been hiking.

But by then Capitol police had already hustled Robson off to the city jail on a charge of carrying a concealed weapon. Unable to post a $5,000 bond, Robson spent the next five days in the city jail, unable to get bail money from his father who lives in England and unable to get a city jodge to hear his case.

Life in the Richmond jail was not to bad, Robson said yesterday after the letter from the justice arrived in Richmond. Cellmates accorded him a certain deference, Robson said.

"Some of them thought I was a hit man," Robson, a chemical engineer said.

Robson's problem ended yesterday morning when Commonwealth's Attorney E.R. Vanghan Jr. dropped the charges in Richmond General District Court after Robson's attorney, Robert N. Johnson, introduced the letter from Powell. The letter called the incident "as innocent mistake."

"Initially, I was shocked when I was informed of the incident by security people here at the Supreme Court," Powell said yesterday. All he knew at first was that somebody had come looking for him with a rifle, the justice said.

"I think the charges would have been dismissed even without the letter," Powell said, because both the prosecutor and the FBI contacted him to verify Robson's story.

Robson turned the gun over to his lawyer to sell, and said he is embarrassed about the affair. He said be did not think the justice would like to see him now, although he has talked with Powell's son in Richmond. Powell said, however, he would be happy to see Robson.

Robson said his main interest is getting back to England and "never to do anything remotely wrong again in my life.

"I just never want to be in a position where I can end up in the clink again," he said.