It was a tough jail with tough inmates, but Cornelius Gaskins, who served part of his 5 1/2 years for armed robbery in Prince George's County jail, remembers most of all a different kind of toughness. It came from his English teacher, Peggy Nolan. She made demands on Gaskins--to hand in well-written papers, to be alert in class, to read the assignments and, most of all, to be aware of both his talent for writing and for the pleasures to be found in reading.

"Thinking of her," said Gaskins, "she was a beautiful teacher. It was excellent to have her in there. She used the red pen every now and then, but I realized I needed that."

Nolan realized it too. Of Gaskins and the other prisoners she has been teaching for the past five years, she says: "I don't ease up just because they're in jail and say 'Oh, you poor thing, I'll go easy on you.'"

Their story is one of two people who understand the score perfectly: Nolan, that prisoners need education desperately and that she finds it joyful to have the chance to use her skills where they are most needed; Gaskins, jailed on his third conviction, seeing that if he kept giving up on himself, everyone else would too.

Nolan, in her late 40s and the mother of three children, began teaching prisoners in the fall of 1977. She had been a part-time faculty member at Prince George's Community College and was asked if she would like to try teaching English at the county jail. She accepted and braced herself for the worst.

That was what she got. For class space, she used a dayroom of a corridor of a cellblock. For a time, at one end open urinals and toilets were in full view, with prisoners not in the class using them while Nolan was teaching.

"Other prisoners would turn up their radios to compete with me while I was trying to teach," Nolan remembers. "That was their way of being mad at the prisoners in my class. It was jail at its worst. Some of the guards were wonderful; others thought this was no place for a woman."

The teacher-student relationship began tentatively.

"He wanted to know if I was real," says Nolan. "He was terribly interested in poetry, and I'd bring him Nikki Giovanni and books like that."

A trust was built. "Cornelius was using writing and reading as a way to keep himself sane in the horrible cruelty of the jail," said Nolan. "He was one of the few in the cellblock who did not get put down or scorned for his lively interest in bettering himself through education."

Gaskins, now 27, was the 12th of 13 children in a Newton Street NE family. At 13, he stole a car. He was caught and served a year at a juvenile facility. At 16, supporting a drug habit, he burglarized a home. He was convicted and served three years: at Lorton, the District of Columbia jail and a halfway house. In 1976, with a $100-a-day drug habit, he committed armed robbery. He pleaded guilty. He was released June 30 of this year. While doing time in four jails in Maryland, he earned an associate degree in criminal justice and successfully completed courses in English, math, psychology, government, accounting and biology.

He now lives with a cousin three doors from his mother's house on Newton Street and is trying to earn a living from commissions on selling encyclopedias. It is hard work and often frustrating, but Gaskins sees it as a beginning.

"Some of the guys (in jail), I think I can honestly say, really don't care . . . Thinking I was totally washed up occurred to me. But it didn't stick."

Nolan is currently in her fourth year of teaching prisoners at the Montgomery County detention center in Rockville. Two years ago, she co- founded with her brother, James Carroll, the Washington Correctional Foundation. One of its purposes is to rally support from organizations and citizens who want to create or improve educational programs in the area's jails.

Walter Ridley, the administrator for youth services at Lorton, says of Nolan almost exactly what Gaskins said: "She's a beautiful human being."

Since the publicity about the Norman Mailer-Jack Abbott relationship, cynicism about befriending prisoners has become common. Those who want to help prisoners are depicted as naive do-gooders who don't understand that cons are ever on the hustle to spring themselves from prison.

When asked about this, Nolan is candid. Saying that she has kept in close touch with Gaskins since his release from jail, she continues: "There is always a risk, but so far it looks good. I'm not signing anything on the Bible that he won't go back, but no one I've taken a personal interest in -- about six men that I keep up with -- has gone back yet. You can't tell, but it looks good. I'm certainly far from being the 'cause' of their change. I'm just a small factor. It's the men themselves."